12.49 Management of acetabular fractures

Restoration of hip joint congruity and stability are the goals of acetabular fracture treatment. The achievement of these goals should minimize pain, prevent post-traumatic osteoarthritis, and thereby improve long-term functional outcome. Although certain fracture patterns may not require surgery to have a satisfactory outcome, in general, a patient with a displaced fracture in the superior weight-bearing area of the acetabulum should be managed with open reduction and internal fixation. However, the surgery is complex and demanding, even for the experienced surgeon, and has the potential for many serious complications. Therefore, many factors, including the patient’s age, general medical condition, and associated injuries, must be considered prior to making definitive management decisions.

Patients with severe associated injuries should be treated non-operatively until their general condition improves. Continued poor general medical status and a long delay (>3 weeks) from injury to possible operative intervention may dictate a non-operative management course. Elderly, debilitated patients and others with pre-existing osteopenia require special consideration since the ability to achieve and maintain an anatomical reduction may be more difficult due to poor bone stock and extensive comminution. Furthermore, these patients often have sustained low-energy trauma resulting in a fracture pattern more amenable to non-operative care. Total hip arthroplasty may be a reasonable option either acutely or as a delayed reconstruction.

In most cases, the patient with a fracture of the acetabulum has sustained high-energy trauma. Therefore, these patients often will have an associated injury that must be identified during the initial work-up. Consequently, the initial evaluation, even in those patients with an apparent isolated injury, should be part of a well-organized overall approach. Associated injuries can be life- or limb-threatening. In contradistinction to the unstable pelvic ring injury, a closed fracture of the acetabulum, occurring alone or in combination with other extremity fractures, should not be considered as the primary cause of hypotensive shock. An alternative source of haemorrhage should always be sought. However, laceration of the superior gluteal artery with severe bleeding can be caused by fractures of the acetabulum having wide posterior column displacement. One must be alert to this possibility, which is treatable by therapeutic embolization.

A detailed physical examination is a necessity. The soft tissues should be carefully evaluated, as soft-tissue injury has important implications for subsequent surgery. Acetabular fracture surgery through a compromised soft-tissue envelope is ill advised due to the increased risk of infection. Closed de-gloving soft-tissue injuries over the trochanteric region associated with underlying haematoma formation and fat necrosis (the Morel-Lavallé lesion) or open wounds may require debridement followed by delayed wound closure. More recently, a percutaneous method has been reported in a small number of patients, using a plastic brush to debride the injured fatty tissue, which is then washed from the wound with pulsed lavage. A medium closed-suction drain is placed within the lesion and removed when drainage is less than 30mL over 24h. Fracture fixation is deferred until at least 24h after drain removal. The prevalence of post-traumatic sciatic nerve injury has been reported as being as high as 29%. Other peripheral nerves, such as the femoral nerve and obturator nerve, may also be injured. A complete and clearly documented neurological examination is extremely important both for patient prognosis and for medicolegal concerns.

Initial acetabular fracture management depends on the specific fracture pattern, the amount of fracture displacement, and the relative stability and congruency of the hip joint. The initial anteroposterior (AP) radiograph of the pelvis (which is often an adjunct to the ATLS^® primary survey) can provide substantial diagnostic information and indicate the need for emergency treatment. This radiograph must be supplemented by further studies (oblique plain films and computed tomography (CT)—see Chapter 12.48) in order to define the injury completely.

Dislocation of the femoral head, which can be diagnosed on the initial AP radiograph, requires prompt reduction as the rate of osteonecrosis increases significantly if reduction is not performed within 12h of the injury. The reduction manoeuvre can often be performed in the emergency room setting. However, adequate sedation and pain medication are necessary. Subsequent failed closed reduction, pre-existing contraindications to conscious sedation, or doctor preference constitute indications for closed reduction using general anaesthesia. Immediately following reduction, confirmatory radiographs should be obtained. There is no need to stress an obviously unstable hip and redislocation may be injurious. Only when the fracture pattern suggests that the hip joint should be stable or stability is equivocal (such as with a small posterior wall fracture) should the hip be taken through a full range of motion to evaluate postreduction stability. As a diagnostic procedure, this examination is best performed using fluoroscopic visualization of the hip joint with the patient under general anaesthesia.

Patients with an acetabular fracture may not require skeletal traction. However, there are notable situations in which skeletal traction (preferably using a distal femoral, rather than a proximal tibial, traction pin) is either mandatory or desirable. Unstable fracture–dislocations require skeletal traction following reduction to prevent recurrent dislocation. When hip stability is in doubt, it is also prudent to use traction, pending further evaluation. Preoperative skeletal traction is also important to prevent further femoral head articular surface damage from abrasion by the raw acetabular bony fracture surfaces and may occasionally improve fracture position (Figure 12.49.1). Skin traction is ineffective and should not be used. Skeletal traction using a trochanteric pin is contraindicated due to its associated high infection risk and ineffectiveness in fracture reduction. In general, fractures with minimal or no displacement, both-column fractures in which the hip joint remains congruent and in acceptable position (so-called secondary congruence), and other displaced fractures not meeting operative criteria initially require only bed rest with symptomatic treatment. However, these patients, as well as those with fractures meeting operative criteria who do not require skeletal traction for fracture management, may benefit from skeletal traction for pain relief.

Operative treatment of acetabular fractures is not an emergency and is generally delayed 3–5 days to allow for stabilization of the patient’s general status and for preoperative planning. However, the time to surgery has been shown to be a significant predictor of radiological and clinical outcome. In one study, a good-to-excellent clinical outcome was more likely when surgery was performed within 15 days for elementary fractures and 10 days for associated types. The indications for emergency fracture fixation are uncommon (see later).

In general, all stable concentrically reduced acetabular fractures not involving the superior acetabular dome can be considered for non-operative management. This group of fractures includes non-displaced and minimally displaced fractures, fractures in which the intact part of the acetabulum is large enough to maintain stability and congruity, and those with secondary congruence (Box 12.49.3). Non-operative management may also be selected for patients with severe osteoporosis or severe underlying medical problems that preclude surgical intervention. This is a relatively small group, consisting mainly of elderly patients.

The condition of the superior dome of the acetabulum is a significant prognostic indicator of clinical outcome. The superior dome of the acetabulum is described as the superior third of the weight-bearing area of the acetabulum. Roof arc measurements can be used to decide whether or not an acetabular fracture has violated the weight bearing dome. This measurement has been used to determine if the remaining intact acetabulum is sufficient to maintain a stable and congruous relationship with the femoral head. In this way, operative verses non-operative treatment can be selected. The roof arc is measured on all three radiographic views with the leg out of traction. The medial roof arc is measured on the AP view. The anterior roof arc is measured on the obturator oblique, and the posterior roof arc is measured on the iliac oblique. To obtain these measurements, the first line is a vertical line through the centre of the femoral head and the second line is drawn from the centre of the femoral head to the fracture location at the articular surface (Figure 12.49.2). Roof arc measurements are not applicable to both-column fractures or those with a fracture of the posterior wall. The previous recommendations were that roof arc measurements greater than 45 degrees on the AP (medial roof arc), iliac oblique (posterior roof arc), and obturator oblique radiographs (anterior roof arc) indicate preservation of the weight-bearing dome, and these patients should be considered for non-operative management. More recently, however, biomechanical analysis has produced different criteria. Non-operative fracture management is considered with a medial roof arc angle of greater than 45 degrees, an anterior roof arc angle of greater than 25 degrees, and a posterior roof arc angle of greater than 70 degrees (Figure 12.49.3).

CT cuts of the superior 10mm of the acetabular articular surface are equivalent to the weight-bearing dome region, and can also be useful in determining if acetabular fracture lines involve this region. Although controversy exists regarding the exact amount of displacement that is considered acceptable when the superior dome of the acetabulum is involved, most authors recommend surgical intervention if displacement exceeds 2mm.

Displaced low anterior column, low transverse and low T-shaped acetabular fractures are amenable to non-operative treatment, provided the fracture position is stable and the joint remains congruent.

Displaced both-column fractures of the acetabulum may be considered for non-operative management in the presence of secondary congruence (see Chapter 12.48, Figure 12.48.11), defined as congruency between the femoral head and the displaced acetabular articular fragments without skeletal traction being applied. Parallelism between the femoral head and acetabular articular surface must be maintained in all three radiographic views, especially in a young patient. In addition, articular fragment displacement and medial joint displacement should not be so excessive as to limit motion. However, it must be recognized that fractures with secondary congruence do not have as good a prognosis as those reduced in anatomical position.

Fractures involving the acetabular walls should be treated non-operatively only if the hip joint remains completely stable. Recurrent dislocation and subluxation have disastrous consequences. Although hip instability is much more common with fractures of the posterior wall, anterior wall fractures are also potentially unstable. CT studies of posterior wall fractures indicate that those involving greater than 40–50% are usually unstable, whereas fractures less than 20–25% are usually stable. However, there is evidence that these radiographic measurements are not reliable. When in doubt, it is safest to assume that all of these fractures are unstable until proven otherwise. Therefore, clinical evaluation of stability is mandatory if non-operative treatment is being considered. As noted previously, this examination is best performed using fluoroscopic visualization of the hip joint with the patient under general anaesthesia. With this method, the patient is placed supine with the hip in neutral rotation and full extension. The hip is then gradually flexed past 90 degrees while progressive manual force is applied through the hip along the longitudinal axis of the femur; simultaneously, fluoroscopic imaging of the hip is performed, first using the AP projection and then using the obturator oblique projection. If the hip appears stable (remains congruent) on this assessment, the exam is repeated with the addition of slight adduction and internal rotation (approximately 20 degrees). Frank redislocation is neither required nor clinically desirable. Therefore, posterior subluxation demonstrated in either view (as evidenced by a widening medial clear space or loss of joint parallelism) is indicative of dynamic hip instability. This technique has been proven to predict long-term stability and outcome. Acetabular wall fracture presenting in the absence of known hip dislocation is no guarantee of hip stability (Figure 12.49.4).

It seems obvious that all non-displaced and minimally displaced acetabular fractures should be considered for non-operative management. However, there have been advocates for percutaneous fracture fixation in this group of patients. The concern centres on the questionable stability of these fractures with the contention that a certain percentage will displace. Therefore early percutaneous fixation would avoid a subsequent more extensive open procedure or prevent the disaster of early traumatic arthritis in those (for whatever reason) not having the benefit of further treatment. However, only a very small number (less than 7%) of these non-displaced and minimally displaced fractures are potentially unstable and will significantly displace without traction. Rather than unnecessarily operating on a large number of fractures to prevent problems in these few or subject all of these patients to prolonged bed rest in traction, it makes more sense to try to identify those at risk for fracture displacement. Dynamic fluoroscopic stress examination with the patient under general anaesthesia, as noted earlier, is one proposed method of identifying these fractures at risk. However, the exact technique for performing this examination is ill defined for fractures other than the posterior wall. Another method is to closely observe all patients presenting with non-operative parameters via weekly radiographic follow-up, being prepared to shift immediately to operative management (percutaneous or otherwise) should joint instability or incongruency be detected.

The non-operative management of patients with acetabular fractures mainly consists of bed rest with joint mobilization and eventual progression to full weight-bearing activity. Bed rest is necessary in the acute injury phase only for symptomatic relief. Mobilization of the patient and the hip joint should follow as soon as symptoms allow. Patients should begin with touch-down partial weight bearing of the affected extremity (<10kg). AP and oblique radiographs should be obtained at frequent intervals (weekly for the first 4 weeks) to confirm maintenance of satisfactory position. When there is adequate fracture healing, usually by 6–12 weeks, the patient should gradually progress to full weight bearing. Joint mobilization should be continued throughout the rehabilitation period. The use of formal physiotherapy or continuous passive motion modalities should be tailored to the individual.

Prolonged traction treatment should be reserved for those patients with operative indications related to fracture displacement, but having medical contraindications. In these cases, traction should be maintained until fracture healing is sufficient to allow progressive weight-bearing ambulation and may range from 4–12 weeks.

Good or excellent results can be achieved when congruency and stability are maintained with non-displaced fractures and some displaced fractures not involving the superior dome. Displaced fractures of the superior acetabular dome and posterior acetabular fractures are generally associated with poor clinical results. Delayed reduction of the hip dislocation, injury to the femoral head, and continued instability are all factors contributing to a poor outcome in patients with acetabular fractures.

Operative treatment is indicated for all acetabular fractures that result in hip joint instability and/or incongruity, no matter what the classification type. This statement applies to displaced fractures as well as to those with occult findings. Posterior and anterior wall fractures with instability of the hip joint require operative fixation. In addition, fragments of bone or soft tissue incarcerated within the hip joint may result in joint incongruity. Open reduction and removal of the loose body or obstructive tissue is indicated to prevent early onset of traumatic arthritis. Internal fixation should be performed in this setting as dictated by hip joint stability parameters.

Fracture displacement in the weight-bearing dome results in joint incongruity and constitutes one of the main indications for open reduction and internal fixation. As described previously, plain radiographs and CT can be effectively used to determine whether an acetabular fracture violates the weight-bearing dome. For the both-column fracture, loss of parallelism between the femoral head and the acetabular articular surface noted on any of the three radiographic views is an indication for operative management.

Acetabular fractures are difficult to define anatomically and radiographically, and especially challenging to treat surgically. However, these articular fractures should be treated according to standard orthopaedic principles: the objectives being stable, anatomical fracture fixation combined with early joint motion.

In general, the surgical treatment of an acetabular fracture is not an emergency. A delay of 3–5 days is commonly employed to allow for evaluation of any underlying medical problems or associated injuries and for preoperative planning. Much of the intraoperative manoeuvring for acetabular fracture reduction is performed indirectly, without direct exposure or complete visualization of the fracture fragments. These techniques rely on the presence of relatively mobile fracture fragments. Ten days following injury, early fracture healing begins to limit this type of fracture mobilization. Two weeks following injury, healing has often progressed to the point that this fracture mobility has been lost and a more extensive surgical approach is required for certain fracture types, such as the transverse, T-shaped, anterior column with posterior hemitransverse, and both-column patterns. After 3 weeks, callus formation is extensive to the point that the fracture is no longer considered to be an acute injury. It has been shown that a good-to-excellent clinical outcome is more likely when surgery was performed within 10–15 days. This compromised outcome is probably related to many factors beyond the more extensive surgical exposure with its attendant higher complication rate, such as acetabular cartilage damage and femoral head erosion. Therefore prolonged delay in operative treatment should be avoided if possible.

Indications for emergency open reduction and internal fixation are uncommon (Box 12.49.5). Treatment of open fractures of the acetabulum should follow the standard principles of open fracture management, which include emergency irrigation, debridement, and fracture stabilization. Fracture stabilization options include acute open reduction and internal fixation or traction followed by delayed open reduction and internal fixation. When an acetabular fracture is directly related to a vascular injury and fixation is an important adjunct to the vessel repair (i.e. femoral artery laceration with anterior column fracture), concomitant open reduction and internal fixation is indicated.

Plain radiographs and CT imaging should allow the surgeon to classify the fracture type and to achieve a precise understanding of the ‘personality’ of the fracture. The three-dimensional CT reconstruction may obscure some fracture lines. However, this study can be very helpful in visualizing the overall fracture pattern in the mind’s eye (Figure 12.49.5). Drawing the fracture on paper or on a whole bone specimen is also very instructive. In this way the appropriate surgical approach, reduction technique, and hardware configuration can be planned with confidence that the required anatomical reduction and stable fixation will be accomplished.

Intraoperative traction is very important in obtaining fracture reduction. Therefore, purpose-specific traction tables, such as the Judet fracture table or the Jackson table, are recommended. The operating table should be radiolucent. Intraoperative C-arm fluoroscopy can then be used to assess fracture reduction and hardware location. Therefore fluoroscopy equipment and trained radiology personnel are needed. An extensive array of instruments and implants is also required (Figure 12.49.6). An oscillating drill is helpful for placing screws deep within the wound.

Anatomical reduction of the intra-articular fracture fragments is the objective of acetabular fracture surgery. While correction of fracture displacement is very important, failure to appreciate and correct malrotation (which is considerable in many of the fracture types) is probably the most common cause of fracture malreduction. Developing an understanding of the deformity (gleaned from the preoperative imaging studies) is critically important. This will facilitate planning of intraoperative reduction manoeuvres. Various tools and techniques developed specifically for acetabular fracture reduction are essential. Long pointed reduction clamps, ball spike pushers, and Farabeuf clamps are extremely helpful in obtaining satisfactory reduction (Figure 12.49.7). Intraoperative traction, to unload the fracture fragments from the considerable deforming forces across the hip, is instrumental in assisting fracture reduction. Traction may be applied manually by a surgical assistant, either pulling on the leg or on a traction pin placed in the greater trochanter or distal femur. However, traction by this means is often difficult to maintain effectively. As noted earlier, operating room tables with traction capability are preferable. On board traction using a Universal Distractor is one possible alternative. A Schanz screw with T-handle attachment is helpful for traction and for direct fracture manipulation. K-wires and cerclage wires can be used to secure provisional fixation, and the reduction should be carefully evaluated using fluoroscopy or plain radiographs prior to permanent hardware placement. Fluoroscopy or intraoperative radiographs should be used throughout the procedure to confirm maintenance of reduction and appropriate placement of hardware (Figures 12.49.8 and 12.49.9).

After an anatomical reduction has been obtained, stable fracture fixation is best accomplished using interfragmentary screws augmented by plates. Cortical screws of 3.5mm and 4.5mm diameter are ideal for this purpose and should be available in lengths up to 110mm. Longer or smaller diameter (2.7mm or 2.0mm) screws may be required depending on the fracture configuration or comminution (Figure 12.49.8). These sizes may not be readily available in standard instrument sets. Therefore, preoperative planning is invaluable in these instances. Reconstruction-type plates of 3.5mm (Synthes or Stryker), which can be contoured to the curved, irregular surface of the pelvis and acetabulum, are appropriate for stable fracture fixation (Figure 12.49.9). Implant sites should be carefully selected to obtain satisfactory bony purchase while avoiding neurovascular injury and intra-articular hardware placement. Experience dictates the quantity of hardware required to achieve a stable fixation construct.

Selection of the appropriate surgical approach is one of the most important aspects of the preoperative planning for acetabular fracture surgery. The main determinants in the decision-making process are the fracture type, the elapsed time from injury to operative intervention, and the magnitude and location of maximal fracture displacement. The mainstay surgical approaches to the acetabulum are the Kocher–Langenbeck, ilioinguinal, iliofemoral and the extended iliofemoral. The first three provide direct access to only one column of the acetabulum (posterior for the Kocher–Langenbeck; anterior for the ilioinguinal and iliofemoral) and rely on indirect manipulation for reduction of any fracture lines that traverse the opposite column. The extended iliofemoral approach affords the opportunity for almost complete direct access to all aspects of the acetabulum.

Variations of the Kocher–Langenbeck include the addition of an osteotomy of the greater trochanteric or moving the proximal limb of the incision slightly more anterior (modified Gibson approach). These variations increase somewhat the anterior extent of the surgical exposure (see later). The modified Stoppa surgical approach, an extension of the standard Pfannensteil incision, is an anterior intrapelvic approach and can be considered as a variation of the ilioinguinal approach. This approach may provide improved visualization of the quadrilateral plate, while avoiding dissection of the femoral nerve and vessels. However, a secondary posterior incision (Kocher–Langenbeck) or one paralleling the iliac crest is often required. In addition, if the surgeon shifts his/her position to the opposite side of the operating room table from the ilioinguinal incision, all of the potential advantages of the modified Stoppa approach can be attained.

Modifications of the extended iliofemoral approach have been developed by others, such as the triradiate approach and the T-shaped variant. Each of these extended approaches has its distinguishing aspects. However, they are all variations on the same theme. The price to be paid for the greater surgical access is a greater risk of surgical complications.

As common sense would dictate, posterior fracture types require a posterior approach and anterior fracture types require an anterior approach. Fractures involving both columns demand some decision-making. In general, acute fractures without displacement through the weight-bearing dome can be reduced through a single surgical approach to that column of the acetabulum having the greatest fracture displacement, as long as the fracture lines traversing the opposite column can be accessed and manipulated by indirect reduction manoeuvres. Fracture mobility is gradually lost over time. Therefore, an extended approach (with its attendant higher complication rate) may be needed for delayed surgery of fractures that were otherwise amenable to a less extensive surgical exposure (see earlier). Other indications for the extended approaches include transverse and T-shaped fractures with displacement through the anatomical roof (weight-bearing area) of the acetabulum (i.e. transtectal fractures), T-shaped fractures having wide displacement of the vertical limb, and both-column fractures with sacroiliac joint involvement or segmental fracturing of the posterior column.

The full extent of an anterior approach is obtainable only with the patient in the supine position. Similarly, the posterior Kocher–Langenbeck approach is fully utilized with the patient prone. A simultaneous anterior and posterior surgical approach with the patient in the lateral position limits the access from either. Lateral patient positioning for other than posterior wall fracture fixation creates a tendency to use a more extensive surgical approach (i.e. extending a Kocher–Langenbeck to a triradiate or using simultaneous anterior and posterior incisions) when, with proper positioning and planning, less may have sufficed (Figure 12.49.10).

The Kocher–Langenbeck approach is ideal for posterior wall fractures and posterior column fractures with or without an associated posterior wall fracture. Transverse and T-type fractures without displacement in the anatomical roof, treated within 15 days of injury, are also amenable to this surgical approach. In addition, for T-shaped fractures, the major displacement should be posterior, with only minor displacement occurring anteriorly at the pelvic brim.

The patient can be placed in the lateral or prone position. However, as noted previously, the prone position is preferred for the more complex fracture types. The knee must remain flexed throughout the procedure to reduce the risk of injury to the sciatic nerve. The incision begins approximately 6cm lateral to the posterior superior iliac spine, courses distally in a curvilinear fashion over the greater trochanter and extends in a mid-lateral position to the midpoint of the thigh. The fascia lata is sharply incised and the gluteus maximus muscle is bluntly divided toward the posterior superior iliac spine. The innervation of the gluteus maximus muscle comes from the inferior gluteal nerve, which runs from posterior to anterior in the muscle. Therefore the splitting of this muscle should stop as soon as the first nerve trunk is met, approximately at the midpoint between the greater trochanter and the posterior superior iliac spine. Next, the insertion of the gluteus maximus muscle into the femur is released. This allows posteromedial retraction of the muscle without excessive stretch on the inferior gluteal nerve. The sciatic nerve is then located along the posterior surface of the quadratus femoris muscle and traced proximally to the piriformis muscle. The short external rotators and piriformis tendon are divided and tagged with sutures to assist with retraction. These tendons should be incised approximately 1.5cm from their trochanteric insertion to avoid injury to the blood supply of the femoral head. Gentle retraction of the short external rotators allows visualization of the posterior column and retroacetabular space but provides only limited protection of the sciatic nerve.

The Kocher–Langenbeck approach provides direct visualization of the entire lateral aspect of the posterior column of the acetabulum (Figure 12.49.11). Visualization may be extended anterosuperiorly by dividing a portion of the gluteus medius insertion or perfor ming a transtrochanteric osteotomy (Figure 12.49.12). Indirect access to the quadrilateral surface can be attained by the palpating finger or the use of special instruments placed through the greater sciatic notch. A posterior capsulotomy allows limited access to the posterior aspect of the joint surface. This access is increased in the presence of a fractured posterior wall. This approach has a relatively high risk for sciatic nerve injury and an intermediate risk for heterotopic ossification.

The modified Gibson approach differs from the Kocher–Langenbeck approach in its proximal dissection such that the interval between the gluteus maximus and tensor fasciae latae muscles is divided rather than splitting of the gluteus maximus muscle (Figure 12.49.13). In this way, the neurovascular supply to the anterior portion of the gluteus maximus muscle is not at risk. In addition, anterosuperior visualization and access are extended (Figure 12.49.12). Having a straight, rather than angled skin incision, may make the modified Gibson more cosmetically appealing, especially in obese female patients. Either the Kocher–Langenbeck or modified Gibson approaches can be combined with a trigastric trochanteric osteotomy, maintaining the gluteus medius, vastas lateralis and gluteus minimus muscle attachments to the mobile trochanteric fragment. In this way, intraoperative dislocation of the femoral head for inspection of the joint is facilitated.

The ilioinguinal approach is indicated for fractures involving the anterior wall and anterior column. Transverse and T-type fractures in which the major displacement is anterior with minimal posterior displacement and both-column fractures having a non-comminuted posterior column fragment can also be managed using this approach. Again, these complex fracture types must not have displacement in the anatomical roof and must be treated within 15 days of injury.

The patient is placed supine on the operating room table. The incision extends from just posterior to the gluteus medius tubercle, paralleling the iliac crest to the anterior superior iliac spine and then coursing medially to the midline ending two finger-breaths above the pubic symphysis. The iliacus muscle is elevated from the internal iliac fossa. The aponeurosis of the external oblique muscle (along with the anterior aspect of the sheath of the rectus abdominis) is then incised from the anterior superior iliac spine to the midline, passing at least 1cm superior to the superficial inguinal ring. The aponeurosis is reflected distally revealing the spermatic cord in the male and the round ligament in the female. This structure is bluntly isolated along with the ilioinguinal nerve and retracted using a rubber sling. The now exposed inguinal ligament is split through its entire length revealing the laterally placed lacuna musculorum contents (lateral femoral cutaneous nerve, the iliopsoas muscle mass and femoral nerve) and the medially placed lacuna vasorum containing the external iliac vessels and lymphatics. The iliopectineal fascia, which separates these lacunae, must be incised to allow access to the quadrilateral plate and true pelvis. Separate rubber slings are placed around the lacuna musculorum contents and the external iliac vessels. In this way medial, middle and lateral surgical access ‘windows’ are created.

The internal iliac fossa, anterior aspect of the sacroiliac joint, and lateral portion of the anterior column can be visualized by retracting the iliopsoas medially. The quadrilateral plate can be accessed by retracting the iliopsoas laterally and the external iliac sheath medially. The superior pubic ramus is visualized by retracting the external iliac sheath laterally and spermatic cord medially. Lateral retraction of the spermatic cord (aided by release of the insertion of the rectus abdominis muscle) allows visualization of the symphysis pubis and access to the retropubic space. Prior to retraction of the vessels, care must be taken to look for an anomalous origin of the obturator artery, known as the corona mortis or other anastomoses between the obturator and the external iliac systems (Figure 12.49.14).

The ilioinguinal approach allows direct access to the entire pelvic brim and the internal iliac fossa (Figure 12.49.15). Indirect access to the quadrilateral surface can be attained by the palpating finger or the use of special instruments. This approach has the lowest rate of heterotopic ossification. The lateral femoral cutaneous nerve, the femoral nerve, the external iliac vessels, and the inguinal canal contents are all at risk for injury.

The iliofemoral approach has limited application. It is the approach of choice for anterior wall fracture variants (see Chapter 12.48, Figure 12.48.8). Although the ilioinguinal is usually the better choice, the iliofemoral approach may be used for high anterior column fractures.

The patient is placed supine on the operating room table. The incision extends from just posterior to the gluteus medius tubercle, paralleling the iliac crest to the anterior superior iliac spine and then coursing distally for approximately 15cm along the lateral aspect of the sartorius muscle. The iliopsoas muscle is elevated off the inner aspect of the iliac crest. The sartorius origin and inguinal ligament are released from the anterior superior iliac spine. The interval between the sartorius and the tensor fascia lata is developed to allow exposure of the anterior hip joint capsule, the anteroinferior iliac spine, and the anterior column as far medial as the iliopectineal eminence.

This approach is fairly simple and low risk. However, access to the anterior column is quite limited. The lateral femoral cutaneous nerve or some portion thereof is usually injured with this approach.

The extended iliofemoral approach is indicated for selected complex acetabular fracture types and for surgery delayed more than 2 weeks following injury (see earlier section on timing of surgery). These include high transverse and T-type fractures involving the acetabular roof (i.e. transtectal fractures) and both-column fractures having a comminuted posterior column component, a displaced fracture through the sacroiliac joint or wide separation of the anterior and posterior columns at the acetabular rim.

The patient is placed in the lateral position and the knee maintained in a flexed position to relax the sciatic nerve. An inverted J incision is used, extending from the posterior superior iliac spine along the iliac crest to the anterior superior iliac spine and then continued distally to the midpoint of the thigh angling toward a point 2cm lateral to the lateral aspect of the patella. The gluteal and tensor fascia lata muscles are elevated from the external surface of the ilium and are hinged on the superior gluteal neurovascular bundle. The hip abductors and the short external rotators are released from their insertion into the greater trochanter to complete the exposure of almost the entire external surface of the bone. Release of the reflected head of the rectus femoris combined with a circumferential capsulotomy at the acetabular rim provides direct visualization of the hip joint. The exposure can be extended medially by release of the sartorius and rectus femoris origins and elevation of the iliacus from the internal iliac fossa. However, this additional muscle stripping creates added risk of iliac wing and acetabular dome devascularization and increased risk of infection.

The extended iliofemoral approach allows exposure of the entire outer surface of the ilium, posterior column, posterior wall, and anterior column to the level of the iliopectineal eminence (Figure 12.49.16). The articular surface is exposed following capsulotomy, and access to the iliac fossa is also possible, as noted earlier. This approach has a high rate of heterotopic bone formation. The risk of infection is significant, over 8% in one series. There is also a risk of injury to the sciatic nerve and the superior gluteal neurovascular bundle. At one time it was postulated that severe abductor muscle necrosis would result from injury to the superior gluteal artery. However, extensive clinical experience and animal studies indicate that this is not a clinically significant problem.

The triradiate approach has indications similar to those for the extended iliofemoral. However, the exposure is more limited, lacking complete visualization of the iliac crest. The skin incision is Y-shaped, with the posterior limb being nearly identical to the Kocher–Langenbeck incision. The anterior limb of the incision extends from the greater trochanter to the anterior superior iliac spine. The skin incision is deepened through the fascia. Posteriorly, the approach is as for the Kocher–Langenbeck. A trochanteric osteotomy is performed to release the abductor insertion, and the glutei and tensor muscles are elevated from the external surface of the ilium. The triradiate approach can be performed when the surgeon cannot address the fracture through an initial Kocher–Langenbeck approach.

Combined anterior and posterior approaches were originally used in sequential fashion when one approach was planned, but proved inadequate for fracture fixation. One example of this is the inability to reduce or fix the posterior column of a both-column fracture initially approached using the ilioinguinal. Use of simultaneous anterior (iliofemoral or ilioinguinal) and posterior (Kocher–Langenbeck) approaches has been advocated for complex fracture patterns. The patient is first positioned supine and then turned 45 degrees toward the side opposite the fracture and secured in this position. The initial incision is used to approach the column with the greatest displacement.

Patients should receive prophylactic intravenous antibiotics, administered preoperatively and continued at least 24h postoperatively. Prophylaxis for thromboembolic disease (mechanical or chemical) should be routinely used during the perioperative period and continued up to 12 weeks postoperatively, until the patient regains mobility. Heterotopic ossification is associated with all approaches that involve stripping of muscle from the external surface of the ilium and is a particular risk of extended surgical approaches. Therefore, prophylaxis should be considered in these cases.

AP and oblique postoperative radiographs should be obtained, and repeat radiographs should be evaluated at routine 4- to 6-week intervals during the early postoperative period to check maintenance of reduction and fracture healing. A postoperative CT scan should be considered if there is concern for intra-articular hardware or inadequate reduction.

Postoperatively, the patient is mobilized as quickly as the associated injuries will allow. Sitting up on the first postoperative day, is followed by formal physical therapy for muscle strengthening and active range of motion exercises on subsequent postoperative days. Total hip arthroplasty precautions should not be needed, as internal fixation has rendered the hip joint stable. Partial toe-touch weight bearing of 10–15kg with crutches or a walker is required for 10–12 weeks. However, progression to full weight bearing must be tailored to the individual. Physical therapy should continue until muscle strength and range of motion are regained or a plateau is reached.

Clinical outcome and the subsequent development of post-traumatic osteoarthritis strongly correlate with the adequacy of fracture reduction. Early studies considered residual displacement of up to 2–3mm as ‘satisfactory’ and demonstrated good, very good, or excellent results in approximately three-quarters of the study group.

A more recent study used less than 2mm of residual displacement as an anatomical reduction and at an average follow-up of 10.9 years demonstrated 81% good or excellent clinical result, whereas only 64% of patients with non-anatomical reduction achieved a good or excellent clinical result. The rate of anatomical reduction was found to decrease with increased fracture complexity, patient age, and time delay to fracture fixation. Many studies have demonstrated the detrimental effect of delay to surgery. This affects the ability to achieve anatomical reduction and clinical outcome. It has been demonstrated that anatomical reduction is more likely if performed within 15 days for elemental and 5 days for associated fracture patterns.

Certain fracture patterns appear to have better outcomes after surgical treatment than others. Both-column fractures are complex injuries and technically demanding. However, they have a generally better outcome than many fracture types, despite a higher rate of non-anatomical reduction. Despite anatomical reduction in only 57% of cases, good to excellent result were achieved in 77% of one study group. Posterior wall fractures present as a straightforward treatment problem with excellent anatomical reduction rates reported as high as 100%. However, despite the anatomical reduction obtained, clinical failure rates as high as 32% have been reported. Other studies have reported better results and this disparity has been shown to be in large part, to the inadequacy of radiographs in assessing the quality of the postoperative posterior wall reduction.

The common major early complications consist of infection, iatrogenic nerve injury, intra-articular screw placement, and thromboembolism. Late complications include heterotopic ossification, post-traumatic arthritis, and osteonecrosis of the femoral head.

The rate of infection is approximately 5% in most series of acetabular fractures treated operatively. The risk of infection is increased in patients with open fractures and local soft tissue injuries such as Morel-Lavallé lesions. Gastrointestinal or urological injuries are also associated with increased infection rates. Appropriate antibiotics, less extensive surgical approaches, and aggressive debridement of open wounds can help to decrease the rate of infection. The adverse affect of a deep postoperative intra-articular wound infection cannot be minimized. Complete joint destruction can be expected in 50% of these cases.

Although the superior gluteal, obturator, or femoral nerves (among others) may be injured during acetabular surgery, the prevalence of these injuries is low. However, iatrogenic damage to the sciatic nerve is one of the major complications encountered in acetabular fracture management. These injuries are most commonly associated with the posterior and extended surgical approaches which involve direct exposure and retraction of the sciatic nerve. However, injury at the time of indirect reduction of posterior column displacement through an anterior surgical approach can also occur.

Iatrogenic nerve injury rates have been reported ranging from 2–9%. Intraoperative sciatic nerve monitoring has been advocated by some authors as a method to decrease the incidence of sciatic nerve injury. However, the rate of nerve injury appears to decrease as surgeon experience increases. A 2% incidence has been reported without nerve monitoring when performed by experienced surgeons in a large centre. At present, there is no clear data indicating that intraoperative somatosensory evoked potential nerve monitoring actually reduces the overall rate of iatrogenic sciatic nerve injury. Spontaneous motor potential monitoring is another option and preliminary results indicate that this method may prove to be more effective. At present, there is no substitute for attention to detail in the operating room with careful patient positioning and good surgical technique.

Although specific rates are not available, intra-articular placement of screws is a documented and often destructive complication of acetabular fracture surgery. Intraoperative fluoroscopy is the best method of preventing this complication and avoiding post-traumatic arthritis.

Post-traumatic and postoperative thromboembolism is a significant problem in acetabular fracture patients. Proximal deep vein thrombosis has been identified using magnetic resonance venography in 34% of acetabular fracture patients. Therefore, some form of mechanical or chemical prophylaxis is recommended to decrease the risk of thromboembolic complications. One study indicated that early (at the time of hospital admission) mechanical prophylaxis with foot pumps and the addition of enoxaparin on a delayed basis (5 days after admission) is a very successful strategy for prophylaxis against venous thromboembolic disease following serious musculoskeletal injury. For any patient who was required to return to the operating room, the enoxaparin was discontinued on the night prior to surgery and was resumed within 12h of surgery. Despite the use of prophylactic treatment, the prevalence of post-traumatic and postoperative thromboembolism approximates 11% and the value of screening, using Doppler ultrasound or magnetic resonance venography remains controversial. The placement of prophylactic vena caval filters is controversial but may be indicated in selected high-risk patients.

Currently, no prophylactic treatment consensus exists. Our approach consists of mechanical sequential compressive devices applied on hospital admission to both lower extremities, low-molecular-weight heparin for chemical prophylaxis as soon as the patient is haemodynamically stable and screening using duplex colour Doppler ultrasound. For patients who require operative intervention, the low-molecular-weight heparin is discontinued on the night prior to surgery and resumed within 36h after surgery. After discharge from the hospital, the patients are maintained on chemical prophylaxis until they have regained mobility, usually 6–12 weeks postoperatively. Vena caval filters are reserved for those high-risk patients having contraindications to chemical prophylaxis.

Heterotopic ossification has been reported as occurring in as many as 90% of patients after acetabular fracture surgery (range 18–90%) with severe involvement as high as 50% in some patient groups. The terminology ‘severe heterotopic ossification’ is often used to describe the amount of heterotopic ossification necessary to impair function. Greater than 20% loss of total hip motion is thought to be the best clinical definition for severe heterotopic ossification. Many reports have used the Brooker classification (Table 12.49.1), which relies solely on the AP radiographic view of the hip, for this determination. However, this radiographic method does not consistently correlate with hip joint motion and generally overestimates the clinical severity of heterotopic ossification. A radiographic classification that would accurately correlate with significant limitation of hip motion should be useful in evaluating the independent effect of heterotopic ossification on functional outcome in patients after acetabular fracture surgery. Adding the standard Judet oblique views (which would routinely be obtained in the course of the patient’s postoperative evaluation) to the AP view and reading them in a logical specified sequence appears to give a more reliable indication of the restriction of motion that can be attributed to heterotopic ossification. Using this modified system, class 0, I, and II typically demonstrate unimpaired range of motion.

The most notable risk factor for heterotopic ossification is stripping of the gluteal muscles from the external surface of the ilium. In a recent series, in which significant heterotopic bone formation was defined as motion limited by greater than 20% and patients were not given prophylactic treatment, the following prevalence figures were reported: Kocher–Langenbeck 8%; extended iliofemoral 20%; ilioinguinal, 2%.

It appears that the rate of heterotopic ossification can be significantly reduced with the use of indomethacin and radiation therapy. A recent prospective randomized study comparing indomethacin and radiation therapy demonstrated both to be safe and effective prophylactic agents. Non-compliance was the problem with indomethacin; radiation was strikingly more expensive. Use of a combination of irradiation and indomethacin essentially eliminated postoperative heterotopic ossification in one series as no progression of heterotopic ossification was noted, even when early ossification was seen on preoperative radiographs.

Heterotopic ossification is a significant potential postoperative complication of acetabular fracture surgery and prophylactic therapy is desirable. However, one must weigh the risk of prophylaxis and its potential for failure against the actual risk of occurrence in each particular clinical situation. A recent study in acetabular fracture patients has shown that the use of indomethacin increases the risk of long-bone non-union. Although genetic alterations in offspring may also be at issue, the possibility of induced malignant disease is the main concern with low-dose radiation therapy. However, for the radiation dosage and methods used for the prophylaxis of heterotopic ossification about the hip, the likelihood of induced malignancy is very low. Based on a review of the current evidence available in the literature, recommendations have been made regarding the use of heterotopic ossification prophylactic treatment (Box 12.49.7). Indomethacin is inexpensive, simple, safe, and probably works. As with other non-steroidal anti-inflammatory drugs, gastric and duodenal mucosal lesions may occur. In addition, gastrointestinal prophylaxis (such as misoprostol) should be considered to decrease the risk of these drug-induced lesions. However, the use of this drug, or that of any other gastroduodenal mucosal protective agent, in acetabular fracture patients receiving indomethacin for heterotopic ossification prophylaxis has not been studied. Irradiation should be considered in high-risk cases (e.g. head injured) and for adult patients (women beyond child-bearing age) requiring an extended surgical approach.

Post-traumatic arthritis is a well-documented complication of patients sustaining a fracture of the acetabulum. The quality of the fracture reduction appears to be the main determinant for clinical outcome and for the risk of late traumatic arthritis. Damage to the femoral head at the time of initial injury is another important factor. Osteonecrosis of the femoral head is known to result from acetabular fracture associated with hip dislocation and can also result in post-traumatic arthritis. However, post-traumatic arthritis is more commonly due to wear of the femoral head against a malreduced fracture and often may be incorrectly attributed to osteonecrosis. Total hip arthroplasty or arthrodesis is indicated for patients with post-traumatic arthritis and disabling pain.

Displaced acetabular fractures in elderly patients may be effectively treated with open reduction and internal fixation. Good or excellent results at 2-year minimum follow-up have been reported, in 16 of 17 elderly (over 60 years old) patients treated surgically. However, elderly patients often have low-energy fracture patterns (anterior column or both-column) that have a relatively good prognosis with conservative treatment. The decision to perform open reduction and internal fixation should be based on the fracture pattern, the medical status of the patient, and the degree of osteoporosis. Extended surgical approaches are to be avoided. The alternative is non-operative treatment followed by total hip arthroplasty, as the symptoms dictate, with the knowledge that the prognosis for conservative treatment is poor. Unfortunately, studies indicate that, overall, the late outcome of total hip arthroplasty after acetabular fracture is inferior to that of arthroplasty performed because of degenerative arthritis. Therefore, open reduction and internal fixation combined with primary total hip arthroplasty, as a single operative procedure, has been advocated for a highly selected group of especially severe acetabular fractures, particularly those in elderly patients.

Fractures of the ipsilateral femoral shaft are common, and should be acutely fixed. Acute fixation of both the femoral and acetabular fracture may be undertaken, but this is often not desirable or logistically possible. If the two procedures are staged, the antegrade operative approach for femoral nailing may compromise a subsequent acetabular approach. Therefore, retrograde nailing of the femoral fracture should be considered.

As noted earlier, the results of total hip arthroplasty after failed acetabular fracture surgery are inferior to those of primary total hip arthroplasty for degenerative hip disease. There is a significantly higher rate of acetabular loosening (53%) and revision (14%) compared with patients who did not previously sustain an acetabular fracture. Factors contributing to these poorer results include the young age of the patients, the predominance of males, and the residual osseous deficiencies. The surgery itself is also technically more demanding. Therefore the performance of acetabular fracture surgery should not be approached as a satisfactory staging procedure prior to a definitive total joint replacement.

Since the initial publications of Judet and Letournel in the early 1960s significant strides have been made in the treatment of acetabular fractures. There is no doubt that excellent results can be obtained by experienced surgeons and the expansion of educational activities specific to acetabular fracture care has increased the number of experienced surgeons. However, acetabular fracture fixation remains extensive surgery with a significant potential complication rate. Not all patients achieve a good or excellent result, related mainly to residual fracture displacement, infection, nerve injury, thromboembolic disease and heterotopic ossification. Efforts continue toward the refinement in operative techniques and improved prophylactic measures. However, the results of Letournel and Judet (1993) remain as the ‘gold standard’. It is yet to be determined whether the advent of intraoperative, fluoroscopically-based three-dimensional image navigation systems, along with improved instrumentation for fracture reduction and fixation through limited-incisions, can better these results.