Intramedullary Total Femur via a Direct Anterior Approach for Complex Revision Total Hip and Knee Arthroplasty

Abstract

Total femur replacement is a well-recognized salvage procedure and an alternative to hip disarticulation in patients with massive femoral bone loss. Compared to conventional total femur replacement, intramedullary total femur (IMTF) requires less soft tissue dissection and preserves femoral bone stock and soft-tissue attachments. Despite these advantages, patients can still anticipate compromised functional outcomes and high complication rates following IMTF. Prior studies describe IMTF with the patient positioned laterally and utilizing posterior or anterolateral approaches to the hip. We describe our IMTF technique performed via the direct anterior approach in the supine position. In our experience, this is an effective method, with potential benefits including intraoperative limb length and rotational assessment, use of fluoroscopy, more convenient exposure of the knee, and potential lower rates of hip instability.

Keywords: Direct anterior approach; Intramedullary total femur; Revision; Total femur replacement; Total hip arthroplasty; Total knee arthroplasty.

Figure 1

A standard operating table with base turned toward the head to allow for fluoroscopic imaging of the entire pelvis. A Montreal post can be placed midline as a peroneal post to allow for traction without the patient drifting down the table.

Figure 2

Use of a De Mayo Knee Positioner (Innovative Medical Products, Plainville, CT) to control the lower extremity during exposure and instrumentation of the knee; may be utilized to apply static traction to the leg as necessary for hip exposure, similar to a dedicated traction table.

Figure 3

Clinical length and rotation determination via palpation of the heels and medial malleoli.

Figure 4

The planned extensile DAA incision: a standard DAA approach with proximal extension, curving along the iliac crest.

Figure 5

Intraoperative fluoroscopy imaging depicting completion of the final tibial component followed by insertion of an IM rod and mating to the proximal body (Orthopedic Salvage System, Zimmer Biomet, Warsaw, IN).

Figure 6

Preoperative radiographs from Case 1. There was a presence of hip disarticulation with an antibiotic cement spacer in the acetabulum. Extensive proximal femoral bone loss was present with an antibiotic-coated nail and multiple cerclage wires about a prior periprosthetic femoral fracture that involved the entire femur down to the metadiaphysis with apparent callous formation and consolidation.

Figure 7

Postoperative radiographs from Case 1. Cup cage construct using a contralateral half-cage and a cemented constrained liner and IMTF construct (Orthopedic Salvage System, Zimmer Biomet, Warsaw, IN).

Figure 8

Preoperative radiographs from Case 2. There was subsidence of the prior proximal femoral replacement with progressive osteolysis, an incomplete cement mantle, and distal third femoral bone loss involving the metadiaphyseal junction and adjacent knee arthritis. The acetabular component appeared to be well fixed and appropriately positioned in the presence of a cemented modular dual mobility liner.

Figure 9

Postoperative radiographs from Case 2. The prior acetabular component was maintained, and the IMTF construct was implanted, bypassing the femoral bone loss (Orthopedic Salvage System, Zimmer Biomet, Warsaw, IN).