国产股骨交锁髓内钉锁钉的生物力学研究

Biomechanical study on the interlocking nails of native femoral interlocking intramedullary nail

目的 :测定股骨交锁髓内钉锁钉的生物力学变化 ,分析易发生疲劳断裂的锁钉位点。方法 :取成人全长新鲜股骨标本 6例 ,远端用牙托粉包埋固定 ,安装交锁髓内钉与锁钉 ,于MTS试验机轴向加载 0～ 1 0 0 0N ,速度为 50N/s。每 1标本模拟 6个状态 :a正常股骨 ;b骨折愈合 ;c稳定骨折 ;d稳定骨折、远端1枚锁钉固定 ;e不稳定骨折 ;f不稳定骨折、远端 1枚锁钉固定。结果 :各种状态下近端锁钉间应变均无显著性差异 (P >0 .0 5) ;近、远端锁钉之间应变存在显著差异 (P <0 .0 5) ;远端锁钉间应变除a及c外均有显著差异 (P <0 .0 5) ;远端仅 1枚锁钉固定时应变增大 ,第 3枚锁钉在所有状态间应变均有明显差异。结论 :骨折线远端的锁钉易发生断裂 ,尤其是靠近骨折线者 ;尽量以

Objective: To analyze the biomechanical changes of interlocking nails and the position of nail where fatigue fragmentation happens easily. Methods: Distal tip of six fresh adults femoral were coated with dental base acrylic resin powder and installed on MTS machine. Axial load on each specimen was 0～1000 N at 50 N/s, each specimen was tested as six stimulative conditions: a, as normal; b, cured fracture; c, stable fracture; d, as c and one distal nail fixed; e, as unstable fracture; f, as e and one distal nail fixed. Results: No marked strain changes of proximal interlocking nails happened ( P >0.05); the changes between distal and proximal were significant ( P <0.05); outstanding strain changes in distal ones except the a and d groups ( P <0.05); among those groups only one distal nail fixed, that one should endure much stress and had more strain. The third nail had marked changes at every condition. Conclusions: Interlocking nails under the crack, especially near it, tend to be broken so that two nails interlocking should be applied to the distal fracture and the position should be apart from the crack.