目的 分析研究正常成人新鲜足标本踝关节在背屈、中立及跖屈不同位置的生物力学分布特性.方法 成人新鲜小腿以下的标本30具分三组,实验夹具直立中立位固定标本于电子万能试验机,将压敏片经踝关节前方置入踝关节,分别在中立位、背屈10°、跖屈30°位时,施加600、900、1 200 N的压力.压敏膜发生着色反应,用FPD305密度仪和FPD306密度压力转换仪分析着色压迹测出压力及压力分布情况.结果 相同角度下不同载荷,踝关节的接触面积位置不发生改变;由背屈到跖屈过程,接触位置由距骨前部变为后部;踝关节接触面积,背屈10°> 中立位> 跖屈30°;踝关节所受压强,背屈10°< 中立位 < 跖屈30°.结论 相同角度下,踝关节的接触位置与面积不随载荷的改变而改变;相同载荷下踝关节力学分布特征在不同角度时显著变化,与解剖结构相对应,可能与不同类型的骨折发生有一定的联系.%Objective To determine the distribution of contact area and pressure of the ankle joint with axial loading at different positions. Methods Specimens consisting of the distal half of the tibia and fibula and the intact ankle and foot, were mounted in a materials testing system on a loading frame that allowed positioning in neutral, and 30 degree of plantarflexion and 10 degree of dorsiflexion. An axial load was applied to the specimens through the tibia with 600 N, 900 N, 1200 N. Pressure-sensitive film were used to make a contact print and analyzed quantitatively to determine total contact area/mean contact pressure with FPD305 density and FPD306 density-pressure cycling instrument. Results The contact area moved from anterior to posterior on the talus surface as the joint moved from dorsiflexion to plantar-flexion. The contact area at 10° dorsiflexion> neutral position> 30° plantarflexion under the same axial load. When pressure was given, the density of pressure 10° dorsiflexion < neutral position < 30° plantarflexion. Conclusion The results demonstrate significant changes in ankle joint contact characteristics at different foot positions; on the other hand, the contact area does not change under variable loads while the ankle joint fixed at a certain degree. The feature of the biomechanics, which base on its anatomy, may be relative to fractures clinically.
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