Rockwood & Green’s Fractures in Adults
6th Edition

Chapter 56
Fractures and Dislocations of the Midfoot and Forefoot
John S. Early
Injuries to the foot can have a dramatic impact on the overall health, activity, and emotional status of patients. A recent study looking at the outcomes of multiple-trauma patients with and without foot involvement found a significant worsening of the outcome in the presence of a foot injury (1). Their conclusion is that more attention and aggressive management needs to be given to foot injuries to improve the outcome of multiply injured patients.
The foot is a difficult appendage to study and diagnose. Its unique function to provide a stable platform for weight transference, as well as adopt to various irregular surfaces, places specific, significant demands on its component parts. To adequately diagnose and treat foot injuries it is important to understand these unique features. Attention to detail is important for accurate diagnosis. Previous chapters have covered the treatment of the hindfoot structures, the talus, and the calcaneus; now the discussion will turn to the midfoot and forefoot.
INJURIES TO THE MIDFOOT
The midfoot is described as the section of the foot distal to Chopart’s joint line and proximal to Lisfranc’s joint line. Five bones comprise the midfoot: the navicular, cuboid, and medial, middle, and lateral cuneiforms (Fig. 56-1). This anatomic unit plays a distinct role in the normal mechanics of foot function (2). There is no bony weight-bearing contact with the ground in this area in the normal foot structure. Despite the presence of many large, broad, flat articular surfaces, this collection of bones is also relatively immobile compared to the rotatory and accommodative functions of the hindfoot and forefoot.
The lack of mobility between the bones of the midfoot is clearly related to its anatomic structure. The stability or resistance to movement in these articulations is due in large part to the numerous dense plantar ligaments, which tightly bind the osseous structures in the midfoot together (Fig. 56-2). These ligaments also carry over to the hindfoot and medial forefoot,
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providing strong mechanical links between the three sections of the foot. The fact that the normal arch shape of the weight-bearing foot can be maintained without the need for muscle action demonstrates the inherent stability supplied by these dense ligamentous structures. Mechanically, this section of the foot can be represented as a multisegmented beam. The strength and stability of the whole structure is dependent on the tensile strength of the plantar-based intersegmental ties between the osseous structures. The only motor unit to completely insert into the midfoot is the tibialis posterior. Its multiple insertions on the plantar surface of the midfoot bones are intertwined with the plantar ligamentous structures to provide dynamic support and mechanical overload protection. There are minor variable insertions of the tibialis anterior and the peroneus longus onto the plantar aspect of the medial cuneiform, but the posterior tibial muscle is effectively the only motor unit to control movement in the midfoot. Its attachment to all five bones of the midfoot ensures movement as a unit.
FIGURE 56-1 Bony anatomy of the midfoot. A. Dorsal view. B. Plantar view. C. Medial view. D. Lateral view. E. Coronal view.
This inherent stability is important for normal foot function. The medial arch provides a protective conduit and alcove for the neurovascular structures and intrinsic musculature of the plantar aspect of the foot. These muscles are extremely important
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to the function and stability of the weight-bearing surfaces of the forefoot. As a rigid beam, the midfoot solidly binds the forefoot to the hindfoot through the full arc of subtalar motion. During weight-bearing, the midfoot acts as a mechanical actuator transmitting the rotational motion of the hindfoot complex to the forefoot (2). The midfoot, because of its axial rigidity, is also responsible for the weight-bearing relationship of the hindfoot to the forefoot. Relative changes in the position of the medial and lateral aspects of the midfoot can lead to significant distortions in forefoot/hindfoot alignment.
FIGURE 56-2 Ligamentous structure of the midfoot. A. The dorsal view shows extensive overlap of the interosseous ligaments. B. The plantar ligaments are thicker than their dorsal counterparts and are dynamically reinforced by the tibialis anterior, tibialis posterior, and peroneus longus tendons. Note the extensive attachments of the tibialis posterior throughout the midfoot bones.
The midfoot is not totally without the potential to move, and cadaveric studies show that motion does occur between the individual bones of the midfoot (3). This motion is small compared to the motion of the subtalar complex and metatarsophalangeal joints, but it plays a role in shock absorption during weight-bearing. The functional descriptive is that of a leaf spring that provides essential dampening and recoil of repetitive loading forces.
In treating midfoot injuries, the relative importance of the various functions of this section of the foot should be considered.
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Stability is of paramount importance. The structural integrity of the five bones and their positional relationship to each other are key to retaining midfoot function. Secondly, maintenance of the normal relationship of the weight-bearing surfaces of the hindfoot to the forefoot should be considered. This requires attention to the maintenance of talonavicular, calcaneocuboid, and fifth tarsometatarsal joint motions. The least important consideration is to maintain the articular integrity of the surfaces between these five bones. They should be readily sacrificed for the restoration of bony stability and the preservation of the major end articular surfaces.
Navicular Fractures
Diagnosis
Injury to the navicular, which disrupts either its position or ability to glide over the talus, can greatly impair foot function. Both direct and indirect forces have a role in disruption of the normal navicular architecture. A direct blow, though uncommon, can cause avulsions to the periphery or crush injury in the dorsal-plantar plane. More often, indirect forces of axial loading either directly along the long axis of the foot or obliquely cause navicular injury. Injury may be sports related, secondary to a fall from a height, or due to a motor vehicle collision (4,5,6). Because of the cross interaction of the surrounding bony and soft tissue structures, injury to adjacent structures is likely and must be carefully ruled out where a navicular injury is found. Significant injury to the cuboid or intercuneiform structures can occur with relatively low-level oblique loads. These collateral injuries must also be recognized and treated accordingly (7).
Cortical avulsion fractures can be the isolated result of a direct blow but also can serve as a subtle marker for significant collateral injury to the midfoot from either a ligamentous or bony standpoint. Careful evaluation of the foot clinically and with stress x-rays should be done to rule out other potential injuries. Tuberosity fractures are usually the result of forced eversion of the foot resisted by the pull of the tibialis posterior tendon. A direct blow can also be responsible for a tuberosity fracture. They rarely displace because of the thick surrounding ligamentous support but can cause significant long-term pain and disability if neglected.
Recognition of navicular injuries ranges from obvious midfoot deformity and loss of function to subtle chronic pain and local tenderness. The contour of two thirds of the navicular is readily palpable in the foot. Following injury, local tenderness to palpation, ecchymosis, or local edema warrants further investigation. Passive motion through the subtalar joint complex should be smooth and comparable to the contralateral side. As with any foot injury, anteroposterior, lateral, medial oblique, and lateral oblique x-ray views should be obtained to ascertain the extent of injury to the navicular, as well as rule out collateral damage. If the patient is at all ambulatory, the initial films should be weight-bearing, single-leg stance if possible, to fully appreciate any ligamentous instability. Medial and lateral oblique x-rays of the midfoot will aid in assessing the lateral pole of the navicular, as well as the medial tuberosity.
It is also important to assess the integrity of the talonavicular joint surface. Because of the concave shape of this structure an accurate assessment of congruity is difficult on plain x-rays. The joint surface is best viewed with anterior-posterior and medial-lateral cuts of the navicular in the longitudinal plane of the foot using computed tomography (CT). This study is also helpful for suspected stress injury (8), which can be differentiated from acute trauma by the history of prodromal symptoms of pain with weight-bearing activity over a period of time, minimal repetitive trauma, and local tenderness over the medial third of the navicular with perhaps subtle or no visible changes on plain x-rays. These studies may help visualize the injury pattern as well as the presence of sclerotic margins.
Suspected injuries to the tuberosity, especially in the presence of an accessory navicular, may require a magnetic resonance imaging (MRI) scan to show the extent of injury to the posterior tibialis attachment or synchondrosis. A focused bone scan can also localize the injury if MRI or CT is not readily available.
Fracture Classification
There are a variety of classification systems discussed in the literature that categorize navicular injuries based on injury pattern. The most commonly used classification has been to categorize the recognized injuries as tuberosity fractures, cortical avulsion fractures, stress fractures, and body fractures. Body fractures are the result of a significant axial load driving the talar head into the navicular. Body fractures have been further divided into types I, II, and III based on proposed mechanism of injury (Fig. 56-3) (6). Although this system does not differentiate treatment needs, it does correlate well with outcome. The more disruptive the injury, the less successful the result.
The Orthopaedic Trauma Association (9) has proposed an extensive fracture classification for navicular fractures under the major heading of 74. This incorporates the present classification and clarifies the patterns. This classification offers an important visual reference to categorize fracture patterns for comparison of treatment methods and clinical results (Fig. 56-4). The designation of navicular fractures under this system observes the format: (74-_ _._). The first space uses an alpha character to clarify joint involvement. The second and third characters are numeric and serve to define pattern and position of the fracture. Group A fractures are extra-articular. The number following denotes fracture type: avulsion (1), split (2), or split/depression (3). The second numeric value describes position: medial (1), lateral (2), or miscellaneous (3). Group B denotes involvement of the talonavicular joint. The first numeric subgrouping describes fracture position: involvement of the lateral half of the navicular in the sagittal plane (1), involvement of the medial half of the navicular in the sagittal plane (2), or horizontal fracture (3). The final numeric designation describes the fracture type: split (1), depression (2), or split/depression (3). Group C fractures involve both the talonavicular and naviculocuneiform
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joints, suggesting severe crush of the navicular structure. There is only one numeric expansion of this group, and it denotes displacement of the injury: undisplaced (1), displaced (2).
FIGURE 56-3 The present popular classification of navicular fractures is comprised of three basic types with a subclassification for body fractures suggested by Sangeorzan. A. Avulsion type fracture can involve either the talonavicular or naviculocuneiform ligaments. B. Tuberosity fractures are usually traction type injuries with disruption of the tibialis posterior insertion without joint surface disruption. C. A type I body fracture splits the navicular into dorsal and plantar segments. D. A type II body fracture cleaves into medial and lateral segments. The location of the split usually follows either of the two intercuneiform joint lines. Stress fractures are usually included in this group. E. A type III body fracture is distinguished by comminution of the fragments and significant displacement of the medial and lateral poles.
Anatomy and Biomechanics
The navicular is the keystone of the medial longitudinal arch of the foot (2). It is wider dorsally and medially than plantarly and laterally. This medial prominence, known as the navicular tuberosity, provides the interim attachment point for the posterior tibialis on its medial inferior surface. Proximally, the articular surface is concave and articulates with the talus. This joint enjoys a significant arc of motion and serves to transmit the motion of the subtalar joint to the forefoot. It is classically the point from which forefoot inversion and eversion is initiated. The distal articular surfaces of the navicular have three separate, broad facets that articulate with each of the three cuneiforms. These joints provide little motion because they mainly play a role in the dissipation of loading stresses. Laterally the navicular appears to rest on the dorsal medial aspect of the cuboid with a variable articular surface.
The ligamentous support for this bone is dense. Thick ligaments plantarly and dorsally support the naviculocuneiform joints. The spring and superficial deltoid ligaments provide strong support to the plantar and medial aspects of the talonavicular joint. These are aided by the calcaneonavicular ligaments dorsally and laterally. There are also strong ligamentous connections between the cuboid and navicular laterally and posteriorly.
Vascular supply to the navicular has been shown to have a radial distribution in the plane of the talonavicular articulation. The dorsalis pedis and the medial plantar artery feed these perforating vessels from the dorsal and plantar surfaces respectively. Perfusion is abundant along the periphery, but it is relatively avascular centrally (10).
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Anatomic variants to be aware of when viewing the navicular involve the shape of the tuberosity and the presence of an accessory navicular (os tibiale externum). These are present up to 25% of the time and 90% are bilateral (2). Clinically the accessory navicular can be seen as a medial prominence on the foot. It can be present in one of these forms: a fused elongation of the normal tuberosity, a bone island with a flat synchondrotic joint separating it from the navicular tuberosity proper, or as a true os separated completely from the navicular (Fig. 56-5). All three variants are completely within the substance of the posterior tibialis tendon.
FIGURE 56-4 The OTA classification for navicular fractures (74). The initial differentiation is by articular involvement. Type A is extra-articular, type B has mainly uniarticular involvement, and type C signifies multiarticular, multifragmented involvement. Further subdivision is by fracture pattern.
Treatment
The decision on how to treat navicular injures depends not on the pattern of fracture, but on the effect it has on the position of the navicular in the midfoot and the congruity of the talonavicular joint. It is important to emphasize again damage to adjacent structures is not unusual and careful assessment of the whole foot needs to be undertaken before treatment is instituted (4,11). The two criteria most important in obtaining a satisfactory outcome are maintenance or restoration of the medial column length and the articular congruity of the talonavicular joint. Irrespective of the pattern produced, all isolated nondisplaced fractures of the navicular should be treated in a short leg cast with non-weight-bearing for 6 to 8 weeks (8,12) (Table 56-1). These patients should be followed frequently initially. Late evidence of instability may be seen once the initial swelling recedes. Repeat weight-bearing x-rays out of plaster should be done at 10 to 14 days after the initial injury to confirm the absence of bony or soft tissue instability. If instability appears
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or other injuries become apparent, appropriate surgical intervention should be considered. Even chronic stress fractures have been seen to do well treated in a casted non-weight-bearing manner for 8 weeks (8,13). The term nondisplaced refers to both the position of the navicular in the midfoot and to the talonavicular joint integrity. The issue of soft tissue instability is also important. Any loss of naviculocuneiform integrity or navicular-cuboid stability should be addressed surgically. Also, if other injuries are present in the foot that require surgical attention consideration may be given to stabilizing this fracture with some form of fixation.
FIGURE 56-5 Accessory navicular. A. Anteroposterior x-ray view. B. CT scan showing synchondrosis between the accessory navicular and the navicular proper.
Surgical intervention should be considered for any unstable injury or fracture resulting in loss of position or loss of articular congruity. Because the joint is concave in shape, 2 mm of separation in any plane is considered to represent incongruity. Authors agree these injuries need to be managed aggressively with surgery (5,6,12). Cortical avulsion fractures found to involve a significant portion of the dorsal anterior surface should be considered for anatomic restoration. Stabilization of individual fragments appears to be best accomplished with either 2.7-, 3.5-, or 4.0-mm screw fixation. Immediate use of autogenous cancellous bone graft should be considered for any area displaying a component of crush injury. If anatomic restoration to 60% or more of the talonavicular surface can be accomplished every effort should be made to salvage the joint (5,6). If, however, greater than 40% of the articular surface cannot be reconstructed, an acute talonavicular fusion should be done to preserve foot alignment.
TABLE 56-1 Closed Management of Navicular Fractures
Indications
  • <2-mm displacement of the talonavicular joint surface
  • No evidence of midfoot instability with weight-bearing or stress views
  • No loss of bony length
Treatment
  • Short leg non–weight-bearing cast for 6 to 8 weeks
  • Recheck stability with stress views at 10 days from injury
  • Progressive weight-bearing in protective brace until asymptomatic
The surgical approach should be based on a complete understanding of the fracture pattern and the associated injuries. The incision should be made in the longitudinal plane, with minimal dissection to prevent significant damage to the vascular supply. The goal in treating injuries involving the talonavicular joint is direct visualization of the articular surface to ensure an anatomic reduction. This is best obtained through a dorsal longitudinal incision over the area in question (Fig. 56-6). If the fracture is in the dorsal-plantar plane the incision should be directly over the fracture. During the approach, great care should be taken to avoid injury to the dorsalis pedis artery and the superficial and deep peroneal nerves, which invariably infringe on the operative field. Fixation for fractures involving the body and the talonavicular surface should be introduced percutaneously.
To maintain the restored length in comminuted fractures, a medial column external fixator can be applied or internal plating can be used to protect the reduction. The use of a long 2.7- or 3.5-mm plate to bridge multiple joints temporarily will also halt excess joint motion until the fracture stabilizes (14).
Postoperative Care
Following surgical fixation of the navicular, patients should be placed in a well-molded plaster cast with the foot in a plantigrade position. Again, I do not recommend off-the-shelf braces because they do not provide full stable contact to the foot for
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the first 6 weeks. Non–weight-bearing should be maintained for a full 3 months to allow for both bony and associated soft tissue healing. If restoration of the talonavicular joint is achieved, non-weight-bearing patient directed range-of-motion exercises of the subtalar joint complex begin at 6 weeks. The patient is kept in a protective removable cast boot at all other times. Progressive weight-bearing as tolerated is instituted at 8 weeks and advanced only as the patient’s symptoms permit. The patient remains in a supportive brace until pain-free full weight-bearing is achieved.
FIGURE 56-8 Reduction and fixation technique for comminuted or displaced navicular fractures. A. Typical fracture pattern with mid to lateral talonavicular disruption. B. Placement and use of an external fixator aids in restoration of length and maintenance of position for fixation. The talonavicular joint is restored and bone graft placed behind it to fill any void. C. Fixation screws are placed into the cuneiforms or cuboid to secure reduction.
TABLE 56-2 Operative Management of Navicular Fractures
Priority of fixation
  • Maintain position of the navicular in the foot
  • Preserve talonavicular congruity
  • Restore attachment of the posterior tibialis tendon
  • Preserve naviculocuneiform articulations
Tips on fixation
  • Use medial distraction to restore navicular volume and visualize talonavicular joint
  • Liberal use of cancellous or corticocancellous graft to fill structural defects
  • Fixation can readily cross into adjacent cuneiforms or cuboid if needed to provide stability
  • Fuse naviculocuneiform joints to achieve medial column stability
Complications
Problems in the near term from navicular fractures include nonunion of the fracture fragments, arthritic degeneration, late instability, loss of normal foot alignment through bony resorption, or collapse and avascular necrosis. Avascular necrosis can be evident as early as 8 weeks from injury and is usually centrally located in the navicular. Without subsequent osseous collapse it is usually asymptomatic. There is no evidence to suggest that avoiding normal weight-bearing in the presence of avascular necrosis once the fracture has completely healed will prevent subsequent collapse. In treating these complications the principle of restoring and maintaining normal bony alignment should remain the primary goal. Collapse of the body without disruption of the talonavicular joint should be addressed with corticocancellous grafting and fusion of the naviculocuneiform joints to restore medial column position. Loss of the talonavicular articular surface requires a talonavicular fusion with bone graft as needed to replace avascular bone and restore column length.
Soft tissue instability with functional loss of the spring ligament can cause pain on weight-bearing and a loss of normal talonavicular alignment when weight-bearing. The picture is similar to that seen with posterior tibial insufficiency, but the pain can be localized to the area under and just proximal to
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the navicular tuberosity. If recognized early enough, surgical reconstruction of the spring ligament can eliminate the pain and correct the deformity.
Navicular Dislocation
Diagnosis
Outside of the neuropathic foot, isolated dislocation or subluxation of the navicular is rare. Most are noted to be part of a significant complex disruption involving most if not all of the midfoot. When it does occur the navicular can be found either medial and plantar to its normal position in the case of neuropathic instability or dorsal as occurs with acute trauma. The trauma mechanism appears to be an initial hyperplantar flexion of the forefoot with subsequent axial loading. The ligamentous disruptions involve the dorsal naviculocuneiform ligaments first, followed by the plantar naviculocuneiform ligaments. The plantar talonavicular supporting ligaments fail last (16). Dislocation in the neuropathic foot appears to be the result of motor pull with ligamentous failure. The tibialis posterior pulls the navicular plantar and medial relative to the foot, with the tibialis anterior and peroneus longus taking the foot dorsally and laterally. The deformity is progressive, creating a large plantar medial bony prominence and the likelihood of ulceration.
Treatment
Treatment follows the same reasoning that applies to fracture management. To maintain proper midfoot alignment, anatomic reduction and stabilization is required. Open reduction is usually necessary to restore both navicular position and articular congruity. I find the dorsal approach to the talonavicular joint most useful. It allows visualization of both the talonavicular and naviculocuneiform articular surfaces. A small external fixator applied to the medial aspect of the talar head and cuneiforms greatly facilitates reduction. Reports in the literature have cited the use of wires and screws to maintain reduction (16,17,18). Wires can be used to cross both the talonavicular and the naviculocuneiform joints. Screws should only be employed across the naviculocuneiform joints. Once reduced the talonavicular articulation is stable (Fig. 56-9).
Complications
Avascular necrosis of the navicular and or Charcot-like collapse of the medial column is a rare but major complication of navicular dislocation. Significant weight-bearing deformity can occur with loss of the normal medial midfoot architecture. Treatment would require a fusion of the involved joints after restoration of the normal architecture with structural bone graft being used to fill all voids. Prolonged non-weight-bearing is advised until a solid fusion is obtained.
Cuboid Injuries
Injury to the cuboid can occur as an isolated entity, but it is usually seen in association with injuries to the talonavicular joint, with injuries to other midfoot structures, or in conjunction with complex Lisfranc joint injuries (4,5,7,19,20). A small medial or dorsal avulsion fracture of the navicular is considered a sign of a possible cuboid injury. Without careful scrutiny, these injuries can be dismissed initially as a lateral ankle sprain. A cuboid injury can be quite subtle, but the long-term consequences to the lateral column of the foot can cause significant mechanical problems (19,21). These structural changes include loss of bony arch support, shortening of the lateral column of the foot, forefoot abduction, and plantar bony prominence. All of these can distort the normal weight-bearing position of the foot.
Diagnosis
Injuries to the cuboid can occur with as little force as an ankle twist or as part of a high-energy multitrauma event. As with any foot injury, cuboid fracture can occur with a direct blow. This type of injury rarely causes articular disruption or axial shortening. More commonly the mechanism of injury is forced plantar flexion and abduction causing a compressive load along the long axis of the cuboid. The resulting injury has been termed a “nutcracker” fracture (21). Variable amounts of axial loading through the fourth and fifth metatarsals add to the variability of the fracture pattern (Fig. 56-10).
Presentation of a cuboid injury can range from subtle to severe distortion of the foot anatomy. Dorsolateral pain swelling and ecchymosis over the lateral midfoot should raise suspicion of a cuboid injury. In the presence of other injuries to the midfoot, such as the navicular, cuneiforms, or tarsometatarsal region, careful inspection of the cuboid and its articulations is warranted to rule out subtle instability or injury.
Plain x-rays, especially a medial oblique view, can be extremely helpful in assessing cuboid injury. Multiple medial oblique views may be needed in order to see the articular outlines of both the calcaneocuboid and cuboid-metatarsal joints. As with other potential midfoot problems, weight-bearing or stress views should be obtained to rule out interosseus instability of the surrounding structures. Loss of structural stability can have just as severe an impact on foot function as a fracture. If injury to the cuboid is suspected or detected on plain films, a detailed CT scan with longitudinal and coronal cuts is necessary to assess the extent of injury and instability. As with other midfoot injuries, loss of structural integrity and stability are of foremost importance, followed closely by tarsometatarsal articular congruity and calcaneocuboid congruity.
In addition to bony injury, isolated subluxation or frank dislocation can occur but is rare. A painful subluxation termed cuboid syndrome has a reported incidence of up to 9% among high-performance athletes and up to 17% for professional ballet dancers (22,23). Symptoms include lateral foot pain radiating to the anterior ankle, fourth ray, or plantar aspect of the midfoot. Usually the patient complains of weakness with forefoot push off. Typically the finding for cuboid syndrome includes a reduction in dorsolateral to plantar medial mobility through the calcaneocuboid joint, peroneus longus spasm, and pain with pressure applied to the plantar aspect of the cuboid. Similar to more
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severe injuries to the cuboid, the mechanism appears to be forced pronation of the midfoot in relation to the hindfoot in the presence of axial loading. This twisting force through the saddle-shaped calcaneocuboid joint can produce incongruity. The presence of the peroneus longus in its fibrous tunnel on the plantar and lateral aspect of the cuboid appears to assist in maintaining the incongruity.
FIGURE 56-9 Neuropathic dislocation of the navicular. A. Anteroposterior x-ray with medial deviation of the navicular. B. Lateral x-ray view showing plantar migration. C,D. Fixation postreduction for fusion of the naviculocuneiform joints.
FIGURE 56-10 X-ray of a cuboid fracture with impaction of the tarsometatarsal joint surface by approximately 1 cm. The arrow marks the subchondral bone of the impacted articular surface.
Complete isolated dislocation is extremely rare and is most likely the result of a direct, medially applied force followed by axial loading or abduction of the foot. When present it is usually in conjunction with other complex injuries to the hind foot and forefoot. The position of the dislocated cuboid is always plantar and medial. Anteroposterior and lateral x-rays that show medial deviation of the cuboid from the lateral border of the calcaneus suggest instability (Fig. 56-11).
FIGURE 56-11 Cuboid dislocation. A. Anteroposterior view of foot showing medial migration of cuboid. B. Lateral film showing plantar migration. C,D. After reduction and fixation with a 3.5-mm screw from the lateral cuneiform into the cuboid.
Classification
Because of the paucity of information in the literature, there is no commonly used classification for isolated cuboid fractures. The OTA has proposed a general classification system for cuboid fractures under category 76 (Fig. 56-12) (9). The designation of cuboid fractures under this system observes the format: (76-_ _._). The first space uses an alpha character to clarify joint involvement. The second and third characters are numerical and serve to define pattern and position of the fracture. Group A fractures are extra-articular. The first numerical subdivision
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denotes fracture pattern: avulsion (1), coronal plane (2), or crush (3). Further numerical use refers only to avulsion fractures and describes their position: anterior (1), lateral (2), or plantar (3). Group B fractures refer to injuries involving one of the two major joint surfaces, either the calcaneocuboid or metatarsocuboid joint. The first numerical division describes fracture position: sagittal plane (1), or horizontal plane (2). The second numerical designation relates to fracture pattern: split (1), depression (2), or split/depression (3). Group C fractures involve both articular surfaces denoting a severe crush injury to the cuboid structure. Further numerical subclassification is used to denote displacement: undisplaced (1), displaced (2). This classification system is useful in categorizing the nature and extent of the osseous injury but offers scant guidelines for management.
FIGURE 56-12 OTA classification of cuboid fractures. Higher letters and numbers denote more significant injury.
There is no standard classification that takes into account structural integrity and interosseus stability. It is perhaps more helpful to categorize the injuries as nondisplaced, unstable, or crush for the purposes of management.
Applied Anatomy
The cuboid is the sole osseous structure of the midfoot considered part of the lateral support column of the foot (2). Its saddle-shaped articulation with the calcaneus acts as a stress valve for the imperfectly matched movements of the talonavicular and subtalar joints. The dorsal calcaneal tuberosity and medial cuboid tuberosity are fashioned to provide bony stability to the joint and prevent dorsal or lateral migration of the cuboid in a weight-bearing situation. Thick plantar and medial ligaments support those respective areas of the articulation. Distally the cuboid provides separate articular facets for each of the fourth and fifth metatarsals. There are variable articular surfaces on the dorsomedial aspect of the cuboid where the navicular and lateral cuneiform come into contact with the cuboid. The thick, broad, longitudinal plantar ligament provides support along the plantar and medial borders of the calcaneocuboid joint. A variable pattern of plantar and dorsal ligaments provides loose support at the tarsometatarsal joints. It is important to realize that the cuboid-metatarsal articulations are more important to overall foot function than the calcaneocuboid articulation. These tarsometatarsal joints provide for nearly all of the dorsal and plantar motion of the lateral column of the foot. Studies have shown up to three times as much available motion at these two joints compared with the medial three tarsometatarsal joints (3). The peroneus longus courses along the lateral and plantar surfaces of the cuboid on its way to the base of the first metatarsal. The importance of the cuboid in the overall function of the foot lies primarily in its structural position as a lateral column spacer secondarily in the function of the fourth and fifth tarsometatarsal joints and thirdly in calcaneocuboid joint motion.
Treatment
As with other midfoot injuries, an isolated fracture of the cuboid with no evidence of loss of bony length or interosseous instability can be treated with nonoperative management. A well-molded cast and an initial period of non-weight-bearing for 4 to 6 weeks is recommended (12). Again, it is important to follow these injuries frequently. Weight-bearing stress x-rays should be obtained 10 to 14 days after the initial assessment to ensure the absence of occult injuries as the swelling subsides (Table 56-3). With the reduction of pain on clinical examination, progressive weight-bearing can be instituted. True cortical avulsion injuries of the cuboid can be allowed to bear weight as tolerated immediately in an off-the-shelf short leg walker until asymptomatic. Again, frequent follow-up is needed to rule out late instability.
TABLE 56-3 Closed Management of Cuboid Injuries
Indications
  • <2 mm displacement of the calcaneocuboid or cuboid-metatarsal joint surface
  • No evidence of cuboid subluxation with weight-bearing or stress x-rays
  • No loss of bony length
Treatment
  • Short leg non–weight-bearing cast for 6 to 8 weeks
  • Recheck stability with stress views at 10 days from injury
  • Progressive weight-bearing in protective brace until asymptomatic
In the presence of instability, more aggressive measures should be taken to restore lateral column function and length. Isolated cuboid-metatarsal instability without cuboid fracture denotes a Lisfranc type injury and is discussed in that section.
Cuboid syndrome with no rotational subluxation noted at the calcaneocuboid joint can be successfully managed closed (22,23). It is important to relax the patient and relieve the peroneal spasm either through gentle massage or mild intravenous sedation in order to allow the joint to “unlock.” The patient is placed in the prone position and the hind foot fully plantar flexed. With relaxation of the peroneal spasm, dorsally directed pressure is placed on the plantar aspect of the cuboid. At the same time, the forefoot is further plantar flexed. Another reduction method can be performed with the patient lying supine and the foot suspended by longitudinal traction applied to the fourth toe and with the forefoot in slight plantar flexion. Vigorous activity after reduction should be avoided for 24 to 48 hours.
Dislocation of the calcaneocuboid joint denotes significant disruption of the plantar support structures of the midfoot. Anatomic reduction and prolonged immobilization is necessary to preserve midfoot stability. Open reduction is recommended along with Kirschner wire (K-wire) fixation across the calcaneocuboid joint to hold the reduction (24,29). At 4 weeks the wires are removed and gentle non-weight-bearing motion is begun. Weight-bearing usually has to await adequate healing of other associated injuries to the foot.
In the face of multiple midfoot injuries, reduction of the cuboid should proceed first followed by the other injuries as the
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cuboid provides plantar support and determines lateral column length for the remainder of the midfoot. Stabilization of the reduction can wait until all reductions are complete.
Management of cuboid fractures is somewhat controversial as the results of individual series are difficult to evaluate because of their small numbers (4,5,20,21). Once disruption of the cortical integrity of the cuboid occurs, significant compaction of bony length and disruption of articular surfaces can occur. Nonoperative care in the face of structural distortion leads to poor results because of late deformity of the foot. The goal of operative management is to restore the lateral column length and plantar support of the midfoot first, preserve the mobility of the tarsometatarsal joints second, and restore articular integrity to the calcaneocuboid joint last. Liberal use of autogenous cancellous bone graft is recommended along with some form of internal or external fixation to maintain and protect the reduction (108).
Postoperative Care
After stabilization of a cuboid injury the involved extremity should not be allowed to bear weight until bony and ligamentous stability is evident clinically. If there is no external fixation present postoperatively, a short leg cast with the foot held in
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neutral, plantigrade position is used to minimize compressive forces across the cuboid for 6 weeks. With external fixation present, some form of plantigrade splint should be used to support the foot and toes in a neutral, plantigrade position. Any reduction pins, including the external fixator, are removed at 6 weeks. After 6 weeks non-weight-bearing, self-directed range-of-motion exercises of the foot through the ankle and subtalar joint should begin with the foot being protected in a removable cast or plantigrade splint. Weight-bearing may begin at 10 weeks and progress as comfort allows in a removable short leg walker.
FIGURE 56-14 Restoration of nutcracker fracture of cuboid. A. Typical fracture appearance in anteroposterior and lateral planes. B. Placement of external fixator to restore normal anatomy. Any defect should be filled with cancellous graft. C. Internal stabilization is possible with a 3.5 tubular plate to maintain reduction and position of cuboid.
Complications
The complications with treating cuboid fractures involve continued or late instability between the cuboid and adjacent structures, loss of lateral column length, or arthritic degeneration (7,19,21). Any alteration of normal cuboid position can have a profound effect on the stability of the whole foot. Abduction of the forefoot and midfoot instability both place the foot at a mechanical disadvantage during weight-bearing, causing a significant alteration of gait and pain. Loss of lateral column length would require a bone graft to restore length with either fusion of the calcaneocuboid joint or opening wedge osteotomy of the cuboid. Even in the presence of significant arthropathy in the fifth tarsometatarsal joint, fusion in this area produces uniformly bad results. Interpositional arthroplasty of the symptomatic fifth tarsometatarsal joint can provide pain relief with continued motion (29).
Injury to the Os Peroneum
The os peroneum is a sesamoid bone lying within the substance of the peroneus longus tendon. It can be found at the level of the cuboid tunnel where the peroneus longus tendon passes under the cuboid or at the level of the calcaneocuboid joint. It
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is present in 5% to 14% of the population and the majority are bilateral and symmetric (11). Injury to this bone can be caused by a direct blow or supination and plantarflexion forces that can place a tensile load across the structure (Fig. 56-17). Fracture of this sesamoid bone can occur with or without disruption of the tendon (30). Patients usually present with lateral ankle pain on weight-bearing resistant to conservative measures. Tenderness can be localized to the plantar lateral aspect of the foot proximal to the base of the fifth metatarsal. Resistance to peroneus longus motion also causes pain. A medial oblique x-ray view will usually reveal the presence of the os peroneum.
FIGURE 56-15 Cuboid fracture involving the calcaneocuboid joint. A. Preoperative lateral x-ray of injury at the calcaneocuboid joint. Note the fracture of the anterior process of the calcaneus contributing to the instability. B. Placement of the external fixator allows restoration of anatomical position. C. The articular surface is reduced and the void is filled with cancellous graft. D. The intact cortex is then reduced under the subchondral lip and held in place with screws secured to the medial wall of the cuboid.
Treatment consists of non-weight-bearing in a cast for a minimum of 6 weeks and then progressive weight-bearing in a cast until asymptomatic. Despite these measures, a painful fibrous union can occur, which is best treated with excision of the bone fragments (30). Wide displacement of the fragments indicates disruption of the peroneus longus tendon, which would need surgical repair. Confirmation of the disruption can be seen on an MRI study of the tendon.
Cuneiform Injuries
Diagnosis
Disruption of the position of any of the three cuneiform bones is a rare injury (5,31,32). Isolated cuneiform dislocations do occur but are more often associated with plantar-based fractures of the bone rather than disruption of the thick plantar ligamentous structure. Commonly, cuneiform injuries are seen in conjunction with tarsometatarsal joint injuries. Whether injury to the cuneiform results in a fracture or fracture dislocation, it is usually the result of indirect axial loading of the bone. The extent of damage is dependent on the presence of concurrent forces acting on the foot in a direction perpendicular to the axial load. Plantar flexion can lead to dorsal dislocation. Dorsiflexion
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can cause significant fracture comminution and shortening. Fracture or fracture dislocation of these bones usually requires significant force and can be a signal of severe ligamentous injury to the whole of the midfoot.
FIGURE 56-16 Alternative methods of stabilizing cuboid fracture repair. A. Interfragmentary screws are best when the outer cortex is relatively intact and resistant to compression. B. Internal bracing can be done with a neutralization plate spanning both joints to hold anatomic alignment. This will have to be removed within 3 months of weight-bearing. C. Continued external fixation is also useful to maintain lateral column length while awaiting bony healing.
Medial cuneiform instability usually occurs with seemingly minimal energy. A twisting injury to the forefoot during sports or a fall can cause shortening of the medial ray as a result of ligamentous disruption of the intercuneiform ligaments (Fig. 56-18) (5). Clinically, a noticeable increase in the size of the first web space has been reported for isolated medial cuneiform injuries. This gap sign is particularly visible when the foot is subjected to full-weight bearing forces (33).
FIGURE 56-17 Fracture of the os peroneum.
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As with all injuries to the foot, diagnosis depends on careful, close examination of the injured foot. Localized tenderness over the cuneiform region, pain in the midfoot with weight-bearing, or discomfort with motion through the tarsometatarsal joints can signify injury to these bones. Anteroposterior, lateral, and oblique x-ray views should be obtained to assess the extent of injury and check for injury to adjacent structures. These should be obtained with single-leg weight-bearing, if possible; otherwise, manual stress views with forefoot inversion and eversion are needed to look for subtle signs of instability. Coronal and longitudinal CT scans of the midfoot can be used to more clearly define the extent of the injury.
FIGURE 56-18 Isolated medial ray instability resulting from disruption of the intercuneiform ligaments. A. Initial non-weight-bearing anteroposterior view showing irregularities in the first-second intercuneiform joint. B. Stress view showing instability. Note that there is no instability of the tarsometatarsal joints. C. Open reduction through a dorsal approach with percutaneous fixation to reduce and stabilize the medial ray.
Classification
The Orthopedic Trauma Association provides the only classification scheme for fractures of the cuneiform bones (75) (9). The designation of cuneiform fractures under this system observes the format: (75()-_ _._) (Fig. 56-19). The first space uses an alpha character to clarify joint involvement. The second and third characters are numerical and serve to define pattern and position of the fracture. Because of the presence of three cuneiforms in order to clarify the injured structure, a number in parentheses should be used to denote the cuneiform in question: medial (1), middle (2), or lateral (3). Group A fractures are extra-articular. The first numerical subdivision denotes fracture pattern: avulsion (1), coronal plane (2), or multifragmented (3). Further numerical use refers only to avulsion fractures and describes their position: anterior (1), medial (2), or plantar (3). Group B fractures refer to injuries involving one of the two major joint surfaces, either the naviculocuneiform or the metatarsocuneiform joint. The first numerical division describes fracture position: saggital plane (1) or horizontal plane (2). The second numerical designation relates to fracture pattern: split (1), depression (2), or split/depression (3). Group C fractures involve both articular surfaces denoting a severe crush injury to the cuneiform structure. Further numerical subclassification is used to denote displacement: undisplaced (1), displaced (2).
Because of the small number of cases in the literature, determination
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of treatment or outcome is not yet possible by this system. Treatment should be based not on the pattern of the fracture but on the presence of instability or shortening.
FIGURE 56-19 OTA classification of cuneiform fractures. To designate the cuneiform involved a number corresponding to that cuneiformis placed in parenthesis between the anatomy designation and the fracture designation. 75(x)- where x equals 1 for medial, 2 for middle, and 3 for lateral.
Anatomy and Biomechanics
The three cuneiform bones sit in the middle of the medial column of the foot and provide the rigid support for the medial longitudinal arch. They constitute the apex of the transverse arch that provides a stable conduit for the plantar musculotendinous and neurovascular structures (2). All are wedge shaped along the axial axis. The medial cuneiform has a plantar base and a dorsal crest. The middle and lateral cuneiforms are reversed, with dorsal bases and plantar crests. Proximally, each cuneiform articulates with approximately one third of the distal navicular. Each cuneiform articulates with its respective metatarsal distally. The third cuneiform rests atop the cuboid laterally and shares a variable articular surface with that bone. There are numerous ligamentous attachments between these three bones and the surrounding structures. Between each of the two cuneiform pairs, there are three distinct connecting ligaments. The weakest link structurally is the medial cuneiform, with its sloping proximal articulation with the navicular and relative paucity of ligamentous attachments to other structures. Of importance also is the fact that there are no ligamentous connections between the first and second metatarsal to stabilize the first ray and dissipate any rotatory forces. Isolated loading of the first metatarsal is resisted only by the strength of the medial cuneiform attachments.
Treatment
In treating cuneiform injuries it is the presence of instability or the loss of position of the individual bones, which requires aggressive treatment. It is the relative stability of the cuneiforms that is most important for proper foot function. Anatomic restoration and maintenance of position is required for satisfactory outcome in these injuries.
The use of closed reduction techniques can be employed with isolated dorsal dislocation of the middle and lateral cuneiforms when there is no evidence of adjacent injury (Table 56-4). Ankle block anesthesia is used to provide relaxation and pain relief for closed reduction and manipulation. Longitudinal traction is applied to the affected ray and with direct dorsal pressure a reduction is attempted. Successful stable, anatomic reduction can be treated with a non-weight-bearing short leg cast holding the foot in a neutral, plantigrade position (34). Off-the-shelf removable walkers should not be used because they permit too much early motion about the injury site and can lead to late instability. Careful follow up is needed to ensure continued reduction. Percutaneous pins or screw fixation can be used to help maintain position.
TABLE 56-4 Closed Management of Cuneiform Injuries
Indications
  • No evidence of midfoot instability with weight-bearing or stress x-rays
  • No loss of bony length
Treatment
  • Short leg non–weight-bearing cast 6 to 8 weeks
  • Recheck stability with stress views at 10 days from injury
  • Progressive weight-bearing in a protective brace until asymptomatic
Nonanatomic reduction or continued instability should be treated with open reduction and pin or screw fixation into adjacent stable structures. Any loss of structural position resulting from bony crush should be corrected with cancellous or corticocancellous bone grafting. Instability of the medial cuneiform requires internal fixation even if closed anatomic reduction is obtained through traction (31,35). There has been a report of the tibialis anterior tendon blocking reduction of a medial cuneiform dislocation. (36).
Complications
Presently there are no reported complications of treated cuneiform instabilities. Nonunion has been reported for medial cuneiform fracture and has been treated successfully with open reduction with internal fixation (37). It appears the only complications are from missed diagnosis or incomplete reductions whereby pain and instability of the midfoot are noted.
Tarsometatarsal Injuries
The spectrum of tarsometatarsal injuries encompasses stable sprains to clinically apparent, grossly unstable deformities.
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Irrespective of the presentation, any injury of the Lisfranc complex can result in prolonged recovery and significant long-term morbidity. It is important to recognize and treat these injuries early and aggressively for best results. Retrospective studies have found up to 20% of these injuries go initially unrecognized and can have significant long-term consequences. High suspicion for this type of injury should be present following motor vehicle trauma. Significant disruptions can occur and undergo spontaneous reduction masking the underlying gross instability.
FIGURE 56-20 Middle cuneiform fracture dislocation. A. Lateral x-ray of a dorsal fracture dislocation of the second cuneiform with a fracture of the third. B. CT scan of bony destruction in the midfoot. C. Complete dislocation of second cuneiform upon opening the skin. D. Rigid internal fixation with 3.5-mm lag screws in attempt to fuse the middle cuneiform to the medial and lateral cuneiforms.
Diagnosis
Injury to the tarsometatarsal joint complex can occur through a wide range of insults. Subtle injury to the ligamentous structure can occur through sports or other low-impact trauma. More significant bony injury and instability usually occur from high-energy trauma such as a fall from a height or a motor vehicle collision. Two mechanisms of injury are described (38,39,40). A direct loading of the joint complex along the dorsal surface in the manner of a crush injury or an object falling on a stationary foot can result in ligamentous or bony disruption anywhere along the joint line. The pattern will vary depending on the point of application of the force. Significant soft tissue damage can occur with this type of injury and hamper subsequent treatment.
Indirect loading is a more common mechanism and can produce significant disruption of the whole complex. It is characterized by longitudinal loading of a plantarflexed foot (39,41,42,43,44).
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This causes hyperplantarflexion across the long axis of the foot, disrupting first the dorsal ligaments and then the plantar ligaments with a variable extent of bony injury. The resulting pattern again is dependent on the amount of force and the presence of secondary forces acting about the long axis of the foot. This is the most common mechanism for sports injuries (Fig. 56-21). There can be a significant amount of collateral injury as well with these injuries. Fractures of the cuneiforms, cuboid, and or metatarsals are common. The second metatarsal is the most frequently fractured. Ligamentous disruptions involving the intercuneiform joints or cuboid stability have also been recorded. Again their presence is dependent on the amount of loading force and the presence of secondary forces. Published studies to date do not show any true relationship between mechanism of injury and the resultant pattern.
FIGURE 56-21 Indirect injury to the tarsometatarsal joints. A. Axial load to the foot in fixed equinus as in football. B. Dorsal directed force from motor vehicle accident. C. Axial loading resulting from a fall from a height.
The diagnosis is based on careful physical examination of the foot in question. In the case of isolated injury, pain anywhere over the tarsometatarsal joint complex is significant for a possible injury. Passive dorsiflexion and plantarflexion of individual metatarsal heads will elicit pain at the proximal articulations. Pain at the midfoot with attempted single limb heel lift also points to a potential Lisfranc injury. The presence of plantar ecchymosis is also suggestive of ligamentous injury.
X-ray evaluation is crucial in the diagnosis and treatment of this injury. It is used to assess the stability of the joint and to catalog the presence of collateral injuries. If possible at the time of presentation, weight-bearing films of the foot in an anteroposterior, lateral, and 30-degree medial oblique position should be obtained. Because of the possibility of spontaneous reduction in these injuries, non-weight-bearing films provide no loading of the ligaments to test their integrity (42).
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Weight-bearing films provide a ready made stress film of the joint complex. If the patient is unable to bear weight because of pain or the presence of other injuries non-weight-bearing films are still useful as a preliminary evaluation. On each of the three views, the observer is looking for a disruption of the normal in line arrangement between the metatarsal base and the opposing tarsal bone. The AP view allows assessment of the alignment of the lateral border of the first cuneiform with the first metatarsal base and the medial border of the second metatarsal base with the second cuneiform (Fig. 56-22). The 30-degree oblique view shows the alignment of the medial border of the third metatarsal with the lateral cuneiform and the medial border of the fourth metatarsal base with the medial border of the cuboid (Fig. 56-23). The lateral view allows a rough assessment of the alignment of the dorsum of the second metatarsal with the middle cuneiform. The position of the second metatarsal on the AP view and the position of the fourth metatarsal on the oblique are the most consistent indicators for unstable injuries.
If weight-bearing views cannot be obtained and suspicion for injury remains high, stress views of the joint complex should be obtained as soon as possible. These are best obtained with anesthesia to minimize pain and muscle guarding. If the patient’s injury permits, a simple ankle block using 0.25% plain Marcaine can provide sufficient anesthesia to perform an adequate stress test. Using a fluoroscopic C-arm, the joint complex should be viewed in both the AP and oblique planes with the hindfoot held stable and a supination—pronation or an adduction—abduction stress applied to the forefoot. Any displacement of normal joint contours greater than 2 mm denotes ligamentous instability (Fig. 56-24). Recently the assessment of the medial column line formed by the medial border of the navicular and medial cuneiform in the AP stress x-ray has been shown as a possible predictor of joint instability (45). Intersection of this line with the first metatarsal base indicates stability of the first tarsometatarsal joint.
FIGURE 56-22 Anteroposterior view of the tarsometatarsal joint. A. Normal joint alignment on weight-bearing. B. Stress view of tarsometatarsal injury with lateral migration of first and second metatarsals.
To better discern the presence and extent of fractures in a Lisfranc injury and to further investigate radiographically stable injuries, a CT scan can be obtained. As a preoperative screening tool a CT scan can be very helpful in identifying collateral occult fractures or dislocations that may also require attention to preserve the stability and function of the foot (46).
Classification
Over the years a number of classification systems have been proposed to describe the resultant instability of severe injuries. Quenu and Kuss (47) first proposed the classification used by many today (Fig. 56-25). It essentially divides these injuries into three types based on the resultant pattern. The recent OTA classification (80-D) also classifies these injuries by the resulting
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deformity (Fig. 56-26). There is no present classification system that has been found to aid in determining appropriate treatment or for predicting outcome in these injuries. No classification system presently accounts for the nondisplaced injury or the incidence of associated fractures.
FIGURE 56-23 Medial oblique view of the tarsometatarsal joint. A. Normal joint alignment on weight-bearing. B. View of tarsometatarsal injury with lateral displacement of fourth metatarsal in relation to the medial border of the cuboid (shown by arrows).
FIGURE 56-24 The use of stress films to identify unstable injuries is important. A. Non-weight-bearing x-ray of midfoot pain. B. A weight-bearing stress view of the same foot showing widening between the first and second rays.
FIGURE 56-25 The common classification devised by Quenu and Kuss. Further subdivisions are used to identify the direction of dislocation in the homolateral pattern (medial or lateral) and the partial disruption (first or lesser).
Anatomy and Biomechanics
The area known as Lisfranc’s joint represents the transition between the midfoot and forefoot. It consists of the three cuneiform-metatarsal articulations and the two cuboid-metatarsal articulations of the fourth and fifth rays (2). The alignment and stability of this joint line is critical for normal function of the foot (Fig. 56-27). The medial to lateral cascade of the distal articular surfaces of the cuneiforms and cuboid provide for the transverse arch of the foot. The metatarsals, with the distal heads placed for forefoot weight-bearing, comprise the distal half of the longitudinal arch. The rigid arch complex provides the plantar structures with an area free from constant compressive forces that can compromise neurovascular structures. Of greater importance is the concept of a rigid lever arm in gait. This arch stiffness permits the smooth transfer of the center of motion during weight-bearing from the ankle to the forefoot. This rigidity allows for smooth heel lift and weight transfer to the opposite leg.
The variability in the motion available in the individual articulations of this complex allows the forefoot to fine tune individual metatarsal head positions to accommodate uneven ground. The normal foot should exhibit an equal weight distribution pattern across the six weight-bearing surfaces of the forefoot, two sesamoids under the first metatarsal head and four lesser metatarsal heads, each surface with an equal load. Motion studies about these joints have shown two distinct components. The medial column (which is a continuation of the talus, the navicular, and the three cuneiforms and their respective metatarsals) and the lateral column represented by the calcaneus, cuboid, and the lateral two metatarsals. These can be thought of as the two sides of a closed triangle with the transverse metatarsal ligament as the base structure uniting the two columns. At the level of the tarsometatarsal joints there is a distinct difference in the amount of motion available. The medial three joints have less than one-third the available mobility of the two articulations that compose the lateral column (3). The relative medial stiffness is due to the importance of structural integrity over mobility. The talonavicular articulation is the major point of mobility in that column. By contrast, the fourth and fifth tarsometatarsal joints represent the major point of mobility in the lateral column, and the need for mobility there is crucial to normal foot motion.
The medial column is not uniformly stiff at the tarsometatarsal joints. They can be further subdivided into a medial and a middle leg (the lateral column represents the lateral leg). The motion of the first tarsometatarsal joint is again three times that of the second and third tarsometatarsal joints. This mobility at the first tarsometatarsal joint allows the insertions of the powerful tibialis anterior and peroneus longus muscles to affect first ray position and adjust the first metatarsal head to allow even
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weight distribution over uneven ground. The middle leg with its intrinsic stability provides the true rigid lever arm about which the other two legs adjust. The lateral leg also has powerful extrinsic motor insertions. The peroneus brevis and peroneus tertius affect positioning and stability of the lateral leg through their insertion on the base of the fifth metatarsal.
FIGURE 56-26 The OTA classification scheme for tarsometatarsal injuries.
The osseus alignment of this joint complex is important to understand for treatment considerations. The first articulation is a broad surface, usually 3 cm deep, and with a broad plantar base and dorsal apex. The second and third are much smaller and triangular in shape with the apex plantar. The second is recessed from the first by approximately 1 cm and from the third by 0.5 cm. The fourth and fifth are more trapezoidal in shape and lie in a separate plane plantar and lateral to the joints of the medial column. The inherent stability of this region is due in part to the recessed second metatarsal base but even to a greater degree to the numerous strong ligamentous attachments across each tarsometatarsal joint and between each ray. There
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is a significant amount of variability in the position and strength of individual ligaments across many of these joints. The important characteristics to note are as follows: (a) the plantar ligaments are significantly stronger than the dorsal ligaments; (b) the multiple ligaments overlap among the joints of the lesser four tarsometatarsal joints; and (c) the Lisfranc ligament, which is the largest and strongest ligament of this joint complex, represents the only ligamentous support between the medial leg and the middle and lateral legs in the forefoot. The Lisfranc ligament originates from the plantar lateral aspect of the medial cuneiform just below the plantar extent of the second tarsometatarsal joint and inserts on the plantar and medial aspect of the second metatarsal base. At best it is an indirect link between the first and second metatarsals. There is no ligamentous connection between the first and second metatarsals.
FIGURE 56-27 The anatomy of the tarsometatarsal joints. A. Proximal view of the cuneiform and cuboid articular surfaces. B. Distal view of the corresponding articular surfaces of the metatarsals. C. A schematic representation of the contour of the tarsometatarsal joint line. Note the keying in place of the base of the second metatarsal.
Treatment
In treating Lisfranc complex injuries, parameters that are important for management are stability and associated fracture management. Extra-articular fractures, which appear with these injuries, should be treated as described elsewhere in this text to preserve that structure’s role in foot function. Intra-articular fractures of the tarsometatarsal joints should be handled in the context of the treatment of the joint complex.
TABLE 56-5 Closed Management of Tarsometatarsal Injuries
Indications
  • <2 mm displacement of the tarsometatarsal joint in any plane
  • No evidence of joint line instability with weight-bearing or stress x-rays
Treatment
  • Short leg non–weight-bearing cast for up to 6 weeks
  • Recheck stability with stress views at 10 days from injury
  • Progressive weight-bearing in protective brace as symptoms abate
Injuries that present with painful weight-bearing, pain with metatarsal motion, and tenderness to palpation but fail to exhibit any instability should be considered a sprain. In addition to the normal concept of rest, ice, compression, and elevation for treating sprains, the need for immobilization is important. These injuries can be severely debilitating and require a long recovery period (41,43). Nondisplaced ligamentous injuries with or without small plantar avulsion fractures of the metatarsal or tarsal bones should be placed in a well-molded short leg walking cast (Table 56-5). Initially the patient is kept non-weight-bearing
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with crutches and only permitted to bear weight as comfort allows. Once full weight-bearing can be accomplished in a cast, the patient is tested for weight-bearing comfort without support. The ability to perform a single-leg heel rise without pain is a good indicator. Only when the patient is pain free out of the cast should rehabilitative therapy begin.
The presence of instability in this region requires anatomic reduction (38,39,44,48,49). The definition of instability presently is defined as a greater than 2-mm shift in normal joint position. Closed manipulation under anesthesia with casting as a definitive treatment has been shown to be a poor choice because maintenance of the reduction is too difficult and residual deformity can lead to significant morbidity. An initial closed reduction should be done for complete dislocations to reduce the tensile pressure on the overlying skin and protect the soft tissues from further compromise. Splinting of the foot in a reduced position should be done until definitive treatment can be performed. Mechanical blocks to reduction include joint surface impaction, interposition of capsule or avulsion fracture fragments, or the interposition of the tibialis anterior at the first-second interspace.
It is generally agreed that the best results are obtained through anatomic reduction and stable fixation (49,50). The only variable that appears to determine outcome in these injuries is the accuracy of the reduction. Recent studies also tend to show that injuries that are purely ligamentous have a tendency toward chronic pain and instability even with initial anatomic reduction and stable fixation (49). The optimal method of fixation and the postoperative management of these patients is not as clear. There are advocates for both closed and open K-wire fixation after either closed or open anatomic reduction. The pins are left in for 6 weeks. Others advocate the use of screw fixation to stabilize the disrupted joints, leaving them across the joints for 3 to 6 months. From the standpoint of stability of fixation, screws appear to be superior at holding a reduction over multiple K-wires in mechanical tests, but the optimal site of screw placement and the need to stabilize the lateral tarsometatarsal joints are in dispute (51).
Open reduction of the Lisfranc complex requires visualization across the whole joint complex. The most common approach is using two longitudinal incisions (Fig. 56-28) (52,53). The first is centered over the first-second intermetatarsal space, allowing identification of the neurovascular bundle and access to the medial two tarsometatarsal joints. A second longitudinal incision is made over the fourth metatarsal. Because of the vertical overlapping of the lateral three metatarsals, this incision allows direct visualization of these tarsometatarsal joints. Variations of these standard incisions may be necessary depending on associated injuries to the cuneiforms, cuboid, metatarsals, and navicular and their articulations. Both of these incisions should be full thickness to the bony surface with a minimum of undermining. Medial or lateral migration in the wound should only be done through subperiosteal dissection to preserve the integrity of the soft tissue envelope.
Inspection of all the involved joint surfaces should be performed before reduction is attempted. Because of the ligamentous interconnection of the lesser metatarsals they must all be free from any restraints to reduction and their joints free of fracture debris or capsular interposition before any one of them can be accurately reduced. Once reduction is accomplished fixation is performed using either fixation screws or K-wires to hold the joints stable (Fig. 56-29).
FIGURE 56-28 The surgical approach to the tarsometatarsal joints of the foot. The medial incision is along the first web space. The lateral incision is over the medial aspect of the fourth metatarsal. This will allow visualization of all joints.
Another unresolved issue is the length of time fixation screws should remain in place after reconstruction. Opinions range from removal before weight-bearing begins to leaving the screws in place at least 12 months or until symptomatic (49). The present trend is to leave them in at least until full weight-bearing has been achieved, though many trauma surgeons leave the screws in place for the first 3 months after weight-bearing.
Postoperative Care
The foot is immobilized in a non-weight-bearing, plantigrade cast for 6 to 8 weeks. Progressive weight-bearing is then permitted as comfort allows. Advancement out of cast immobilization is done once pain-free full weight-bearing is achieved. Internally placed hardware is removed from across the joints at 6 to 9 months after initial treatment.
Complications
Irrespective of the mechanism of injury, pattern of disruption, or x-ray evidence of joint degeneration, the best results are dependent only on the ability to obtain and maintain an anatomic reduction of the joint complex (38,44). Reduction not only refers to the position of the tarsometatarsal joints but the restoration of the arch and the return of midfoot stability. The major complications of this fracture complex are incomplete reduction, loss of reduction or post-traumatic arthropathy (54,55). The x-ray appearance of degeneration of the joint is not unusual with this injury and does not correlate well with clinical symptoms. Anatomic reduction of the joint complex with medial column arthrodesis is the treatment of choice for symptomatic arthropathy (55,56,57).
There is also a high incidence of missed or delayed diagnosis with these injuries. If the injury is recognized within 6 weeks of onset, anatomic reduction and stabilization is the treatment of choice. After 6 weeks, anatomic reduction is difficult and the results are poor (54). These injuries are best treated with medial column fusion when the patient is symptomatic (Fig. 56-32). Realignment of a long displaced joint can be difficult because of the soft tissue contractures. Before attempting reduction, complete soft tissue release of all malaligned joints should be done to allow movement as a unit. Resistance to realigning the lesser metatarsals can come from contracture of the peroneus brevis muscle. This muscle can be lengthened in the sheath posterior to the distal fibula, allowing easier reduction of the lesser joints. Again fusion of the fourth and fifth tarsometatarsal joints should be avoided if at all possible.
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INJURIES TO THE FOREFOOT
The forefoot serves two purposes during gait. As a unit it provides a broad plantar surface for load sharing. Weight-bearing studies show that the two sesamoids and the four lesser metatarsal heads share an equal amount of the forefoot load in normal gait. The platform is structured to also be mobile in the sagittal plane. This provides the forefoot with the ability to alter the position of the individual metatarsal heads to accommodate uneven ground. This ability to alter position allows the forefoot to maintain a relatively even pressure distribution on the plantar skin, protecting it from local injury. Though the forefoot appears to work as a single unit, it parts are distinctly different and need to be treated accordingly in the case of injury (2).
FIGURE 56-32 Late tarsometatarsal injury. A. Weight-bearing x-ray of painful midfoot now 5 months from injury. Note the displacement of the joints and the loss of definition. B,C. Realignment and fusion of the medial column using a screw pattern similar to acute stabilization. Note the satisfactory restoration of the lateral joint space.
Metatarsal Fractures
Metatarsal fractures are common injuries that usually result from the direct blow of a heavy object dropped onto the forefoot. Such a direct force can result in the fracture of any metatarsal at any point. Indirect forces, particularly twisting the body with the toes fixed (as when a person catches the toe of the shoe in a narrow opening), apply torque to the foot, producing fractures of the metatarsal shafts, particularly spiral fractures of the middle three metatarsals. Avulsion fractures, particularly the base of the fifth metatarsal, are common. Stress fractures also occur commonly in the metatarsals, particularly at the second and third metatarsal necks and at the proximal portion of the shaft of the fifth. Despite the relative insignificance usually relegated to metatarsal injuries, they can lead to significant limitations if ignored (53,54,59).
Diagnosis
The diagnosis of a metatarsal fracture by any mechanism is relatively easy if it is looked for. The advantage is that there is no significant soft tissue envelope surrounding these bones to hide any deformity or swelling. The presence of pinpoint tenderness, palpable nonpitting edema, crepitance, or deformity is readily apparent. The patient usually complains of pain in the dorsum of the foot, which increases with weight-bearing. The dorsum of the foot is usually swollen and ecchymotic. In the first few hours after injury it is usually easy to find point tenderness
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over the fracture site. One should be wary of closed crush injuries to the forefoot. Significant swelling or soft tissue tightness should lead one to suspect a compartment syndrome. If it is suspected, it is imperative that operative decompression of the plantar and interosseus compartments be done on an emergency basis. The fractures can be stabilized percutaneously at that time.
In the case of isolated injuries to the foot, weight-bearing films should be obtained in the anterior-posterior and lateral planes. Except in the case of an isolated direct blow initial films should include the whole foot to rule out other potential collateral injuries that may also require attention. In the absence of other injuries, repeat films specifically of the forefoot should be obtained to better define the pathology. Whole foot radiography tends to overexpose the forefoot/metatarsal head region making x-ray evaluation difficult. A lateral x-ray of the metatarsals is important for judging sagittal plane displacement of the head. Other studies are rarely needed to evaluate acute fractures. With evidence of a proximal intra-articular fracture of any metatarsal it is important to rule out disruption of the tarsometatarsal joints and instability of the Lisfranc joint.
Stress fractures are also common in the metatarsals. It is important to find the underlying cause of the stress fracture. They occur individually as a response to locally high repetitive loads that exceed the body’s reparative mechanism. The underlying cause can range from local changes in the sagittal position of adjacent metatarsal heads, to a tight gastrocnemius, to underlying metabolic bone disease causing osteopenia. Any mechanical reason for the overload should be addressed at the same time as the fracture. As with traumatic injuries any significant displacement of the metatarsal head from its normal position should be addressed with reduction and stabilization. Failure to treat the cause as well as the deformity may doom the other lesser metatarsals to the same fate as the local force load is transferred from one metatarsal to the next (Fig. 56-33).
Classification
The Orthopedic Trauma Association classification for metatarsal fractures permits a detailed description of the fracture pattern of each bone but does not offer any insight to overall stability or treatment. The designation of metatarsal fractures under this system observes the format: (81()-_ _._), in a fashion similar to the metacarpals of the hand. To denote which metatarsal the classification refers to, an alpha identifier should be placed in parentheses beside the major designation: first metatarsal (T), second metatarsal (N), third metatarsal (M), fourth metatarsal (R), fifth metatarsal (L). The alpha subclassification represents fracture complexity while the numerical subgroupings denote fracture position and pattern. Group A denotes extra-articular and simple diaphyseal fractures. Group B involves partial articular and diaphyseal wedge fractures. Group C involves complex articular or diaphyseal fractures. The first numerical subgrouping denotes area of involvement: proximal metaphyseal (1), diaphyseal (2), distal metaphyseal (3). The second and third numeric designations are for fracture pattern designation and can vary depending on the group and first numeric designation (Fig. 56-34).
FIGURE 56-33 Stress fractures of the metatarsal bones. These two x-ray views show the progression of fractures from medial to lateral along the metatarsals in an insensate individual.
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Anatomically, the metatarsals fall into three distinct groups: the first and fifth metatarsals because of their location and unique functions and the central metatarsals because of their interconnectivity.
FIGURE 56-34 OTA Classification for metatarsal fractures. Modifiers are used to specify the metatarsal involved and follow the classification number: T, great; N, index; M, middle; R, ring; L, little. (J Orthop Trauma 1996;10[suppl 1]).
FIGURE 56-35 Three zones of proximal fifth metatarsal fracture. Zone 1: Avulsion fracture. Zone 2: Fracture at the metaphyseal-diaphyseal junction. Zone 3: Proximal shaft stress fracture.
At one time all fractures of the base of the fifth metatarsal were referred to as Jones fractures. We now recognize that there are probably three distinct fracture patterns that occur here (60,61) (Fig. 56-35). A true Jones fracture is acute in nature and occurs in zone 2 at the metaphyseal diaphyseal junction. The relative frequency of these fractures was shown in a busy general orthopedic practice to be approximately 93% zone 1, 4% zone 2, and 3% zone 3 (62).
First Metatarsal
Anatomy and Biomechanics
The first metatarsal is unique in many ways. Its configuration is shorter and wider than that of the lesser four metatarsals. The lack of interconnecting ligaments between the first and second metatarsal bones allows independent motion. Strong, thick ligaments that make up the capsule of the first tarsometatarsal joint support its resting position. There are two powerful motor attachments to its base. The anterior tibialis inserts on the plantar medial aspect of the first metatarsal base, and the peroneus longus attaches onto the plantar lateral base of the first metatarsal. These two muscles exert significant influence on the position of the first metatarsal head. The tibialis anterior serves to elevate the first metatarsal and the peroneus longus acts to plantar flex the head. The first metatarsal head supports two sesamoid bones that provide two of the six contact points of the forefoot. This translates to the first ray essentially supporting one third of the forefoot weight at any one time (2).
The surgical approach for fracture of the first metatarsal to some degree depends on the configuration of the fracture. For simple avulsions at the metatarsal base an incision directly over the fracture may be best for direct vision of reduction. For the majority of proximal and midshaft fractures a dorsal-lateral approach through the first-second intermetatarsal space is adequate for visualization of reduction and fixation. This incision can be extended distally and proximally to allow access for a bridging plate if needed. The approach should be done carefully to avoid unnecessary disruption of tissue planes. In this area of the forefoot lie the dorsalis pedis artery and the deep peroneal nerve. Branches of the superficial peroneal nerve can be found overlying the deeper structures. These structures need to be identified and protected during the surgical dissection and closure.
Treatment
There are significant forces acting through the first metatarsal during gait, and it is therefore important to maintain its normal position in relation to the foot. The best way to determine operative or nonoperative treatment is with stress x-ray films. Manual displacement of the position of the first metatarsal through the joint or fracture site represents an instability that requires fixation. If no evidence of instability can be seen on stress films of the fracture, and no other injury of the midfoot or metatarsals is evident, isolated first metatarsal fractures can be adequately treated in a short leg cast with weight-bearing as tolerated for 4 to 6 weeks (Table 56-6). It is important when casting this injury to position the foot in a plantigrade position yet without placing dorsally directed pressure on the first metatarsal. The best way to apply the cast is with the patient in the prone position with knee of the affected limb flexed to 90 degrees, placing gentle pressure on the lesser metatarsals to obtain a plantigrade position. Activities are then advanced as tolerated in a walking cast until there is comfortable full weight-bearing before advancing to regular shoes or increased activity.
Any evidence of instability or loss of normal position of the metatarsal head should be treated with operative stabilization. The goal is to restore and maintain the normal position of the first metatarsal head in relation to the others (52,59).
The method of fracture fixation is dependent on fracture configuration. Simple fractures of the shaft or either articular surface can be fixed with percutaneous smooth wires or by open reduction with screw fixation. Plate and screw fixation should be used for transverse or minimally comminuted fractures where inadequate fixation will occur with screws or wires alone. External fixation should be considered with severe midshaft or head comminution or open injuries. The fixator is used to restore first metatarsal axial length and alignment with the forefoot without further compromise to the soft tissues.
TABLE 56-6 Closed Management of First Metatarsal Fractures
Indications
  • No evidence of bony instability with weight-bearing or stress x-rays
  • No loss of bony length
Treatment:
  • Short leg non–weight-bearing cast for 4 to 6 weeks
  • Recheck stability with stress views at 10 days from injury
  • Progressive weight-bearing in protective brace until asymptomatic
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Postoperative Care
Poststabilization care revolves around the health of the soft tissues and the rate or evidence of bony healing. Non-weight-bearing status is maintained for 8 to 10 weeks. Those fractures internally fixed are placed in a short leg cast. In the presence of external fixation, a removable molded splint is used to maintain the foot in a plantigrade position. Active and passive motion of the great toe is encouraged in the early postoperative period if it is not included in the fixation. Once bridging callus is identified on x-ray, the external fixator is removed, and the patient is allowed to advance weight-bearing in a removable walker as tolerated. Internal fixation that is bridging the tarsometatarsal joint is left in place for up to 6 months before being removed. Progression of activity is based on patient comfort. A full-length in-shoe orthotic device with medial support for the first metatarsal arch is used for up to 1 year.
FIGURE 56-37 Comminuted fracture of first metatarsal. A,B. Anteroposterior and lateral of injury. C. Open reduction of joint and fracture fragments. Because of the proximal comminution a bridging one-third tubular plate was used to stabilize the tarsometatarsal joint. D,E. Two-year postinjury weight-bearing films show maintenance of the joint line. The bridging plate was removed at 6 months.
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Complications
Malunion, nonunion, arthritic degeneration of the tarsometatarsal and metatarsophalangeal joints are all possible complications of first metatarsal fractures. Transfer metatarsalgia to the lesser toes can occur with shortening of the first metatarsal length. Secondary surgery may be necessary to realign or bone graft the fracture.
FIGURE 56-38 The use of the external fixator for severe first metatarsal fractures. A,B. Injury films showing significant disruption of the metatarsal shaft. C,D. Placement of an external fixator with restoration of metatarsal length and alignment.
Central Metatarsals
Anatomy and Biomechanics
The four lesser metatarsals each provide only one contact point on the plantar weight-bearing surface (63). There are significant ligamentous structures that link each of the bones to their adjacent neighbors. At the base of each of these bones is a series of three ligaments (dorsal, central, and plantar), which act to stabilize and support each with their neighbor. The central three have no extrinsic motor insertions. Their role is for structural support. They do provide for the origin of dorsal and plantar interossei muscles. The plantar muscles insert into the medial aspect of the associated proximal phalanx. The tendon of the dorsal muscle, however, inserts into the plantar aspect of the proximal phalanx of its medial neighbor. Finally, there is the thick transverse metatarsal ligament distally, which connects the metatarsals indirectly by linking the plantar plates of the adjacent metatarsophalangeal joints. There is also a cascade of allowable increase in motion through
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the tarsometatarsal joints, beginning at the second metatarsal and going out to the fifth. It is this increase in motion in the sagittal plane that allows for significant adaptability to terrain by the metatarsal heads. It is also the relative resistance to motion at the second and third tarsometatarsal joints that causes stress fractures to be seen more commonly in these two metatarsals.
FIGURE 56-39 Displaced first metatarsal head fracture. A. Injury film showing disruption of all metatarsal heads. B. The use of two smooth wires to stabilize the reduction of the first metatarsal head.
Treatment
Fractures of the central metatarsals are much more common than first metatarsal fractures and can be isolated or part of a more significant injury pattern (64,59). As with the first metatarsal the emphasis is on the resulting position of the metatarsal head. Though there is little in the literature documenting specific criteria for unacceptable position, the problems of transfer metatarsalgia and shoe wear are well known in fractures that allow significant changes in the normal position of the metatarsal head (Table 56-7). The criterion most often mentioned is that any fracture displaying more than 10 degrees of deviation in the dorsal plantar plane or 3 to 4 mm of translation in any plane should be actively corrected (Fig. 56-40) (59).
The vast majority of isolated individual central metatarsal fractures can be treated closed (11,64). That is not to mean they should be ignored. Isolated midshaft fractures, whether comminuted or simple, are usually quite stable, with little shortening, and can be managed adequately with hard-sole or stiff shoes and progressive weight-bearing as tolerated. Any appreciable deviation in metatarsal head position should be addressed with reduction and possibly pinning to maintain normal forefoot alignment.
TABLE 56-7 Closed Management of Central Metatarsal Fractures
  • In situ management
    • Indications
      • <10 degrees angulation along long axis
      • <4 mm translation of shaft
    • Treatment
      • Hard-sole or stiff-soled shoes with weight-bearing as tolerated
  • Closed reduction
    • Indications
      • >10 degrees angulation
      • >4 mm translation
      • No loss of length
    • Treatment
      • Closed manipulation with gravity traction
      • Hard-sole shoe with progressive weight-bearing as tolerated
Postoperative Care
Postoperative care involves placing the patient in a short leg cast for 2 weeks with the foot in a plantigrade position to allow soft tissue healing. The patient is permitted to bear weight through the heel during this time. With
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removal of the sutures a removable cast is used to maintain normal foot position until the patient is comfortable to bear weight, usually 4 to 6 weeks. The pins are removed at 4 weeks unless they are bridging a bony gap. In that case, cancellous bone grafting is done at the time of reduction and the pin remains until x-ray evidence of bony consolidation is seen or the patient is bearing weight without pain.
Complications
Complications from treating central metatarsal fractures usually stem from incomplete restoration of plantar anatomy (64). This is not possible in some cases, no matter how diligent one is. Also, just because there is a recognizable deformity once bony healing has occurred does not guarantee that a patient will have clinical symptoms. In those patients who are symptomatic upon restoration of bone stock and healing of soft tissues, simple osteotomies can usually correct the symptomatic deformity. Other causes of a poor outcome are more related to the energy of the initial trauma. Fracture comminution, soft tissue injury, and open injuries were noted to lead to late symptoms of pain and stiffness irrespective of the type of intervention (64).
Fifth Metatarsal
Diagnosis
Injuries to the fifth metatarsal are usually discussed separately from those of the other metatarsals because of the different venues where these injuries are seen. Although injury to this area does occur with motor vehicle collisions, the majority of injuries are related to sporting or athletic activities. These fractures are separated roughly into two groups: proximal base fractures and distal spiral or dancer’s fractures. Proximal fifth metatarsal fractures are further divided by the location of the fracture and the presence of prodromal symptoms (61,62,65,66,67,68,69) (Fig. 56-42).
An avulsion fracture or zone 1 injury, at the base of the fifth metatarsal usually occurs from an indirect load. Sudden inversion of the hindfoot with weight on the lateral metatarsal, places tension along the insertion of the lateral band of the plantar aponeurosis, which inserts into the proximal base of the fifth metatarsal causing disruption of the bony cortex. The peroneus brevis appears to have little effect on this fracture pattern. This same mechanism can also produce lateral ligament injury at the ankle, and, therefore, it must be ruled out in patients who complain of lateral ankle pain after a twisting injury. This is easily done by directly palpating the bone and resisting active eversion of the foot. Both will produce pain if injury is present. A direct blow to the tuberosity area can also produce an avulsion type injury but usually exhibits more comminution and involvement of the fifth tarsometatarsal joint. The fragment size may vary from a small fleck to a fragment encompassing almost the entire tuberosity. Only rarely is the articulation of the fifth tarsometatarsal joint involved. The fracture is usually minimally displaced and stable because of its attachment to the plantar aponeurosis.
Zone 2 injuries are true Jones’ fractures. They represent an acute injury caused by adduction of the forefoot resulting in a fracture at the proximal metaphyseal-diaphyseal junction of the bone. The fracture propagates from the lateral aspect of the proximal metatarsal toward the four-five articular surface. It can progress proximally into the metatarsocuboid joint and exhibit comminution. It is a fracture resulting mainly from tensile stress along the lateral border of the metatarsal.
FIGURE 56-42 Fracture of the fifth metatarsal base. A. Zone 1 injury with comminution. B. Zone 2 injury. C. Zone 3 injury with six-month history of pain.
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The third type of fracture seen in the proximal fifth metatarsal is now referred to as a proximal diaphyseal stress fracture. These are relatively rare, are seen mainly in athletes, and occur in the proximal 1.5 cm of the shaft of the metatarsal. Repetitive cyclic loads as seen in high-level athletics appear to be the underlying mechanism for these injuries. The fracture is induced by tensile forces resulting in microfractures at the lateral cortex. Continued loading propagates the fracture medially. The presence of clinical symptoms before the x-ray visualization of the fracture are classic in this pattern. Weeks to months of pain with exertion at the lateral border of the proximal metaphysis can be seen. X-ray examination reveals a variable fracture length with sclerotic margins and variable callus.
The remainder of the fifth metatarsal fractures not resulting from a direct blow have been termed dancer’s fracture (70). The usual pattern is a spiral, oblique fracture progressing from distal-lateral to proximal-medial. The mechanism of injury a rotational force being applied to the foot while it is axially loaded in a plantar flexed position. The usual method is by rolling over the outer border of the foot.
Anatomy and Biomechanics
The fifth metatarsal is distinguished from the other lesser metatarsals in that it does have major motor insertions at its base. The peroneus brevis attaches on the dorsal aspect of the tubercle of the fifth metatarsal, and the peroneus tertius attaches on the dorsal aspect at the proximal metaphyseal diaphyseal junction. Functionally the peroneus tertius acts as a balancing force to forefoot dorsiflexion counteracting the natural inversion tendency of the tibialis anterior. The peroneus brevis serves as more of an antagonist to posterior tibialis function to maintain the position of the foot under the talus. There is also a strong attachment of the plantar fascia to the plantar aspect of the tubercle.
In the adolescent population there is an apophysis at the tuberosity that can be confused for a fracture (61). A fracture would not have the smooth radiolucent line parallel to the metatarsal shaft. Also in this area are two sesamoid bones, which should not be mistaken for a displaced fracture. The os perineum is located within the tendon of the peroneus longus and can be found on the lateral border of the cuboid. The os vesalianum is found just proximal to the base of the fifth metatarsal medial to the insertion of the peroneus brevis. Its smooth contours, in contrast to a fracture, should distinguish it from an acute injury (2).
The blood supply to the fifth metatarsal has been studied in depth in an attempt to understand the problem with proximal metatarsal nonunion. It is similar to the other metatarsals in that a single nutrient artery enters from the medial cortex at the junction of the proximal and middle thirds of the diaphysis and supplies the shaft. Secondary epiphyseal and metaphyseal arteries supply the base and tuberosity (2).
In the rare instance in which open reduction of or access to the proximal tuberosity is necessary, great care should be taken during the approach. The sural nerve, the insertion of the peroneus brevis, and the insertion of the peroneus tertius, as well as the lateral anchor for the extensor retinaculum are all within the surgical margins (71). Damage to these structures should be avoided. If there is a need to access the fracture directly through one of the tendon insertions, it appears to be better to make a “z” cut transection of the structure and repair it than to remove it from its bony insertion.
Treatment
There are numerous studies in the literature looking at various treatment aspects for the variety of fractures seen in the fifth metatarsal (61,69,72,73) (Table 56-8). The conclusion is that zone 1 injuries, as well as distal fractures, can be treated quite well by closed means. Avulsion fractures and dancers’ fractures do well if treated symptomatically (69,70,73). A soft Jones dressing, a stiff-soled shoe and casts have been shown to be equally effective. Symptoms can last for 6 to 8 weeks but the fractures usually heal fully. In adolescents, whether pain in this area is from a true fracture or from apophysitis, the treatment is the same.
The treatment of acute injuries of the proximal diaphysis, zone 2, is controversial. Part of the problem appears to be the mixing of acute and chronic injuries in earlier series. These act as two different fracture populations in which those with prodromal symptoms are more likely to have difficulty healing and should be considered as zone 3 injuries. Looking specifically at acute zone 2 injuries, treatments ranging from symptomatic protection to short leg casting or surgery have been reviewed (74,75,76). Short leg casting with weight-bearing progression as tolerated appears to give the best results. The cast is left on for 8 to 10 weeks.
Zone 3 injuries are those that occur distal to the proximal tuberosity and present with prodromal symptoms before complete fracture. It is this particular entity that poses problems because of its tendency toward nonunion (73). Successful treatment of this fracture pattern requires more aggressive treatment than that used for other fracture patterns in the fifth metatarsal. Initial treatment is between casted non-weight-bearing for up to 3 months versus surgical intervention with grafting and internal compression (61,68). In the fractures with a short period of localized pain with activity before diagnosis, non-weight-bearing casting offers results comparable to those with surgery (65).
TABLE 56-8 Closed Management of Fifth Metatarsal Fracture
Indications
  • Acute injury without prodromal symptoms
  • Chronic injury without adequate closed treatment
Treatment
  • Zone 1
  • Weight-bearing as tolerated with hard-sole shoe
  • Zone 2
  • Weight-bearing cast for 8 to 10 weeks
  • Zone 3
  • Non–weight-bearing cast up to 3 months
  • Weight-bearing when pain free on examination
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Surgical intervention should be left for the symptomatic nonunion that occurs mainly with a zone 3 injury. Best results are obtained with open debridement of the nonunion site and cancellous bone grafting. Rigid intramedullary compression of the fracture is used to stabilize the injury. The approach is along the lateral border of the fifth metatarsal just above the abductor digiti quinti muscle (Fig. 56-43). The proximal tip of the tuberosity is identified, as well as the nonunion site. The fracture site should be completely opened with osteotomes or a high-speed burr. The medullary canal should be cleared of any sclerotic debris. The void created by the debridement needs to be completely filled with autograft. Axial compression can be obtained with a cortical or cannulated screw 3.5-mm or larger to tightly fit the metatarsal canal. Using fluoroscopic imaging the screw is introduced through the proximal tuberosity across the fracture. According to cadaveric studies, the insertion point for intramedullary fixation is 1 cm dorsal to the palpable inferior margin of the proximal tuberosity and just medial to the peroneus brevis insertion. The drill, or guide pin, should proceed in a plantar direction at an angle 7 degrees off the plantar surface of the foot with the ankle in neutral (74). The sural nerve is only 5 mm or so dorsal to the insertion site and should be shielded from injury. The screw should engage the cortical bone of the distal fragment without distorting metatarsal alignment for best results. Surgical stabilization does not permit early return to activity with these fractures. Short leg casting and protected weight-bearing similar to the treatment of early zone 3 injuries is necessary to have the best chance of healing (66).
FIGURE 56-43 Surgical approach to the base of the fifth metatarsal. Structures to identify and protect include the sural nerve, the abductor digiti quinti tendon and the peroneus brevis tendon.
Complications
Complications from this injury, if treated properly, are rare. For zone 1 fractures, nonunion can occur but is usually asymptomatic and requires no intervention. There are reported incidences of pain from sural nerve entrapment or tarsometatarsal joint pain with nonunion (75). In these instances these fracture fragments should be excised. If the symptomatic nonunion is large enough to involve the insertion of the peroneus brevis, it is big enough for fixation and cancellous bone grafting using a 3.5-mm or 4.0-mm lag screw.
The reported incidence of nonunion among zone 2 and 3 injuries is due more to the method of treatment. These fractures need a period of immobilized non-weight-bearing to minimize complications. Surgical failures are a factor of resuming activity too soon, inadequate grafting, or incomplete debridement of the sclerotic medullary canal (66).
Metatarsophalangeal Injuries
Injury to the metatarsophalangeal joint complex can occur in isolation, as well as be a small part of a high-energy, multiple injury trauma (11,76). It occurs most commonly at the first metatarsophalangeal joint complex during sports but can also be an isolated injury to a lesser metatarsophalangeal joint. The importance of first metatarsophalangeal joint stability should not be underestimated. It provides for stable load sharing between the metatarsal head and the distal pad of the respective toe. Dorsiflexion motion provides for a smooth transition between heel off and toe off during weight-bearing gait. It is important to be aware of the potential for injury to this joint with any form of loading trauma to the foot because of the significant long term problems of pain and instability if left untreated.
Injuries to the First Metatarsophalangeal Joint Complex
Anatomy and Biomechanics
The bony architecture of the metatarsophalangeal joint is comprised of a cam-shaped metatarsal head and a matched concave articulation on the proximal phalanx. These contours contribute little to the overall stability of the joint. Stability is provided by the complex structure of the joint capsule and ligaments. The capsule is normally thin and weak dorsally. The plantar capsule is a thick weight-bearing structure with strong attachments to the base of the proximal phalanx. There is a thinner, more flexible attachment to the plantar aspect of the metatarsal head proximally. Imbedded in this plantar structure are two bones known as sesamoids, which articulate directly with the metatarsal head. It is the medial and lateral sesamoid that are the two ground contact points for weight-bearing through the first metatarsal. Between these two sesamoids and plantar to the intersesamoid ligament runs the flexor hallucis longus tendon.
At the proximal end of this complex are multiple intrinsic motor insertions that exert significant control over the stability and position of the joint. Medially, the medial head of the flexor hallucis brevis inserts directly into the proximal aspect of the medial sesamoid. The adductor hallucis partially inserts along the medial border of the medial sesamoid but also continues distally to insert on the medial plantar tubercle of the proximal phalanx and the transverse lamina of the extensor aponeurosis. This motor complex provides dynamic resistance to valgus stress on the great toe. The lateral head of the flexor hallucis brevis inserts on the proximal aspect of the lateral sesamoid. The oblique and transverse heads of the adductor hallucis muscle insert mainly along the lateral border of the sesamoid but have extensions into the lateral plantar tubercle of the proximal phalanx, the lateral capsular complex, and the tunnel of the flexor hallucis longus. This motor complex resists varus stress applied to the great toe. There are no tendinous insertions present on the metatarsal head (Fig. 56-44).
Two sets of ligaments provide the only significant attachments of the metatarsal head to the joint complex. The better known set of ligaments is the medial and lateral collateral ligaments extending from the metatarsal head to the medial and lateral base of the proximal phalanx. The second set is known as the medial and lateral metatarsosesamoid ligaments. They form a strong attachment between the medial and lateral edges of the respective sesamoids and the medial and lateral sides of the metatarsal head.
Sensation to the great toe is divided into four longitudinal quadrants. Dorsal medially, sensation is supplied by the medial dorsal cutaneous branch of the superficial peroneal nerve. The dorsal lateral aspect is usually a continuation of the first web space innervation by the terminal branches of the deep peroneal
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nerve. Plantarly, the medial and lateral plantar hallucal nerves from the medial branch of the posterior tibial nerve provide sensation to the great toe. These nerves run just medial and lateral to their respective sesamoids and can be easily injured by traumatic or iatrogenic means (2).
FIGURE 56-44 Functional anatomy of the first metatarsophalangeal joint. A. Dorsal view of plantar ligamentous structure of the plantar plate. B. Lateral view depicting the ligamentous attachments between the metatarsal head and the plantar plate and proximal phalanx.
Diagnosis
Injury to the first metatarsophalangeal joint complex is common in sports (77,78,79). It is behind only knee and ankle injuries in importance for time lost from athletic activity. The spectrum of involvement is wide, from minor sprain to frank dislocation or disruption of the complex (80,81). The mechanism of injury can be quite variable, making the diagnosis in multiple trauma difficult. Hyperdorsiflexion (turf toe) (77,78), plantar flexion (sand toe) (79), valgus, and varus stresses have all been described for this injury. In all instances there is simultaneous axial loading of the joint. The amount and rate of force application determine the extent of the injury.
Diagnosis requires suspicion of an injury on the part of the examiner and close physical examination. A simple avulsion fracture from the metatarsophalangeal joint may be a sign of traumatic joint instability (78). Pain with weight-bearing or exertional activities may be the only clue to an isolated mild injury. Ecchymosis and swelling are not always present initially. The presence of deformity such as the loss of the normal parabolic cascade of the toes is evidence of a possible injury. Besides close palpation to determine the point of tenderness, it is important to discern the structures involved. The presence of passive and active stability is important to note. Both the range of joint motion and relative stability in all planes should be checked and compared with the contralateral joint to assess for subtle differences. Acute instability in any plane denotes a significant injury (76). Another useful tool to assess stability is the dorsoplantar translation test (Fig. 56-45). Increased translation relative to the contralateral side denotes significant instability of the capsuloligamentous complex (78).
FIGURE 56-45 Stability test for metatarsophalangeal joint. A. Position of hands to test dorsal-plantar stability. B. Direction of motion.
X-ray studies should include weight-bearing anteroposterior and lateral views of the forefoot to clearly define the area in question and prevent overexposure. Also both medial and lateral oblique views and a sesamoid view are needed to fully assess the joint. Even in the case of frank persistent dislocation,
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plain films should be obtained before attempted reduction to determine the position and condition of the sesamoids. The films may reveal the presence of intra-articular or extra-articular fractures, avulsion injuries of the medial or lateral collateral ligaments, or displacement of the sesamoid structures. Proximal, distal, or divergent migration of the sesamoids either together or separately may occur. A sesamoid fracture or separation through a bipartite synchondrosis is possible. A comparable view of the contralateral side may be helpful in discerning any changes in the sesamoid complex position. On the anteroposterior view the distance between the base of the proximal phalanx and the distal pole of either sesamoid should be within 3 mm of the same distance on the contralateral foot (82). If a partite sesamoid is present, the normal distance between the proximal phalangeal base and the distal pole of the sesamoid should be less than 10 mm for the tibial sesamoid and 13 mm for the fibular sesamoid. Greater distances denote possible plantar plate disruption (82). Care must be taken in the presence of bipartite sesamoids because the incidence of bilaterality is quite variable. The two factors most important in determining a treatment plan are first the presence of a dislocation and second the joint stability once reduced.
Classification
There exists no classification system that encompasses the full spectrum of injury possible at the first metatarsophalangeal joint. Sprains or nondisplaced injuries (turf toe) have been classified into grades I, II, and III based on pain and instability (78) (Table 56-9). Treatment and outcome for these injuries correlate well with the initial grade. Dislocations were first classified by Jahss and later modified as other variations on the general pattern were reported (Fig. 56-46). In general, type I dislocations involve an intact plantar plate. Type II involve partial disruption of the plantar plate in some manner. Jahss type III dislocations have a complete dissociation of the plantar plate from the base of the proximal phalanx. The OTA system classifies the dislocation of all joints involving the toes under the 81-D heading. They are further divided by the joint involved and the direction of the dislocation (Table 56-10).
FIGURE 56-46 Modified Jahss classification of first metatarsophalangeal dislocations. A. Type I: Dorsal dislocation without disruption of sesamoid complex. Usually not reducible closed. B. Type IIA: Dislocation with longitudinal disruption of plantar plate and intersesamoid ligament. Noted by increased distance between sesamoids. C. Type IIB: Partial disruption of plantar plate with disruption of either medial or lateral sesamoid. D. Type IIIA: Complete soft tissue disruption of the plantar complex from the proximal phalanx. E. Type IIIB: Complete plantar plate disruption including disruption of one sesamoid.
TABLE 56-9 Classification of Turf Toe Injuries
  Signs and Symptoms Pathology Treatment Course
Grade I Plantar or medial tenderness
Minimal swelling
No ecchymosis
Intrasubstance stretch of capsular structures Rest
Ice
Compression
Elevation
May play with protection
Grade II Diffuse tenderness
Mild to moderate swelling
Ecchymosis
Decreased range of motion
Tear of capsular structures Include buddy taping with above protocol Up to 2 weeks loss of activity
Grade III Severe diffuse tenderness, maximally dorsally
Marked swelling and ecchymosis
Marked decrease range of motion
Capsular tear with articular compression injury usually dorsally Add immobilization until able to bear weight comfortably. Use stiff forefoot insert to resist metatarsophalangeal joint dorsiflexion 3 to 6 weeks loss of activity
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Treatment
When presented with an acute injury to the first metatarsophalangeal joint, two factors determine treatment: the ease of joint reduction and the resultant stability. The term turf toe (77,78) is generally used to discuss injuries without a history of dislocation to the great toe. Sand toe (79) is a more recent term used to describe specifically an injury to the dorsal capsule of any toe. Treatment for these injuries is akin to treating sprains in other joints, with a period of rest and immobilization depending on the severity of the injury (77,78,79). Rest, ice (slurry baths), compressive wraps, and immobilization or protected weight-bearing are used to aid in recovery of the joint. Stiff-soled shoes or rigid inserts are used initially for weight-bearing to minimize capsular stretch. Activity is advanced as symptoms abate. Operative intervention is rarely indicated except in cases of intra-articular fractures or significant discrete instability (77). The presence of avulsion fragments in the face of significant valgus instability may need to be addressed by open reduction with internal fixation or debridement and ligamentous repair (78). Displaced intra-articular fractures or osteochondral lesions should be fixed or debrided depending on their size.
TABLE 56-10 OTA Classification of Metatarsophalangeal Dislocations
Metatarsophalangeal designation: 81-D1
   Dislocation direction modifier
      .12 medial
      .13 lateral
      .53 dorsal
      .54 plantar
   Digit modifier
      (T) Great toe
      (N)Second toe
      (M) Middle toe
      (R) Fourth toe
      (L) Little toe
The experience reported in the literature on treating acute dislocations is sparse. All agree that dislocations of the first metatarsophalangeal joint should be immediately reduced to minimize any further compromise to the soft tissues. Initial reduction can be obtained with gravity traction using finger traps attached to the first toe to suspend the heel off the ground. An easy reduction usually denotes a significant injury of the plantar plate and has no inherent stability once reduced (80,81,83,84). In the case of an intact plantar plate the initial dislocation is usually not reducible by closed means. Associated fractures of the metatarsal or disruption of the tarsometatarsal joint can make closed reduction of the dislocated metatarsophalangeal joint possible. In these cases, reduction of the joint should be done before achieving bony stabilization proximally (80). Many dislocations that occur as a result of high-energy trauma have plantar wounds. In the rare instance when a closed reduction is obtained and no further instability is noted, conservative treatment measures are instituted for the joint as described for sprains.
In the presence of an irreducible joint or a grossly unstable joint, operative intervention becomes necessary to restore stability and function. The irreducible joint is usually due to the intact plantar plate resting dorsal to the metatarsal head (Jahss type I). Apparent irreducibility can also occur with a longitudinal split of the plantar plate that allows the metatarsal head to button-hole through (Jahss type IIA). The difference between these two types can easily be discerned on the AP x-ray film by the wide dissociation of the sesamoids in the type II pattern (80). The difference is important for planning the operative approach. A dislocation with an intact plantar plate can be approached either plantarly or dorsally. If the surgical approach is not limited by soft tissue injury, the dorsal approach appears to be the more acceptable way and eliminates the potential of iatrogenic injury to the plantar hallucal nerves (80).
The approach is a straight longitudinal one and requires plantarly directed pressure on the plantar plate to reduce it around the end of the metatarsal head. As a result of the significant disruption of the collateral ligaments, the reduced joint should be immobilized in a rigid dressing until tenderness on examination is diminished sufficiently to begin active motion and weight-bearing. Then the regimen for sprain care should be followed.
Dislocation involving disruption of the plantar plate usually results in significant residual instability of the joint. Disruption can manifest itself in many ways, including complete disruption of the plate from the proximal phalanx, a longitudinal split, or some combination involving disruption of either the medial or lateral sesamoid (Fig. 56-47). This disruption presents as either a fracture of the sesamoid or separation of a bipartite synchondrosis. Either way, it denotes a significant disruption of the stabilizing mechanism of this joint. Treatment and surgical approach is based on the goal of restoring structural integrity to the joint. To reduce and repair the plantar plate it is best to use a medial longitudinal approach to be able to access both the dorsum of the joint for reduction and the plantar aspect for plantar plate repair. Avulsion of the plantar plate from the proximal phalanx should be repaired with sutures through drill holes from the plantar aspect to the dorsum of the proximal phalanx. Disruption of the intersesamoid ligament is sutured together. Great care should be taken not to include the flexor hallucis longus in the repair. Free movement of the tendon should be visualized with isolated motion of the interphalangeal joint after the repair is complete. Sesamoid fracture or separation should be reduced and held with cerclage or soft tissue sutures. In the case of severe comminution, unilateral removal of the sesamoid with repair of the resulting defect can be considered. The repaired plantar structure is protected from dorsiflexion for up to 6 weeks before starting non-weight-bearing motion and then progressed along the same guidelines as for sprain care.
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Complications
Failure to diagnose the acute injury or recognize instability presents the greatest complications. Significant stiffness and disruption of the normal weight-bearing position of the great toe can lead to permanent changes in gait mechanics and a reduction in activities because of pain. The development of hallux rigidus may be in part a result of recurrent injury to this joint. Valgus instability can lead to hallux valgus deformity. Late instability or the appearance of osteochondral fragments should be watched for closely and treated aggressively by surgical repair of the disrupted structures. Sesamoid nonunions, fibrous unions or arthropathy can also appear with these injuries. Treatment of these complications should follow those outlined for care of the isolated injury. Complications appear to be minimized with aggressive stabilization and rehabilitation of the joint.
FIGURE 56-47 X-ray film of type IIA dislocation of the first metatarsophalangeal joint. A. Anteroposterior view with loss of joint space and widening of the intersesamoid space. B. Lateral view with sesamoid noted behind metatarsal head and complete dislocation of joint.
Sesamoid Fractures
Anatomy
The sesamoids as discussed in the preceding section are an integral part of the capsuloligamentous structure of the first metatarsophalangeal joint. They function within the joint complex as both shock absorbers and fulcrums in supporting the weight-bearing function of the first toe. Their position on either side of the flexor hallucis longus forms a bony tunnel to protect the tendon (85). The medial plantar branch of the posterior tibial artery provides the vascular supply to the sesamoids. Medial and lateral branches enter each sesamoid, respectively, at the proximal pole. Secondary vessels enter the sesamoids from the plantar surface. Lesser vessels about the periphery do not appear to pierce the outer cortex of the sesamoid to add to the osseous circulation (86,87).
During its formation a sesamoid may have one or more ossification centers that may not unite. This gives rise to partite sesamoids. The medial sesamoid exhibits a partite appearance 10 times more often than the fibular sesamoid. The problem is the variability in their presence. There is a reported incidence of anywhere from 5% to 30% in the general population. The reported incidence of bilaterally also varies between 25% and 85% (88,89). Both of these variables make using contralateral views to rule out a fracture difficult.
Diagnosis
There is a wide spectrum of injury possible with the sesamoids, with diagnoses ranging from sesamoiditis to stress fracture, to acute fracture (11,85). The mechanism of injury varies with the diagnosis. Direct blows such as a fall from a height or a simple landing from a jump as in ballet can cause an acute fracture. Acute fractures can also occur with the hyperpronation and axial loading seen with joint dislocations. Repetitive loading from improper running usually gives rise to the more insidious stress fracture. The major fracture pattern is transverse in nature and seen with indirect or repetitive injuries. Comminuted or stellate patterns are noted in cases of direct loading. The medial sesamoid is more often injured.
Injury to the sesamoid, irrespective of the ultimate diagnosis, usually presents itself as a localized pain on the plantar aspect of the joint directly under the sesamoid involved. The presence of a soft tissue callus under the sesamoid denotes a chronic process. Active or passive dorsiflexion of the metatarsophalangeal joint can initiate or exacerbate the pain. Swelling is occasionally seen.
Anteroposterior, lateral, and tangential or sesamoid x-ray views should be obtained of the first metatarsophalangeal area in all cases. Because normal foot films tend to overexpose and obscure the bony anatomy of the forefoot, it is important to specify coned-down views to get the best exposure to visualize
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this area. The sesamoid view should be adjusted to allow visualization of the metatarsal-sesamoid joint surface. In the case of partite sesamoids a similar view of the contralateral side can be helpful but need not be taken routinely because the variability in the presence of bilateral partite sesamoids makes comparison difficult. The absence of bilateral partite sesamoids does not confirm the presence of a fracture (2,82).
Close inspection of the sesamoid in question may be the best way to discern between a partite sesamoid and an injury. Partite sesamoids have smooth sclerotic edges, and the sum of the partite sesamoid’s parts makes a sesamoid larger than a normal one. In contrast, with a fracture the following are found:
  • A fracture margin on a sesamoid is rough and irregular.
  • Because of the tight support of the plantar plate there is minimal separation unless the plate is torn.
  • The sum of the fracture fragments should equal a normal sesamoid size.
  • Fracture callus is usually apparent on subsequent follow-up.
One should not forget, however, that injuries can happen with a partite sesamoid also. If clinical symptoms point to an acute injury of a partite sesamoid, stress views of the joint are recommended to rule out disruption of the synchondrosis. This is done by taking an anteroposterior view of the sesamoids with the toe dorsiflexed and comparing it to an unstressed view. Varus or valgus stress can be added to place further tension on the side of suspected injury. Significant separation indicates at least partial disruption of the plantar plate and may denote plantar plate instability (83,90).
The use of a technetium bone scan to identify sesamoid injury has been touted in the past as a useful tool. Recent studies of its reliability show a low specificity in identifying sesamoid injuries (88). Focused CT scans or MRI studies may aid in the diagnosis of these injuries (91,92).
Treatment
Presently, the accepted treatment for any type of stable injury to the sesamoid alone is conservative in nature (Table 56-11). Cast immobilization with a toe plate provided to prevent dorsiflexion of the metatarsophalangeal joint as well as a midfoot ridge to minimize forefoot weight-bearing should be used for a period of 4 to 6 weeks. The longer period appears to be needed for stress-related injuries. As symptoms abate, treatment is progressed to a stiff-soled shoe to restrict dorsiflexion for a further 4 to 6 weeks. This time period is based on the patient’s clinical response. Accommodative inserts that unweight the injured sesamoid can also be used at this time. Complete relief of symptoms can take as long as 6 months (93,94,95). In cases of significant displacement suggesting plantar plate injury, treatment should follow the guidelines for joint dislocation with plate disruption as described earlier.
TABLE 56-11 Closed Management of Sesamoid Fractures
Indications
  • Stable, intact plantar plate
  • Closed injury
  • Treatment
  • Stiff-soled shoe
  • Weight-bearing as tolerated
  • Orthotic insert to unweight painful area
  • Short leg walking cast with toe plate to immobilize MTP joint for severe pain
With prolonged symptoms and failed conservative therapy, either excision of the sesamoid or bone grafting of the ununited defect should be done. Complete excision has been the treatment of choice but is not without complications (96). If the articular surface of the sesamoid is intact and the cartilage is healthy, an attempt at bone grafting of the defect should be undertaken (97).
The medial sesamoid is approached through a medial longitudinal incision (Fig. 56-48). The joint is inspected for articular congruity. Whether grafting or excising, great care must be taken to maintain the integrity of the plantar complex. For grafting, the sesamoid should be approached just plantar to the insertion of the abductor hallucis tendon and only the medial wall exposed. No further plantar or proximal dissection should be done, to minimize damage to the sesamoid blood supply. The cortex is disrupted by drill holes and the void filled with cancellous graft. A circumferential cerclage stitch of nonabsorbable suture can be placed around the sesamoid parallel to the articular surface and in the substance of the plantar plate to provide some stability and compression. In the case of sesamoid excision, the sesamoid should be carefully shelled out from the plantar plate. Sutures should be placed across the void to maintain plate continuity and reconstruct the short flexor mechanism. The abductor hallucis tendon should be advanced into the distal capsule to enhance the repair.
Approach to the lateral sesamoid is more difficult. Both dorsal and plantar approaches have been described. Both go through the first intermetatarsal space. The dorsal incision appears to be the better approach for isolated sesamoid pathology. Direct visualization of the joint surface and minimal disruption of the blood supply occurs with this route. This approach is more difficult if there is an associated disruption of the plantar plate, which may be better addressed through a plantar incision. Either way, great care must be taken not to injure the lateral plantar nerve just lateral to the lateral sesamoid (Fig. 56-49). The actual approach to the sesamoid, whether grafting or excising, should be directly lateral through the plantar plate. Great care, again, should be taken to minimize any disruption to the plate. In the case of sesamoid excision, the adductor tendon should be advanced into the distal aspect of the plantar plate to strengthen the defect left by the sesamoid removal.
In the rare case in which both sesamoids appear to be involved, every effort should be made to not excise both. Significant
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disruption of the plantar plate integrity and function occurs with the loss of both.
FIGURE 56-48 Surgical approach to the medial sesamoid. The incision is medially based along the metatarsophalangeal joint to allow both intra-articular and extra-articular access to the tibial sesamoid. It is important to identify and protect the plantar-medial nerve lying medial to the sesamoid. Careful dissection along the plantar plate will expose the medial sesamoid for excision or fixation.
Postoperative Care
After surgical intervention, the postoperative course should mirror the initial conservative course in treatment. Long-term use of orthotic inserts with arch support and protection of the injured sesamoid should be routinely considered. With chronic sesamoiditis the use of devices that help restrict metatarsophalangeal dorsiflexion may also be helpful in reducing recurrence.
FIGURE 56-49 Surgical approach to the fibular sesamoid. The incision is plantar, based between the palpable second metatarsal head and the lateral sesamoid. Careful dissection is needed to identify and protect the lateral plantar nerve just lateral to the sesamoid. From this approach the sesamoid and lateral tendinous insertions are visualized.
Complications
Nonunion of these fractures, as well as unrecognized fractures, can lead to significant pain and restriction of activity. Chronic pain despite appropriate treatment is also a problem. The treatment of last resort, surgical excision, also can lead to significant problems. Late deformities resulting from the imbalance in the dynamic mechanism caused by the loss of a sesamoid or damage during surgery to plantar plate complex integrity can lead to hallux varus or hallux valgus deformities, as well as a cock-up toe. Transfer metatarsalgia onto the remaining sesamoid or to other metatarsals may occur. These problems are best minimized by meticulous attention to detail during surgery and the use of orthotics to improve load sharing along the forefoot.
Lesser Metatarsophalangeal Injuries
Anatomy
The metatarsophalangeal joints of the lesser toes are much like the great toe in that their stability comes from the ligamentous attachments and position of the plantar plate. In the case of the lesser toes the plantar plate is actually an intra-articular portion of the transverse intermetatarsal ligament connecting all the lesser toe metatarsophalangeal joints. It is attached to each metatarsal by medial and lateral metatarsoglenoid ligaments. Medial and lateral metatarsophalangeal collateral ligaments attach between the metatarsal head and the base of the articulating phalanx. There are no motor attachments directly into this complex. Positional response is due to the dynamic position of the distal segments of the toes.
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Diagnosis
Like those of the great toe, injuries to the lesser metatarsophalangeal joints are rare. The literature describes only two types of traumatic injuries, hyperdorsiflexion and hyperplantarflexion with axial loading (11,79,98). Isolated hyperdorsiflexion injuries without dislocation are not mentioned in the literature. Hyperflexion injuries of the lesser toe are only mentioned in the presence of the sand toe (79) type of injury of the first metatarsophalangeal joint. Dislocations of the lesser toes do occur with forced dorsiflexion and axial loading and are reported as a part of multiple trauma in motor vehicle collisions. Lateral, medial, or plantar displacement forces have also resulted in dislocations at these joints.
Examination reveals pain and swelling in the forefoot about the joint in question. Disruption of the normal parabolic cascade of the toes is visible in the plane of the deformity (Fig. 56-50). In dorsal dislocations the metatarsal head is prominent plantarly and the toe appears hyperextended. X-ray views of the forefoot in the AP, lateral, and oblique planes will aid in the diagnosis and help to rule out associated fractures and disruptions of surrounding joints. Ipsilateral foot fractures and dislocations are often associated with these injuries.
Treatment
Initially, closed reduction should be attempted for a lesser toe metatarsophalangeal dislocation. Usually a circumferential ankle block with 0.25% Marcaine can be used to reduce discomfort and relax the patient after a thorough examination of the foot. Finger traps to the affected toe(s) are used for gravitational traction to stretch out the joint tissues. The toe is then hyperdorsiflexed at the dislocated joint; the phalanx is pushed distally beyond the end of the metatarsal, and then brought into plantarflexion. This maneuver will be successful half or more of the time (98).
In the event closed reduction is not successful, open reduction is performed through a dorsal approach. In almost all cases the pathology preventing reduction has been found to be the plantar plate (98). One case report found the flexor digitorum longus to be a block to reduction for a fifth metatarsophalangeal dislocation (99). Once reduced, the joint should be assessed for residual stability. Temporary pinning to stabilize the joint is recommended.
Beware of obtaining only an incomplete closed reduction. Postreduction AP x-rays should be obtained and checked closely for any asymmetry between the joint spaces of the lesser metatarsophalangeal joints. Widening of a single joint space may be due to an incarcerated plantar plate.
Postoperative Treatment
The postreduction treatment for lesser joint injuries is similar to that for great toe injuries. Weight-bearing and progression of activities depend on symptoms. Pins used to stabilize joints initially should be removed at 3 weeks.
FIGURE 56-50 Lesser toe dislocation at the metatarsophalangeal joint. A. Clinical view of widened web space and individual clawing of involved toes. B. X-ray of the involved joints shows unreduced dislocations of the second and third joints.
Complications
It is important to recognize and treat these injuries early. Problems with residual pain and stiffness are most
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often related to a missed diagnosis or late or recurrent instability. The presence of other injuries to the ipsilateral foot also has a dramatic effect on outcome. Isolated injuries treated with early reduction and rehabilitation have the best outcome.
Injuries to the Toes
Phalangeal Fractures
Phalangeal fractures are the most common injury to the forefoot. The proximal phalanx of the fifth toe is the one most often involved (11). In fact, fracture of the proximal phalanx of any toe is much more common than fracture of the middle or terminal phalanx.
Diagnosis
Two mechanisms are responsible for the majority of phalangeal fractures. A direct blow such as a heavy object dropped onto the foot usually causes a transverse or comminuted fracture. The second or stubbing injury is the result of axial loading with secondary varus or valgus force resulting in a spiral or oblique fracture pattern (11,52). This mechanism is most likely to produce clinical deformity.
Pain, ecchymosis, and swelling are the usual presenting signs and symptoms with these injuries. Also, difficulty with shoe wear and pain with ambulating bare foot or with supple shoes is common. Occasionally the patient will relate a history of acute deformity with spontaneous or manipulated reduction. X-ray examination is important in differentiating between a sprain, dislocation, and or a fracture. Standard AP and lateral films of the forefoot should be obtained.
Classification
The OTA fracture classification is the only classification that allows an accurate description of the fracture pattern involved (9). The designation of phalangeal fractures under this system observes the format: (82()|_ _._), in a fashion similar to the metatarsals of the foot. To denote which ray the classification refers to, an alphanumerical identifier should be placed in parentheses beside the major designation: first toe (T1/2), second toe (N1/2/3), third toe (M1/2/3), fourth toe (R1/2/3), fifth toe (L1/2/3). The second numerical designation denotes whether it is the proximal, (1), middle, (2), or distal, (3), phalanx that is involved.
The alpha subclassification of a phalanx fracture represents fracture complexity while the numerical subgroupings denote fracture position and pattern. Group A denotes extra-articular and simple diaphyseal fractures. Group B involves partial articular and diaphyseal wedge fractures. Group C involves complex articular or diaphyseal shaft fractures. The first numerical subgrouping denotes area of involvement: proximal metaphyseal (1), diaphyseal (2), distal metaphyseal (3). The second and third numerical designations are for fracture pattern designation and can vary depending on the group and first numerical designation (Fig. 56-51). There is no data to show its effectiveness with determining care and predicting outcome with these fractures.
Treatment
Fractures of the phalanges are uniformly painful and usually require modified shoe wear and analgesic medication for 2 to 3 weeks. All nondisplaced fractures irrespective of their articular involvement can be treated with stiff-soled shoes and protected weight-bearing with advancement as tolerated. The use of a buddy taping technique between adjacent toes may improve pain relief and help stabilize potentially unstable fracture patterns (11,52) (Table 56-12).
Fractures with clinical deformity require reduction. Closed reduction is usually adequate and the result is usually stable (11). Reduction is obtained with gravity traction and axial realignment (Fig. 56-52). With the great toe, stabilizing the proximal fragment for reduction is usually no problem. For the lesser toes, the use of a pen or pencil in the web space adjacent to the apex of the fracture can provide the rigid surface to allow three-point bending pressure against the fracture (Fig. 56-53). With extra-articular fractures, axial alignment and rotation are important in fracture reduction. Axial shortening does not adversely affect function. With extra- articular fractures, the adequacy of the reduction is determined by the clinical appearance of the toe in relation to its neighbors and not its appearance on x-ray. The nail bed should be rotated into a position similar to adjacent toes, and the toe’s axial position should be aligned with the normal cascade of the other toes. Once satisfactory clinical alignment is obtained, the toe can be buddy taped to its neighbor for added stability. Lamb’s wool or other soft, nonabsorbent material should be placed in the web space to minimize maceration of the soft tissues. Sometimes, with the great toe, short-term immobilization in a plaster splint may be necessary to hold the reduction.
Operative reduction is reserved for those rare fractures in which gross instability or persistent intra-articular discontinuity is present (Fig. 56-54). This problem usually arises when there is an intra-articular fracture of the proximal phalanx of the great toe or multiple fractures of lesser toes. A grossly unstable fracture of the proximal phalanx of the first toe should be reduced and can be fixed with percutaneous K-wires or mini fragment screws. Unstable intra-articular fractures of any joint despite adequate reduction should be reduced and fixed to avoid late malalignment (Fig. 56-55).
Weight-bearing is permitted in open-toed stiff-soled shoes as soon as tolerated. Percutaneous fixation is usually removed at 4 weeks and buddy taping begun until the appendage is asymptomatic with full weight-bearing.
Complications
Complications arise from these injuries in the form of continued abnormal alignment. This can provide problems with shoe fit and wear, as well as soft corn lesions between toes due to bony prominences. The most frequent cause I have seen is due to missed diagnosis. Rotational deformities will cause abnormal joint function and can result in progressive deformity. Late deformities, if symptomatic, should be treated with refracture and pinning.
Dislocations of the Interphalangeal Joint
Injury to the interphalangeal joint is usually due an axial load applied at the terminal end of the digit (98). The majority occur
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in the proximal joint, are dorsal in direction, and occur to exposed, unprotected toes. This type of injury may be clinically indistinguishable from a phalangeal fracture. Pain or stiffness with motion and dorsal-plantar thickening of the toe to palpation are seen clinically. AP and lateral x-ray films of the toes should be viewed carefully for subtle joint differences. Especially with the interphalangeal joint of the hallux, partial spontaneous reduction with interposition of the plantar plate or sesamoid will cause a subtle widening of the joint on x-ray examination. Complete reduction is required to restore normal function (Table 56-13).
FIGURE 56-51 OTA classification for phalangeal fractures. Modifiers to designate phalanx and toe involved: T1/T2 great toe, N1/N2/N3 for index toe, M1/M2/M3 for middle toe, R1/R2/R3 for ring toe, and L1/L2/L3 for little toe. (J Orthop Trauma 1996;10[suppl 1].)
Treatment
Closed reduction under digital block and longitudinal traction is the treatment of choice for these injuries. Opinions as to the ease with which reduction can be obtained vary in the literature. In all cases of difficult reduction, the dorsally displaced plantar plate has been described as the block to reduction (98). In my personal experience I find longitudinal traction
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followed by plantar flexion can help with closed reduction. A dorsal surgical approach to the joint is recommended if closed reduction fails. This allows easy reduction of the displaced plantar plate. Once reduced the interphalangeal joint is stable and can be adequately treated with buddy taping and progressive activity as tolerated.
FIGURE 56-52 Left. Displaced intra-articular fracture of the interphalangeal joint of the great toe. Center. After the application of longitudinal traction, stable acceptable alignment is achieved. Right. One year later the fracture is healed and the patient is asymptomatic.
FIGURE 56-53 A method of closed reduction for displaced proximal phalanx fractures. A hard object, such as a pencil, is placed in the adjacent web space and used as a fulcrum for reduction.
FIGURE 56-54 X-ray films showing an irreducible intra-articular fracture of the fifth proximal phalanx. This would require open reduction and pinning.
FIGURE 56-55 Unstable fracture dislocation of the first distal phalanx. A. Anteroposterior view of the initial instability. B. Initial reduction with continued incongruency of the joint and continued instability on movement. C. Internal fixation with 2.7-mm screw to reduce the joint and provide stability for motion.
TABLE 56-12 Closed Management of Toe Fractures
In situ management
Indications
  • Stable, clinically aligned toe
  • No intra-articular displacement
  • Closed injury
Treatment
  • Buddy tape to medial toe
  • Weight-bearing as tolerated
  • Stiff-soled shoe to minimize dorsiflexion
Closed reduction
Indications
  • Clinical malalignment
  • Extra-articular fracture
  • Comminuted intrarticular
Treatment
  • Closed reduction and buddy tape weight-bearing as tolerated
  • Instability may require surgical intervention
TABLE 56-13 OTA Classification of Interphalangeal Dislocations
Proximal interphalangeal joint designation: 81-D2
Distal interphalangeal joint designation: 81-D3
Dislocation direction modifier
      .12 medial
      .13 lateral
      .53 dorsal
      .54 plantar
Digit modifier
      (T) Great toe
      (N) Second toe
      (M) Middle toe
      (R) Fourth toe
      (L) Little toe
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Reduced interphalangeal dislocations have surprisingly few complications. The problems stem from either missed dislocations or recurrent instability. This problem is seen mainly with the fifth toe. Treatment involves resection arthroplasty to restore toe alignment and stability.
MULTIPLE (HIGH-ENERGY) INJURIES
Though isolated injuries are the usual result of trauma to the foot, anytime a violent force is applied to the foot, the extent of the injury may be greater than initially appreciated. Great care in determining the full extent of the injury is crucial to determining proper care. Accurate, timely assessments of the soft tissue viability and bony and ligamentous stability are the keys to treating a multiply injured foot.
With high-energy injuries there is a high likelihood of open injury. Regardless of the mechanism of injury all open wounds in the foot should be thoroughly debrided as soon as feasible. Complete surgical debridement of all contaminated and necrotic tissue is the most important step in wound management. Often with injuries to the foot, multiple debridements are required to ensure a clean wound before closure is attempted. As with all open wounds, tetanus prophylaxis should be given at the time of presentation and short-term, prophylactic, broad-spectrum antibiotic coverage used until closure. Unless infection supervenes, antibiotics are usually stopped within 24 hours of wound closure to minimize the risk of nosocomial infection. Aggressive soft tissue management is important and closure of wounds either directly or with transferred tissue should be done when the wound is clean, stable, and within 1 week of presentation (100).
Management of bony stability is often difficult in these patients because of the extent of injury to the foot and other areas. Occult fractures and instabilities, if left untreated, can significantly affect the patient’s outcome. Stress x-rays are essential to elicit ligamentous and bony instability not readily apparent otherwise. CT scan of the area in question along longitudinal and coronal planes can reveal individually nondisplaced fractures that together may result in significant instability of the foot.
Once identified, the treatment of multiple injuries usually follows closely the suggested treatment of each individual injury. The overall objective is to preserve circulation and sensation. This may require modification of normal surgical approaches to reach all injuries with a minimum of dissection. Preservation of the plantar skin and fat pads is essential. For proper foot function, maintenance of a plantigrade position and bony stability are priorities. Preserving gross motion is desirable and should focus on the talonavicular, calcaneocuboid, cuboideometatarsal, and metatarsophalangeal joints. The remainder can be considered expendable if necessary to achieve overall foot stability.
The initial reduction of the injuries should be performed at the time of presentation to minimize further soft tissue trauma. In the presence of open injuries, temporary bony stability should be achieved with K-wires or external fixation at the time of initial debridement. Definitive fixation should be reserved for the time of final debridement and wound closure whether by local tissue or free muscle flap. Bony stability facilitates soft tissue healing. With multiple adjacent, apparently individually stable fractures, percutaneous fixation is still recommended to ensure maintenance of overall foot stability and allow earlier motion of adjacent critical joints. Postoperative care is based on the specific injuries present and the treatment given.
COMPARTMENT SYNDROMES OF THE FOOT
Although the presence of compartment syndromes of the upper and lower extremities is well recognized in the treatment of trauma, compartment syndrome of the foot is still an under-recognized condition. The last 20 years have seen a dramatic increase in the recognition and treatment of this entity. There are a number of different types of injuries that in particular have been associated with foot compartment syndrome. Though crush injuries have a high incidence of probability of causing a compartment syndrome (up to 27% [100]), the presence of multiple forefoot fractures, a Lisfranc fracture-dislocation, or a calcaneal fracture can produce dangerously high foot compartment pressures also.
The diagnosis of compartment syndrome of the foot requires a careful examination. The usual signs used in other areas (increased pain, decreased sensation, or pain with passive motion) are unreliable in the foot. The injury alone is usually sufficient to cause significant pain. The most important factor in identifying a compartment syndrome is a high index of suspicion. Marked swelling of the foot or multiple significant structural disruptions with intact skin should arouse suspicion. The best objective means of determining the presence of compartment syndrome is to measure the compartment pressures with invasive catheterization. The threshold should be a measured pressure that is less than 30 mm Hg below the patient’s diastolic blood pressure. This threshold takes into account the possibility that the patient may present in a hypotensive state. Multiple reading sites and rechecks over a period of hours may be necessary to rule out the presence of increased compartment pressures. It is important to try and reach the calcaneal compartment for pressure reading, because it appears to be the most sensitive (101).
Anatomy
There are nine separate compartments to the foot (Fig. 56-56) (102). The medial compartment contains the abductor hallucis and flexor hallucis brevis muscles and is located plantar and medial to the first metatarsal. The lateral compartment contains the abductor digiti minimi and the flexor digiti minimi brevis and is found on the inferolateral surface of the fifth metatarsal. The central compartment is divided into superficial and deep portions. The deep or calcaneal compartment contains the quadratus plantae muscle. The superficial portion contains the flexor digitorum longus and brevis muscles. Dorsally, between
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each of the metatarsals lie the dorsal and plantar interosseous muscles, which appear to lie in a separate compartment defined by each intermetatarsal space. In the plantar aspect of the forefoot distal and deep to the quadratus plantae is the oblique head of the adductor hallucis, which also appears to have its own fascial compartment.
FIGURE 56-56 Schematic cross-section of the foot at the proximal metatarsal level. The major compartments are outlined in their approximate position. The quadratus plantae and adductor hallucis compartments share the space defined as the deep central compartment but have separate fascial boundaries.
Treatment
Once suspicion for a compartment syndrome exists (unless invasive pressure measurements can conclusively show normal compartment pressures), release of the foot compartments should be done. Presently the most reliable way to decompress all compartments including the deep calcaneal is through a three incision approach (Fig. 56-57) (101). The two dorsal incisions are placed one medial to the second metatarsal shaft and one lateral to the fourth metatarsal shaft. Blunt dissection is done between the interosseous muscles and the fascia to the deep compartments. The lateral compartment is reached by releasing the fascia attached to the inferolateral aspect of the fifth metatarsal through the lateral incision. The third, medial incision is used to access the medial and central compartments more fully. The incision is within the arch of the foot along the muscle body of the abductor hallucis. Dissection is carried both dorsal and plantar to this muscle, freeing it from the plantar fascia and the attachment to the bony structures dorsally. This will also disrupt the superficial and deep components of the central compartment and allow access to the adductor muscle belly. The medial dissection carries the greatest risk. The lateral plantar nerve and vessels lie on the quadratus muscle and can be seen with the release of the compartment. The wounds should be closed in a secondary fashion 5 to 7 days later.
Complications from a compartment syndrome can occur with or without timely treatment. A missed compartment syndrome usually results in fixed clawing of the toes requiring surgical release and realignment because of pain and poor shoe wear fit. Communication between the compartments of the foot and the deep compartment of the leg, resulting in adjacent compartment pressure elevation, has been reported; should this occur, it can further complicate treatment (101). Fasciotomy has its risks also. Loss of the dorsal skin bridge is possible with the two dorsal incisions approach, but this complication appears to be due more to the initial tissue trauma than the surgical procedure. Damage to plantar structures can occur if careful dissection is not done.
NEUROPATHIC INJURIES
Neuropathic (Charcot) arthropathy is a chronic, progressive destruction of joint integrity affecting one or more peripheral articulations. This process appears to result from the disturbance of normal pain and proprioceptive sensation in the foot. In systemic diseases such as diabetes, associated metabolic abnormalities such as the glycolization of collagen may also contribute to the destructive process. The interposition of glucose molecules within the collagen fibers disrupts the interstrand binding and can significantly weaken the strength and integrity of tendons and ligaments. The end result is a complete disruption of normal
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mechanical function and shape in the foot, which can lead to significant morbidity in the affected patient.
FIGURE 56-57 Recommended method of foot fasciotomy. A. Relative incision locations on the foot surface. B. Path of blunt dissection through the dorsum of the forefoot. C. The position and direction of the medial incision to reach the calcaneal and oblique adductor hallucis compartments.
Extensive research into the causes and effects of this process has revealed important data for the clinical management of these patients. This process of joint destruction is progressive. Animal studies have shown that the appearance of a Charcot process is due to repetitive trauma that goes unrecognized or unchecked. The longer the destructive forces are present, the greater is the destruction and resultant deformity. These in vivo studies also showed that an initial fracture must be present before the cascade of bony destruction and resorption could occur; ligamentous disruption by itself does not initiate the process. Of greatest importance, however, is the information that if the initial injury is recognized and protected from further trauma, it will heal and not go on to Charcot destruction (103,104,105,106).
Treatment and Classification
The key to treating these patients is to recognize early both the nature of the injury and the loss of protective sensation. The types of injuries encountered are no different from those of normal sensate individuals, and they exhibit the same underlying mechanisms of injury. The differences, when present, are usually noticed in the decreased amount of force present to cause the injury or the relative lack of discomfort in the patient for the injury noted. Many of these patients do complain of pain, but this appears to be due more to the soft tissue edema than to the underlying osseous injury.
In this population of patients, information about their systemic condition and their ability to heal is of paramount importance in deciding treatment for their injury. Consideration of such factors as the level of their glucose control, nutritional status, and vascularity all relate directly to their ability to recover from injury. Diabetic patients with poor glucose control can exhibit decreased collagen synthesis, impaired cellular proliferation, and decreased granulocyte function, all of which can have profound effects on wound healing. Tight control of glucose concentrations can to some degree reverse these problems (107,108). Serum glycohemoglobin can be used as a measure of a patient’s recent past glucose control (108,109). Over the 120-day life of the red blood
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cell, glucose enters at a concentration dependent on the amount of free glucose in the blood. In a nonenzymatic reaction it irreversibly binds to hemoglobin, forming glycosylated hemoglobin. This amount of glycosylated hemoglobin is directly proportional to the average concentration of free glucose seen by the cell over its life. Nondiabetic individuals have a glycohemoglobin level of between 4% and 6%. Ideally, a glycohemoglobin level less than 8.5% for a diabetic patient denotes tight control of their daily blood sugar (108).
Protein malnutrition is known to cause wound healing problems in diabetics. Adequate healing has been obtained with serum albumin levels greater than 3.5 g/dL, and a total lymphocyte count of at least 1500 (106,109,110).
Finally, the vascular status of the injured limb is of paramount importance in treating these injuries. Without an adequate vascular supply, healing of damaged tissues will not occur, regardless of the treatment option chosen. Every patient should have the vascular status of the injured limb documented as soon as the initial edema recedes. Both arterial Doppler and transcutaneous oxygen pressure techniques are recommended to assess the limb for adequate healing potential (103,104,105,106). For midfoot and forefoot injuries, arterial toe pressures greater than 40 mm Hg appear to signal adequate vascular supply for healing. In the face of vascular compromise, assessment by a vascular surgeon should be done before definitive treatment to determine if improving vascular flow is an option.
The goal in deciding treatment for these patients should be to minimize deformity, maximize stability, and protect the skin from subsequent pressure abnormalities. The question of surgical versus nonsurgical treatment is not yet completely resolved. In the face of an ongoing Charcot process, with a warm, erythematous, edematous foot with significant bony destruction, conservative management is advocated. By definition, this is not an acute injury but rather a situation that has been developing over weeks or even months. It requires prolonged total contact casting and non-weight-bearing to attempt to control the deformity and stop the repetitive trauma in time for the process to burn itself out. There is no place for surgical management in the face of an active Charcot process.
The difference of opinion comes in how to treat the truly acute injury in a diabetic patient before significant bony destruction occurs. Initially, all neuropathic patients should undergo immediate immobilization and elevation with strict non-weight-bearing of the extremity. This is done to reduce the acute edema and protect the appendage from further injury. X-ray examination is performed to determine the exact extent and stability of the injury. The studies should mirror those for similar injuries in non-neuropathic patients. Stress films are important to completely assess underlying bony stability.
The literature is sparse on treating neuropathic injuries in the midfoot and forefoot. The treatment of ankle fractures in diabetics by nonoperative means has shown uniformly bad results, pointing to the need for stabilization to achieve healing of these fractures. One of the major fears in operatively managing these patients is the problem of wound complications caused by the surgery. This is not to be taken lightly. Great care should be taken to minimize trauma to the tissues during both the surgical approach and wound retraction. The literature suggests that, with such careful attention, diabetic wounds will heal without problems if an adequate vascular supply is present.
Essentially the same principles should be followed for acute injuries in a neuropathic foot as you would with an otherwise normal individual. Closed treatment should be considered if the injury is isolated and stable. Prolonged immobilization in a non-weight-bearing posture is recommended. Weight-bearing should only be allowed after clear x-ray evidence of healing is present. One should remember that these patients have compromised protective sensation and may not be able to protect incompletely healed fractures. Therefore, they have the potential to initiate a Charcot process with repetitive loading without even knowing it.
Surgical stabilization should only be used in those individuals who present with unstable injuries without evidence of bony reaction. Any nontraumatic bony fragmentation or periosteal reaction is an absolute contraindication to surgery, and these injuries should be treated as an early Charcot foot with immobilization. The truly acute unstable injury can be approached in the same manner that the injury would be cared for in the non-neuropathic patient. Open reduction with internal fixation have been shown to give these patients the best chance for a stable foot.
Postoperative Care
The presence of neuropathy requires that these patients be treated differently from non-neuropathic patients. The loss of protective pressure, position, and or vibratory sensation does not allow them the ability to self-assess the amount or effect of weight-bearing or motion on the injury. Without exception these patients should be kept strictly non-weight-bearing and immobilized until the foot is cool and without evidence of edema and complete healing on x-ray examination is evident. The use of a well-molded total contact cast is preferred to protect foot alignment and prevent skin breakdown. The immobilization period is prolonged and as a rule of thumb should be at least twice as long as one would do for a normal injury. Three to six months is not unusual. Once healing is evident on x-ray examination, the return to normal weight-bearing in a diabetic shoe should be gradual. Initial weight-bearing should be done with a cast and advanced to proper shoe wear only after full weight-bearing in the cast is obtained without any disruption or swelling of the foot. This usually takes a further 4 to 6 weeks to allow the bone to adjust to the increased pressure of weight-bearing.
Complications
Treatment of acute injuries in a diabetic patient has all the potential complications that treating similar injuries in a non-neuropathic patient would. Nonunion, malunion, hardware failure and avascular necrosis can occur. Neuropathic arthropathy can also occur. In the face of early weight-bearing or late instability, repetitive injury can restart the process of bony destruction and resorption. That is why it is very important to closely monitor and advise this population of patients on the need for prolonged protection and personal vigilance in caring for these injuries.
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