有限元分析髓芯减压并同种异体植骨治疗股骨头缺血性坏死的生物力学改变

目的:分析髓芯减压并同种异体植骨治疗早期股骨头缺血性坏死的临床应用。方法:选取收治的1例早期股骨头缺血坏死男性患者，入院后术前对患侧股骨头行多层螺旋CT扫描，然后将CT扫描的图片资料导入专业的有限元分析软件，建立股骨头缺血坏死的有限元模型，在有限元模型上模拟进行髓芯钻孔减压术，隧道植入骨块到软骨下骨约0~6 mm处，自体松质骨夯实。双足站立位为股骨头的模拟受力体位，髋关节的负荷条件为:外展肌合力M、髂胫束力T以及髋关节接触力J分别为1 060、1 721、1 621 N，选取90°、120°以及150°的坏死角度，分别计算未处理过的股骨头坏死模型的塌陷值、行单纯髓芯减压以及行髓芯减压加植骨时的塌陷值。结果:股骨头的正常骨质杨氏模量高于坏死骨的杨氏模量，正常骨质的横向变形系数低于坏死骨。行股骨头髓芯钻孔减压术后，股骨头的塌陷值显著增加，而减压隧道植入同种异体骨后，其塌陷值显著减低，但高于正常的股骨头。同时，由于股骨头坏死角度的增加，其塌陷值也明显增加。结论:髓芯钻孔减压并同种异体植骨术能有效增进坏死区的骨质修复，加强减压通道所致股骨头支撑结构的改变，防止股骨头关节面的塌陷。

Biomechanical changes of avascular necrosis of the femoral head treated by core decompression and allogeneic bone grafting: a finite element analysis

Objective To analyze the clinical application of core decompression combined with allogeneic bone grafting in the treatment of early avascular necrosis of the femoral head.Methods A patients with early avascular necrosis of the femoral head was enrolled.Multi-slice spiral CT scan was performed on the affected femoral head before operation,and the obtained CT image was then imported into a professional finite element analysis software for establishing a finite element model of avascular necrosis of the femoral head.The simulation of core decompression was conducted on the finite element model.The allogeneic bone was grafted to the subchondral bone at about 0-6 mm through compression channel,and the autologous cancellous bone was compacted.Biped standing position was adopted as the simulated force position of the femoral head.The load-bearing conditions of the hip joint were as follow:the abductor muscle force M,iliotibial tract tendon force T and hip joint contact force J were 1060,1721 and 1621 N,respectively.The necrosis angles of 90°,120°and 150°were used to calculate the collapse value of the untreated femoral head necrosis model and the collapse values after treatments with core decompression only or core decompression combined with bone grafting.Results The Young's modulus of the normal bone of the femoral head was higher than that of the necrotic bone,while the lateral deformation coefficient of the normal bone was lower than that of the necrotic bone.After the femoral head core decompression,the collapse value of the femoral head was obviously increased,and after that the allogeneic bone was grafted in the decompression channel,the collapse value was remarkably reduced,but still higher than that of the normal femoral head.Meanwhile,due to the increase in the necrosis angles of the femoral head,its collapse value was also significantly increased.Conclusion Core decompression combined with allogeneic bone grafting can effectively improve the bone repair in the necrotic area,strengthen the deformation of the femoral head support structure caused by the decompression channel,and prevent the collapse of the femoral head joint surface.