The main reasons to consider hip arthroplasty after failed treatment of a hip fracture are fracture nonunion or failure of internal fixation, osteonecrosis of the femoral head, or progression of hip joint arthritis. The first 2 typically occur early after the fracture; the latter often occurs late.

Patients with failed hip fractures typically are very disabled, and effective operative means of salvaging the problem are essential.

Failed hip fractures can be divided intellectually into 4 main groups: (1) failed femoral neck (FN) fractures in younger patients, (2) failed FN fractures in older patients, (3) failed intertrochanteric (IT) fractures in younger patients, and (4) failed IT fractures in older patients.

Failed FN in younger patients often may be salvaged with head sparing procedures, most commonly valgus producing IT osteotomy that puts the fracture in compression and allows healing. Good results can be obtained, even if moderate-sized areas of femoral head osteonecrosis are present.

Failed FN fractures in older patients and those with notably compromised bone are usually best treated with conversion to hip arthroplasty.

Failed IT fractures in younger patients typically are treated with repeat open reduction and internal fixation using rigid fixation, autologous bone grafting as needed, and deformity correction.

Failed IT fractures in older patients most commonly are treated with conversion to hip arthroplasty, although in some patients with good remaining bone and a good remaining hip joint another attempt at internal fixation may be indicated. Stronger indications for conversion to hip arthroplasty are poor bone quality, loss of bone in key areas needed for stability and fixation, damage to the acetabulum by screw cut out or arthritis, advanced hip arthritis or femoral head osteonecrosis. Advantages of arthroplasty are fracture healing is not required because the fracture is excised and rapid mobilization is possible (which is important to many elderly patients who have already been immobilized owing to the failed fracture for a period of time).

Most patients having hip arthroplasty for failed hip fracture have had previous internal fixation. Before conversion to hip arthroplasty, infection should be excluded. History of wound healing problems, drainage, or systemic symptoms should raise concern as should physical findings of erythema or wound drainage. Most patients should be screened with erythrocyte sedimentation rate and C-reactive protein. If findings are concerning, advanced imaging and/or hip aspiration may be considered.

Patients having conversion arthroplasty after fracture often have weak bone (typically this is why the fracture occurred in the first place, and disuse osteopenia as the fracture fails exacerbates this problem). This places patients at risk for intraoperative and postoperative fracture (of the acetabulum and femur) and also at risk for implant loosening (of the acetabular and femoral components). Cemented implants can reduce the risk of fracture and early loosening, particularly for the femur.

Conversion to hemiarthroplasty or total hip arthroplasty (THA) both are options. Hemiarthroplasty is a high stability bearing and is a smaller operation than THA; however, pain relief is less reliable. Hemiarthroplasty may be considered for very infirm or minimally ambulatory patients. For most other patients, THA, which is associated with more reliable pain relief, is preferred.

Patients having conversion arthroplasty after fracture commonly are at high risk for hip instability owing to age, cognitive factors, neuromuscular or balance factors, or anatomic abnormalities such as compromise of the greater trochanter (GT) in patients with previous IT fractures. High stability bearings such as large-diameter femoral heads (36 mm or greater) or dual mobility implants may be considered.

If hardware is in place, understand what hardware is present (including the manufacturer) and the specifics of how to remove the hardware. Make sure the instruments, which may be manufacturer specific, are available for hardware removal.

Routine hip arthroplasty instrumentation. If cementation is anticipated, have all the needed materials for cementation, including cement guns and cement restrictors.

Hip arthroplasty implants for the planned procedure. If an uncemented cup is planned, have available cups that allow for cup fixation screw augmentation. For failed FN fractures have available cemented or uncemented femoral implants (depending on surgeon preference—see following text), typically of standard length. For failed IT fractures, extended neck implants, calcar replacing implants, or distally fixed implants that allow the surgeon to compensate for deficient proximal bone usually are needed. Have available implants that can bypass screw holes in the proximal femur.

Instrumentation to remove the hardware that is in place. This often is manufacturer specific.

Broken screw removal instruments, including trephines and reverse thread screw extractors.

Cerclage cables and wires.

High-speed burrs with various sized tips.

Have intraoperative radiography or fluoroscopy available as needed.

Lateral decubitus or supine as per surgeon preference.

Make sure to include access to most of the femur in the operative field, including any areas that need to be accessed for hardware removal.

For cases that will be more difficult consider placement of a Foley catheter.

For most failed FN fractures conversion to arthroplasty can be done via posterior, anterolateral/direct lateral, or direct anterior approach based on the surgeon’s preference. However, cementation of the femoral component is preferred for many of these patients with very poor bone (owing to risk of femoral loosening and postoperative fracture with uncemented implants) and cementation is more difficult to do well through the direct anterior approach.

For failed IT fractures, the operative approach often is dictated by the anatomy of the GT. If the GT is malunited in a position that impedes access to the femoral canal, or nonunited (Figure 13.2A), a trochanteric slide (see Chapter 4) or extended greater trochanteric osteotomy may be indicated. If this is not the case, a routine posterior or anterolateral/direct lateral approach may be used.

The operative approach should provide for access to the hardware that will require removal.

Usually some or all of the scar from previous internal fixation may be used, but this is dependent on the previous scar position and the planned new operative approach. Try to avoid parallel scars very close to one another to avoid devascularization of a skin bridge.

Discuss medical issues (often present in these cases) with internal medicine and anesthesia teams.

Failed FN fracture: template for acetabular and femoral components, including implant size and position. If the leg is shortened template to restore leg length: plan how any existing hardware will be removed.

Failed IT fracture: template for acetabular and femoral components, including implant size and position. If the leg is shortened, template to restore leg length: typically there is more calcar bone loss than is obvious, and implants that make up for bone in this area often are needed. Consider stem length: in most older patients plan to bypass holes or defects left in the proximal femur by a distance equal to about 2 femoral canal diameters. Plan how any existing hardware will be removed.