人工股骨的研制及在股骨颈骨折生物力学研究中的应用

目的 比较人工与防腐股骨颈骨折模型在股骨颈骨折生物力学研究中的力学差异.方法 选取股骨颈长度相似的防腐股骨标本5个,自制聚甲基丙烯酸甲酯（PMMA）人工股骨标本5个,制备内收型（Pauwels角70°）股骨颈骨折模型,均用动态套筒式三翼钉固定断端.标本摸拟人体单足站立位固定于英斯特朗-8874液压伺服力学实验机上,以速率10 mm/min线性载荷0～1 200 N分级加载,测定2种标本 1200 N载荷下股骨上段11个关键点的应变值;测定不同载荷下头下沉位移、主压力侧的应变值和主张力侧的应变值.结果 1200 N载荷下,应变值变化最明显的区域均集中于2种标本股骨头-颈结合部下方的压应变位置,并在6号电阻应变片的位置出现峰值,其数值差异有显著性意义（P＜0.01）;同一载荷下2种标本之间比较头下沉位移,差异有显著性意义（P＜0.05）.结论 动态套筒式三翼钉固定股骨颈骨折稳定可靠;在进行股骨颈骨折的生物力学实验研究中,往往需要大量的股骨标本,在股骨标本获得日益困难的情况下,人工股骨标本在一定程度上可以替代防腐股骨进行股骨颈骨折生物力学研究.

Development of artificial femoral neck and its application in the study of biomechanics

Objective To compare the biomechanical difference between embalmed femoral specimens and artificial femoral neck fracture models. Methods Five embalmed human femoral specimens were selected with similar length of femoral neck, and five PMMA femurs were made, and adductor type (Pauwels angle 70° )femoral neck fracture model were prepared and fixed with dynamic sleeve three-wing screw. Specimens were fixed at simulated uniped standing position at Instron-8874 servo-hydraulic mechanical testing machine. Linear load of 0～1 200 N was loaded at the rate of 10 mm/min and strains at 11 key points under 1 200 N load were measured, as well as head sink displacement and the strain at principal pressure side and principal tension side under different loads. Results There was a strengthening peak at the number six resistance strain gage under the 1 200 N load,the numerical difference of the two groups was statistically significant(P＜0.01 ). Head sink displacements of the two kinds specimens were compared under the same load, and the difference was significant (P＜0.01). Conclusion Dynamic sleeve three-wing screw has the good biomechanical stability for treatment of femoral neck fracture. Experimental study on the biomechanics often needs lots of femoral specimens. It is feasible to take the artificial femur as substitute to a certain extent to face the ever increasing difficulty to obtain human femoral specimens for biomechanical experiments.