髋动力螺钉拧入股骨头时扭力矩和把持力的相关性研究

Relationship between the Torque and Holding Power of DHS Fixed in Femoral Head

目的测量髋动力螺钉(DHS)拧入股骨头的最大扭力矩和螺钉在股骨头中的最大把持力,分析两者的相关性。方法 10具新鲜尸体的成对股骨标本20根,复制股骨转子间骨折模型并行标准DHS固定,测量DHS拧入时的最大扭力矩Tmax,然后测试DHS从股骨头中沿DHS长轴方向拔出时的最大抗拔出力Fmax,回归分析两者的相关性。结果 20组Tmax-Fmax数据中,Tmax平均值为(5.75±0.99)Nm(4.3Mm～7.4Nm),Fmax平均值为(1249.2±138.3)N(1023N～1476N);将螺钉的Tmax及Fmax设为自变量与应变量,两者的Pearson相关系数r=0.86,经验公式:Fmax=115.5×Tmax+584.3。结论髋动力螺钉(DHS)拧入股骨头的最大扭力矩和螺钉在股骨头中最大把持力呈正相关,通过经验公式在测得Tmax后就可以准确计算出Fmax。

Objective The maximum torque to insert DHS into femoral head and the holding power as DHS pulled out from femoral head was measured, and then the degree of correlation between them was revealed. Methods The model of intertrochanteric fracture fixed with DHS was established in l0 pairs, 20 cases of fresh femur samples. The torque to insert DHS into a femoral head was measured from torsional screwdriver and the maximum torque （Tmax） were recorded, then the maximum holding power （Fmax） as DHS was pulled out from femoral head along with its long axis measured from biomechanical machine. The Pearson correlation analysis between Tmax and Fmax was performed then. Results Twenty pairs of Tmax-Fmax data were recorded, the average Tmax was （5.75 ± 0.99） Nm （4.3 Mm 7.4 Nm） while Fmax was （1 249.2 ± 138.3） N （1 023 N - 1 476 N） and the Pearson correlation coefficient of Tmax-Fmax got r = 0.86. The empirical formula was Fmax = 115.5 x Tmax ± 584.3. Conclusions There is a positive correlation between Tmax and Fmax, and Fmax can be calculated by the empirical formular from Tmax which can be easily measured during inserting DHS into femoral head.