Rockwood & Green’s Fractures in Adults
6th Edition

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.

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
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).

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).

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.

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
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.

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.

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).

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
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.

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
the navicular tuberosity. If recognized early enough, surgical reconstruction of the spring ligament can eliminate the pain and correct the deformity.

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 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).

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.

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

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.

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).

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

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.

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.

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.

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.

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
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).

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
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.

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).

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
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.

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).

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.

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

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.

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.

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.

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).

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.

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).
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.

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).
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.

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).

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

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.

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
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.

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
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.

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.

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
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).

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.

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.

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.

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
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).

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).

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.

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).

Injury to the interphalangeal joint is usually due an axial load applied at the terminal end of the digit (98). The majority occur
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).