[Comparative stability evaluation of dynamic hip screw and gamma-nail osteosyntheses in unstable pertrochanteric femoral osteotomies].

In 24 human cadaver femora standardized instable pertrochanteric osteotomies were created. The right and left femur of each pair were alternately selected for osteosyntheses with the gamma nail and the dynamic hip screw. Afterwards an examination of stability was performed. Cyclical loads were increased in 500 N increments to the maximum loading capacity, while the deformation rate was continuously measured. Radiographs were taken to prove the results of loading. The mean deformation was much greater in the DHS group than for the gamma nail, the maximum load to failure was significantly lower. Femoral shaft fractures caused by the loading occurred five times as often in the gamma nail osteosyntheses than in the DHS.