Review Question - QID 219757

This patient has sustained a Vancouver B1 periprosthetic proximal femur fracture. The fracture extends to the level of the femoral component but the stem is stable within the proximal femur. Open reduction and internal fixation of this fracture is indicated (answer choice 1).

Periprosthetic femur fractures about total hip arthroplasty (THA) are an increasingly common problem and the most common type of periprosthetic fracture. The most commonly used classification system is the Vancouver system, which is outlined in Illustration A. Vancouver A fractures are trochanteric fractures, with subclassifications of greater and lesser trochanteric fractures. Vancouver B fractures are fractures with extension at the level of the femoral component, with subclassifications of 1, 2, and 3. The hallmark of B1-type fractures is a stable stem, while B2 and B3 are unstable. B3 fractures are unstable and with inadequate proximal femoral bone stock. Vancouver C fractures are distal to the tip of the femoral component. Treatment algorithms of Vancouver B fractures are dictated by the stability of the stem. The most reliable assessment of femoral component stability is intraoperative assessment, as there is up to a 20% discrepancy between preoperative and intraoperative assessment of femoral component stability in the setting of Vancouver B-type fractures. For stable stems, open reduction and internal fixation is indicated. In select unstable stems, open reduction and internal fixation may be considered but the gold standard remains revision to a longer diaphyseal engaging stem that bypasses the fracture with optional adjuncts such as cortical strut allograft, cable, cerclage, or other additional fixation. Proximal femur replacement may be considered in severe proximal bone defects.

Patsiogiannis et al. performed a literature review of periprosthetic hip fractures. They note an incidence of postoperative fracture after THA at 1% after primary and 4% after revision THA. The majority are caused by ground-level falls. They review the Vancouver classification and the surgical indications for each type. They note several studies that suggest Vancouver B1 and select Vancouver B2 fractures may be treated with open reduction and internal fixation.

Marsland et al. performed a similar review of periprosthetic femoral fractures. They note that radiologic assessment of stem stability may misdiagnose a stable stem up to 20% of the time. The authors recommend intraoperative stress of the femoral component to determine a treatment plan, and note that revision of unstable stems to bypass the fracture site remains the most reliable intervention for Vancouver B2-type fractures.

Figures A and B are AP and lateral radiographs of the left femur demonstrating a well-positioned femoral component with a spiral fracture that extends to the level of the stem, however without disruption of the proximal metaphyseal fit. There is no evidence of subsidence or peri-implant lucency.

Illustration A reviews the Vancouver classification of postoperative periprosthetic femur fractures around THA.

Incorrect Answers:
Answers 2-5: This fracture is classified as Vancouver B1 as it extends to the level of the stem, and there is no evidence of implant loosening or instability as dictated by intraoperative findings and preoperative radiographs. Treatment of choice is open reduction and internal fixation.