下胫腓前韧带撕裂对胫距关节面生物力学的影响

目的:探讨下胫腓前韧带撕裂后,距骨滑车上关节面压力与其分布的面积变化情况,为临床治疗下胫腓前韧带撕裂提供依据。方法:取6具成人新鲜踝关节标本,男4具,女2具;年龄25～60岁,平均44.6岁。将踝关节标本去除皮肤、肌肉等软组织,保留踝关节囊、内外侧韧带及下胫腓联合韧带。用特制夹具将踝关节固定于中立位,分别用压敏片测量在700N轴向负荷下,每个下胫腓前韧带完整的踝关节(控制组)与下胫腓前韧带撕裂的踝关节(断裂组)距骨滑车上关节面的平均压强、压强峰值及应力分布面积并进行统计分析。结果:控制组与断裂组应力分布面积分别为(367.8±54.0)mm2和(386.0±53.7)mm2;压强分别为(1.40±0.12)MPa和(1.70±0.35)MPa;压强峰值分别为(2.60±0.33)MPa和(3.20±0.32)MPa。从实验结果看,下胫腓前韧带断裂后,应力分布面积变化不显著(t=0.021,P=0.983),应力分布发生改变,应力集中区域向后外侧转移,平均压强(t=4.140,P=0.020)及压强峰值增加(t=3.169,P=0.010)。结论:下胫腓前韧带断裂时,距骨外旋,其滑车上关节面平均压强、压强峰值及应力分布发生变化,可能会导致创伤性关节炎,应该手术治疗,恢复其正常解剖关系。

Biomechanical effect of anterior lower tibiofibular ligament rupture on tibiotalar articular surface

Objective:To investigate the changes between pressure of trochlea of talus surface and distribution of area after anterior lower tibiofibular ligament rupture,and provide basis for treating anterior lower tibiofibular ligament rupture. Methods:Six fresh adult ankle joint specimens(4 males and 2 females,ranging age from 25 to 60 years,with an average of 44.6 years) were adopted. The specimens were removed from skin and muscles,remained ankle joint capsule,medial and lateral ligaments and anteroinferior tibiofibular ligament. The ankle joint was fixed with a special fixture in neutral position. Pressure sensitive film(700 N axial load ) was respectively used to measure mean pressure,peak pressure and stress distribution area of the upper articular facet of talar trochlea of the normal ankle joint and the ankle joint with anterioinferior tibiofibular ligament rupture. Results:The stress distribution areas of the control group and the ruptured group were respectively (367.8±54.0) mm2 and(386.0±53.7) mm2; the mean pressures were respectively(1.40±0.12) MPa and (1.70±0.35) MPa; the peak pressures were respectively (2.60±0.33) MPa and (3.20±0.32) MPa. The experimental results showed that the change in stress distribution area after anterioinferior tibiofibular ligament rupture was not significant(t=0.021,P=0.983). When stress distribution changed,the region of stress concentration transferred to poster lateral,and mean pressure(t=4.140,P=0.020) and peak pressure(t=3.169,P=0.010) increased significantly. Conclusion:When anterior lower tibiofibular ligament rupture occurs,mean pressure,peak pressure and stress distribution of pressure of trochlea of talus surface is changed,which may cause traumatic arthritis,and surgical treatment is considerably used to restore normal anatomy.