距下关节融合对中后足周围关节活动度影响的生物力学实验研究

目的分析研究正常新鲜足标本在正常情况下进行距下关节融合后对跟骰、距舟关节和踝关节的三维运动度的影响程度。方法采用新鲜足标本12例，将距下关节融合后，通过加载使足产生某种形式的运动，用三维数字化坐标仪测量跟骰、距舟关节和踩关节各关节组成骨在某种运动状态下的相对三维坐标位移，通过矩阵转换和求解非线性函数方程计算其三维旋转角度，了解跟骰、距舟关节和踝关节在距下关节融合前后2种状态下的相对运动范围，确定距下关节融合后对于周围足踝关节运动的影响程度。结果距下关节融合前后跟骰、距舟关节和踝关节在背屈一跖屈、内翻一外翻、内收一外展轴的三维运动范围之间的统计学分析显示存在显著性差异（P＜0．01），各关节平均三维运动范围受限程度分别为36．14％、38．36％、21．84％。结论距下关节融合后对跟骰、距舟关节和踝关节的活动度存在一定的限制作用，降低了前足与后足的协同性，可能增加足跗关节间退行性关节炎发生，但保留了距舟、跟骰关节的大部分活动。

Experimental Study of Effect of Subtalar Joint Arthrodesis on Middle and Hind Foot Motion

Objective To investigate the properties of middle and hind foot(including calcaneocuboid joint,talonavicular joint and ankle joint)motion and changes after subtalar joint arthrodesis.MethodsTwelve fresh frozen adult leg-foot specimens were mounted in a coordinated system.A Steinmann pin was perforated across the calcaneus,cuboideum,talus and naviculare as markers.The displacements of the marked points in the coordinated system were recorded when subtalar joint was fixed respectively.Through matrix translation and Euler equation,the angle of the calcaneus,cuboideum,talus and naviculare rotation were calculated,representing the motion of the calcaneocuboid joint,talonavicular joint and ankle joint in different condition.The statistical analysis were also done between different conditions.ResultsThree dimensional(3-D)motion was observed in middle and hind foot motion.Arthrodesis of subtalar joint would affect the middle and hind foot motion significantly(P<0.01).The affection of the range of the motion in calcaneocuboid joint,talonavicular joint and ankle joint after subtalar joint arthrodesis was 36.14%,38.36%,and 21.84%.ConclusionThe motions of calcaneocuboid joint,talonavicular joint,and ankle joint are partly limited after subtalar joint arthrodesis.But the majority of the calcaneocuboid and talonavicular joint's motions are retained.