缺血坏死股骨头负重区抗压强度生物力学分析

Biomechanical analysis of weight-bearing area of the necrotic femoral head

[目的]对比研究正常股骨头、塌陷前期、塌陷早期和塌陷晚期股骨头负重区生物力学特性。[方法]取单侧新鲜人股骨头6个作为对照组;髋关节置换中取出人股骨头57个,将其中新鲜头下型骨折股骨头作为实验1组,其余坏死股骨头按塌陷前期、塌陷早期和塌陷晚期分成实验2、3、4组。在AGS-10KND万能生物材料实验机上进行力学性能测试,观察5组标本股骨头负重区的力学刚度及强度,对每个标本的测试结果进行标准化后行统计学分析。[结果]5组标本的刚度由高到低依次为对照组、实验1、2、3、4组;5组标本的最大负载由高到低依次为实验1组、对照组、实验2、3、4组。5组刚度及最大负载经多样本方差分析,差异有显著性意义(P<0.01);刚度及最大负载行两两比较t检验,对照组和实验1组间无统计学差异,其他组间两两比较均有显著性差异(P<0.05)。[结论]股骨头坏死晚期负重区力学性能明显降低,导致股骨头塌陷并逐步进展。塌陷前期是保留股骨头治疗股骨头坏死,为坏死股骨头软骨下骨提供足够的力学支撑,防止股骨头塌陷变形的关键时期。

[Objective]To study the biomechanics of weight-bearing area of avascular necrotic femoral head at different stages.[Methods]Biomechanical test on weight-bearing area was made for 57 moist femoral heads obtained in operation,which were divided into 4 groups： group of femoral neck fracture（group 1）,group of pre-collapse（group 2）,group of early collapse（group 3）,group of advanced collapse（group 4）.Six fresh moist human femur specimens were used as normal control.[Results]The descending order of the stiffness was normal group,groups 1,2,3 and 4,and of the max load was group 1,normal group,groups 2,3 and 4.There was significant difference in the stiffness and the max load among the 5 groups with analysis of variance（P0.01）.On the stiffness and the max load,significant statistic difference was found in multiple comparison（P0.05）,except normal control group and groups 1.[Conclusion]The mechanical properties of weight-bearing area of avascular necrotic femoral head decreased progressively,which resulted in progressively collapse of femoral head.The pre-collapse stage is the key stage for sustaining the femoral head shape with enough power for mechanical support of the weight-bearing area of avascular necrotic femoral head.