[Total femur replacement following multiple periprosthetic fractures between ipsilateral hip and knee replacement in chronic rheumatoid arthritis. Case report of 2 patients].

Periprosthetic femur fractures are one of the most severe complications in hip surgery. Osteoporosis as seen in patients with rheumatoid arthritis could favour such fractures, which are located mostly between the stems of the hip and knee prostheses. A traumatic event is not even required. The fracture rate increases with predisposing factors, such as preliminary changes of the prosthesis or osteoporosis. This paper reports two patients with rheumatoid arthritis (males, 54 and 71 years old) with femur fractures after total hip and knee replacements. Both had a severe osteoporosis caused by a long-term steroid therapy. Consecutively, both patients showed refractures of the femur with loosening of the osteosynthetic material, so that a total femur replacement was required. However, both patients are able to walk. To reduce the risk of femur fractures between the tips of knee and hip prostheses it is advisable to use knee prostheses without a proximal intramedullary stem. In this way pressure stress is reduced.