Review Question - QID 218100

This patient has startup thigh pain which is suggestive of aseptic loosening of the femoral component and confirmed intraoperatively. If a surgeon plans to revise the femoral stem and is having exhaustive difficulty removing the cement mantle, an extended trochanteric osteotomy can be utilized to facilitate the removal of her current implant and underlying cement mantle while minimizing her risk of intraoperative fracture.

The extended trochanteric osteotomy (ETO) is a powerful operative exposure technique primarily used in revision total hip arthroplasty (THA) cases. Removing a well-fixed femoral component can be considerably difficult and risks possible femoral perforation, bone loss, and intraoperative fracture. At its essence, the ETO aims to elevate the greater trochanter with a contiguous meta-diaphyseal bone (12-14cm in length and importantly containing vastus ridge) to facilitate exposure of the proximal third of the femur. This technique preserves soft tissue attachments and allows for direct visualization of the femoral canal for implant removal, cement/restrictor removal, and placement of diaphyseal engaging implant (i.e. fluted tapered stems). In this case, given her age and osteoporosis, this patient is at considerable risk for intraoperative fracture while trying to remove her current implant. An ETO would facilitate her implant/cement removal and facilitate conversion to a longer stem-diaphyseal engaging implant (Illustration A).

Sambandam and colleagues provided an overview of the indications, techniques, and outcomes of utilizing an ETO. They discuss the primary indications to include: (1) removal of a well-fixed cemented femoral stem (2) removal of a well-fixed cementless femoral stem (3) difficult extraction of a cement mantle (4) need for enhanced acetabular exposure and (5) varus remodeling of the proximal femur in which adequate reaming and fixation of a diaphyseal engaging revision stem would not be possible. They further discuss the different ETO approaches and osteotomy fixation strategies including wires, cables, suture, and/or plate fixation. The authors provide tips/tricks for performing an ETO and conclude that it is an important tool for the revision surgeon’s armamentarium for a variety of clinical scenarios.

Abdel and colleagues reviewed their institutional (Mayo Clinic, Rochester) long-term results in which an ETO was utilized in revision arthroplasty cases. Their primary indications for ETO were aseptic loosening (65%), periprosthetic joint infection (18%), and periprosthetic fracture (6%). The authors reported 612 cases with roughly half of cases utilizing the Paprosky ETO (Illustration B) and the other half utilizing the Wagner ETO (Illustration C). They found that radiographic and clinical union was achieved in 98% of patients at a mean of 6 months with limited risk for complications (>1cm ETO fragment migration in 7% of cases, intraoperative ETO fragment fracture in 4% of cases, and ETO nonunion in 2% of cases). Their reported 10-year survival rate free of reoperation for any reason was 82%. The authors concluded that ETO serves as a powerful tool in revision arthroplasty with high union rates and minimal risk for trochanteric migration.

Figure A shows an AP radiographic imaging with this patient’s right-sided, cemented hemiarthroplasty. Illustration A shows their revision arthroplasty construct to include the utilization of an ETO (fixed with cables) and modular, diaphyseal engaging implant. Illustration B is a figure of the Paprosky ETO method from Abdel and colleagues’ article. Illustration C is a figure of the Wagner ETO method from Abdel and colleagues’ article.

Incorrect Answers:
Answer 1. Even if a short metaphyseal stem could be placed, the prior cement mantle would notably hinder the ability for biologic fixation to occur due to the prior interrupted endosteal blood supply from previous cementation. In addition, any cement remaining within the metaphysis could further hinder the ability of biological fixation as well.
Answer 2. Impaction bone grafting is a potential approach to treating femoral bone loss in the revision hip arthroplasty setting however with previous loose stem cement mantle, gaining enough space for impaction grafting would be difficult and likely to fail.
Answer 3. Attempting to re-cement into an old cement mantle is reasonable only if the prior cement mantle is well fixed to the bone. In this case the cement has loosened and wouldn't be amenable to a cement in cement technique.
Answer 5. Two staged revision arthroplasty with the placement of an antibiotic spacer would be considered appropriate in the setting of chronic periprosthetic infections. However, this patient’s lab values and aspiration ruled out chronic PJI.