Femoral Revision: Allograft Prosthetic Composites and Proximal Femoral Replacement

Key Points

  • Revision of the femoral component in patients with failed total hip replacement with significant proximal femoral bone loss of more than 5 cm distal to the lesser trochanter may be accomplished by the use of allograft prosthetic composite (APC) or proximal femoral replacement (PFR).

  • The use of proximal allograft aids trochanteric and abductor repairs, resulting in lower rates of abductor impairment, limping, instability, and dislocation compared with PFR. Even when the host greater trochanter is destroyed, the use of proximal femoral allograft incorporated with abductor tendon allograft enables host abductor tendon repair.

  • Prerequisites for the use of APC include access to banked bone, expertise in the use of massive structural allograft, patient commitment to a postoperative rehabilitation program, and the ability of the patient to tolerate a prolonged surgical procedure. Failing that, the alternative use of PFR is advised.

  • In our current practice, we use APC in younger, higher-demand patients who will potentially require multiple revision surgeries and reserve the use of PFR for older, lower-demand, and medically frail patients.

  • For adequate initial APC implant stability, we use a long reciprocating stepped or oblique cut at the graft-host junction bounded by multiple cerclage wires and reinforced with cortical strut allograft as biologic plating. We avoid distal implant cementation, and we believe that distal implant press fit is not essential for initial implant stability.


Revision total hip arthroplasty (THA) in patients with severe proximal femoral bone loss is challenging. Bone loss extending more than 5 cm distal to the lesser trochanter precludes the use of most conventional THA techniques. Salvage procedures such as excision arthroplasty have shown poor results. Arthrodesis is difficult to achieve. Viable options include the use of allograft prosthetic composites, proximal femoral replacements, and impaction bone grafting techniques. The use of allograft prosthetic composites and proximal femoral replacements will be discussed in this chapter.

Proximal femoral replacement (PFR) is defined as a metal femoral implant that is proximally connected to a femoral head to articulate with the acetabulum and distally fixed to the host femur. It may be cemented or uncemented, modular or nonmodular. Historically, PFR was used after tumor resection. The initial designs were cobalt-chrome monoblock with incremental length segments cemented into the distal femur. Later developments included modularity to better accommodate leg length and porous coating to promote bony ingrowth at the junction with extracortical bone bridging, although this concept has not been shown to occur with predictability even with bone grafting. Indications recently have been expanded to include nonneoplastic conditions such as failed THA with massive proximal femoral bone loss and periprosthetic fractures.

Allograft prosthetic composite (APC) in revision THA is defined as a long femoral stem prosthesis that is proximally incorporated into a proximal femoral bone allograft. This technique has gained popularity over the past decade with several encouraging longer-term reports.

When comparing APC with PFR, the advantages of using PFR include easier availability without the need for access to banked bone, easier implantation without the need for expertise in the use of massive bone allografts, and shorter operative duration with potentially lower blood loss and infection rates. The theoretical risk of disease transmission via the allograft bone is also avoided. Patients with PFR are generally allowed to bear weight earlier in the postoperative period and have less demanding postoperative rehabilitation programs.

Revision THA with PFR, however, is associated with higher dislocation rates. PFR provides poor attachment of host bone and soft tissue, leading to weaker abductors and a higher rate of a Trendelenburg lurch. There is also the disadvantage of violating the host distal femoral canal with reaming for stem cementation or press fitting, which is undesirable with regard to bone preservation, especially in younger higher-demand patients. In terms of survival rates, reports have suggested higher rates of loosening and failure with PFR.

The use of APC has the potential to restore proximal femoral bone stock and minimize host distal canal violation to preserve bone stock to aid future reconstructions. By avoiding cementing or significant reaming for press fitting the implant distally, the distal host canal is relatively preserved. The use of proximal allograft aids host bony and soft tissue attachment—in particular, the host greater trochanter. When the host greater trochanter is destroyed, the use of proximal femur–abductor tendon allograft facilitates host abductor tendon repair. APCs with trochanteric and abductor repairs have lower rates of abductor impairment, limping, instability, and dislocation compared with PFR.

Indications and Contraindications


The general indication for the use of APC or PFR is significant proximal femoral bone loss of greater than 5 cm distal to the lesser trochanter. Bone loss may be caused by tumor resection, previous THA infection, periprosthetic fracture (e.g., Vancouver B3), or osteolysis.

In general, APC is used in younger, higher-demand patients, who will potentially require multiple revisions and who are able to safely comply with the extensive rehabilitation protocol.


Patients with absolute general contraindications to APC and PFR include those who are medically unfit for major surgery, those with unresolved superficial or deep hip infection, and patients who will not be cooperative with the postoperative rehabilitation program. Another contraindication is the ability to reconstruct the femur using alternate techniques, such as modular tapered fluted stems. Relative general contraindications include morbid obesity and poor central or peripheral perfusion. After radiation therapy, APC should not be used because of poor potential for healing at the host-allograft junction. In this setting, PFR is preferred. Finally, lack of familiarity with the technique or limited experience in revision THA on the part of the surgeon or the surgical team are contraindications to these complex techniques; such cases should be referred to centers with more experience with these techniques.

Another contraindication is lack of access to a local or commercial bone bank. In that case, alternate techniques should be used or the patient should be referred to another center with expertise in this technique.

Preoperative Planning

Because the use of PFR is technically similar to that of most distal fixation stems, with the exception of the need for fixation of the hip abductors to the stem, we will focus on the technical details associated with APC.

Allograft Prosthetic Composites

Allograft Availability

We recommend acquiring fresh-frozen allograft from a tissue bank that is accredited by the American Association of Tissue Banks. In general, these allografts are irradiated for sterility and are stored at −70°C.

Preoperative planning is required so that the correct sizes of allograft and implant can be ordered. Anteroposterior (AP) pelvis and full femur radiographic views with a calibrated radiographic marker are obtained to estimate the length and diameter of the graft and implant required. The allograft length is estimated from the length of the proximal femoral deficiency. This usually correlates with the distance from the center of rotation of the hip joint to the level in the distal femur where adequate bone stock is present to support the allograft. This estimation should take into account apparent and functional leg length discrepancy due to stem subsidence or periprosthetic fracture. A graft that is substantially longer than estimated is ordered to allow for intraoperative adjustments and should account for a minimum step cut of 3 to 5 cm at the allograft host-bone junction. The estimated stem length should be generously longer than the estimated graft length. Ideally, there should be a minimum of 2 cortical diameters of stem length beyond the host-graft junction, with the anticipated stem tip more than 4 to 6 cm away from the knee joint, if possible.

In the revision arthroplasty setting, the graft canal diameter is typically narrower than the host canal, which is often widened by cortical thinning from osteolysis and cavitation around previous loose femoral components, infection, or fracture. Avoid choosing a graft with an outer diameter that is substantially narrower than the host to reduce the risk of unstable intussusceptions and uncontrolled subsidence postoperatively. Ideally, the outer diameters of the graft and host should be matched at the distal graft-host junction for optimal junctional stability. Alternatively, using a slightly narrower graft to telescope into the host distal femoral canal by 1 to 2 cm and ensuring initial junctional fixation stability may enhance union and long-term stability ( Fig. 103.1 ).

Fig. 103.1, Preoperative (A) anteroposterior (AP) and (B) lateral distal femoral radiographs showing uncontained severe femur bone loss.

Ruling Out Infection

Preoperative workup should exclude infection using serologic inflammatory markers (C-reactive protein [CRP], erythrocyte sedimentation rate [ESR]). If necessary, other workup as discussed elsewhere in this book may be necessary. The operation should not be booked until the surgeon is reasonably certain that infection is not a cause of failure. While 1-stage exchange arthroplasty may be done for infection, there is no role for PFR in 1-stage exchange arthroplasty.

Equipment and Implants

Patients with severe proximal bone loss who require revision THA usually have had multiple previous hip surgeries with poor soft tissue function and an increased risk of instability and dislocation. We often consider the potential need for using large bearings, dual mobility, or constrained liners. In patients with poor abductor function and/or a destroyed greater trochanter, we would also consider the use of proximal femur allografts with attached abductor tendon allograft for attaching the host abductor tendon remnant to the allograft tendon. Alternatively, if no gluteus medius or minimus remains, gluteus maximus can be advanced and repaired to the abductor insertion point on the allograft.

Leg Length Discrepancy

Preoperative assessment for leg length discrepancy will guide the amount of leg lengthening during surgery. Apparent leg length difference measured clinically is correlated with radiographic assessment using an AP pelvic radiograph and 3-foot standing view radiographs when available. Significant fixed flexion or adduction contracture may require releases intraoperatively. Our guidelines for safe limb lengthening with regard to risk for sciatic stretch are 4 to 5 cm in the acute setting with previously equal limbs (e.g., before periprosthetic fracture) and 2 to 3 cm in limbs with long-standing leg length discrepancy (e.g., persistent shortening after THA for severe congenital hip dislocation).

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