[Internal fixation for intertrochanteric fracture. Biomechanical study].

ABSTRACT

A Type IIIa intertrochanteric fracture was made on the preserved femurs of adult cadavers. The fracture was fixed by 4 methods: Percalcar Steinmann's pins, Knowle's pins, Nail plate and Angle plate. The loading limit of the fixations were 150, 140, 70 and 40 kg respectively. In fatigue test the loading ability of the percalcar Steinmann's pins were 4 times greater than that of Nail plate or Angle plate. In Nail plate and Angle plate. The pathological section of the upper femur showed the most bony destruction was at the trabecula beneath the lateral cortex, and in the percalcar Steinmann's, it was at the neck trabecula, where the cal car plays an important role in supporting the loading of the lowest pin. It was found that the level arm was shortened and the loading ability increased. As the direction of the lowest pin was nearly parallel to the loading axis of the hip. The calcar suffered less shearing force. These findings showed that the percalcar Steinmann's pins fixation is the best in these 4 methods.