[Mechanical principles of L-trapezoid compression plate in the fixation of trochanter fractures].

Three pairs of human cadaver femur were used for simulation electric test with load on both legs and single leg. An Evans III osteotomy was made, and stabilized with L-trapezoid compression plate (L-TCP). L-angled plate (L-AP) 95 degrees and 130 degrees respectively. The results demonstrated that the stability of fixation of L-TCP was significantly greater than L-AP. Since the cancellous screw of L-TCP can hold the proximal fragment and forms a stable triangular truss with the L end, the bony support of the medial posterior part can be reconstructed by holding the lesser trochanter with the lag screw. From June 1980 to August 1990, 68 patients with 71 trochanter fractures and osteotomies were treated with L-CTP. 54 patients with 57 fractures and osteotomies were followed up for 6-52 months. All fractures and osteotomies were healed. No bone cutting off failure was encountered. The hips and knees of 51 patients (54 limbs) (94.8%) showed excellent and good functions. Infection occurred in 3 patients (4.4%). Varus deformity developed in 2 patients with an Evans IV fracture, and plate fracture occurred in one of them.