Biomechanical analysis of the mechanism of interlocking nail failure

摘要: From December 1986 to May 1989, 412 patients with 274 femoral and 144 tibial fractures were treated Grosse-Kempf interlocking nails at our hospital. 324 cases (78.6%) followed-up for least 1 year (average 23 months). There 13 breakages in the locking femora none tibiae. The recorded incidence of breakage femur is therefore 4.7% (13/274). mechanisms nail failure are stress concentration around screw hole slot, nicking during drilling holes, too close proximity fracture, larger loading over proximal femur. 4.9% upper third, 1.9% mid-third, 8.2% distal third (P > 0.05, χ2 test). site most risk first especially if it near fracture site. Prevention involves using a diameter sufficient length, improving surgical technique, allowing only protected weight bearing. Management by insertion new implant supplementary cancellous bone grafting can gain satisfactory results.