不同负荷形态对股骨头缺血性坏死影响的有限元素分析

Biomechanical effect of loading modes on femoral heads with avascular necrosis： a finite element analysis

目的 利用两种不同的负荷形态来评估缺血性坏死体积大小及位置对股骨头应力的影响。方法 建立骨盆、软骨及股骨的三维有限元素模型，以骨盆施加负荷及股骨头处直接给予负荷两种不同的负荷形态来分析不同坏死体积大小和位置的影响。结果 在利用骨盆施加负荷时，当股骨头缺血性坏死体积越大或越靠近上侧，坏死区域内的平均von Mises应力越大，坏死区域和健康股骨交界处的平均von Mises应力也越大。但在只给定股骨头上负荷的组别中，缺血性坏死体积对von Mises应力的结果与骨盆施加负荷的趋势相反。结论 根据模拟结果中von Mises应力而言，股骨头缺血性坏死越靠近上侧塌陷风险越高，其坏死位置比坏死体积大小更为重要；就坏死区域和健康骨质交界处平均von Mises应力而言，当坏死区域和健康股骨质交界处的平均von Mises应力增大，会加速坏死体积的扩张。

Objective To evaluate the effects of size and location of avascular necrosis on the stress at femoral heads with 2 loading modes. Methods Three-dimensional finite element models of the pelvis, cartilage, and femur were developed. The effects of different sizes and locations of the necrotic femoral heads on the stress at femoral heads were analyzed. Two loading modes were applied in the analysis： loading through the pelvis and loading directly on the femoral head. Results In simulation of loading through pelvis, when the necrotic size increased or the location was nearer to the superior side, the average yon Mises stresses in the necrotic region and at the interface between necrotic region and normal bone increased. In simulation of direct loading on the femoral head, the effect of necrotic size on the yon Mises stress presented a contradictory trend as compared with the model of loading through pelvis. Conclusions Based on the bone yon Mises stress, the necrosis at the superior region indicates a high risk of collapse, irrespective of the lesion size. Based on the average interfacial yon Mises stress, the enlarged lesion size may accelerate the necrotic lesion.