Review Question - QID 219789

Proximal fragment migration is a known complication of extended trochanteric osteotomies (ETOs) that can be mitigated by the use of a plate and cable construct (Answer 5).

Extended trochanteric osteotomy is a reliable and useful tool in revision total hip arthroplasty (THA). ETOs provide surgeons increased access and exposure to the proximal third of the femur for implant or cement mantle extraction. While an ETO is employed to avoid catastrophic events during surgery, complications still exist. Nonunion, intraoperative fracture, proximal migration, infection, and stem subsidence are among the most common complications. To reduce the incidence of nonunion and trochanteric migration, much attention has been paid to various fixation techniques. Cerclage cables have long been the mainstay of fixation strategies, but combinations of plate and cable constructs have shown superior prevention of proximal fragment migration.

Malahias et al. published a systematic review of the clinical and radiographic outcomes of performing an ETO during aseptic revision THA. The authors included 19 studies and 1,478 ETOs to study union rate, femoral stem subsidence, and type of fixation. The mean union rate was 93.1% in the included studies. The overall rate of substantial stem subsidence (> 5 mm) was 7.1%. Several studies compared the outcomes of ETO fixation techniques and found significantly lower proximal fragment migration when a plate and cable combination construct was used. The authors recommend the use of a trochanteric plate with cables as the first choice for fixation of an ETO.

Abdel et al. performed a retrospective review of 612 ETOs performed at their institution with a median follow-up of 5 years. Radiographical and clinical union was achieved in 98% of patients at a mean of 6 months. The authors found a mean migration of the proximal fragment of 3 mm prior to union. Fragment migration > 1 cm occurred in 7% (n=37) of the studied patients. Nonunion occurred in 2% (9) of patients, intraoperative fracture occurred in 4% (22), and postoperative fracture in 7% (41). The authors conclude from this large series that ETOs are a relatively safe and reliable procedure with an important role in revision THAs.

Figure A demonstrates the aseptic loosening of a cemented femoral stem.

Incorrect Answers:
Answer choice 1: The hip should not be abducted more than 10-15 degrees during trochanteric reattachment and fixation. Once the hip is adducted, excess strain and avulsion or nonunion may occur.
Answer choice 2: Osteotomy length is associated with proximal trochanteric migration. Specifically, osteotomies shorter than 10 cm are at a higher risk of developing trochanteric migration. The typical recommended length for osteotomies is 12-14 cm.
Answer choice 3: A cerclage cable distal to the osteotomy site is used to mitigate the risk of fracture propagation. This cable would not minimize the risk of proximal fragment migration.
Answer choice 4: Cortical strut allografts can be used during ETO to mitigate the risk of junctional failure, particularly in the setting of bone loss. Strut allografts have not been shown to prevent migration of the osteotomized fragment, however.