Fractures of the Acetabulum and Pelvis

Nondisplaced and Minimally Displaced Fractures

Fractures that traverse the weight-bearing dome, but are displaced less than 2 mm, may be appropriate for treatment with non–weight bearing for 6 to 12 weeks, depending on the fracture characteristics ( Table 56.1 ). Radiographs should be obtained immediately after the patient is first mobilized and frequently thereafter to ensure that no displacement has occurred. Occasionally this requires a repeat CT scan to assess maintenance of reduction.

Fractures With Significant Displacement but in Which the Region of the Joint Involved is Judged to be Unimportant Prognostically

This determination is made with the roof arc measurements at 45 degrees for each roof arc: medial, anterior, and posterior ( Fig. 56.20 ). Vrahas, Widding, and Thomas questioned whether the 45-degree value is the most appropriate for each roof arc. In a study of cadaver hips, they proposed acceptable roof arc measurements as 25 degrees for the anterior roof arc, 45 degrees for the medial roof arc, and 70 degrees for the posterior roof arc. As a rough guide, they recommended ORIF of displaced fractures exiting the posterior column above the upper border of the ischial spine, as well as of fractures exiting the anterior column through the iliac wing.

Displaced fractures through the weight-bearing dome in a young patient with more than 2 mm of displacement should be treated operatively. These fractures tend to displace, leading to inferior results. In the modern era, virtually no fractures are treated definitively by traction to maintain a reduction involving the acetabular dome.

Fractures with a posterior wall component, especially when associated with posterior fracture-dislocations of the hip, require separate consideration and are evaluated after closed reduction. Larger posterior wall fragments lead to posterior hip instability and require fixation. Three well-described methods, that of Calkins ( Fig. 56.21 ), Keith ( Fig. 56.22 ), and Moed ( Fig. 56.23 ), have been used for determination of wall size in comparison to the normal acetabulum. Critical wall size resulting in instability is determined by the method of measurement, with Calkins, Keith, and Moed hypothesizing that walls larger than 40%, 65.7%, and 50%, respectively, based on their measurements, were going to be unstable. They also theorized that fragments smaller than 20%, 44.8%, and 20% based on measurements by the methods of Calkins, Keith, and Moed, respectively, would be stable. However, only 2 years later Moed et al. published another study warning against the use of CT findings as the sole predictor of stability. Their follow-up found that inappropriate nonoperative treatment (i.e., nonoperative management of an unstable hip) would have occurred in 6% (11/180) of patients and inappropriate operative treatment (i.e., operative fixation of a stable hip) would have occurred in 16% (28/180) of patients. This finding was further reinforced by Firoozabadi et al. when they showed that 23% of fractures smaller than 20% of the wall were unstable. These fractures did tend to extend more cranially (5.0 mm from the dome compared to 9.5 mm from the dome); however, this was not found to be a reliable predictive factor in determining stability. While these measurements can aid the surgeon, an examination under anesthesia (EUA) remains the gold standard for predicting posterior instability after acetabular fracture involving less than 50% of the wall, with operative management without EUA indicated for those involving more than 50%.

Tornetta described EUA of the acetabulum after utilizing fluoroscopic stress views of 41 hips with acetabular fractures for which ORIF was not indicated based on roof arcs of 45 degrees, a subchondral CT arc of 10 mm, displacement of less than 50% of the posterior wall, and congruence on the anterior-posterior and Judet views of the hip. He either sedated or anesthetized patients and stressed their fractures in the direction of the deforming force for each fracture pattern while fluoroscopically viewing the fractures on all three standard radiographic views. He found that three of these hips subluxated on stress views without frank instability noted clinically, and these fractures underwent ORIF. These hips would have passed the traditional clinical test of stability by flexing the hip to 90 degrees. The same preference for dynamic fluoroscopic stress testing has been stated by other authors when comparing CT criteria for stability in posterior wall fractures to fluoroscopic EUA.

We have adopted this technique of performing stress views under fluoroscopy when patients are considered for nonoperative treatment of smaller posterior wall fractures. We view the pelvis in the obturator oblique view, flexing the hip to 90 degrees, providing adduction and internal rotation. A static fluoroscopic image is then obtained. While posteriorly directed pressure is applied through the knee with enough force to rock the pelvis (50 to 100 lb), a spot fluoroscopic view is obtained and scrutinized to assess subluxation ( Fig. 56.24 ).

Stable hips are treated like a pure dislocation of the hip. We still prescribe posterior hip precautions for the first 6 weeks, with touch-down weight bearing on crutches for 2 weeks, followed by progressive weight bearing, then full return to activity at 6 weeks. Following this assessment and treatment technique, Grimshaw and Moed reported the radiographic outcome of 15 nonoperatively treated patients with small posterior wall fractures that were stable with EUA. At a minimum of 2 years after injury, none of the patients showed incongruence or joint space narrowing.

Medical Contraindications to Surgery

In patients with multiple trauma, medical contraindications from multisystem injury are common, even in previously healthy patients. Although early fracture fixation and mobilization are basic tenets of polytrauma treatment protocols, complex fractures may require long operative procedures with significant blood loss. On occasion, the severity of the medical condition mandates that operative intervention be delayed. If deemed needed, the articular cartilage of the hip should be protected during these delays by placing the patient in skeletal traction. On occasion, severe head trauma with a tenuous, evolving spectrum of injury may preclude a surgical procedure; however, a head injury in itself is not necessarily a contraindication to surgery. The eventual neurologic outcome frequently cannot be reliably assessed in the immediate postinjury period, when acetabular ORIF can most reliably be performed.

Percutaneous fluoroscopic screw fixation has been recommended for suitable fractures in severely injured patients, in patients with significant medical comorbidities, and by some authors for patients over the age of 60. In our practice, although not a substitute for formal ORIF, it serves as an excellent alternative in select patients ( Fig. 56.26 ). Gary et al. reported the use of percutaneous screw fixation in acetabular fractures in patients 60 years of age and older assessed 6.8 years after the index surgery. At final follow-up, approximately 30% had been converted to total hip arthroplasty. They found that in the patients who retained their native hips, their short musculoskeletal functional assessment was similar to two series of formal ORIF in this age group, and that the Harris Hip Scores in those patients converted to total hip replacement were similar to those reported for acute total hip replacement for acetabular fracture. In medically compromised patients in whom a full open approach may not be possible, percutaneous management may offer improved pain control, earlier mobilization, and prevention of skin breakdown, deep venous thrombosis (DVT), and other medical complications.

Local Soft-Tissue Problems, Such as Infection, Wounds, and Soft-Tissue Lesions From Blunt Trauma

An open wound in the anticipated surgical field is a relative contraindication, as is systemic infection. More ominous in fractures around the acetabulum is the Morel-Lavallée lesion, a localized area of subcutaneous fat necrosis over the lateral aspect of the hip caused by the same trauma that caused the acetabular fracture (see Chapter 53 ). Judet and Letournel found that in their series approximately 8% of patients who sustained a blow to the greater trochanter had a clinically significant Morel-Lavallée lesion. The size and extent of this lesion are variable, with as many as 46% of “closed” injuries being culture-positive at initial debridement, and operating through it has been associated with a higher rate of postoperative infection, with as high as 12% infection rates being reported with repeated postoperative wound debridement, packing, and healing by secondary intention. However, Tseng and Tornetta described an alternative method of percutaneous decompression and debridement with delayed ORIF until at least 24 hours after drains were removed, which was performed when output was less than 30 mL per day. While they reported no infections in any patient treated percutaneously, of the two fractures that were fixed through a Kocher-Langenbeck approach, one required a surgical exploration of the wound because of persistent drainage (see Technique 53.1). Alternatively, some fractures can be treated through anterior approaches, thus avoiding the affected area. The presence of a significant Morel-Lavallée lesion should be suspected in any patient with hypermobility of the skin or a fluid wave in the subcutaneous tissue. The CT scan, if available, should be scrutinized for a fluid collection in the subcutaneous tissues.

The presence of a suprapubic catheter was previously considered a contraindication to acetabular ORIF by the ilioinguinal and anterior intrapelvic (AIP) approaches. Bacterial colonization of the catheter had been anecdotally reported to increase the rate of infection; however, a recent series using the National Trauma Data Bank (NTDB) showed no increase in infectious complications in patients undergoing pelvic or acetabular surgery who had a suprapubic catheter. As a large database study, these findings are certainly promising but not always representative of findings in smaller controlled groups; thus, when possible, through primary repair of the bladder rupture and Foley catheter drainage, we still attempt to avoid suprapubic catheter placement.

Elderly Patients With Osteoporotic Bone

Traditionally, there was a concern for loss of reduction due to inadequate fixation in osteoporotic bone; however, a small series by Helfet et al. questioned this this concern, as only one patient in 18 lost reduction during the healing period. Carroll et al. found that in 84 patients over the age of 55 years who had initial ORIF for their acetabular fractures, nearly 31% (26/84) required conversion to total hip arthroplasty within 5 years of their initial surgery. Similarly, a study from a level 1 trauma center found that 28% of patients over the age of 60 years required a total hip arthroplasty within 2.5 years of their injury. Superior medial impaction of the dome, or the “gull sign,” particularly correlated with a poor outcome ( Fig. 56.27 ).

Ryan et al. reported a series of patients ages 60 years or older who had acetabular fractures that met traditional operative criteria. Although this was a small series of only 27 patients, they found that only 15% (4/27) required conversion to total hip arthroplasty and the remaining 85% had WOMAC and SF-8 scores consistent with those of patients with a normal hip.

In our practice, elderly patients with fracture morphology consistent with poor outcomes (e.g., large areas of impaction or “gull sign”) are routinely treated with ORIF and acute total hip arthroplasty. Comminuted and impacted fractures in high-comorbidity elderly patients often are treated with early mobilization and nonoperative management, with a discussion that delayed surgery may be required if the patient develops symptomatic arthritis. The benefit of nonoperative management in these patients is that many will do well without any surgery and those who do require surgery will have a more predictable delayed total hip arthroplasty that requires less time, less blood loss, and a lower rate of transfusion than patients who have had ORIF.

Fracture Characteristics

Operative indications for acetabular fractures traditionally include (1) 2 mm or more of displacement in the dome of the acetabulum as defined by any roof arc measurements of less than 45 degrees on any of the three Judet views or 10 mm on CT cuts, (2) subluxation of the femoral head noted on any of the three standard radiographic views or CT, (3) posterior wall fractures involving more than 40% of the joint, and (4) dynamic instability of the hip allowing subluxation in posterior wall fractures involving less than 40% of the joint.

Incarcerated Fragments in the Acetabulum After Closed Reduction of a Hip Dislocation

Small avulsed fragments of the ligamentum teres that stay sequestered in the cotyloid fossa and do not affect the congruency of the hip probably do not require excision. Fragments noted on CT to be lodged between the articular surfaces of the femoral head and the acetabulum warrant excision, as do fragments in the cotyloid fossa large enough to cause subluxation of the joint. Fluoroscopic and arthroscopic techniques of fragment removal have been described, although most often this is performed through an open approach, up to and including need for surgical dislocation.

Prevention of Nonunion and Retention of Sufficient Bone Stock for Later Reconstructive Surgery

This last indication for ORIF should be applied only in cases of extreme deformity because total hip arthroplasty after failed ORIF of an acetabular fracture may be more difficult than hip arthroplasty after nonoperative management. Scarring from previous surgeries, implants, and heterotopic bone can complicate such secondary reconstruction. Percutaneous fixation may be considered in patients who are at high risk of conversion to total hip arthroplasty but have displacement that is concerning for nonunion of the columns required for standard cup placement. We use this technique to mobilize these patients, using limited column fixation to prevent gross displacement of the fracture. After fracture healing, conversion to total hip arthroplasty can be done if the patient’s symptoms warrant (see Fig. 56.27 ). This topic is covered in more detail later (see Total Hip Arthroplasty as Treatment of Acetabular Fracture).

Anterior Intra-Pelvic Approach

Developed by Letournel in the 1960s, the traditional ilioinguinal approach consists of three windows through a single skin incision, extending from the iliac crest to the midline, above the symphysis. The lateral window extends lateral to the iliopsoas (iliopectineal fascia), the middle window is between the iliopsoas and the external iliac vessels, and the medial window is medial to the external iliac vessels. The originally described ilioinguinal approach involved a medial window developed lateral to the rectus muscle or through a tenotomy of the rectus tendon; however, most surgeons who use the ilioinguinal approach now combine the ilioinguinal and AIP approaches, working through a window between the rectus muscle bodies along the linea alba. Traditionally, most surgeons prefer to use skeletal traction on a radiolucent flat-top table for most fractures treated through an anterior approach. Use of a triangle under the hip helps to relax the iliopsoas and improve visualization through the lateral window.

More complicated fractures may require one of the extensile approaches, such as the extended iliofemoral approach described by Letournel and Judet, the triradiate approach of Mears and Rubash, or the T-approach described by Reinert et al. The use of extensile approaches have largely fallen out of favor in the last decade, mostly because of the morbidity of these extensive dissections, but they remain a viable option for certain fracture patterns. The historic indications include associated both-column fractures with posterior wall displacement or a segmental posterior column or transtectal T-shaped fractures with significant displacement of both columns, especially in a young patient. If an extensile exposure is used, confirmation of the patency of the superior gluteal artery with angiography has been recommended because this may be the only vascular pedicle supplying the abductor muscles. This recommendation was based primarily on clinical observation of patients with extensile exposures as well as concerns about the collateral circulation of the abductor muscle mass, and was further supported by cadaver studies. This recommendation is not universally accepted and was not supported by a canine study with ligation of the superior gluteal artery followed by various surgical approaches showing ischemia, yet no frank necrosis with extensile approaches. Caution is still recommended in considering the use of an extensile approach with a suspected superior gluteal artery injury.

To prevent complications of extensile exposures, limited exposures and indirect reduction techniques have been recommended, as have combined anterior and posterior approaches for some fractures. Our preference is to perform consecutive approaches separately, with an anterior approach and then a posterior one, or vice versa, depending on the fracture pattern, rather than performing such approaches simultaneously with the patient in a “floppy lateral” position. When performing sequential anterior and posterior approaches, care must be taken to avoid placing implants into the portion of the fracture that will be accessed by the opposite approach. While the “floppy lateral” position with simultaneous anterior and posterior exposures avoids this problem, visibility and access are compromised, especially from the anterior approach, because the patient is not truly supine.

Posterior Wall Fractures

The most common acetabular fracture treated by the average orthopaedist is the posterior wall fracture. These fractures are, for the most part, treated through a Kocher-Langenbeck approach (see Technique 1.74) with the patient positioned either prone or in the lateral decubitus position on a fracture table or with the leg free. When positioning the patient, the sciatic nerve should be considered; flexion of the knee with slight extension of the hip can reduce tension throughout the case. If the fracture extends superiorly into the dome, the modified Gibson approach or a digastric trochanteric osteotomy can be done to allow additional exposure. The trochanteric fragment can be displaced anteriorly to expose the supraacetabular surface of the ilium. If a modification of the standard approach is planned, this also should be taken into consideration. While the digastric osteotomy can be done with the patient prone, if there is any possibility of requiring a surgical dislocation, this can be done only with the patient in the lateral position. During the approach, care should be taken to avoid splitting the gluteus maximus past the first neurovascular branches, which can result in denervation and abductor weakness. The short external rotators must be released approximately 1 cm from their insertion to avoid injury to the deep branch of the medial femoral circumflex artery as it arises from the muscle body of the quadratus femoris and passes posterior to the obturator internus tendon immediately adjacent to its insertion on the femur.

The hip is distracted to clear any incarcerated fragments before reduction of the wall fragments. A close inspection is made for marginal impaction of articular fragments into the intact posterior column. Marginal impaction, which occurs in more than 22% of isolated wall fractures and should be scrutinized on the preoperative CT scan and intraoperatively, is elevated and bone grafted or fixed using a bone graft substitute. If necessary, the technique described by Giannoudis, Tzioupis, and Moed for two-level reconstruction of comminuted posterior wall fractures with marginal fragments secured by subchondral mini-fragment screws is used ( Fig. 56.31 ). After reduction of the wall fragments, provisional fixation with Kirschner wires can be used while definitive fixation is performed with lag screws, when possible, and a contoured reconstruction plate placed from the ischium, over the retroacetabular surface onto the lateral ilium ( Fig. 56.32 ). Intraarticular screw placement must be avoided. Intraoperative fluoroscopy in multiple views should be used to ensure that all screws are extraarticular. When necessary, the C-arm position can be modified to allow further “over the top” range of motion to obtain the necessary views ( Fig. 56.33 ).

The use of spring plates has been advocated to improve stability in comminuted fractures. These can be made from one third tubular plates by cutting or breaking the plate through the last screw hole and bending down the remaining end as tines, which are used to capture bone fragments that cannot be easily fixed with screws. Premade spring plates also are available, which are preferable because of their metallurgy, which uses spring steel. The spring plate is slightly over-contoured so that when the reconstruction plate is applied over the spring plate the captured fragments are held firmly in position. A Kirschner wire can be used to sound the edge of the bony acetabulum and ensure the tines of the plate are not overlying the femoral head. The tines should be placed over bone and not over the soft tissues of the labrum alone. This technique is useful in fractures with multiple fragments and fractures that extend close to the acetabular rim ( Fig. 56.34 ).

Other less commonly used techniques for the fixation of posterior wall fractures include the use of locking reconstruction plates with unicortical locking screws in the posterior wall to allow positioning of the plate closer to the acetabular rim without penetrating the articular surface of the wall. Another reported technique is the use of cervical H-shaped plates to substitute for comminuted posterior wall cortical bone while supporting underlying articular fragments that have been reduced.

Although a posterior wall fracture is the easiest fracture pattern to reduce, the reported long-term results after this fracture have varied, with upwards of 20% of patients requiring conversion to total hip arthroplasty at some point and those with more complex fracture characteristics having even higher rates of conversion. Osteonecrosis of the femoral head because of associated hip dislocation, marginal impaction, multiple fracture fragments, and osteochondral injuries of the femoral head all adversely affect the outcome of these fractures.

Posterior Column Fractures

Isolated posterior column fractures are relatively uncommon and, if significantly displaced, require ORIF ( Fig. 56.35 ). The main indication is instability of the hip, and low column fractures with a posterior roof arc angle of 70 degrees or more can be treated nonoperatively. The utility of dynamic stress for evaluation of posterior column fractures has not been as well described as it has for posterior wall fractures. Traumatic injury to the sciatic nerve is relatively more common compared with other fracture patterns, as is entrapment of the superior gluteal bundle due to the cranial extension of the fracture line into the greater sciatic notch. The Kocher-Langenbeck approach is used routinely. Rotational deformity in addition to displacement must be corrected by placement of a Schanz screw in the ischium to control rotation while the fracture is reduced with a small fragment Jungbluth reduction clamp. Typical fixation is with lag screws combined with a contoured reconstruction plate along the posterior column. A secondary plate, more peripheral, can assist with rotational control.

Anterior Wall and Anterior Column Fractures

Isolated anterior wall fractures are uncommon and sometimes associated with anterior hip dislocation. Fractures requiring surgery are best accessed through an ilioinguinal approach or a lateral window with an anterior superior iliac spine osteotomy.

Anterior column fractures are approached similarly, with the addition of an AIP approach when necessary. Reduction is through correction of medialization and external rotation. This most often is done with a Farabeuf clamp and ball spike or an offset clamp. Fixation is with a contoured plate or LC-2 style screw along the pelvic brim ( Fig. 56.36 ). The acetabulum here is thin, and screws generally should not be placed in this region. Anterior column fractures that exit higher through the iliac wing require fixation along the iliac crest, as well as either plate or screw fixation. Kazemi and Archdeacon have advocated percutaneous fixation of select minimally displaced anterior column fractures with immediate weight bearing. While they achieved excellent radiographic outcomes in 19 of 22 patients followed more than 1 year, our preference is to protect weight bearing in most patients. In elderly patients, for whom protected weight bearing may not be possible, placement of percutaneous fixation may prevent future displacement and allow earlier mobilization.

Transverse Fractures

These fractures, although classified as simple, present a spectrum of difficulty. Selection of the appropriate approach is crucial because fractures with primarily anterior displacement can be difficult to reduce through a posterior approach. Transtectal fractures, or fractures that occur through the dome above the cotyloid fossa, have the worst prognosis, and accurate reduction is essential. Juxtatectal fractures, those that occur at the junction of the cotyloid fossa with the articular surface, also usually require reduction, whereas infratectal fractures frequently can be treated nonoperatively if roof arc measurements are appropriate with no subluxation of the femoral head.

Reduction and fixation can be performed through either an anterior or a posterior approach. This should be based on the aspect of the fracture with the most displacement. Most isolated transverse acetabular fractures without an associated pelvic ring injury have posterior displacement, as the fracture hinges on the intact symphysis. If a posterior approach is used, this should be done with the patient prone rather than in the lateral decubitus position, unless a surgical dislocation is planned. If the patient is placed in the lateral decubitus position, the weight of the leg tends to displace the ischiopubic fragment medially. Collinge, Archdeacon, and Sagi studied patients with transverse fractures treated either in the lateral or prone positions and found that using Matta’s radiographic criteria for reduction, prone positioned patients had anatomic reductions in 61% (<2 mm of residual fracture displacement), whereas in lateral-positioned patients 42% were graded as anatomic.

Typically, we use a small Jungbluth clamp on the posterior column to reduce the fracture while rotation is controlled by a Schanz screw in the ischium. Alternately, a short-angled pelvic clamp can be placed through the greater sciatic notch to control the anterior reduction. This technique is especially pertinent with an associated wall fracture that extends medially over the entire outer table, limiting the ability to place a Jungbluth clamp. Care must be taken to not place pressure on the sciatic nerve with clamps placed through the sciatic notch. The reduction can be assessed directly by palpating the reduction of the quadrilateral surface through the greater sciatic notch. Anterior column fixation is usually achieved first, with a lag screw placed with fluoroscopic guidance. Care must be taken with placement of the anterior lag screw to prevent shearing of the fracture. Often a transverse lag screw will provide more optimal trajectory than a traditional anterior column screw down the ramus. Posterior fixation typically is with a contoured plate along the posterior column preceded by a lag screw if the fracture orientation is appropriate.

From the ilioinguinal approach, reduction is usually accomplished by using plate reduction along the anterior column to close the fracture gap; a large spiked reduction clamp placed on the quadrilateral surface and the lateral surface of the ilium in the region of the anterior inferior spine controls medial displacement and rotation of the caudal fragment. Typical fixation is a contoured plate along the pelvic brim with lag screws directed down the posterior column ( Fig. 56.37 ). On occasion, combined approaches are necessary for more complex transverse fractures or those that are delayed in operative intervention.