新型股骨转子间骨折内固定器(记忆合金钉板)的生物力学评价

目的:对治疗骨质疏松性股骨转子间骨折的新型内固定器进行生物力学评价。方法:设计一种新型的股骨转子间骨折内固定器,用福尔马林固定的经X线片证实为骨质疏松并排除骨折和肿瘤的尸体股骨标本11根,模拟股骨转子间骨折,随机分为记忆合金钉板固定组(6例)和DHS固定组(5例)并进行生物力学测试,比较两组股骨头垂直位移1mm时的压缩刚度、加载350N时的股骨头垂直位移、股骨颈扭转1°时的扭矩、扭矩为3.5Nm时股骨颈的扭转角度。结果:记忆合金钉板与DHS固定比较,上述指标经统计学分析,P值分别为0.930、0.248、0.417、0.622,差异无显著性意义;但记忆合金钉板较DHS固定,骨质的进一步破坏少,能保持股骨近段结构上的完整性。结论:记忆合金钉板内固定骨质破坏少、固定可靠,能有效治疗骨质疏松性股骨转子间骨折。

Biomechanic evaluation of shape memory alloy plate for treating intertrochanteric fracture

Objective: To evaluate the biomechanical characteristics of the new shape memory alloy plate for treatment of osteoporotic and intertrochanteric fractures. Mehtods: A new internal fixation system for the fixation of intertrochanteric fracture was designed according to the shape recovery characterization of memory alloy. 11 human osteoporotic cadaver specimens excluding tumor and fracture were selected and simulated intertrochanteric fracture, and then they were randomly divided into 2 groups: 6 cases fixing by memory alloy plate were taken as experimental group and 5 cases by DHS (dynamic hip screw) as control group. Those indexs, including vertical compressive stiffness at the average displacement of femoral head of 1mm, vertical displacement at 350N loading, torsion stiffness at torsion angle of femoral neck of 1 degree and torsion angle of femoral neck at torsional arm of 3.5Nm, were measured and compared between two groups. Results: The biomechanical comparison showed that there was no significant difference between memory alloy system and DHS fixation, and P value was 0.930, 0.248, 0.417 and 0.622 respectively. There was no continuous destruction of bone happened in memory alloy system group. Conclusions: Shape memory alloy system has less bone destruction and it is strong enough for the treatment of osteoporotic and intertrochanteric fracture.