Periprosthetic hip and knee fractures: the scope of the problem.

This review covers the present incidence, site, and outcome of periprosthetic fractures of the hip and the knee. Fractures can occur intraoperatively or postoperatively as an early or a late complication. Late postoperative fractures are related to osteolysis secondary to wear debris. These late fractures will become more prevalent with time. Intraoperative fractures can be avoided by careful technique and improved instrument design. Fractures can affect the acetabulum, femur, and trochanter of hip replacements: and the femur, tibia, and patella of knee replacements. The femur is most commonly involved for both joints. Stress fractures have been described as a rare complication of both sites of arthroplasty. If the fracture is recognized and the bone stock is good, a good outcome can be achieved if rigid fixation is obtained Unfortunately poor bone stock is often present, leading to late periprosthetic fractures, which compromise the outcome.