ⁿ

 

 

 

^DEFINITION

^{A posterior wall fracture is one of the elementary fracture types as described by Letournel and Judet.6 It is a fracture of the posterior rim of the socket portion of the ball-and-socket joint of the hip ( FIG 1).}

^{The disruption separates a segment of articular surface that involves varying amounts of the bony posterior wall of the acetabulum. It can exist as one single fragment or as several comminuted pieces.}

^{The wall fracture can exist alone or as part of an associated acetabular fracture.}

^{By definition, the posterior column, and therefore the ilioischial line, remains intact despite varying amounts of retroacetabular surface disruption.}

 

^{FIG 1 • AP (A) and Judet (B,C) radiographs of a posterior wall fracture. The posterior wall fracture fragment is outlined.}

^ANATOMY

 

^{The hip is a constrained ball-and-socket joint composed of the femoral head as the ball and the acetabulum as the socket.}

 

^{The capsule surrounding the joint extends from the bony acetabular rim to the intertrochanteric line anteriorly and to the femoral neck posteriorly. It is thickened in specific areas, creating ligaments.}

 

 

^{Anteriorly, the iliofemoral Y ligament exists as two bands. The inferior capsule is supported by the pubofemoral ligament and the posterior capsule is strengthened by the ischiofemoral ligament.}

 

^{The acetabular labrum is a fibrocartilaginous structure attached to the bony rim, deepening the socket and making}

 

³⁵⁶

^{the joint more stable. It adds an additional 10% of coverage to the femoral head.}

 

^{The acetabulum is composed of two columns, two walls, and the roof within the pelvis. The anterior and}

^{posterior columns form an inverted Y and are attached to the sacrum via the sacral buttress. The articular surface of the joint sits on the anterior and posterior walls and the roof, which is located within the arms of the Y.}

 

 

^{The anatomic roof is located between the anterior inferior iliac spine and the ilioischial notch of the acetabular margin.6}

 

^{The weight-bearing dome, as determined by 45-degree roof arc measurements on anteroposterior (AP) and Judet radiographs, is the most important articular portion of the acetabulum. This functional aspect of}

 

^{the acetabulum includes the excursions of all resultant force vectors during normal daily activities.9 Two additional segments should also be considered separately.}

 

^{The posterosuperior segment is the bridge between the roof and the posterior wall.}

 

 

^{The posteroinferior segment is the lower part of the posterior wall and the posterior horn of the cartilage.6}

 

 

^{Due to the large area of muscular attachments, the blood supply to the acetabulum is vast.6 Small arteries start peripherally and flow centrally, parallel to each other.}

 

 

^{The largest nutrient foramina on the internal aspect of the ilium is reliably located 1 cm lateral to the sacroiliac joint and 1 cm above the iliopectineal line. It is fed by a branch of the iliolumbar artery.}

 

^{A branch of the superior gluteal artery feeds the largest nutrient foramina on the external surface in the center of the iliac wing, just anterior to the anterior gluteal line.}

 

^{The obturator artery supplies foramina in front of the sciatic notch just below the iliopectineal line and in the roof of the obturator canal. The body of the pubis is also supplied by the obturator artery. A branch of this artery, the acetabular branch, feeds the cotyloid fossa via a number of small perforators.}

 

^{A complete vascular circle supplies multiple nutrient vessels around the periphery of the acetabulum. The artery of the roof of the acetabulum (from the superior gluteal artery), the obturator artery, and the inferior gluteal artery are main contributors.}

 

^{The iliac crest, from the anterior inferior iliac spine posteriorly to the auricular articular surface of the sacroiliac joint, is supplied by branches of the external anterior iliac artery, branches of the fourth lumbar artery, and branches of the iliolumbar artery.}

 

^{The sciatic buttress receives its blood supply from multiple branches of the superior gluteal artery.}

 

^PATHOGENESIS

 

^{Acetabular fractures occur when a force is transmitted from the femur, through the femoral head, to the acetabulum. The specific pattern of the fracture is determined by the position of the hip at the time of injury and the magnitude of the force of the trauma.}

 

 

^{A common mechanism of injury of posterior wall fractures and fracture-dislocations is a motor vehicle crash in which the unrestrained patient is sitting with a flexed knee and the knee strikes the dashboard, creating an axial load along the length of the femur, loading the posterior aspect of the acetabulum.}

 

^{Posterior wall fractures of the acetabulum occur when the hip is flexed to 90 degrees and is in neutral coronal and axial plane orientation. In this position, when an axial load is applied to the femur, the posterior articular surface of the joint is stressed. The amount of comminution, displacement, and articular impaction will depend on the quality of the bone and the magnitude of the force.}

 

 

^{A typical posterior wall fracture is completely below the roof of the acetabulum.}

 

^{With less hip flexion and a force applied along the axis of the femoral shaft, a superior posterior wall variant will result, which includes part of the adjacent roof.}

 

^{A posterior inferior fracture includes the inferior horn of the articular surface, the subcotyloid groove, and often the superior ischium.}

 

^{Extended fractures, massive posterior wall fractures, and transitional forms are mentioned for completeness but are outside the scope of this chapter.}

 

^{A variation of a posterior wall fracture is a fracturedislocation, which involves single or multifragmented pieces of the posterior wall separated by the dislocating femoral head. This pattern is often associated with impaction of the articular surface of either the head or the wall (FIG 2).}

 

 

^{With a posterior wall fracture or fracture-dislocation, one of two possibilities exists for the capsule.}

 

 

^{The capsule can rupture and allow the head to dislocate.}

^{In this scenario, varying sizes of wall fragments and labral injury can exist.}

 

^{Alternatively, the capsule can remain intact to the wall fragment and to the femur, with all of the displacement (or even the dislocation) occurring through the fracture site.}

 

^{The size of the posterior wall fragment and the integrity of the capsule and the labrum play a role in hip stability.}

^{Despite attempts to quantitate fragment size to define operative indications,2, 5, 7, 16 stress examination remains the only method to predict instability.14}

 

^{When the capsule remains intact and the head dislocates, the fracture edges often fragment. This creates osteochondral fragments, which can lead to impaction or incarceration of the pieces upon reduction of the femoral head.}

 

 

 

^{FIG 2 • Axial CT cut showing impaction. The impacted fragment (arrow) is rotated with the articular cartilage now facing laterally.}

 

 

³⁵⁷

^{NATURAL HISTORY}

 

^{The goal of the treatment of acetabular fractures is to achieve a stable, congruent hip joint with an}

^{anatomically reduced articular surface. Anatomic reduction and stabilization will decrease the incidence of posttraumatic arthritis.8}

 

^{Although fractures of the posterior wall are common, representing 24% of Letournel and Judet's initial series, they are frequently reported as having poor results, with 10% to 30% of patients developing posttraumatic arthritis within 1 year.}

 

^{Nonoperative treatment is unsuccessful, and Epstein3 has documented that 88% of patients treated with closed reduction alone had unsatisfactory long-term results.}

 

 

^{Roof arc and subchondral arc measurements do not apply to typical posterior wall fractures; however, the size of the posterior wall fragment may play a role.}

 

^{Multiple authors have attempted to define the size of the fragment that will predict instability.}

 

 

^{In cadaveric studies, fragments that include greater than 50% of the wall were always unstable, whereas those less than 20% were stable.5, 16}

 

^{A clinical study revealed that acetabuli with less than 34% of the posterior wall intact were unstable and those with greater than 55% intact were stable.2}

 

^{Dynamic stress examination that uses fluoroscopy to assist with the detection of subtle subluxation can define a stable or unstable joint without depending on fragment size measurements.14}

^{PATIENT HISTORY AND PHYSICAL FINDINGS}

 

^{Acetabular fractures are often the result of high-energy trauma, therefore other associated injuries must be sought.}

 

^{Hemorrhage and hemodynamic instability are rarely associated with isolated fractures of the posterior wall; however, the superior gluteal artery and vein may be lacerated when fractures extend to the greater sciatic notch.}

 

^{Patients will frequently present with hip or groin pain and a shortened lower extremity due to the posterior, superior dislocation of the femoral head.}

 

^{Soft tissue injuries around the pelvis are uncommon because the mechanism of injury is indirect. Nonetheless, the skin overlying the hip and pelvis of any pelvic or acetabular fracture should be carefully evaluated for any subcutaneous fluctuance, ecchymosis, or cutaneous anesthesia.}

 

 

^{The Morel-Lavallée lesion, a subcutaneous degloving injury, although a closed injury, is culture positive in}

^{up to 40% of cases.4 Initial débridement of these lesions as well as a delay in internal fixation is recommended by some authors.}

 

^{Soft tissue injuries at the knee are more common and often missed. Ligamentous or chondral injuries are often discovered on secondary survey, but only if they are considered and a careful and thorough examination is performed.}

 

^{The incidence of damage to the femoral head is unknown as the head is not routinely dislocated during fixation of the acetabular fracture for complete evaluation. However, it is not surprising when associated femoral head fractures or chondral lesions are noted as the large amount of force needed to cause the acetabular fracture is transmitted via the femoral head.}

 

^{Careful neurologic examination at the time of injury reveals deficits in up to 30% of cases. The peroneal division of the sciatic nerve is the most commonly seen nerve injury, especially when the femoral head is dislocated posteriorly.}

 

^{Other ipsilateral extremity injuries often discovered include fractures of the femur, tibia, and foot.}

 

^{IMAGING AND OTHER DIAGNOSTIC STUDIES}

 

^{The diagnosis and classification of an acetabular fracture is made from the initial trauma AP radiograph.}

 

 

^{Two 45-degree oblique radiographs (Judet views) must be obtained also to aid in classification and treatment planning.}

 

^{Completing the five views of the pelvis series with pelvic inlet and outlet views allows potential injuries to the pelvic ring to be evaluated.}

 

^{A computed tomography (CT) scan of the pelvis will assist in defining displacement, intra-articular fragments, marginal articular impaction, and associated femoral head injuries.}

 

 

^{The size of the posterior wall fragment can also be determined more accurately using a CT scan, which is optimally obtained after the initial reduction.}

 

^{The size and number of incarcerated fragments can be more precisely determined with a CT scan. Preoperative planning allows determination of the size and number of free fragments that must be removed from the joint as well as the location of any impaction that must be elevated.}

 

 

^{DIFFERENTIAL DIAGNOSIS}

 

^{Posterior hip dislocation Associated acetabular fracture}

^{Associated transverse and posterior wall fracture Associated posterior column and posterior wall fracture Associated T-shaped fracture}

^{Associated both-column fracture Pelvic fracture}

^{Femoral head fracture}

^{Proximal femur fracture}

 

 

^{NONOPERATIVE MANAGEMENT}

 

^{Nondisplaced, stable fractures with a congruent joint can be treated with protected, foot-flat weight-bearing restrictions if no instability is evident on fluoroscopic-assisted stress examination.14}

 

^{Posterior wall fractures that present dislocated should be considered a surgical emergency.}

 

 

 

^{A prompt closed reduction with satisfactory general anesthesia is recommended. The surgeon should check the femoral neck before reduction.}

 

^{Once reduced, the joint should be evaluated fluoroscopically in both the AP and obturator oblique views for}

^{stability: The joint should be axially loaded with the hip in flexion and in flexion plus adduction.14 Only if the joint is stable (nonsubluxated) is nonoperative management sufficient.}

 

^{SURGICAL MANAGEMENT}

 

^{Surgical management of acetabular fractures is technically demanding. The goal of surgery is to obtain an anatomic reduction of the joint surface and to create a congruent and stable hip joint while avoiding complications.}

 

 

³⁵⁸

 

^{Other factors that play a role in surgical management include surgeon experience and the timing of operative intervention.}

 

 

^{Letournel and Judet described their learning curve in 4-year intervals.}

 

^{They also reported reduced ability to achieve anatomic reduction when fractures are operated on more than 21 days after injury.}

 

^{Unlike most conditions in orthopaedic surgery, all displaced fractures of the acetabulum, which include}

^{marginal impaction, are indicated for surgery unless specific criteria for nonoperative management are met.15 These include the following:}

 

 

^{A congruent hip joint on AP and Judet radiographs and on CT scan}

 

^{An intact weight-bearing surface, as defined by roof arc measurements and subchondral arc measurements on CT scan}

 

 

^{At least 50% of the posterior wall intact on CT scan}

 

 

^{A stable joint, including on a dynamic stress examination Patient factors must also be considered.}

 

^{Age, bone quality, comorbidities, preinjury functional status, type of employment, and personal expectations all must factor into the decision-making process.}

 

^{Preoperative Planning}

 

^{Open reduction and internal fixation of a posterior wall fracture is based on evaluation of the AP pelvic and Judet view radiographs and the CT scan.}

 

^{The surgeon should closely evaluate the films for a transverse component, which may be overlooked on initial viewing.}

 

^{The identification of marginal impaction necessitates elevating the articular cartilage and packing behind it with some form of bone graft or bone void filler to reconstruct the joint surface successfully (see FIG 2).}

 

^{Careful review of the CT scan will allow identification and quantification of the number of intra-articular fragments that exist to ensure that all foreign bodies are removed from the joint upon exploration.}

 

^Positioning

 

^{Most acetabular surgeons position the patient prone on a fracture table (FIG 3).}

 

 

^{The affected side is suspended using a distal femoral traction pin.}

 

^{The peroneal post must be appropriately padded to prevent pudendal nerve palsy.}

 

^{The affected leg is placed in traction, with the hip in extension and the knee flexed to at least 80 degrees; the foot is well padded and secured in a fracture table boot in the resting position. Sequential compression devices are applied to both lower extremities.}

 

^{Traction is positioned to pull in line, neutral abduction-adduction, neutral internal/external rotation, with the table's arm holding the foot free enough to allow internal and external rotation intraoperatively.}

 

^{The contralateral leg is in extension in a fracture table boot with the foot well padded and in neutral position.}

 

 

 

 

^{FIG 3 • Prone positioning on a fracture table with the affected leg in distal femoral skeletal traction, the hip extended, and the knee flexed to at least 80 degrees. Sequential compression devices are in place on both lower extremities.}

 

^{Pads are placed to support both thighs.}

 

 

^{Chest pads are positioned to allow adequate room for the abdomen and breasts and for chest excursion. Arms are abducted to 90 degrees at the shoulders and 90 degrees at the elbows.}

 

^{Once positioning is completed, posteroanterior and oblique views are obtained with the C-arm before draping or preparation to ensure that the hip is reduced and that the necessary images can be obtained.}

 

 

^{The obturator oblique view can be obtained by rotating the C-arm 45 degrees toward a lateral view.}

 

^{Pushing upward on the anterior superior iliac spine can assist with the last 15 degrees of rotation to obtain an iliac oblique view, an image that most C-arms cannot otherwise obtain.}

 

^{In certain circumstances, such as presence of a free fragment in the joint that may be difficult to access, lateral positioning may be necessary.}

 

 

^{The patient is turned lateral on a radiolucent table with appropriate padding, including an axillary roll and protection of the peroneal nerve at the fibular head on the down leg.}

 

^{The authors prefer a beanbag with a large gel pad, although Stulberg hip positioners or a peg board are also adequate if limited concerns for a lengthy procedure.}

 

^{The affected extremity is draped free so the leg can be moved intraoperatively to allow for subluxation or redislocation of the femoral head through the fracture as needed to access the fragment.}

 

^{Care must be taken throughout the procedure to ensure knee flexion and hip extension to decrease risk to the sciatic nerve.}

 

^{Once positioning is complete and prior to draping, C-arm images are obtained to ensure adequate radiograph visualization is obtainable.}

 

^Approach

 

^{The posterior wall of the acetabulum is accessed via the Kocher-Langenbeck approach.}

 

 

³⁵⁹

 

^TECHNIQUES

• ^{Kocher-Langenbeck Approach}

^{Incision and Dissection}

^{The incision is based on two limbs (TECH FIG 1A).}

^{One starts at the posterior tip of the greater trochanter and extends distally along the posterior aspect of the femoral shaft, distal to the trochanter and the gluteal crease, which serves as an external landmark for the gluteus maximus tendon.}

^{The proximal limb extends about 45 degrees toward a spot 1 cm cephalad to the posterior superior iliac spine. The length of this limb depends on the amount of posterior column that must be accessed.}

^{The skin and subcutaneous tissue are divided down to the fascia lata and the gluteal aponeurotic fascia.}

^{Once identified, the tensor fascia lata and iliotibial band are sharply divided longitudinally in line with the underlying femoral shaft (TECH FIG 1B).}

^{To open the proximal limb, the surgeon sharply divides the gluteal aponeurosis and then gently splits}

 

^{the gluteus maximus muscle via finger dissection.}

 

^{The surgeon must watch for crossing vessels and cauterize them before they are torn.}

 

^{The nerves that innervate the proximal third of the gluteus maximus will cross in this area, about halfway between the greater trochanter and the posterior superior iliac spine. The surgeon should stop splitting at the first nerve trunk to prevent postoperative palsy.}

 

^{The Charnley retractor is helpful for holding the fascia away from the operative field. The surgeon must take care not to insert too deeply to prevent iatrogenic injury to the sciatic nerve.}

 

^{The bursa over the trochanter is often hemorrhagic from the injury and can be resected at this time if it is large and hindering visualization (TECH FIG 1C).}

 

 

 

^{TECH FIG 1 • A. Kocher-Langenbeck incision. B. The surgeon divides the fascia and then splits the gluteus maximus muscle. C. With the Charnley retractor in place, the surgeon excises the bursa if it obstructs visualization.}

 

^{Protecting the Sciatic Nerve}

 

^{The sciatic nerve is identified. This can be difficult owing to the conditions of the traumatized tissues; often, it will be easiest to identify the nerve in an area of healthy tissue, such as at the level of the quadratus femoris.}

 

^{If overall visualization is inadequate at this point, the gluteus maximus tendon can be divided at its insertion on the femur. A cuff of tissue is left on the femur so an adequate repair can later be performed.}

 

^{With the posterior aspect of the gluteus medius tendon retracted anteriorly, the piriformis tendon can be identified (TECH FIG 2A).}

 

^{It can be helpful to internally rotate the leg to put the short external rotators and the piriformis on stretch to assist with identification.}

 

^{In some cases, the short external rotators have been avulsed by the dislocation.}

 

^{It is easier to palpate the edges of the piriformis tendon with a finger and then pass a finger behind the tendon to better isolate it.}

 

^{The surgeon confirms that the correct muscle has been identified by following its path backward and toward the greater sciatic notch.}

 

^{Once isolated, the tendon is tagged and divided at its attachment to the femur (TECH FIG 2B). This tag suture is used to retract the muscle posteriorly (TECH FIG 2C).}

 

^{With the piriformis retracted, the sciatic nerve should now be easily visible, lying over the short external rotators. The surgeon visually examines the sciatic nerve for any contusion or laceration.}

 

^{Next, the surgeon identifies the tendon composed of the superior and inferior gemelli and the obturator internus.}

 

^{Another tag suture is passed through this tendon, and it is released from the femur.}

 

 

³⁶⁰

 

 

 

 

^{TECH FIG 2 • A. By retracting the gluteus medius anteriorly, the piriformis and obturator internus}

^{tendons are revealed. B. Piriformis and obturator internus tendons are tagged and released from their insertion on the proximal femur. C. Using the tag sutures, the piriformis tendon can be retracted posteriorly. D. Retracting the piriformis allows identification of the sciatic nerve resting on the short external rotators. By using the tag suture on the obturator internus tendon to retract it posteriorly, the sciatic nerve will be protected and safely retracted out of the operative field. E. Femoral head and posterior wall fragments are visible.}

 

 

^{Because the piriformis lies superficial to the sciatic nerve, it will not retract or protect the nerve.}

 

^{In contrast, the gemelli and the obturator internus can be used to effectively protect and retract the sciatic nerve posteriorly (TECH FIG 2D).}

 

^{By pulling upward on this tag stitch-tendon, the surgeon can pass a finger into both the greater and lesser sciatic notches, beneath the muscle, and therefore the nerve, making a path.}

 

^{A sciatic nerve retractor can then be placed along this path, into either notch. (Care should be exercised if a retractor must be placed into the greater sciatic notch due to the presence of the superior gluteal neurovascular bundle.)}

 

^{By continuously checking that the external rotators are above the retractor, the surgeon can ensure that the sciatic nerve is protected. In addition to protecting the nerve, this helps to retract the soft tissues and provides excellent visualization of the retroacetabular surface.}

 

^{The posterior hip capsule, the fracture line, and the posterior wall fragment are now within the surgical field (TECH FIG 2E).}

• ^{Fracture Site Exposure and Débridement}

   

  ^{With the retroacetabular surface now exposed, the fracture site and the joint must be débrided and prepared.}

   

  ^{By removing any residual hematoma from the field, the posterior wall fragment and the posterior column will become easily visible.}

   

  ^{The posterior column is inspected carefully for any nondisplaced transverse fracture line. It is better to recognize this early than to displace it later.}

   

  ^{The surgeon “books open” the fracture site by flipping the wall piece out into the wound.}

   

  ^{The posterior wall piece will typically remain attached by the capsule and some periosteum. The surgeon strips away from the wall any periosteum that may be preventing}

   

  ³⁶¹

  ^{its mobilization, taking care not to injure the labral attachments. The surgeon must be sure to peel all the periosteum off the fracture edges. Direct visualization of interdigitation at the fracture site is vital in judging anatomic reduction, and the rate of nonunion is low after reduction and fixation of acetabular}

  ^fractures.8

   

  ^{It is often necessary to sharply dissect the overlying gluteus minimus muscle from the posterior wall to allow mobilization.}

   

  ^{The femoral head will be easily visualized once the wall is mobilized and the interior of the hip joint is inspected.}

   

  ^{Any damage to the femoral head is noted.}

   

  ^{Intra-articular fragments can be removed and the joint can be irrigated to remove any other debris.}

   

  ^{With the fracture table used to pull traction, the joint can be distracted, which will assist with joint débridement. If the fracture table allows such movement, the hip can be flexed to assist with fragment}

  ^removal.

   

  ^{If there is concern that a fragment remains in the joint, a 70-degree arthroscope can be used while distracting the hip to visualize the anterior joint and to identify the fragment. This is especially helpful if you are in the prone position and on a table without hip flexion capabilities. Useful instruments to reach around the head to secure a fragment include a curved Kocher and a Cooley vascular clam}

   

  ^{Alternatively, if in the lateral position, a formal surgical dislocation with a trochanteric osteotomy can be performed (see Cha 37). This will allow easy access to any fragments in the joint and evaluation of the entire articular surface directly.}

   

  ^{The intact segment must be prepared in a similar fashion.}

   

  ^{The surgeon strips any additional periosteum and soft tissue that remains attached to the intact retroacetabular surface at the fracture edge. Again, this area will later be inspected for fracture line interdigitation.}

   

  ^{Any soft tissue is elevated from the top of the ischium. This will prepare the ischium to receive the reconstruction plate.}

   

  ^{The soft tissues superolateral to the acetabulum, on the outer table of the ilium, must be elevated in preparation to receive the proximal aspect of the plate. In this area, it is often necessary to elevate the overlying gluteus minimus muscle.}

   

  ^{It is safe to pass an elevator under the abductor muscles, staying on bone, down toward the iliac crest at the level of the anterior superior iliac spine. A spiked Hohmann retractor inserted in this path can also assist with retraction and visualization.}

   

  ^{With the fracture bed, the joint, the wall fragment, and the intact segment débrided, fracture reduction is the next ste}

• ^{Fracture Reduction}

  ^{Reduction of Marginal Impaction}

   

  ^{Careful dissection of the posterior wall fragments and the intact portion of the pelvis is necessary for an accurate reduction.}

   

  ^{Preoperative review of all the radiographic images will normally identify any marginal impaction, which must be reduced.}

   

  ^{When the femoral head is sitting in the acetabulum, the areas of impaction can be reduced to the head.}

   

  ^{An osteotome is placed deep to the depressed subchondral bone. Gentle malleting allows the osteotome beneath the impacted bone. By manipulating the bone and its overlying cartilage, the articular surface is reduced to the femoral head with its intact cartilage.}

   

  ^{Once reduced, there will be an empty space deep to the subchondral bone where the osteotome entered and the original bone collapsed. This area is packed with an osteoconductive bone void filler that can provide structure and prevent recollapse. Options include autogenous cancellous bone, allograft cancellous bone chips, and calcium sulfate bone graft substitute.}

   

  ^{As in other areas of the body, overreduction is better than underreduction, as often there is settling.}

   

  ^{Once the fracture bed has been meticulously débrided of fracture hematoma and soft tissue, interdigitation of the posterior wall to the remaining intact retroacetabular surface can be visualized.}

  ^{Reducing the Posterior Wall Fragment}

   

  ^{With the marginal impaction reduced, attention is turned to reducing the posterior wall fragment into its}

  ^{bed in the intact acetabulum.}

   

  ^{The wall fragment is flipped into its bed.}

   

  ^{Using a ball spike pusher, the surgeon gently manipulates the piece until a smooth, convex retroacetabular surface with no external step-offs is obtained. If this cannot be produced, the wall piece is flipped out of its bed again and the surgeon looks for a cause of the malreduction. If the fragment does not reduce perfectly at the retroacetabular surface, it will not be reduced perfectly at the joint.}

   

  ^{Once reinspection is complete, the wall is reintroduced to its bed. The piece is manipulated into place. Gentle persuasion with a mallet can help the fragment find its home, especially if marginal impaction reduction required grafting.}

   

  ^{Provisional fixation is placed next. This can hold the fragment in place while the surgeon evaluates the reduction and places the definitive internal fixation.}

   

  ^{If multiple wall fragments exist, careful planning of the order of reduction is vital. Often, certain pieces must be reduced first, as the cortical shell of other fragments may need to rest outside of the cancellous bone attached to its neighboring fragment. Without attention to this detail, an anatomic reduction may be impossible.}

   

  ^{Provisionally holding a multifragmented posterior wall can be difficult. Multiple Kirschner wires or spring plates may be needed. Sometimes, only the definitive fixation can be used.}

   

   

  ³⁶²

• ^{Internal Fixation}

  ^{Provisional Fixation}

   

  ^{Once the posterior wall pieces are reduced, provisional fixation to hold the fragment in place can make the overall procedure easier.}

   

  ^{Options for provisional fixation include either interfragmentary lag screws (2.7 or 3.5 mm) or Kirschner wires.}

   

  ^{By using a ball spike pusher, the fracture fragment is stabilized within its bed, and a Kirschner wire or a lag screw can be placed to hold the reduction.}

   

  ^{We prefer to use 2.7-mm lag screws. With these screws, the heads sit flush with the bony cortex and do not interfere with the subsequent placement of the definitive fixation.}

   

  ^{An alternative to a lag screw is the use of one or multiple Kirschner wires. If Kirschner wires are used, the reconstruction plate can be placed around the wires without difficulty, and subsequent removal is easy.}

   

  ^{Occasionally, when the posterior wall piece is small orcomminuted, lag screws and Kirschner wires may not be possible. A spring plate can be used (similar to when preventing medial wall “kick-up”).}

   

  ^{The end hole of a one-third tubular plate is cut into a V, creating tines. The plate is bent so the tines can effect a reduction.}

  ^{This plate can be used as provisional fixation to hold a small wall fragment in place or as a spring plate to prevent the medial aspect of a large wall fragment from kicking u}

   

  ^{The tines and a portion of the plate are placed over the wall fragment. The fracture edge is spanned with the remaining plate. Either of the remaining holes of the plate can be used for screw placement, depending on the size of the wall being stabilized.}

   

  ^{The plate is positioned so it is possible to drill outside of the joint. Once secured, this spring plate will prevent the wall piece (if small) or the medial fracture edge (if the wall piece is large) from kicking up or}

  ^displacing.

  ^{Reconstruction Plate Stabilization}

   

  ^{Now that the wall piece is reduced, it is definitively stabilized with a 3.5-mm pelvic reconstruction plate (TECH FIG 3).}

   

  ^{Most commonly, a slightly underbent, contoured eight-hole plate is used. It is fashioned to sit at the edge of the posterior wall, from the top of the ischial tuberosity to the bone posterior to the anterior inferior iliac spine.}

   

   

   

  ^{TECH FIG 3 • The surgeon reduces the posterior wall piece in the fracture bed and fixes it with a buttress plate placed along the edge of the wall.}

   

   

  ^{By using a finger or a Kirschner wire to feel the edge of the wall and the labrum, the surgeon can ensure that there is no portion of the plate resting on the labrum or in the joint. Placement in this location provides the greatest biomechanical advantage in buttressing the wall.}

   

  ^{It is not unusual for the reconstruction plate to sit on top of the heads of the lag screws or rest over the tines of the spring plate.}

   

  ^{With the plate adequately contoured and positioned, it is initially fixed to the pelvis at the level of the ischial tuberosity.}

   

  ^{The surgeon drills into screw hole no. 2 from the distal aspect of the plate, which should be resting within the recess at the top of the ischial tuberosity. The surgeon aims distally and medially into the proximal portion of the ischium. There will be good bone in this location.}

   

  ^{Next, the plate position is checked again, at the edge of the wall but not impinging on the labrum, and then a ball spike pusher is placed into screw hole no. 8.}

   

  ^{Because the plate is underbent, use of a ball spike pusher and the first proximal screw, placed in screw hole no. 7, will compress the plate to the posterior wall, further enhancing reduction, fixation, and stability of the posterior wall fragment.}

   

  ^{The surgeon must take care not to violate the joint or the femoral head while drilling. In most patients, screw holes no. 7 and no. 8 are proximal to the joint even when drilling “straight” across.}

   

   

  ^{The plate will now be holding the reduction, so if any Kirschner wires were used, they can be removed. The surgeon should note whether the medial aspect of the fracture fragment springs up with removal}

  ^{of the Kirschner wire. If it does, further fixation will be required in addition to the primary reconstruction plate.}

   

  ^{This is an excellent time to obtain C-arm images to evaluate the reduction and to ensure that the screws have been placed extra-articularly.}

   

  ^{One or two additional screws should be placed in the proximal end of the plate, and at least one more screw needs to be inserted into the distal part of the plate, at the most distal hole.}

   

  ^{The most distal screw can be placed into the ischium, toward the tuberosity, where one should find great bony purchase.}

  ^{Checking the Fixation}

   

  ^{Once the final screws are placed, the surgeon evaluates the retroacetabular surface, ensuring that the medial aspect of the fracture piece has not kicked u}

   

  ^{If the medial wall kicks up, it must be further stabilized.}

   

  ^{A lag screw can be used in the same way as previously described.}

   

  ^{A three-hole one-third tubular plate spring plate is another option, as described.}

   

  ^{Once the medial aspect of the wall is reduced and stabilized, the smooth convexity of the retroacetabular surface should once again be restored.}

   

  ^{Any traction that has been applied to the extremity is removed.}

   

  ^{Final C-arm images are obtained to be sure that the joint is reduced and congruent and that all screws are out of the joint.}

   

  ^{The proximal screws are best seen with an obturator oblique view.}

   

  ^{The distal screws are best confirmed as extra-articular with the iliac oblique view.}

   

   

  ³⁶³

• ^{Wound Closure}

 

^{The wound is copiously irrigated.}

 

^{The surgeon checks the integrity and condition of the sciatic nerve one final time.}

 

^{A Hemovac drain is placed on the bone, along the posterior aspect of the posterior wall. A long path will help prevent inadvertent pullout of the drain and will allow hematoma to drain over a long distance.}

 

^{The first stage of closure is to reattach the piriformis and the external rotators. This can be accomplished in several different ways, including drill holes into the greater trochanter or suturing to the gluteus medius tendon. The authors prefer to suture to the tendon, a site shorter than the original insertion site, to decrease the risk of pullout or failure of the repair.}

 

 

 

^{TECH FIG 4 • Postoperative AP (A) and Judet (B,C) radiographs.}

^{If the gluteus maximus tendon was released, it is repaired next.}

^{Typically, the tendon edges are easily visualized and sutured to each other.}

^{Any injured or devitalized muscle should be further débrided to decrease the risk of heterotopic ossification.}

^{Next, the fascia lata is identified and closed watertight.}

^{Routine soft tissue closure is performed. We prefer to decrease dead space, and therefore areas for hematoma to collect, with a layered closure, when possible, between the fascia lata and the skin.}

^{We prefer to obtain an AP pelvis radiograph with the patient supine on the regular hospital bed to inspect the reduction, the fixation, and the joint before extubation (TECH FIG 4).}

 

 

PEARLS AND PITFALLS
	Table and ▪ Using a fracture table, prone positioning, and distal femoral skeletal traction positioning reduce the risk of injuring the sciatic nerve. The hip is extended and the knee flexed to at least 80 degrees in the prone position on the table at all times, allowing the surgeon to concentrate on the procedure. Freedom is allowed in the internal-external rotation plane during the procedure to aid in soft tissue identification and manipulation and to allow differentiation between the femoral head and the edge of the posterior wall.     Internal ▪ The reconstruction plate is placed at the lateral edge of the posterior wall to gain fixation maximum buttressing capability. A Kirschner wire is used to feel the edge of the wall and the beginning of the labrum to clearly define location if unable to visualize with certainty. The plate is underbent to assist with the reduction.     Superior ▪ These fractures should be stabilized with a superior antiglide plate in addition to posterior the traditional wall fractures plate. buttress     Imaging ▪ Intraoperative C-arms often rotate to only 30 degrees “over the to” To obtain an adequate iliac oblique image, the surgeon can push up on the anterior superior iliac spine, which will further rotate the pelvis and provide a more familiar radiographic image. The surgeon must be certain that all screws are out of the joint. With a convex joint, if the screw is completely out on one image, it is located outside of the joint.     Transverse ▪ The surgeon must look for it. fracture     Medial wall ▪ Often, the medial aspect of the posterior wall piece will kick up when the plate kick-up along the edge of the wall is secured. To prevent this, the surgeon must first look for it and recognize it. Then, a three-hole one-third tubular plate, with one distal hole cut into a V to act as a hook (or a tubular 2.7-mm minifragment plate), can be placed along this medial aspect of the fracture. One or two screws can secure this

 

^{plate, which will function as a spring plate and prevent the medial wall from kicking}

^{u This will help restore the smooth convexity of the retroacetabular surface.}

 

 

 

³⁶⁴

^{POSTOPERATIVE CARE}

 

^{A drain is maintained until drainage measures less than 30 mL in a 24-hour period.}

 

 

^{Antibiotics are prophylactically used until 24 hours after the drain is discontinued or until the wound is completely free of any drainage.}

 

^{Often, hip wounds will have serous drainage for several days postoperatively. It is the authors' opinion that this signifies that the wound is not sealed and therefore the patient should continue to receive prophylactic antibiotics.}

 

^{Indomethacin 25 mg is given orally three times a day to prevent heterotopic ossification.}

 

 

^{Chemical deep venous thrombosis prophylaxis is given at the surgeon's discretion, plus sequential compression boots for mechanical prophylaxis.}

 

^{Physical therapy restrictions}

 

 

^{No active range of motion at the hip}

 

^{Passive range of motion only; this is easily accomplished with use of a continuous passive motion (CPM) machine.}

 

^{Any necessary flexion limit will be determined by intraoperative evaluation.}

 

^{Foot-flat weight bearing for 3 months is instituted immediately and patients are allowed to get out of bed the next day, once they understand their limitations.}

 

 

^{This weight-bearing restriction (about 30 pounds) unloads the weight of the extremity from the hip joint.}

 

^{By choosing foot-flat weight bearing and no active muscle contraction, the joint reaction forces of the hip joint are decreased to attempt to further protect the internal fixation and cartilage during the reparative and healing process.}

 

^{At the 3-month mark, with evidence of callus on the radiographs, weight bearing will be advanced to partial weight bearing, with the patient and the physical therapist advancing further as tolerated.}

 

^{Strengthening and gait training will begin at this time, with special concentration on the hip abductors.}

^OUTCOMES

^{The outcome of an acetabular fracture after surgical intervention correlates with the quality of reduction and avoidance of complications.}

^{Although regarded as the simplest type of acetabular fracture, most posterior wall fractures are either comminuted or have marginal impaction, making anatomic reduction difficult and clinical outcomes worse than for most more complex, associated types of acetabular fractures.1, 13}

^{Letournel and Judet6 reported only a 93.7% perfect reduction rate for posterior wall fractures and an 82%}

 

^{good to excellent clinical outcome.}

^{Matta8 reported 100% anatomic reduction of posterior wall fractures in his series but only 68% good to}

^{excellent clinical outcome. Similarly, Moed et al12 had 97% perfect reductions and 89% good to excellent clinical outcomes for their series.}

 

 

 

^{COMPLICATIONS}

^{Posttraumatic osteoarthritis was reported in 17% (97 of 569) of Letournel and Judet's patients operated}

^{on within 3 weeks of injury with at least 1 year of follow-u6 It occurred in 10.2% (43 of 418) of hips after perfect reductions and in 35.7% (54 of 151) of hips after imperfect reductions. The incidence of osteoarthritis for posterior wall fractures was 22.7% (22 of 97). It occurred in 16% (19 of 119) of patients with perfect reductions. The rate after perfect reductions is higher compared to perfect reductions for all types of acetabular fractures (16% vs. 10.2%, respectively).}

^{Matta8 reported a 32% (7 of 22) clinical failure rate despite perfect reduction of posterior wall fractures, which was higher than for any other fracture pattern in his series.}

^{Infection after acetabular surgery is reported in about 2% to}

^{5% of patients.6, 8, 9 It can be intra-articular or extra-articular, depending on the approach used. The presence of a soft tissue injury, such as a Morel-Lavallée, can increase the risk of infection.4, 6}

^{Heterotopic ossification occurs after use of the extended iliofemoral approach, the Kocher-Langenbeck approach, or the ilioinguinal approach when it is combined with elevation of the external fossa. Letournel}

^{and Judet6 reported it in 20% (41 of 208) of operatively treated posterior wall fractures. They also reported a decrease from 24.6% (123 of 499) in all cases via all approaches before treatment to prevent formation to 10.2% (5 of 49) in patients receiving indomethacin for prophylaxis to 0% (0 of 29) in patients receiving both indomethacin and radiation therapy.}

^{Indomethacin is generally considered safe and effective, although a randomized trial has questioned its use in prevention.10}

^{The unknown long-term complications associated with radiation therapy, however, make it generally not recommended for isolated posterior wall fractures in young, healthy patients.}

^{Avascular necrosis of the femoral head must not be confused with rapid mechanical wear or deterioration due to osteochondral injury. Epstein3 reported a rate of 5.3% in operatively treated posterior wall}

^{fractures. Letournel and Judet6 reported a 7.5% incidence after posterior dislocation (17 of 227) and a total of 22 of 569 (3.1%) fractures operated on within the first 3 weeks after injury.}

^{The rate of iatrogenic nerve injury, typically the sciatic nerve, is reported to be about 2% (range 2% to 18%) in the hands of experienced surgeons.6, 9, 11}

 

^REFERENCES

1. ^{Baumgaertner M. Fractures of the posterior wall of the acetabulum. J Am Acad Orthop Surg 1999;7:54-65.}

    

    

2. ^{Calkins M, Zych G, Latta L, et al. Computed tomography evaluation of stability in posterior fracture}

   ^{dislocation of the hi Clin Orthop Relat Res 1988;227:152-163.}

    

    

3. ^{Epstein H. Posterior fracture-dislocations of the hip: long-term followu J Bone Joint Surg Am 1974;56:1103-1127.}

    

    

4. ^{Hak D, Olson S, Matta J. Diagnosis and management of closed internal degloving injuries associated with pelvic and acetabular fractures: the Morel-Lavallee lesion. J Trauma 1997;42:1046-1051.}

    

    

5. ^{Keith J, Brashear H, Guilford W. Stability of posterior fracture-dislocations of the hip: quantitative assessment using computed tomography. J Bone Joint Surg Am 1988;70A:711-714.}

    

    

6. ^{Letournel E, Judet R. Fractures of the Acetabulum. Berlin: Springer-Verlag, 1993.}

    

    

7. ^{Lieberman J, Altchek D, Salvati E. Recurrent dislocation of a hip with a labral lesion: treatment with a modified Bankart-type repair. J Bone Joint Surg Am 1993;75A: 1524-1527.}

    

    

   ³⁶⁵

    

8. ^{Matta J. 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;78A:1632-1645.}

    

    

9. ^{Matta J, Anderson L, Epstein H, et al. Fractures of the acetabulum: a retrospective analysis. Clin Orthop Relat Res 1986;205: 230-240.}

    

    

10. ^{Matta J, Siebenrock K. Does indomethacin reduce heterotopic bone formation after operations for acetabular fractures? J Bone Joint Surg Br 1997;79B:959-963.}

     

     

11. ^{Middlebrooks E, Sims S, Kellam J, et al. Incidence of sciatic nerve injury in operatively treated acetabular fractures without somatosensory evoked potential monitoring. J Orthop Trauma 1997;11: 327-329.}

     

     

12. ^{Moed B, Willson Carr S, Watson J. Results of operative treatment of fractures of the posterior wall of the acetabulum. J Bone Joint Surg Am 2002;84A:752-758.}

     

     

13. ^{Saterbak A, Marsh L, Nepola J, et al. Clinical failure after posterior wall acetabular fractures: the influence of initial fracture patterns. J Orthop Trauma 2000;14:230-237.}

     

     

14. ^{Tornetta Non-operative management of acetabular fractures: the use of dynamic stress views. J Bone Joint Surg Br 1999;81B:67-70.}

     

     

15. ^{Tornetta Displaced acetabular fractures: indications for operative and nonoperative management. J Am Acad Orthop Surg 2001;9:18-28.}

     

     

16. ^{Vailas J, Hurwitz S, Wiesel S. Posterior acetabular fracture-dislocations: fragment size, joint capsule, and stability. J Trauma 1989;29(11):1494-1496.}