1 Introduction

Fractures of the acetabulum are the result of high-energy trauma. Long-term function of the hip joint may be compromised in many cases regardless of treatment choice [1–5]. The rationale for decision making and the goals of initial treatment include restoration of major anatomical relationships of the pelvis and an anatomical reduction of the acetabular joint surface. If displaced fractures involving the weight-bearing surface of the acetabulum are left unreduced, a poor result may be expected regardless of the method of treatment. Therefore, if an acetabular fracture is significantly displaced, an anatomical reduction should be performed and early range of motion should be established to prevent posttraumatic osteoarthritis and restore function of the joint [6–9]. However, even when these goals are achieved, acetabular fractures are associated with a high rate of late posttraumatic degenerative changes, as much as 57% in some reports [3–5]. Hip joint degeneration may result from imperfect reductions, chondral injuries to the acetabulum, femoral head lesions, and preexisting arthritis. Cartilage necrosis may be caused by unrecognized intraarticular hardware, sepsis, or as a result of the initial traumatic insult to the articular cartilage. Posttraumatic avascular necrosis of the femoral head has been reported to range from 2–40% following acetabular fracture [10–12] and can negate the benefits of an anatomical reduction with stable fixation and early range of motion.

2 Total hip arthroplasty for failed treatment of acetabular fractures

Total hip arthroplasty (THA) is a reasonable treatment option for patients who present with symptomatic posttraumatic arthritis or avascular necrosis with collapse of the femoral head as a result of an acetabular fracture [13–16]. Although other procedures, such as arthrodesis, historically have been preferred for patients who are young, obese, or involved in heavy manual labor, whereas THA has become more standard and the primary definitive treatment for older patients, more sedentary individuals, or those unwilling to accept traditional arthrodesis. Patients for whom ipsilateral knee or lumbar spine pathology presents a relative contraindication to hip arthrodesis, THA may also be the best surgical option [17–19].

Pritchett and Bortel [20] evaluated 19 patients who underwent THA using a cementless acetabular component for a failed central acetabular fracture. At a mean 2 years follow-up, excellent overall short-term results were reported with a mean Harris Hip Score of 84, even though many patients had fibrosis, contracture, and unequal limb lengths. Fifteen patients had undergone prior hip surgery of an unspecified nature. Similarly, the percentage of the fractures treated by closed or open method is not specified.

Romness and Lewallen [15] retrospectively studied 55 primary cemented THAs in 53 patients who had a history of acetabular fracture, 13 of whom were treated initially with open reduction and internal fixation. They compared their results with those in another series [16] from the same institution. Stauffer’s series [16] included 231 routine Charnley cemented THAs with an average 10-year postoperative evaluation. Romness and Lewallen [15] reported significantly higher acetabular loosening and revision rates (39%) in comparison with arthroplasties performed for degenerative arthritis (5%) in Stauffer’s series. Both series had similar rates of femoral loosening and revision.

Another study [14] reviewed the records of 39 patients with unspecified acetabular fractures who eventually underwent THA. Initially, management was an open reduction and fixation in 14 patients and closed treatment in 16 patients. A comparison of hip arthroplasty outcomes after closed versus open management of acetabular fracture was not performed. The most common reason for arthroplasty was persistent or recurrent subluxation. The investigators reported improvement in most patients despite a high-complication rate, including dislocations, acetabular cement fracture, severe heterotopic bone formation, and deep sepsis resulting in total failure of the arthroplasty.

A series of 66 patients who were operated on during a 15-year period and who underwent cemented Charnley low-fraction THA following failed treatment of an acetabular fracture was presented [13]. Most cases were posterior wall fracture dislocations and central acetabular fractures treated nonoperatively. Only 13 cases were treated initially by open methods. Excellent short-term results were reported, with a mean postoperative assessment of 3.5 years.

Some [1] reported the findings of long-term evaluation of 55 consecutive patients with 56 acetabular fractures: 11 treated operatively and 45 nonoperatively. These surgeons discouraged open treatment of acetabular fractures as initial management. They recommended hip arthroplasty as a secondary procedure, which was performed in six patients following failed closed or open treatment of an acetabular fracture.

Bellabarba et al [21] reported on the intermediate findings of 30 THAs performed for posttraumatic osteoarthritis, using a cementless hemispheric fiber-metal-mesh-coated acetabular component. They reported similar results compared with arthroplasties performed for nontraumatic arthritis, regardless of whether the acetabular fractures were treated surgically or nonoperatively.

Total hip arthroplasty after acetabular fracture is most commonly indicated in patients with symptomatic post-traumatic arthritis with or without avascular necrosis of the femoral head. Failure of internal fixation with dislocation or subluxation of the femoral head following initial osteosynthesis also commonly leads to hip arthroplasty.

3 Early THA for acute treatment of acetabular fractures

Displaced acetabular fractures in the elderly occur primarily from a fall while ambulating. An ever-increasing aging population requires that surgeons will need to pay attention to the special considerations required by elderly patients with acetabular fracture [22]. The elderly patient often presents with multiple medical problems, preexisting degenerative joint disease, and osteoporosis resulting in highly comminuted acetabular fractures. Fractures in this population often present with significant anterior column comminution, dome impaction, quadrilateral plate displacement with femoral head protrusio, and associated ipsilateral femoral head and neck fractures [22–24] ( Fig 2.14-1 ).

Historically, because of the technical difficulties of achieving stability of the acetabular component, initial management of an acetabular fracture with primary THA was rarely indicated. Circumstances in which arthroplasty was a consideration included certain pathological fractures, patients with preexisting symptomatic hip arthritis, and rare instances of associated femoral side injuries, including head-splitting fractures that preclude a satisfactory operative result, or significantly displaced ipsilateral femoral neck fractures [25].

The use of hip arthroplasty for the initial management of acetabular fractures is not new. Westerborn [26] reported encouraging results with the use of immediate vitallium mold arthroplasty in six cases of central acetabular fracture dislocation. Rowe and Lowell [5] described a series of 93 consecutively treated patients with acetabular fractures, two of whom underwent immediate cup arthroplasty. Kelly and Lipscomb [27] presented seven satisfactory results using primary mold arthroplasty in eight patients with posterior fracture dislocation involving one-third to half of the femoral head.

Coventry [28] reported five patients with subacute and chronic unreduced fracture dislocations of the hip that were managed with a one- or two-stage cemented Charnley THA. He recommended THA for acetabular fractures in elderly patients with serious medical conditions, and in patients with delayed presentation, or patients with a missed diagnosis. He reported almost normal functional restoration of the hip.

Jolly and Mears [25] recommend expanding the indications for immediate hip arthroplasty for acetabular fractures with certain risk factors. General factors are advanced aged, serious medical conditions, such as obesity, diabetes mellitus, and significant cardiopulmonary disease. Local factors are osteopenia and high-risk fracture types, especially those with an extensive-associated abrasive or impacted injury to the femoral head, acetabulum, or both. In their series, following an initial open reduction and internal fixation, one-third of the high-risk fracture types, which included T-type, posterior column-posterior wall, and transverse posterior wall, progressed to THA. A delay in treatment beyond 1 month was considered an additional risk factor ( Fig 2.14-2 ).

More recently, the indications for acute THA for the initial treatment of acetabular fractures in the elderly have been expanded. Mears and Velyvis [29] suggest hip arthroplasty in patients demonstrating severe intraarticular comminution (10 or more fragments), full-thickness cartilage loss, acetabular impaction involving > 40% of the weight-bearing dome, and ipsilateral femoral head impaction. Further indications are preexisting degenerative joint disease, and ipsilateral femoral head and femoral neck fractures. In their series many acetabular components showed subsidence, yet most cups settled into a position of stability and bone in-growth, with no late cup or stem loosening. These authors suggest a surgical team experienced in both acetabular trauma and hip arthroplasty.

Hip arthroplasty for acute acetabular fractures presents several technical challenges. Although acetabular fracture fixation using a multihole arthroplasty cup can be successful [29], some cup subsidence typically occurs ( Fig 2.14-3 ). Current recommendations suggest simultaneous open reduction and internal fixation of at least one of the acetabular columns, which provides a more stable press-fit of the acetabular component ( Fig 2.14-4 ).

Since the anterior column and anterior weight-bearing dome of the acetabulum are typically involved, open reduction and internal fixation of the anterior column portion of the fracture can be achieved through the proximal extent of the anterior iliofemoral approach, with the hip arthroplasty portion of the procedure performed through the distal aspect of the incision using a modified Hueter approach [30, 31] ( Fig 2.14-5 ).

If the posterior wall of the acetabulum is highly comminuted and nonreconstructable, a bulk femoral head autogenous graft can be successfully used to provide posterior stability for the acetabular component, placed through a posterior surgical approach. If the native femoral head is avascular or rendered traumatically useless, then femoral head allograft is a useful adjunct. The bulk graft is contoured to the posterosuperior acetabular defect, stabilized with multiple 3.5 mm cortex screws, and then reamed to provide secure fixation for the acetabular component ( Fig 2.14-6 ).

Morselized cancellous allograft can be layered along the acetabular dome and medial acetabular wall using the acetabular reamer on reverse, providing an osteoconductive substrate for bone formation through the process of creeping substitution ( Fig 2.14-7 ). Acute hip arthroplasty for acetabular fracture mandates a 12-week period of nonweight bearing to allow for fracture healing and bone in-growth to the acetabular component.

In the older age group, the associated both-column fracture may exhibit secondary congruence of the hip. Despite an unusual radiographic appearance, the results may be satisfactory if the injury is managed nonoperatively [5]. If hip arthroplasty is eventually required, it can be performed on the hip with no previous surgery, avoiding the technical problems associated with a previous surgical procedure.