[Treatment of peritrochanteric fractures: biomechanical considerations].

Biomechanical considerations are relevant in the treatment of peritrochanteric fractures. Concomitant diseases and osteoporosis place high demands on the primary stability of the operative treatment. In the situation of unstable fractures (AO/ASIF 31-A2 and A3), even normal activities of life can easily exceed the critical limits of stability, which can result in implant failure. Both intramedullary and extramedullary implants are used successfully in the treatment of even unstable fractures. Different variations in the implant design and anchorage of the load carrier of the femoral neck are available and may have different biomechanical characteristics. Biomechanical tests show that new developments of implants can increase stability. Nevertheless, accurate reduction and operative technique is essential to ensure uneventful fracture healing. Although some supportive measures are very promising, such as augmentation, further research is required to increase stability in the unstable and osteoporotic fracture situation.