[Studies on the stability of pertrochanteric fractures following the application of various osteosynthesis techniques with special reference to torsional forces at the proximal femur].

Fourteen different commonly used osteosyntheses for unstable pertrochanteric fractures with medial bone defect were systematically analysed concerning their stability. For this purpose the deformation and the maximum stability of 36 surgically stabilized fractured femora from donor corpses were tested. For the experimental investigations the hip force FM was not only induced on the femora in orthograde direction but also in an inclination of 45 degrees of anteflexion of the femur as it appears during walking up stairs. As a result, all tested osteosyntheses had significantly lower maximum stability and greater deformation if the hip force was induced on the anteflexed femur in contrast to orthograde loading. From our analysis clinically important conclusions can be drawn concerning the operation techniques and the post-operative after treatment concepts.