骨质疏松股骨转子间不稳定型骨折人工股骨头置换的三维有限元应力分析

Three-dimensional finite element analysis of artificial femoral head replacement for unstable femoral intertrochanteric fractures

背景:人工股骨头置换的出现为股骨转子间不稳定型骨折的临床修复提供了新思路。但人工假体置换可能会对原有的股骨生物力学稳定性产生影响,导致各种不良后果的出现。目的:采用三维有限元方法分析人工股骨头置换修复骨质疏松股骨转子间不稳定型骨折的应力变化。方法:在接受健康体检的人群中随机选择1名老年男性志愿者,对左侧股骨进行螺旋CT扫描,建立人体股骨、假体三维有限元模型。模拟人体攀爬楼梯的实际工况,利用三维有限元模型,分析各项力学指标,包括股骨体表、假体以及假体柄周围骨性通道的应力分布情况。结果与结论:在正常状态下,人体股骨内外侧受力基本处于一致的状态。应力按照从近端向远端逐渐增大的情况变化。假体应力存在集中情况,并集中于中段。对假体柄前内侧的应力分布情况进行分析,获得假体及相应股骨内松质骨界面的应力分布情况,经分析可以发现,处于一致的应力变化趋势。结果提示,人工股骨头置换并不会对人体股骨的总体应力分布模式产生明显的影响,总体的应力分布并没有发生变化,依然按照从近端向远端逐渐增大的情况变化,且最大应力区域位于全长股骨中段位置。进行重建之后,股骨距部未观察到明显的应力集中情况。

BACKGROUND： Artificial femoral head replacement provides a new idea for the repair of unstable intertrochanteric fracture. Artificial prosthesis replacement may affect original femoral biomechanical stability and lead to a variety of adverse consequences. OBJECTIVE： To analyze the stress distribution of femoral head replacement in the treatment of unstable femoral intertrochanteric fractures with three-dimensional finite element analysis. METHODS： One male old volunteer was randomly selected from population who underwent health examination. The left femur was scanned with spiral CT, and the three-dimensional finite element models of the human femur and prosthesis were established. The three-dimensional finite element model was used to simulate the actual working conditions of human climbing stairs, and the stress distribution of the bone channels around the surface of the femur and the prosthesis was analyzed with three-dimensional finite element analysis. RESULTS AND CONCLUSION： Under normal condition, the stress of the human femur was in a consistent state. Stress changed gradually from the proximal end to the distal end. The stress of the prosthesis was concentrated in the middle section. The prosthesis of inner stress distribution was analyzed to obtain stress distribution of prosthesis and femur cancellous bone interface. The analysis found that stress change trend was consistent. The results suggest that artificial femoral head replacement does not have a significant effect on the overall stress distribution of the human femur, and the overall stress distribution does not change, and the maximum stress region is located in the middle of the whole femur. After the reconstruction, the stress concentration of the femur is not observed.