Rockwood & Green’s Fractures in Adults
6th Edition

Chapter 42
Fractures of the Acetabulum
Mark C. Reilly
Fractures of the acetabulum remain one of the most challenging fractures for the orthopaedic surgeon to understand and successfully treat. Most acetabular fractures that require operative treatment are best treated at a specialized center by surgeons who routinely treat such injuries. All orthopedic surgeons, however, should be comfortable in the diagnosis of these fractures and familiar with which injuries may require operative reduction.
The historical literature is replete with colloquial descriptions that generally classified acetabular fractures by the direction of displacement of the femoral head or by the apparent location of the fracture on the anteroposterior (AP) pelvis x-ray. Thus, terms such as “medial wall fracture” or “superior dome fracture” were commonly used but had little to offer the surgeon in understanding the anatomy of the fracture lines (1,2,3). Fractures of the acetabulum were typically managed nonoperatively and satisfactory results occasionally reported, but it was recognized that a poor result was certain if the hip was not congruent (2,3).
Disappointed with the results of treating acetabular fractures nonoperatively, Judet and Letournel analyzed the innominate bone anatomy. They conceived of the acetabulum as being composed of two columns of bone, in the shape of an inverted Y, which supported the articular surface of the acetabulum. These columns were, in turn, connected to the sacroiliac articulation by a thick strut of bone lying above the greater sciatic notch, which they termed the sciatic buttress (Fig. 42-1). Recognizing that the plane of the ilium was approximately 90 degrees to the plane of the obturator foramen and that both of these structures were oriented roughly 45 degrees to the frontal plane, they proposed that the AP pelvis and two 45-degree oblique views be used to study the x-ray anatomy of the acetabulum. After understanding the x-ray landmarks on the intact dry innominate
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bone, these landmarks were analyzed in fracture cases. From this process came the first systematic classification of acetabular fractures, based on the anatomical pattern of the fracture (4).
FIGURE 42-1 The acetabulum is supported by two columns in the shape on an inverted “Y.” These are in turn linked to the sacrum by the sciatic buttress. (Redrawn after Letournel E, Judet R. Fractures of the acetabulum, 2nd ed. Berlin: Springer-Verlag, 1993.)
It quickly became obvious to Judet and Letournel that the then available surgical exposures were not sufficient to allow access to the areas of the innominate bone involved in some fractures and additional surgical approaches were devised which would allow treatment of these injuries (4,5). Using this protocol of interpreting the x-rays, identifying and understanding the fracture pattern, choosing the appropriate surgical approach and striving for an anatomic reduction of the innominate bone, Letournel and Judet published the largest series of operatively treated acetabular fractures (6). Their results are still considered the gold standard of what can be obtained in the treatment of these difficult injuries.
Obtaining excellent results in the treatment of acetabular fractures is dependent on restoring a congruent and stable hip with an anatomically reduced articular surface. The long-term follow-up studies of Letournel and Matta demonstrate that fractures reduced to within 1mm of residual articular displacement have less of an incidence of posttraumatic arthritis and have a more durable and long-lasting functional hip joint than those fractures with 1 to 3 mm of residual displacement (6,7). Surgeons undertaking acetabular fracture surgery should recognize that accepting, or not recognizing, even a minute intraarticular malreduction may have an irrevocable effect on the patient’s life and their chance to recover a pain free and functional hip (Fig. 42-2).
Pelvic and acetabular fracture surgery has emerged as a subspecialty of orthopaedic fracture surgery due in part to the large amount of specialized equipment, acetabular fracture tables and ancillary help required to appropriately treat patients with these injuries. Additionally, surgeons in specialized centers may treat large numbers of these injuries, resulting in less complications, better outcomes and a continued evolution in the techniques and instrumentation that help assure the best possible results for patients with these complex and often devastating injuries (Fig. 42-3) (6,7,8).
FIGURE 42-2 The AP x-ray of an 18-year-old boy, 6 months after treatment of an associated both column acetabulum fracture. The anterior column malreduction and the resultant articular incongruity has led to a loss of the articular surface in a relatively short time. The patient went on to require arthrodesis of the hip.
PRINCIPLES OF MANAGEMENT
Mechanism of Injury
Acetabular fractures occur as force is transmitted from the femur to the pelvis via the femoral head. The fracture pattern, therefore, is dependent on the position of the hip at the time of injury, as well as the direction and magnitude of the impact (Table 42-1) (6). An axial load applied to the femur when the hip is flexed, drives the femoral head against the posterior articular surface of the acetabulum. In internal rotation and adduction,
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the femoral head may dislocate without causing a fracture. A neutral hip position may produce a fracture of the posterior wall while an abducted position will produce a transverse fracture in association with the posterior wall. The magnitude of displacement as well as the comminution or degree of articular impaction depends on the magnitude of the force applied as well as the strength of the bone it is applied to. A relatively low-energy injury may produce a severely comminuted fracture in an osteoporotic patient. This must be taken into account when evaluating a patient for associated injuries as these are most commonly related to the high-energy injuries.
FIGURE 42-3 AP x-ray of a 26-year-old woman 8 years after treatment of an associated posterior column plus posterior wall fracture. The patient has a clinically and radiographically normal hip.
TABLE 42-1 Force Applied Versus Fracture Pattern
Force Hip Abduction Hip Rotation Fracture Pattern
Along axis of femoral neck Neutral Neutral AC + PHT
Neutral 25° ER Anterior Column
Neutral 50° ER Anterior Wall
Neutral 20° IR T-shaped
Neutral 50° IR Posterior column
Adduction 20° IR Transtectal transverse
Abduction 20° IR Juxta/Infratectal transverse
Along axis of femoral shaft (hip flexed 90°) Neutral Any Posterior Wall
Abduction Any Transverse + Posterior Wall
Adduction Any Posterior Hip Dislocation
Along axis of femoral shaft (hip extended) Neutral Any Posterior-superior fx of PW
Abduction Any Transtectal transverse
From Letournel E, Judet R. Fractures of the acetabulum, 2nd ed. Berlin: Springer-Verlag, 1993.
Clinical Evaluation
Of primary initial importance in the patient with a suspected pelvic or acetabular fracture is to rule out other life-threatening injuries. Although exsanguinating hemorrhage can occur with acetabular fractures, it is a rare occurrence with isolated injuries. More commonly, no presenting hemodynamic instability is present or at most, transient hypotension and a single bleeding vessel are identified, having been lacerated by a fragment of bone. The superior gluteal artery or vein may be injured by fractures involving the greater sciatic notch. Persistent hemodynamic instability should be investigated and possibly treated with selective angiography (9,10,11). Up to 57% of patients with acetabular fractures will have an associated injury and this must be kept in mind during their evaluation (7,12). The fact that most acetabular fractures are not associated with significant hemorrhage does not mean that trauma patients with acetabular fractures do not also have other potential sources (head, chest, abdomen) of hemodynamic instability. The acetabular fracture surgeon should be involved early on in the patient’s management as the treatment of associated injuries such as ostomy placement, suprapubic catheterization or angiographic embolization may potentially alter the surgical management of the patient’s fracture (11,13).
A secondary survey will identify most of the associated musculoskeletal injuries. Most commonly, injuries to the knee such as patellar fractures, chondral injuries, or ligamentous injuries may be present. These may be difficult to fully assess prior to the treatment of the acetabular fracture but a high degree of suspicion must be held for any patient complaining of knee pain after their injury. Treatment of associated femoral or hip injuries may be performed but incisions should be carefully planned so as not to interfere with the subsequent articular exposures.
A careful evaluation of the skin overlying the hip, pelvis, and thigh may identify an area of subcutaneous degloving (Morel-Lavalleá lesion). These may be initially recognized by a fluid wave on palpation or may be later identified by the presence of a fluctuant, circumscribed area of cutaneous anesthesia and ecchymosis. These injuries, even when closed, are associated with a significant incidence of positive bacterial culture. Some authors have recommended initial deábridement of the lesions and delayed acetabular fracture fixation if the fracture surgery must be performed though such a lesion (14).
Neurologic injuries occur in up to 30% of cases and are usually partial injuries to the sciatic nerve. The peroneal division is more commonly injured than the tibial division and injury overall is more commonly seen when the femoral head is posteriorly dislocated (6,7,12,15,16,17,18,19). Although the superior gluteal nerve is particularly at risk with some fractures extending into the greater sciatic notch, it can be impossible to assess hip abduction strength in a patient with an acute fracture. The true incidence of this neurologic injury is probably underreported (18).
Examination of the limb may fail to identify a dislocation of the hip. Unlike the situation of the isolated posterior hip dislocation, in the face of a displaced acetabular fracture, the
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femoral head may be dislocated without the flexed, adducted, internally rotated position of the leg being present (15,20,21). The lower extremity may be externally rotated or in neutral position and only slight shortening present. This underscores the need for early and complete x-ray evaluation of the acetabulum in addition to clinical evaluation. Closed reduction of associated hip dislocations should be performed as urgently as possible to reduce the risk of osteonecrosis of the femoral head. Persistent subluxation of the hip may be caused by either the fracture displacement or from intra-articular fracture fragments and should be treated with urgent skeletal traction to prevent the head from wearing against the fracture edge or incarcerated fragment (Fig. 42-4) (15,22).
Acetabular fractures may also be seen in association with pelvic ring disruptions. It is important to note these concurrent injuries as the management of the patient’s acetabulum fracture may be altered in the face of a displaced pelvic ring injury. Posterior pelvic ring disruptions usually require reduction and fixation prior to surgical treatment of most acetabulum fractures in order to recreate a stable posterior pelvis to reduce the acetabulum to. Contralateral rami fractures may affect the surgeon’s decision to use intraoperative traction as the presence of a peroneal post may be a deforming force on certain acetabular fractures and possibly prevent reduction. Concurrent symphysis dislocations may also complicate the reduction of acetabular fractures and may lead the surgeon to select an alternate surgical approach.
FIGURE 42-4 Obturator oblique view of an 84-year-old woman 10 days after an associated anterior wall plus posterior hemitransverse fracture. No traction was applied to correct the subluxation of the hip. The femoral head shows evidence of severe wear from abrading against the edge of the intact articular surface.
Radiographic Evaluation
The initial diagnosis of the acetabular fracture is made from the trauma AP pelvis x-ray. The two 45-degree oblique views (Judet views) are also obtained to aid in classification of the fracture and to identify fracture displacements which may not be appreciable on the AP x-ray. These plain x-rays should be obtained with the patient out of traction as this may otherwise lead to a false impression of hip joint congruity or an underestimation of fracture displacement. The Judet views (obturator oblique and iliac oblique) are obtained by rolling the patient 45 degrees in relation to the x-ray beam. This may be difficult and painful for the patient and premedication is often required. If the patient is in the angiography suite, these images can be obtained digitally without having to roll the patient (23). It is crucial that the pelvis is rotated far enough that the appropriate view is obtained. As previously noted, since the iliac wing and obturator foramen are roughly 90 degrees to each other, an inadequately obtained x-ray may not demonstrate the x-ray landmarks necessary for fracture pattern determination. While not mandatory for the evaluation of the acetabulum, obtaining the 40 degree caudocranial (pelvic inlet) and craniocephalic (pelvic outlet) projections are needed to diagnose and characterize concurrent injuries to the pelvic ring.
The x-rays are evaluated with regards to several landmarks (Table 42-2) (6). These landmarks are radiodensities created by cortical bone that the x-ray beam is directly tangent to. These x-ray landmarks are referred to as “lines” but are often not created by a single discreet structure or line on the bone. On the AP pelvis x-ray, six lines are identified: the iliopectineal line, ilioischial line, x-ray roof (sourcil), x-ray teardrop, anterior rim (acetabulo-obturator line), and posterior rim (ischioacetabular line) (Fig. 42-5). The iliopectineal line is generally considered to be a marker of the anterior column and through its anterior two-thirds, it represents pelvic brim. More posteriorly, the iliopectineal line is created by the inner cortical surface of the sciatic buttress. The ilioischial line is considered to represent the posterior column but is not actually created by the posterior border of the innominate bone but rather by the cortex of the quadrilateral surface. Thus, fractures which separate a piece of the quadrilateral surface will be seen to disrupt the ilioischial line but may not violate the posterior border of the innominate bone. The radiographic roof represents the cranial portion of the acetabular articular surface—but only that portion whose subchondral bone is tangent to the x-ray beam. The clinical importance of this fact is that fractures in the coronal plane that disrupt the weightbearing dome of the acetabulum may show only subtle alterations or no evidence of disruption of the radiographic roof on the AP pelvis x-ray. The radiographic teardrop is made up of a confluence of radiographic lines. The lateral limb of the teardrop represents the floor of the cotyloid fossa while the medial limb represents the lateral wall of the obturator canal.
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Because these two structures are physically separate, fractures like that seen in the stem of certain “T-shaped” fractures may split the two limbs of the teardrop. The anterior and posterior rim shadows are projections of the edges of the acetabular rim and give some information about the integrity of the acetabular walls.
TABLE 42-2 Information Obtained from X-Ray Landmarks on Each Standard View
X-Ray View Information Regarding
AP Pelvis
Iliopectineal line Anterior column
Ilioischial line Posterior column
Posterior lip Posterior column or wall
Anterior lip Anterior column or wall
Roof Superior articular surface
Teardrop Relationship of columns
Iliac Oblique
Greater and lesser sciatic notch Posterior column (posterior border of innominate bone)
Quadrilateral surface of ischium Posterior column (posterior border of innominate bone)
Anterior lip Anterior column or wall
Iliac wing Anterior column
Roof Superior articular surface
Obturator Oblique
Pelvic brim Anterior column
Posterior rim Posterior column or wall
Obturator ring Column involvement
Roof Superior articular surface
The obturator oblique view is obtained when the pelvis is rotated 45 degrees with the inured side up. The anterior column and the posterior wall are well visualized as is the obturator foramen and the ischial ramus. An appropriately performed obturator oblique view will usually show the coccyx centered over the femoral head (Fig. 42-6). The iliac oblique view demonstrates the posterior border of the innominate bone including the greater and lesser sciatic notches and ischial spine. It is on this view that disruptions of the ilioischial line of the AP x-ray can be confirmed to disrupt the posterior border of the bone as opposed to being confined to the quadrilateral surface. The anterior wall of the acetabulum is also well visualized (Fig. 42-7).
A computed tomography (CT) scan of the pelvis is also obtained and can better define rotational displacements, intra-articular fragments, marginal articular impactions, and associated femoral head injuries (Fig. 42-8) (24,25). The CT is also helpful in determining an accurate assessment of the size of a posterior wall fragment (26,27). It is not prudent, however, for the surgeon to rely on the CT scan alone as fractures and displacements that occur in the plane of the imaging will be underappreciated or averaged out. A three-dimensional (3D) reconstruction of the CT may be helpful for understanding the relationships between multiple sites of injury, but is not a replacement for plain x-rays. For the surgeon inexperienced in interpreting the plain x-rays, the 3D CT may help in a better
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overall understanding of the fracture pattern but, due to averaging, cannot be relied on for an accurate representation of fracture lines with minimal displacement.
FIGURE 42-5 Radiographic lines of the acetabulum on the AP pelvis x-ray. 1: Iliopectineal line. 2: Ilioischial line. 3: Radiographic teardrop. 4: Sourcil (roof). 5: Anterior rim. 6: Posterior rim.
FIGURE 42-6 Radiographic lines of the acetabulum on the obturator oblique x-ray. 1: Iliopectineal line. 2: Posterior rim. Note also the view of the obturator foramen as well as the ischial ramus.
The understanding of the fracture pattern can be enhanced by drawing the fracture lines from the x-ray landmarks onto a dry bone model or a line drawing of the pelvis as seen on each x-ray view. Only by understanding the location and orientation of each fracture line can the fracture pattern be truly appreciated.
Fracture Classification
The classification of acetabulum fractures that is most widely used is that of Letournel and Judet (4,5,28). This system divides fractures of the acetabulum into five simple (elementary) and five complex (associated) patterns. The five elementary fracture patterns are the anterior wall, anterior column, posterior wall, posterior column, and transverse fractures (Table 42-3). The elementary fracture patterns were defined as those that separated all or part of a single column of the acetabulum. The anterior and posterior column fractures separate the entire column from the intact innominate while the anterior and posterior wall fractures separate only a portion of the column’s articular surface. The integrity of the obturator foramen and the ischiopubic (inferior) ramus can aid the surgeon in making this distinction. The fifth elementary fracture pattern is the transverse
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fracture. This is a single fracture line that traverses both the anterior and posterior columns of the acetabulum but was included in the elementary patterns “by virtue of [the fracture’s] purity of pattern.” It is important to realize that there is no anatomic dividing line at which the anterior column changes to the posterior column. Rather, column fractures are classified with respect to which portion of the innominate bone they separate from the intact portion of the ilium, not where in the ilium they occur.
FIGURE 42-7 Radiographic lines of the acetabulum on the iliac oblique x-ray. 1: Posterior border of the innominate bone. 2: Anterior rim.
FIGURE 42-8 CT scan of a patient with a posterior wall fracture. Note the significant marginal impaction of the posterior articular surface.
The associated patterns are either a combination of elementary patterns or an elementary pattern with an additional fracture line(s). The five associated fracture patterns are the posterior column plus posterior wall, anterior wall/column plus posterior hemitransverse, transverse plus posterior wall, T-shaped, and associated both column fracture (Table 42-3). With the exception of the posterior column plus posterior wall fracture, fracture lines involve both anatomic columns of the acetabulum in all of the associated patterns.
TABLE 42-3 Fracture Classification of Letournel and Judet
Elementary Fractures
Posterior wall
Posterior column
Anterior wall
Anterior column
Transverse

Associated Fractures

Posterior column + wall
Anterior + posterior hemitransverse
Transverse + posterior wall
T-shaped
Associated both column
As with any classification system which is primarily based on anatomy, there are transitional fracture patterns that have aspects of multiple fracture types and do not clearly fall into one distinct fracture pattern. Despite this, the classification scheme of Judet and Letournel has persisted as the most familiar and reproducible system (Fig. 42-9). Beaule et al examined the intraobserver and interobserver reliability of the classification system and found substantial agreement in an unweighted kappa analysis (29). The reliability of the classification system improved to excellent when surgeons who routinely operate on acetabular fractures were studied. In this study and others, using CT or 3D CT reconstructions did not improve the reliability of the classification over the standard three plain x-rays (29,30,31). Although recent efforts have been made to incorporate the Letournel and Judet system into a comprehensive classification of fractures, the result, to date, has not proved to be as clinically applicable.
PATHOANATOMY OF FRACTURES
Elementary Fracture Patterns
Posterior Wall Fractures
Fractures of the posterior wall involve disruption of variable amounts of the posterior rim of the acetabulum. They may be a single fragment (30%) or multifragmentary. They are the most common acetabulum fracture, accounting for nearly a third of all fractures (6,7,8). Fractures of the posterior wall are best viewed on the AP and obturator oblique x-rays although the CT scan is helpful in measuring the size of the articular defect as well as identifying marginal impactions. The AP pelvis x-ray will generally reveal a disruption only in the posterior rim shadow. If the wall fragment is large enough and cranial in location, the roof shadow may also be disrupted. The obturator oblique x-ray will demonstrate the size and multifragmentary nature of the fracture. The iliac oblique view will reveal that the posterior border of the innominate bone is uninvolved and that there is no associated fracture of the inferior ramus (Fig. 42-10A–C). Posterior wall fractures are often associated with marginal impaction of the articular surface (25,26,32). This is a rotated and impacted osteochondral fragment that is displaced as the femoral head dislocates and the wall fractures (Fig. 42-11). This may occur with any fracture pattern but has been documented in up to 23% of posterior hip fracture-dislocations (Brumback et al [25]) and 21% of posterior wall fractures (Letournel [6]).
Posterior Column Fractures
Fractures of the posterior column involve detachment of the entire ischioacetabular segment from the innominate bone and represent 3% to 5% of acetabular fractures (6,7,8). The fracture begins at the posterior border of the innominate bone, near the apex of the greater sciatic notch. It descends across the articular
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surface, quadrilateral surface, ischiopubic notch (roof of the obturator canal), and finally across the inferior ramus. On the AP x-ray, the ilioischial line, the posterior rim, and the inferior ramus are disrupted. The disruption of the posterior rim will be seen in only one location, where the fracture line crosses the rim. This is in distinction to the posterior wall fracture where the posterior rim will be seen to be disrupted in two locations, separating a portion of the articular surface. The iliac oblique x-ray demonstrates the fracture crossing the posterior border of the bone. The fracture of the ischiopubic ramus and posterior rim are confirmed on the obturator oblique. The iliopectineal line is preserved on all views. The femoral head follows the displacement of the posterior column posteriorly and medially (Fig. 42-12A–C). Fractures of the posterior column are notoriously unstable and skeletal traction is frequently required to keep the femoral head reduced beneath the intact portion of the roof. The posterior column fracture frequently fractures the greater sciatic notch at or above the location of the superior gluteal neurovascular bundle. In widely displaced fractures, it is common to find the neurovascular bundle in the posterior column fracture site and it must be carefully extracted before reduction of the fracture to prevent iatrogenic injury.
FIGURE 42-9 The classification system of Letournel and Judet.
FIGURE 42-10 X-rays of a posterior wall fracture. The AP view demonstrates disruption of the posterior rim shadow, subluxation of the femoral head and the posterior wall fragment. Also seen is an intraarticular fragment within the cotyloid fossa (A). The obturator oblique view demonstrates the magnitude of the articular surface involved as well as confirming the subluxation of the femoral head and the intraarticular fragment (B). Although the posterior wall is visible, the iliac oblique view reveals the intact posterior border as well as the subluxation of the femoral head (C).
FIGURE 42-11 Intraoperative photo of a marginal impaction fragment. The hip is viewed from posteriorly. The femoral head is easily seen due to the impaction of the articular surface of the posterior wall into the posterior column (arrows). (Courtesy of Paul Tornetta III, MD.)
FIGURE 42-12 X-ray appearance of the posterior column fracture. On the AP view, the displacement of the ilioischial line is apparent while the iliopectineal line is seen to be intact (A). The obturator oblique view confirms the anterior column to be intact and demonstrates the fracture of the ischial ramus (B) while the iliac oblique view demonstrates the disruption of the greater sciatic notch and the displacement of the posterior column (C). (Courtesy of Michael Stover, MD.)
FIGURE 42-13 X-ray appearance of the anterior wall fracture. On the AP view, the disruption of the iliopectineal line is seen in two locations (A). The obturator oblique confirms this and demonstrates that the femoral head remains congruent to the anterior wall segment (B). The iliac oblique view confirms the posterior border of the bone to be intact. The ilioischial line disruption seen on the AP view is due to a fragment of quadrilateral surface comminution and does not represent a fracture through the posterior border of the innominate bone (C). This explains the normal position of the ischium despite the ilioischial line displacement. (Courtesy of Michael Stover, MD.)
Anterior Wall Fractures
The anterior wall fracture begins below the anterior inferior iliac spine (AIIS), crosses the articular surface to the pelvic brim, and proceeds down the quadrilateral surface to the ischiopubic notch. A secondary fracture line through the superior ramus detaches the anterior wall portion. Anterior wall fractures are rare, and constitute only 1% to 2% of all fractures (6,7,8). The anterior rim shadow and the iliopectineal line on the AP x-ray will show displacement in two locations but all posterior landmarks will remain intact. A portion of the quadrilateral surface may be detached with the anterior wall and this may result in an apparent “thinning” or reduplication of the ilioischial line but some portion of the line will remain intact. Femoral head subluxation is commonly seen and the head will be noted to follow the anterior wall fragment, particularly visible on the obturator oblique x-ray (Fig. 42-13A–C).
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Anterior Column Fractures
The anterior column fractures make up 3% to 5% of all acetabulum fractures (6,7,8). Anterior column fractures separate the anterior border of the innominate bone from the intact ilium. The anterior column fracture is named by where the fracture exits the anterior aspect of the bone. High anterior column fractures exit the iliac crest, intermediate fractures exit the anterior superior iliac spine (ASIS), low fractures exit the psoas gutter just below the AIIS, and very low anterior column fractures exit the bone at the iliopectineal eminence (Fig. 42-14). All anterior column fractures, regardless of where they exit the bone superiorly, cross the pelvic brim, proceed down the quadrilateral surface, and enter the ischiopubic notch, ultimately ending in a fracture of the inferior ramus. Typically, the lower the fracture crosses the anterior border of the bone, the more inferior is the site of fracture of the ischiopubic ramus. As in the anterior wall fractures, it is common for a portion of the quadrilateral surface to be detached as a separate fragment but the posterior border of the innominate bone remains intact. The iliopectineal line is disrupted in one location on the obturator oblique and AP views. The hallmark that distinguishes the very low anterior column fractures from the anterior wall fractures is the fracture of the inferior pubic ramus and the single break in the iliopectineal line. The femoral head displaces with the anterior column fracture. The typical displacement is an external rotation of the anterior fragment about the femoral head, allowing the head to move medial and cephelad (Fig. 42-15A–C).
FIGURE 42-14 The various subgroups of the anterior column fracture: (A) very low, (B) low, (C) intermediate, and (D) high. (Redrawn after Letournel E, Judet R. Fractures of the acetabulum, 2nd ed. Berlin: Springer-Verlag, 1993.)
Transverse Fractures
Transverse fractures comprise 5% to 19% of acetabular fractures (6,7,8). They are the only elementary fracture pattern that breaks both the anterior and posterior border of the innominate bone. The fracture separates the innominate bone into two pieces: the upper iliac piece and the lower ischiopubic segment. The upper fragment is intact to the ilium while the ischiopubic fragment rotates about the symphysis pubis. This results in a medial and cephelad displacement of the head, as it follows the ischiopubic segment. This rotation also typically produces a greater translational displacement of the transverse fracture at the posterior border rather than the anterior border of the bone. Transverse fractures are subdivided by where the fracture crosses the articular surface. Transtectal fractures cross the weightbearing dome
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of the acetabulum. Juxtatectal fractures cross the articular surface at the level of the top of the cotyloid fossa. Infratectal fractures cross the cotyloid fossa (Fig. 42-16). As the location of the fracture moves more cranially on the articular surface, the orientation of the fracture also becomes more vertical and the size of the intact remaining articular surface decreases. This has definite implications for the surgical treatment of these injuries. The AP x-ray demonstrates a disruption of both the ilioischial and iliopectineal lines as well as the anterior and posterior rim shadows. In transtectal fractures, the x-ray roof will be displaced as well. The oblique views will show disruption of the pelvic brim as well as the posterior border of the bone. The ischial ramus will not be fractured (Fig. 42-17A–C).
FIGURE 42-15 X-ray appearance of the anterior column fracture. The AP view demonstrates the fracture from the iliac crest to the hip joint with disruption of the sourcil. A small area of comminution at the pelvic brim is noted. The ischial ramus fracture is also noted (A). The obturator oblique demonstrates the single break in the iliopectineal line where the anterior column fracture crosses the pelvic brim. Although difficult to see, the disruption of the ilium can be appreciated as a reduplication of the cortical lines of the internal iliac and fossa and external wing of the ilium (B). The iliac oblique view confirms the posterior border of the bone to be intact (C).
FIGURE 42-16 The various subgroups of the transverse fracture. Infratectal type (A), juxtatectal type (B), and transtectal type (C). (Redrawn after Letournel E, Judet R. Fractures of the acetabulum, 2nd ed. Berlin: Springer-Verlag, 1993.)
Associated Fracture Patterns
Posterior Column Plus Posterior Wall
The posterior column plus posterior wall fracture is a combination of the two elementary fracture patterns, posterior column and posterior wall, and makes up 3% to 4% of fractures (6,7,8). The posterior column fracture divides the posterior border of the innominate bone and the ischium to produce a free ischioacetabular fragment. The posterior wall component can be thought of as articular comminution of the posterior rim where the posterior column fracture traverses it. The femoral head is frequently dislocated on presentation, with the femoral head following the ischioacetabular fragment and dislocating cranially and posteriorly. The posterior wall fragment remains with the femoral head while dislocated but typically stays in a displaced position once the femoral head is reduced. The posterior wall fracture may block reduction of the hip by interposition between the head and the posterior column or by incarcerating within the joint. Radiographically, the disrupted landmarks, as expected, are the ilioischial line, posterior border of the innominate bone, and the posterior rim. The x-ray roof may also be displaced depending on how cranial the posterior wall component extends. The displacement of the posterior column may be difficult to assess on the AP x-ray as posterior displacement of the column may result in the ilioischial line maintaining an almost normal relationship to the x-ray teardrop (Fig. 42-18A–C).
Anterior Column or Wall Plus Posterior Hemitransverse
The anterior plus posterior hemitransverse patterns involve either an anterior wall or column fracture as the primary fracture line. An associated transverse fracture component propagates from the anterior fracture across the articular surface to the posterior border of the innominate bone. This posterior hemitransverse fracture is identical to the posterior half of a transverse fracture and may occur at any of the levels described above. The anterior plus posterior hemitransverse group makes up about 7% of fractures; over three-fourths of which involve the anterior column rather than the wall (6,7,8). Radiographically, these fractures exhibit all the features of an anterior wall or column fracture, but with displacement of the ilioischial line and a fracture line that crosses the posterior border of the bone on the iliac oblique. The displacement of the hemitransverse fracture component is generally less severe than that of the anterior fracture. However, the rotation of the posterior column component may allow more anteromedial translation of the femoral head and striking displacements in comparison to the isolated anterior column fracture (Fig. 42-19A–C).
The associated anterior plus posterior hemitransverse as well as the isolated anterior column fractures are common fracture patterns seen in the elderly after a fall onto the hip. The fracture pattern is often complicated by impaction of the medial roof of the acetabulum and has been termed the “gull wing” sign based on the x-ray appearance on the AP x-ray (Fig. 42-20). The presence of this impaction is a poor prognostic sign. Anglen et al have demonstrated a difficulty in maintaining a congruent reduction of the hip in this situation (33).
Transverse Plus Posterior Wall Fractures
The transverse plus posterior wall fracture combines the elementary transverse and posterior wall fracture patterns and
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makes up 20% of all fractures (6,7,8,). As with the elementary patterns, the transverse component may be trans-, juxta- or infratectal and the posterior wall component may be single or multifragmentary and associated with marginal impaction. Dislocation of the femoral head occurs in up to 96% of these fractures and the dislocation may be either posteriorly through the wall defect or medially through the transverse fracture (Fig. 42-21A–C). Distinction between the two is important as an attempted reduction of a posterior dislocation by axial traction alone may be unsuccessful and result in additional chondral injury to the femoral head as it is dragged across the fracture surface. Early recognition of posterior dislocations is necessary to minimize such complications as osteonecrosis, sciatic nerve injury, and femoral head damage.
FIGURE 42-17 X-ray appearance of the transverse fracture. The AP pelvis view demonstrates disruption of 5 of the 6 x-ray landmarks of the acetabulum, indicating that this is a transtectal transverse fracture. Note the subluxation of the femoral head away from the intact portion of the acetabular roof (A). The obturator oblique view shows the subluxation of the femoral head with the displacement of the ischiopubic segment and verifies that the ischial ramus is not broken (B). The iliac oblique shows where the transverse fracture exits the greater sciatic notch and again confirms the subluxation of the femoral head (C).
FIGURE 42-18 X-ray appearance of the associated posterior column plus posterior wall fracture. The AP pelvis x-ray shows the disruption of the ilioischial but not the iliopectineal lines and the posterior rim shadow is seen to be disrupted and the posterior wall fragment can be appreciated overlying the roof of the acetabulum (A). The obturator oblique view is unfortunately inadequately rotated and therefore the displacement of the posterior wall fragment is difficult to visualize. The ischial ramus fracture is present but also difficult to appreciate (B). The iliac oblique demonstrates the disruption of the greater sciatic notch and the posterior wall fragment can be seen superimposed on the roof of the acetabulum (C).
FIGURE 42-19 X-ray appearance of the associated anterior wall plus posterior hemitransverse fracture. The AP pelvis x-ray demonstrates the medial subluxation of the femoral head with segmental displacement of the iliopectineal line. The ilioischial line displacement is noted and unlike the anterior wall fracture, the relationship of the ischium to the ilioischial line is preserved. Wear of the femoral head is seen laterally where the head is articulating with the edge of the intact roof (A). The obturator oblique x-ray appears similar to that seen in the isolated anterior wall fracture but the fracture is seen to be multifragmentary with impaction. Disruption of the posterior rim shadow is appreciated (B). The iliac oblique shows the disruption of the posterior border of the innominate and displacement through the greater sciatic notch (C).
FIGURE 42-20 The “gull wing” sign represents impaction of the acetabular roof and is a poor prognostic sign may present difficulties in maintaining the reduction of the fragment. Displacement of the fragment may allow subluxation of the femoral head and an incongruous hip joint.
T-Shaped Fractures
The T-shaped fracture represents 7% of acetabular fractures and involves a transverse fracture with an associated vertical fracture line (6,7,8). The vertical stem usually propagates from the transverse fracture, across the quadrilateral surface and cotyloid fossa, enters the obturator foramen through the ischiopubic notch and ends in a fracture of the ischial ramus. Thus, the ischiopubic segment created by the transverse fracture is divided into a posterior (ischial) and anterior (pubic) articular segment. Radiographically, the identification of the transverse fracture in the presence of a fracture of the ischial ramus leads the surgeon to recognize the T-shaped fracture. Displacement of the stem of the T may cause the ilioischial line to appear duplicated. Likewise, the relationship between the ilioischial line, which remains with the posterior column, and the teardrop, which remains with the anterior column, may be disrupted (Fig. 42-22A–C). Diagnosis of the T-shaped fracture and recognition of columnar displacements, both in relation to the intact innominate bone and to each other, is crucial in treating the T-shaped fracture. The T-shaped fracture may also be associated with a posterior wall fracture. This subgroup of fractures is generally included in the transverse plus posterior wall pattern but has been noted to have the worst prognosis of any subgroup of fractures. Finally, fractures of the posterior column with anterior hemitransverse associated fractures are classified as T-shaped.
Associated Both Column Fractures
The associated both column (ABC) fracture is the most common of the associated fractures, making up 23% of all acetabular fractures (6,7,8). By definition, all ABC fractures have no portion of the acetabular articular surface remaining intact to the innominate bone and there is a split between an anterior and posterior column component. Within this definition, there is room for many different fracture patterns. In its most simple form, an anterior column fracture may be associated with a simple posterior column fracture (Fig. 42-23). This is the exception and usually there are secondary fractures of both columns. Even in very comminuted associated both column fractures, the acetabular labrum usually remains intact. Therefore, as the femoral head medializes due to muscular pull, the articular fragments may each rotate around, yet remain congruent to, the femoral head. This creates a situation unique to associated both column fractures which is known as “secondary congruence” (6,34). The x-ray “spur sign,” when present, is pathognomonic for the associated both column fracture (Fig. 42-24). This is seen best on the obturator oblique projection and represents the external cortex of the most caudal portion of the intact ilium (Fig. 42-25A–C) (35,36). It is generally seen only in the ABC because the femoral head medializes with all portions of the acetabular articular surface.
TREATMENT OPTIONS
Nonsurgical Treatment
Unlike most articular fractures in which specific operative indications are cited, fractures of the acetabulum are generally considered injuries requiring operative treatment unless certain nonoperative criteria are met (17,37,38,39). Fracture displacement and location, stability of the hip and patient related factors must all be considered (Table 42-4).
The magnitude of displacement of articular injuries is often of primary concern in determining the need for surgical treatment. Numerous biomechanical pressure contact studies have been performed for various fracture patterns [posterior wall (40,41,42), transverse (42,43,44,45), anterior column (45,46,47), and associated both column (48)] and have all shown that disruption of the articular surface results in an increase in the peak and mean contact pressure and a redistribution of the loadbearing within the joint. All of these studies have suggested that displacements within the articular surface of the hip joint may be poorly tolerated. This is supported by clinical observations by Matta et al in a retrospective review of nonoperative management, which identified that fractures displaced greater than
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3 mm were associated with fair or poor clinical results in 41 of 53 (77%) fractures (37).
FIGURE 42-21 X-ray appearance of the associated transverse plus posterior wall fracture (transtectal pattern). The appearance on the AP x-ray is quite similar to that of the pure transverse fracture with disruption of 5 of the 6 x-ray landmarks. The posterior wall fragment is seen as an oblique cortical line overlying the intact roof (A). The obturator oblique nicely demonstrates the transverse fracture, the subluxation of the femoral head with the ischiopubic fragment as well as the posterior wall fragment. It is easy to see on this view how the femoral head may abrade against the fracture edge while the hip is subluxated (B). The iliac oblique view highlights the fracture line exiting the greater sciatic notch as well as revealing a fragment of impacted articular surface (C).
FIGURE 42-22 X-ray appearance of the T-shaped fracture (transtectal pattern). The appearance on the AP pelvis x-ray may be distinguished from the transverse fracture by the presence of the fracture of the ischial ramus. In this case an associated posterior wall fracture and dislocation of the ipsilateral sacroiliac joint are also noted (A). The obturator oblique allows better visualization of the stem of the T as it enters the roof of the obturator foramen and is associated with the ischial ramus fracture. The posterior wall fragment is also well visualized (B). The iliac oblique view demonstrates the disruption of the greater sciatic notch and subluxation of the femoral head (C).
Although fracture displacements of greater than 3 mm are generally treated surgically, certain fractures may be amenable to nonsurgical treatment despite the magnitude of the displacement. Roof arc measurements were described by Matta et al as a way to quantify the amount of remaining intact weightbearing articular surface after fracture (37). Medial, anterior, and posterior roof arcs of greater than 45 degrees as measured on the AP, obturator, and iliac oblique x-rays have been used to define the intact weightbearing dome. The roof arc angles are measured by drawing a vertical line through the center of the femoral head on the AP and Judet views. A second line is drawn through the center of the head to the location of the fracture at the articular surface (Fig. 42-26). The resultant angle may be used to determine fractures appropriate for nonoperative management. Geometric analysis of the angles by Olson and Matta has shown that the cranial 10 mm of the acetabulum on the CT scan corresponds to the area defined as this weight-bearing dome by roof arcs (38). It has been postulated that fractures that do not involve this dome are unlikely to lead to posttraumatic arthrosis and are, therefore, candidates for nonsurgical treatment (38,49,50).
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Prerequisites for nonsurgical treatment of acetabulum fractures include both intact roof arc measurements and congruence of the femoral head to the intact acetabulum on AP and Judet x-rays taken out of traction.
FIGURE 42-23 Line drawing of an associated both column fracture, which is relatively uncomplicated despite separating all portions of the articular surface from the intact ilium. (Courtesy of Joel Matta, MD.)
FIGURE 42-24 The x-ray “spur sign” (arrow) is pathognomonic for the associated both column fracture and represents the most caudal portion of the intact ilium.
FIGURE 42-25 X-ray appearance of an associated both column fracture. Despite disruption of all six of the x-ray landmarks, the femoral head is seen to remain congruent to the roof and anterior column fragment. The position of the head on the AP x-ray is medialized as well as cranially displaced. Subluxation of the symphysis pubis due to the displacement of the superior pubic ramus fragment is noted (A). The obturator oblique demonstrates the spur sign as well as confirming the congruence between the femoral head and acetabulum (B). The iliac oblique view reveals loss of congruence between the femoral head and the posterior column (C). This fracture is thus indicated for surgical treatment.
TABLE 42-4 Criteria for Nonoperative Management
Roof arcs >45 degrees
No fracture involvement in cranial 10 mm of joint on CT (CT subchondral arc)
No femoral head subluxation on three x-rays, taken out of traction
For posterior wall fractures: less than 40% of width of wall on CT
Roof arc measurements are not applicable to associated both column fractures because there is no intact portion of the acetabulum to measure. Instead, perfect secondary congruence of an associated both column fracture on all three standard x-rays, taken when the patient is out of traction, is necessary for nonsurgical treatment. Although a fracture healed with secondary congruence may have an adequate articular surface, the resultant shortening of the limb and medialization of the hip may not be acceptable. Secondary congruence alone, therefore, is necessary but not a sufficient criterion for nonsurgical treatment. Reviewing 91 fractures managed nonoperatively, Letournel identified 13 associated both column fractures which had secondary congruence and were followed for an average of 4.3 years. Of these, all had good or very good outcomes by d’Aubigne-Postel grading (Fig. 42-27) (6).
FIGURE 42-26 Measurement of roof arc angles on the AP (medial) and iliac obliques (posterior). This fracture may be amenable to nonoperative management.
FIGURE 42-27 AP pelvis x-ray of a 79-year-old man with an associated both column fracture. Although perfect secondary congruence was not present, medical co-morbidities prevented operative treatment (A). X-ray at 3 years. Despite some initial increase in displacement and further medialization of the femoral head the fracture healed. The patient has achieved his preinjury functional status (B).
Roof arc measurements are also not applicable to fractures of the posterior wall. The criteria for nonoperative management of posterior wall fractures are the size of the wall defect and its effect on the stability of the hip. Vailas performed sequential osteotomies of the posterior wall of the acetabulum in cadavers and assessed the resultant hip stability. Osteotomies involving greater than 50% of the width of the posterior wall were found to result invariably in hip instability while hips with less than 25% of the width of the posterior wall removed were all stable. In those between 25% and 50%, stability was dependent on the magnitude of the associated capsular injury (51). Keith et
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al repeated the study but used CT to quantify the size of the wall osteotomy. Greater than 40% of the wall involved was found to result in instability; less than 20% proved stable (27). Clinically, Calkins et al reviewed CT scan data for evidence of subluxation. When greater than 50% of the posterior wall remained, no subluxation was seen. This, however, was a static evaluation with the hip in extension (52). Dynamic stress views of hip stability after fracture as described by Tornetta, taken while the patient is under anesthesia, may be useful in determining whether the hip joint is stable after posterior wall fracture (50). Based on cadaveric data alone, surgical intervention should be considered for fractures involving more that 20% of the width of the wall on the CT scan (27,40,41,51). Any subluxation of the femoral head, particularly easy to see on the obturator oblique view, should lead the surgeon to consider operative treatment (Fig. 42-28).
Fractures displaced less than 2 mm may be appropriate for nonoperative management regardless of location (3,6,37,38,49,50). If nonsurgical management is selected for fractures in the weightbearing dome, careful x-ray follow-up is required to ensure no further displacement occurs. The surgeon should follow the fracture with the x-ray that allows the best visualization of the fracture, even if this is with a CT scan in some selected cases. Stress views of the acetabulum, generally taken in the operating room, also contribute valuable information about the stability of the fracture pattern and its likelihood to displace. Tornetta prospectively examined 41 acetabular fractures appropriate for nonoperative management by displacement and roof-arc criteria. Three were found to have hip instability and required operative treatment. The remaining patients showed no displacement during healing and no evidence of arthritis at over 2-year follow-up (50).
In addition to fracture location, displacement, and stability, patient-related factors such as age, preinjury activity level, functional demands, and medical comorbidities must be considered when determining whether a patient is best served by surgical or nonsurgical treatment. Nonsurgical treatment of elderly or infirm patients, with planned subsequent arthroplasty if symptomatic arthritis develops, may be appropriate—particularly if the fracture displacement is minimal (53,54).
Operative Treatment
Once the decision for surgical treatment has been made, it should be performed expeditiously. In general, the earlier the surgery is performed, the easier the reduction is obtained. Fractures operated over 3 weeks from injury are more difficult to reduce and the results obtained in the treatment of these fractures are inferior (6,55). Except in the situation of an irreducible hip dislocation, progressing neurologic deficit, open fractures, or vascular injuries, surgery for a fracture of the acetabulum is not emergent (22). Rather, the surgery should be performed when the surgical environment is optimized, the surgical team is prepared and the surgeon is able to devote the appropriate time and attention to detail.
FIGURE 42-28 Intraoperative stress views demonstrate subluxation of the femoral head away from the sourcil. The patient is indicated for operative reduction and fixation.
Open anatomic reduction and internal fixation is the treatment of choice for displaced fractures of the acetabulum (6,7,8,56,57). The goal of surgical treatment is to obtain an anatomic reduction of the articular surface while avoiding complications. This treatment restores the contact area between the femoral head and the acetabulum, produces a stable hip joint, and maximizes the potential for long-term survival of the hip. The patient’s clinical outcome correlates with the quality of the articular reduction. Matta and Letournel have both shown that the most significant factor that determines outcome after operative treatment of acetabular fractures is the accuracy of the surgical reduction (6,7). In addition, the results of perfect reductions (<1 mm of residual displacement) are superior to those of imperfect (1–3 mm) and poor (>3 mm) reductions at long-term
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follow-up (Table 42-5) (6,7). Even when posttraumatic arthritis was seen after a perfect articular reduction, Letournel found that 50% of the time, the arthritis presented between 10 and 25 years after injury. In contrast, after imperfect reduction, 80% of the cases of arthritis appeared within the first 10 years after injury (6). To maximize the patient’s quality of life following injury, the surgeon must strive for an inframillimetric reduction with every fracture.
TABLE 42-5 Operative Reduction versus Clinical Results
  Excellent Good Fair Poor
Anatomical (< 1 mm) 46% 37% 5% 12%
Imperfect (1–3 mm) 33% 35% 14% 18%
Poor (>3 mm) 17% 33% 11% 39%
From Matta JM. Fractures of the acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury. J Bone Joint Surg Am 1996;78(11):1632–1645.
TABLE 42-6 Results of Operative Management of Acetabular Fractures
Type of Fractures Clinical Results Percentage of Excellent Results
Excellent Very Good Good Fair Poor Total
Posterior wall 87 6 3 4 17 117 74.00%
Posterior column 9 1 1 11 81.82%
Anterior wall 6 1 1 1 9 66.67%
Anterior column 12 1 1 2 16 75.00%
Transverse 17 1 1 19 89.47%
T-shaped 20 3 3 26 76.92%
Transverse and posterior wall 49 16 10 9 17 101 48.51%
Posterior column and 5 1 2 1 8 17 29.41% posterior wall
Anterior column and posterior 26 5 4 3 3 41 63.41% hemitransverse
Both column 76 21 14 11 13 135 56.30%
Total 307 54 36 30 65 492 62.40%
62.40% 10.98% 7.32% 6.10% 13/21% 100%
From Letournel E, Judet R, eds. Fractures of the acetabulum, 2nd ed. New York: Springer-Verlag, 1993.
The results of open reduction and internal fixation of acetabular fractures are varied in the literature and difficult to interpret. However, the three largest series reporting outcomes after acetabular fracture all report good or excellent results in 75% to 81% of fractures at long-term follow-up (Table 42-6) (6,7,8). Other studies that have also reported the accuracy of the articular reduction have similarly found outcomes to be dependant on the reduction (56,57,58,59,60,61,62). The most common outcome instrument used in the assessment of acetabular fracture outcome has been the modified rating scale of d’Aubigne and Postel. This scale rates pain, walking and range of motion each on a 6-point scale. Matta’s modification of the scale asks the patient whether pain has prevented any return to recreational or vocational activities (7). Moed et al investigated the correlation between the Merle d’Aubigne scale and the musculoskeletal function assessment evaluation (MFA). While he did find a correlation between the two scores, patients in his evaluation who had high Merle d’Aubigne scores, still showed alterations in their MFA scores, indicating that they did not have a complete return to preinjury
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function (56). They did, however, demonstrate MFA scores roughly comparable with patients treated for proximal femur fractures. It is unknown how these results differ from the functional results presented by Matta.
The one situation in which the accuracy of the articular reduction has not seemed to correlate with the outcome has been in the treatment of the posterior wall fracture. Letournel noted (and Matta later confirmed) that there appeared to be a disproportionately large number of poor results after posterior wall fracture, despite a high percentage of anatomic reductions (6,7). Letournel reported 94% perfect reductions after the treatment of posterior wall fractures. Despite this, poor results were seen in 15% of patients. Moed also identified poor results in 10% of 94 patients with posterior wall acetabular fractures despite 98% perfect reductions as graded by plain x-rays (32). When CT scans were used as well, however, the accuracy of the articular surface reduction was found to be imperfect in 52 of 67 patients in whom postoperative CT scans were available (63). Following this information, the accuracy of the reduction of the articular surface was again found to be strongly predictive of the final outcome. Postoperative CT appears to be a more accurate means of documenting the articular reduction after posterior wall fracture (24,63).
Closed reduction and percutaneous fixation has been proposed for elderly patients with acetabular fractures as well as for simple fractures with minimal displacements (64,65,66,67). While no data exist to demonstrate how patients treated in this manner fare as compared to those treated with open reduction, preliminary results have been presented. Starr et al demonstrated an average residual articular displacement of 3 mm in a small group of elderly patients in whom an anatomic reduction was felt to be unobtainable. After 1 year of follow-up, 5 of the 21 patients available for follow-up had already undergone total hip arthroplasty (67). Until such time as long-term outcome studies are available to show a benefit to percutaneous fixation of acetabular fractures, the technique cannot replace the gold standard of open reduction and internal fixation.
Two studies in the literature, one by Wright et al and another by Kaemppfe et al, reported significantly lower rates of good and excellent outcomes and markedly higher complication rates than expected (68,69). These studies reflect the results of multiple surgeons operating on a relatively low number of acetabular fractures and suggest that specific treatment protocols and centralization of care might contribute to reduced complications and improved care.
Surgical Indications
The indications for surgical treatment of an acetabulum fracture include loss of congruence between the femoral head and the acetabulum on any view (AP or Judet x-rays), displacement of greater that 2 mm within the superior articular surface (weightbearing dome), retained intraarticular fragments, and greater than 25% of the width of the posterior wall on CT. Lack of secondary congruence for an associated both column fracture is also considered an indication for operative treatment.
Surgical Approaches
The choice of surgical approach is determined by the fracture pattern. A single surgical approach is generally selected with the expectation that the fracture reduction and fixation can be completely performed through the one approach (6,28,70,71). The most commonly used surgical approaches to the acetabulum are the Kocher-Langenbeck, the ilioinguinal, and the extended iliofemoral approach. The Kocher-Langenbeck is used for fractures involving the posterior portion of the innominate bone while the ilioinguinal is used for fractures involving the anterior portion. The extended iliofemoral approach is an extensile approach developed to allow maximal simultaneous access to both columns of the acetabulum. It is most often used in associated fracture patterns that are surgically treated more than 21 days after injury or on certain transverse or both column pattern fractures with complicating features that are not amenable to treatment by either of the two more limited approaches.
Kocher-Langenbeck
The Kocher-Langenbeck approach allows complete exposure of the retroacetabular surface distally as far as the ischial tuberosity. The greater and lesser sciatic notches are visualized by transecting the piriformis and obturator internus tendons and dissecting subperiosteally into the notches. The most caudal portion of the ilium is accessible but the superior gluteal neurovascular bundle limits proximal exposure. Osteotomy of the greater trochanter allows increased anterior iliac exposure but proximal access is still largely limited. The quadrilateral surface and pelvic brim are accessible by palpation through the greater sciatic notch. The Kocher-Langenbeck approach is used for all posterior wall, posterior column, and posterior column plus posterior wall fractures. It is also used for most transverse, transverse plus posterior wall fractures and many T-shaped fractures (Table 42-7). Although most surgeons are more comfortable with lateral positioning, the weight of the operative leg tends to cause medial displacement of the femoral head and articular fragments. In addition, access through the greater sciatic notch for palpation or clamp placement is impaired. Prone positioning of the patient in traction neutralizes the weight of the leg, facilitating reduction of transverse fracture patterns. The hip and knee position is also controlled to minimize iatrogenic nerve injury, particularly with clamp placement through the greater sciatic notch (72). The position of the femoral head is controlled and improves the repositioning of free osteochondral or impacted fragments using the head as a template.
Although surgeons are familiar with the posterior approach to the hip, there are special considerations when exposing an acetabular fracture. Transecting the piriformis and obturator internus tendons must be performed at least 1 cm from the greater trochanter to avoid injury to the ascending branch of
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the medial femoral circumflex artery. Dissection caudal to the inferior gemellus on the femur must be avoided, also to preserve the blood supply to the femoral head (Fig. 42-29). If more caudal exposure of the ischium is necessary, elevation of the quadratus femoris muscle can be performed from its ischial attachment rather than its femoral side. Excessive cephelad and lateral retraction of the abductors can place harmful tension on the superior gluteal neurovascular bundle. If additional cephelad and anterior exposure is required, to secure buttress plate fixation for a cranially located posterior wall fracture for instance, anterior extension of the exposure can be accomplished without excessive traction on the abductors or superior gluteal neurovascular pedicle by using a flip osteotomy of the greater trochanter (73,74,75,76,77). This osteotomy splits the ridge on the posterior aspect of the greater trochanter and exits anteriorly just medial to the gluteus medius and minimus insertions. Some fibers of the gluteus minimus tendon are transected from the anterior trochanter but the majority of the tendon insertion remains with the trochanteric fragment. This is also referred to as a digastric osteotomy as the abductor and vastus lateralis insertions both remain on the trochanteric fragment. The insertion of the piriformis tendon remains on the intact proximal femur. This protects the blood supply to the femoral head from the ascending branch of the medial femoral circumflex artery. Anterior exposure is then facilitated by retraction of the trochanteric fragment anteriorly. Cranial exposure is still limited by the superior gluteal neurovascular bundle and if more cranial exposure of the posterior iliac wing is thought to be necessary, an extensile approach should be chosen primarily.
TABLE 42-7 Choice of Surgical Approach for Each Fracture Pattern
Fracture Type Approach
Elementary
   Posterior wall Kocher-Langenbeck
   Posterior column Kocher-Langenbeck
   Anterior wall Ilioinguinal
   Anterior column Ilioinguinal
   Transverse
      Infratectal/juxtatectal Kocher-Langenbeck
      Transtectal Extended Iliofemoral or Kocher Langenbeck
Associated
   Posterior column + wall Kocher-Langenbeck
   Anterior + posterior Hemitransverse Ilioinguinal
   Transverse + posterior wall
      Infratectal/juxtatectal Kocher-Langenbeck
      Transtectal Extended Iliofemoral or Kocher-Langenbeck
   T-Shaped
      Infratectal/juxtatectal Kocher-Langenbeck or combined
      Transtectal Extended Iliofemoral or combined
   Associated both column Ilioinguinal
Ilioinguinal
The ilioinguinal approach allows access to the internal aspect of the innominate bone from the sacroiliac joint to the symphysis pubis. Direct visualization of the internal iliac fossa, pelvic brim, quadrilateral surface, and superior pubic ramus is achieved. Limited access to the external aspect of the iliac wing is possible by release of the abductor origin. The ilioinguinal approach is used for most anterior wall and anterior column fractures as well as most anterior column plus posterior hemitransverse fractures and associated both column fractures (Table 42-7) (35,36,70).
The ilioinguinal approach consists of three windows. The lateral window is exposed by the subperiosteal elevation of the iliacus muscle from the internal iliac fossa. It allows exposure of the iliac crest, internal iliac fossa medially to the sacroiliac joint and distally to the pelvic brim. The middle window is created by the release of the iliopectineal fascia, retraction of the iliopsoas and femoral nerve laterally and the external iliac artery and vein medially. This window allows exposure of the anterior wall, pectineal eminence, pelvic brim and quadrilateral surface. The lateral femoral cutaneous nerve is identified and protected throughout the procedure. While working within the middle window, the pulse in the external iliac artery should be frequently checked as thrombosis or intimal injury may occur with prolonged tension on the artery. The medial window is classically created by transecting the ipsilateral rectus abdominis tendon, allowing access to the space of Retzius and the superior ramus (Fig. 42-30). Alternately, the skin incision may be extended across the midline and a modified Stoppa midline approach made through the linea alba between the rectus muscles (78,79,80). This has the added advantage of allowing improved visualization of the quadrilateral surface to the lesser and greater sciatic notches. A retropubic vascular anastamosis is commonly found and must be identified and ligated prior to exposing the ramus (81).
The approach may also be modified to allow extended access. Mast described improved access to the external aspect of the ilium by positioning the patient in the semilateral position and extending the skin incision to the posterior superior iliac spine (82). The posterior aspect of the abductor origin and a portion of the gluteus maximus origin are detached from the external aspect of the ilium. This may be helpful if there is a sacroiliac fracture-dislocation component to an associated both column fracture for instance. Ganz has also described a modification of the classic ilioinguinal approach to develop the plane between the sartorius and tensor fascia lata muscle distal to the inguinal ligament (83). This allows access to the anterior hip capsule for capsulotomy and may improve visualization of small anterior rim fracture fragments. The standard skin incision may be used but is typically moved a few centimeters distally to facilitate this exposure.
FIGURE 42-29 Kocher-Langenbeck approach. The skin incision parallels the shaft of the femur to the tip of the greater trochanter and then proceeds toward the posterior superior iliac spine (A). The fascia lata and gluteus maximus have been split. The short external rotators are seen with the sciatic nerve lying on the dorsal surface of the quadratus femoris. The gluteus maximus tendon has been transected (B). The retroacetabular surface is exposed by transecting the tendons of the piriformis and obturator internus and reflecting them back toward the sciatic notches. A capsulotomy is shown but is rarely used clinically (C).
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Extended Iliofemoral
The extended iliofemoral approach was developed by Letournel as a surgical approach to the external aspect of the acetabulum and innominate bone. The approach, derived from the Smith-Petersen approach, provides maximum simultaneous access to both columns of the acetabulum. The entire lateral aspect of the iliac wing, the anterior column to the level of the iliopectineal eminence, the retroacetabular surface and the interior of the hip joint are accessible. In addition, limited exposure of the internal iliac fossa is also possible by release of the iliacus, sartorius, and inguinal ligament origins. Exposing the internal iliac fossa, however, risks some avascularity to the anterior superior iliac spine. Secure repair of these structures as well as protection of the vascularity of the bone may be facilitated by performing an osteotomy of the ASIS. As originally described, the exposure requires elevation of the abductors from the lateral surface of the ilium as well as release of the gluteus minimus and medius tendons from the greater trochanter of the femur. Alternately, the greater trochanter may be osteotomized. The abductor muscle mass is then reflected posteriorly with the tensor fascia lata, pedicled on the superior gluteal neurovascular bundle (Fig. 42-31).
Reinert et al have described a modification of the extended iliofemoral approach that, in addition to osteotomies of the ASIS and greater trochanter, adds an osteotomy of the iliac crest. While this allows for secure bony repair of the abductor origin, it may obscure the reduction of anterior column fracture fragments in which the iliac crest is a necessary landmark to ensure reduction (84,85).
The extended iliofemoral approach is reserved for associated fracture patterns that are operated greater than 21 days following injury. It is also used for certain transverse plus posterior
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wall, T-shaped or associated both column fractures with special circumstances (Table 42-7) (4,11,55,86,87,88).
FIGURE 42-30 Ilioinguinal approach. The skin incision starts roughly 3 cm proximal to the symphysis pubis, crosses the anterior superior iliac spine, and parallels the iliac crest past its most convex portion. The iliacus muscle has been dissected subperiosteally from the internal iliac fossa and the external oblique aponeurosis has been incised and reflected distally (A). The floor of the inguinal canal has been opened and the iliopectineal fascia is seen to be separating the femoral nerve and iliopsoas from the external iliac vessels (B). The exposure is complete. The lateral window exposes the internal iliac fossa to the sacroiliac joint and pelvic brim (C). The middle window exposes the pelvic brim to the pectineal eminence, the quadrilateral surface and the anterior wall (D). The medial window seen here has been created by transecting the rectus abdominis tendon. The spermatic cord is retracted laterally and the space of Retzius, superior ramus and symphysis pubis are visualized (E).
Combined Approaches
The ilioinguinal and Kocher-Langenbeck approaches can be combined and either performed simultaneously or sequentially (89). Two simultaneous approaches theoretically allow access to both the anterior and posterior columns without the morbidity of the extended approach. The combined access, however, does not include the exposure of the external surface of the posterior-superior ilium that the extended iliofemoral approach (EIF) allows. In addition, patient positioning frequently compromises both exposures. Frequently only the lateral window of the ilioinguinal can be used. This combination may be helpful in the transtectal transverse fracture pattern to allow direct clamp placement on the anterior limb of the transverse. More commonly, sequential ilioinguinal and Kocher-Langenbeck approaches may be used for anterior plus posterior
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hemitransverse, T-shaped or associated both column fractures where the surgeon is only able to achieve a reduction of one column though the first approach.
FIGURE 42-31 The extended iliofemoral approach. The skin incision runs from the posterior superior iliac spine to the anterior spine and then curves to lie on the anterior-lateral thigh (A). The abductors have been reflected subperiosteally from the external ilium and reflected posteriorly with the tensor fascia lata muscle. The fascia separating the tensor from the rectus is split and the ascending branch of the lateral femoral circumflex vessels are ligated (B). The abductor tendons are here transected from the greater trochanter. Alternately a trochanteric osteotomy can be performed (C). The piriformis and obturator internus tendons have been transected and the exposure to the external ilium is completed. A capsulotomy is shown (D).
Triradiate
The triradiate incision is created by the addition of an anterior-superior extension from the Kocher-Langenbeck, allowing the abductors to be reflected cranially and posteriorly with a trochanteric osteotomy (86,90). The approach affords a similar access to the articular surface as the extended iliofemoral approach but incomplete exposure of the lateral aspect of the ilium. The triradiate approach is not commonly used but theoretically allows a surgeon, performing a Kocher-Langenbeck approach, the option of extending that approach in the event additional cranial exposure of the ilium is found to be necessary.
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COMPLICATIONS
Posttraumatic Arthrosis
The primary complication after fracture of the acetabulum is posttraumatic arthrosis. Although symptomatic arthritis after acetabular fracture is generally treated with arthroplasty, arthrodesis and osteotomy remain viable treatment options. Posttraumatic arthritis is more common after poor articular reductions than after a perfect reduction (6,7,8,57,96). Long-term studies have demonstrated that fractures reductions to within 1 mm of residual displacement have better long-term outcome and a lower incidence of arthritis than those with greater than 1 mm of displacement. In addition, if arthritis develops after a perfect reduction, the onset tends to be later and the progression slower than arthritis that develops after a poor reduction (6).
Heterotopic Ossification
Heterotopic ossification is related to the degree of soft tissue disruption, from either the injury or the surgical approach. Other factors associated with the formation of heterotopic ossification include head injury, prolonged mechanical ventilation, and male gender (Fig. 42-46) (97,98,99). Use of an extensile approach also contributes to the formation of heterotopic ossification and is probably caused by the amount of muscle dissection and elevation from the ilium (85,86,87,88,97,100). Most patients who develop heterotopic ossification after acetabular fracture do not have functional restrictions of their hip motion. Prophylactic treatments for heterotopic ossification include 6 weeks of indomethacin use (25 mg tid), single dose external beam radiotherapy (700 cGy), or a combination of both treatments (98,100,101,102,103,104,105). Burd et al prospectively compared Indomethacin and radiotherapy in 166 patients. Of the patients treated with indomethacin, 11% developed grade 3 or 4 ossifications, compared with 4% in those treated with radiotherapy. Although this was not a statistically significant result, both treatments compared favorably with 16 untreated patients in whom 38% developed high-grade ossifications (106).
The indications for prophylaxis remain unclear. Heterotopic ossification formation is most likely when an extensile approach is used and least likely after the ilioinguinal approach (107). In the series of very experienced acetabular fracture surgeons, the incidence of heterotopic ossification without the use of prophylaxis is as low, or lower, than that reported by other less experienced
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authors with the use of prophylaxis. McLaren initially reported in 1990 that heterotopic bone formation was seen in 50% of 26 patients who did not receive indomethacin postoperatively and in only 6% of 18 patients who did receive it (108). Moed and Maxey, early in their learning curve, also found that the use of indomethacin reduced the overall incidence and severity of heterotopic bone formation in 20 patients when compared with the treatment results of their prior 46 patients (109). Matta, however, in the only prospective randomized study of indomethacin versus no prophylaxis after acetabular fracture surgery, found Brooker grade 2 or higher ossifications in 4 of 57 patients receiving indomethacin versus 1 of 44 patients with no prophylaxis (107). Rath et al found that deábridement of devitalized gluteus minimus muscle following reduction and fixation through the Kocher-Langenbeck approach reduced the incidence of clinically significant ossification to 10% without prophylaxis (110). This is still higher than that reported by Matta. On the basis of these studies, it is difficult to ascertain the interrelation of prophylaxis and surgical technique but it would appear that both probably have significant contributions. Even in the largest series, however, the significant incidence of heterotopic ossification with the use of an extensile approach [Letournel (6) 57%, Matta (7) 20%] would seem to mandate prophylaxis in these cases.
FIGURE 42-46 A,B. X-rays 9 months after reduction and fixation of a transverse plus posterior wall acetabular fracture operated through a Kocher-Langenbeck approach. The patient required mechanical ventilation for roughly 4 weeks postinjury due to concurrent head and chest trauma. Severe grade 4 heterotopic ossification and near ankylosis of the hip joint is seen (A). AP x-ray 6 months after heterotopic ossification resection and removal of hardware shows slight narrowing of the superolateral joint space. The patient’s hip is rated 5.6.5.
Venous Thromboembolism
Deep venous thrombosis (DVT) and pulmonary embolism are common complications after pelvic or acetabular fractures treated without prophylaxis. Geerts et al identified a 61% incidence of DVT after pelvic injury when no prophylaxis was used (111). Chemoprophylaxis with low-molecular weight heparin or warfarin sodium may reduce the incidence of thromboembolic disease, particularly in association with mechanical prophylaxis. Multiple studies using chemoprophylaxis, however, have still identified an incidence of DVT between 10% and 34% of patients with pelvic injuries (112,113,114). Duplex ultrasound is typically used preoperatively to identify patients with venous thrombosis; however, it is limited in its ability to detect proximal thrombi. Montgomery et al reported on the use of magnetic resonance venography to identify asymptomatic thrombi in patients about to undergo surgical treatment of their pelvic or acetabular fracture. Thirty-four percent of 101 patients were identified as having thrombi proximal to the popliteal fossa (114). Despite the suggestion that magnetic resonance venography is more sensitive than ultrasound at detecting proximal thrombi, there may be a significant false-positive rate. Stover et al prospectively screened patients with both magnetic resonance venography (MRV) and contrast-enhanced CT. Positive MRV was found in 13% but contrast venography did not confirm a clot in any of these patients (false-positive rate 100%) (115). The indications for the use of MRV and its true accuracy remain to be determined. If thrombi are confirmed present, the placement of an inferior vena caval filter is generally recommended before fracture surgery (116,117).
Neurologic Injury
Sciatic nerve injury may occur in up to 30% of acetabular fractures (118). This incidence emphasizes the need for a thorough and complete neurologic evaluation of all patients with fractures of the acetabulum. Iatrogenic neurologic injury has been reported
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in 2% to 15% of patients who were surgically treated for acetabular fractures. The majority of these injuries are to the sciatic nerve during a posterior approach (19,118,119,120,121,122,123,124). Intraoperative neurologic monitoring has been recommended, but there is no evidence that the routine use of monitor- ing lowers the incidence of iatrogenic injury, particularly in the hands of experienced acetabular fracture surgeons (19,120,122). It is clear, however, that the surgeon must be constantly on guard to protect the sciatic nerve from damage, particularly when reduction clamps or retractors are within the sciatic notch. Control over the hip and knee position cannot be overemphasized (72). Prior to using skeletal traction to maintain the hip extended and the knee flexed during distraction of the femoral head, the incidence of iatrogenic sciatic nerve palsy in Letournel’s series was nearly 20%. This incidence dropped to 3.3% by the last 211 cases in the series with the above-mentioned techniques (6).
The most common neurologic injury after treatment of an acetabular fracture is to the lateral femoral cutaneous nerve (LFCN) after the ilioinguinal approach (35,36,125). Despite taking all appropriate measures to protect the nerve, during even a routine surgery the nerve may become stretched or attenuated. Clinically most patients experience a region of cutaneous anesthesia in the LFCN distribution that becomes dysesthetic over time but ultimately resolves. Warning the patient of this likelihood preoperatively is important because even though the symptoms are generally well tolerated by the patient, they are nevertheless bothered enough by their symptoms to seek reassurance that they will resolve.
Infection
Deep infection after the operative management of acetabular fractures has been reported in the range of 1% to 10% (6,32,36,126,127,128,129,130). Infections of the acetabulum were more common prior to the use of prophylactic antibiotics and suction drainage. Recent reports have highlighted several associations. The severe closed soft tissue degloving injury known as the Morel-Lavallee lesion has been demonstrated to significantly increase the risk of infection. Hak et al reported 3 of 24 patients with such a lesion became infected, and 42% of the lesions, when drained, were culture positive (14). Infection has also been reported in conjunction with postoperative irradiation. Haas et al reported infection in 6 of 66 patients who were treated with postoperative radiation to diminish heterotopic ossification (126). This is one of the highest reported rates of infection after acetabular fracture. Other authors have reported lower rates of infection after extensile approaches and irradiation (85,104).
Infection after acetabular surgery can be a devastating complication. The results, however, are somewhat dependent on the surgical approach. If an infection involves the joint itself, the results are uniformly bad. This would is usually the case when a surgical approach is used that exposes the joint directly, such as the Kocher-Langenbeck or an extensile approach. In contradistinction, patients treated operatively via the ilioinguinal approach who become infected have a much better chance at a good outcome. This is likely because the reduction of the joint is indirect by restoration of the internal contour of the innominate bone without direct joint exposure. Thus, deep infection may remain extra-articular, sealed off from the joint by the fracture reduction and healing.
Treatment of infection is similar to other anatomic regions. If the infection is early, then hardware preservation is attempted to maintain the stability of the hip until union, then it is removed. Late infection is treated with hardware removal. In all cases, long-term culture-specific antibiotics, usually an empiric course of 6 weeks, is used.
CONTROVERSIES AND FUTURE DIRECTIONS
The best reported outcomes after treatment of acetabular fractures demonstrate that nearly 80% of patients can have good or excellent results after operative treatment of their injury (6,7,8,62). This still leaves a substantial percentage of patients for whom good outcomes are not achieved. Future directions should emphasize avoiding posttraumatic arthritis and operative complications, as these remain the primary causes of a poor outcome after acetabular fracture. Good or excellent results after acetabular fracture are primarily related to the quality of the articular reduction as shown by both the large series of Letournel and Matta (6,7). Further refinements in surgical technique, improvements in reduction tools and innovations in implants will continue to help surgeons improve their ability to obtain and maintain anatomic articular reductions. Improved intraoperative imaging such as the use of intraoperative CT scanning, improved fluoroscopic evaluation, and perhaps the use of arthroscopy for direct visualization of the articular surface may also play a role in enabling the surgeon to improve the quality of their reduction.
Reducing complications may also improve the overall outcome after acetabular fracture. Improved means of heterotopic ossification and deep venous thrombosis prevention may prove successful. Limiting surgical dissections by continuing to refine the use of less extensile exposures may also limit complications. Percutaneous fixation of acetabular fractures has been suggested (64,66,67,131). The placement of percutaneous screws across acetabular fractures is not particularly challenging, particularly when aided by fluoroscopic visualization or computer assisted surgical navigation. The challenge for future development is the ability to obtain the perfect articular reduction in a minimally invasive fashion. Although percutaneous fixation of acetabular fractures may reduce the incidence of approach related complications, such as heterotopic ossification, wound complications, and neurologic injury, only in concert with a reduction of the articular surface will this likely improve on the current gold standard.
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Not all fractures of the acetabulum, however, are perfectly reconstructable. In addition, there are some patients where the operative morbidity may not be justified given the expected result. Fractures complicated by extreme osteopenia, preexisting arthritis or large degrees of articular impaction continue to routinely fail current reconstructive techniques (33,53,54). Elderly patients with significant medical comorbidities may not tolerate an extensive reconstructive procedure and may not be able to comply with the postoperative weightbearing restrictions. Some of these patients will be better served with total hip arthroplasty. Unfortunately, primary arthroplasty to treat acetabulum fracture has been associated with a significantly higher complication rate and poorer outcomes than standard primary arthroplasty (132,133,134,135). The indications for primary arthroplasty are still to be determined and the techniques to avoid higher complication rates need to be refined. Nevertheless, primary arthroplasty may be indicated when there is significant femoral head injury present, circumferential marginal impaction or in the elderly patient with medial roof impaction (“gull wing”) as these all seem to be subgroups with poorer outcomes after open reduction internal fixation.
CONCLUSION
The treatment of fractures of the acetabulum is technically demanding. Letournel documented the “learning curve” phenomenon of these injuries. For instance, his incidence of anatomic reductions for T-shaped and transverse plus posterior wall fracture patterns increased from roughly 40% in the first 8 years to nearly 95% after 30 years experience (6). Several studies of multiple surgeons performing occasional acetabular fracture surgeries have shown substantially higher rates of poor outcomes and surgical complications. Kaempffe and Wright both documented fair/poor results in 55% and 56%, respectively, of operatively treated fractures when multiple surgeons operated on a few fractures per year (68,69). This can be contrasted to the studies of Letournel, Matta, and Mayo, all single surgeon large series, where fair/poor long-term results after acetabular fracture treatment ranged from 19% to 25% (Table 42-8) (6,7,8).
TABLE 42-8 Complication Rates in Various Series of Acetabular Fracture Treatment
Study Patient Years H.O. Infection Nerve Palsy AVN PE Fair/Poor Results
Letournel 569 33 5% 4% 3% 5% 1.4% 19%
Matta 262 14 5% 5% 3% 3% 8% 24%
Mayo 163 7 12% 4% 3% 1% 25%
Kaempffe 50 10 58% 12% 8% 10% 56%
Wright 56 5 49% 5% 6% 23% 55%
Although a strong correlation exists between perfect articular reduction and good clinical outcome, other factors are also important. Posterior hip dislocation, osteonecrosis, femoral head cartilage damage, and surgical complications may adversely affect results despite anatomic reduction. Older patient age has also been found to be an independent factor that affects outcome. Delayed treatment of fractures of the acetabulum adversely affects outcome. Healing of fracture lines commonly necessitates the use of extensile approaches and contraction of the soft tissues makes obtaining anatomic reduction more difficult. Even if an anatomic reduction is obtained, the clinical results are not equivalent to those obtained in acute fractures. In one series, good or excellent results were obtained in only 67% of those patients with an anatomic reduction (55). Surgical complications were also higher than in the treatment of acute fractures. Prior surgical malreduction has also been associated with poorer clinical outcomes. Although in one study, good and excellent results were obtained in 42% of surgical revisions, anatomic reductions could be obtained after revision surgery in only 56%. Outcome was strongly correlated with delay between malreduction and revision surgery. These finding emphasize the importance of early operative treatment of acetabular fractures by surgeons trained in pelvic fracture surgery (136). Overall, in the hands of experienced fracture surgeons, good to excellent results are seen in 76% to 78% of associated acetabular fractures and 74% to 84% of elementary fractures. Despite the impression that elementary fracture patterns are in some way “easier” to treat, no statistical improvement in results is seen in the elementary fracture patterns compared to the associated ones. In most evaluations, the posterior wall fracture makes up a disproportionately large share of the poor results.
Perfect reduction of the displaced acetabulum fracture has been shown to contribute most strongly to long-term survival of the hip joint. Using a standardized protocol of preoperative evaluation, surgical indications and selection of appropriate surgical approach may maximize the experienced fracture surgeon’s ability to obtain a perfect articular reduction. Although the extensile approaches may be associated with a higher rate
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of complications, selecting a limited surgical approach that does not allow an anatomic reduction does the young, active patient a disservice. Poor clinical results following acetabular fracture are most commonly associated with articular malreduction and operative complications.
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