Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Foot Ankle Int. 2011 Nov;32(11):1017-22. doi: 10.3113/FAI.2011.1017.
The objective of this study was to evaluate the bone rotation of each joint in the hindfoot and compare the load response in healthy feet with that in flatfeet by analyzing the reconstructive three-dimensional (3D) CT image data during weightbearing.
CT scans of 21 healthy feet and 21 feet with flatfoot deformity were taken in non-load condition followed by full-body weightbearing load condition. The images of the hindfoot bones were reconstructed into 3D models. The volume merge method in three planes was used to calculate the position of the talus relative to the tibia in the tibiotalar joint, the navicular relative to the talus in talonavicular joint, and the calcaneus relative to the talus in the talocalcaneal joint.
The talar position difference to the load response relative to the tibia in the tibiotalar joint in a flatfoot was 1.7 degrees more plantarflexed in comparison to that in a healthy foot (p = 0.031). The navicular position difference to the load response relative to the talus in the talonavicular joint was 2.3 degrees more everted (p = 0.0034). The calcaneal position difference to the load response relative to the talus in the talocalcaneal joint was 1.1 degrees more dorsiflexed (p = 0.0060) and 1.7 degrees more everted (p = 0.0018).
Referring to previous cadaver study, regarding not only the cadaveric foot, but also the live foot, joint instability occurred in the hindfoot with load in patients with flatfoot.
The method used in this study might be applied to clinical analysis of foot diseases such as the staging of flatfoot and to biomechanical analysis to evaluate the effects of foot surgery in the future.
本研究旨在评估足后关节在各个关节的骨旋转，并通过分析负重状态下重建的三维（3D）CT 图像数据，比较健康足与扁平足的负荷反应。
对 21 例健康足和 21 例扁平足患者进行非负重状态下的 CT 扫描，然后进行全身负重状态下的 CT 扫描。将足后骨的图像重建为 3D 模型。在三个平面上使用容积合并法计算距骨相对于距下关节胫骨的位置、跟骨相对于距骨在跗骨间关节的位置以及跟骨相对于距骨在跟距关节的位置。
与健康足相比，扁平足足距下关节距骨在负重状态下相对于胫骨的位置差异为跖屈 1.7 度（p = 0.031）。跗骨间关节距骨相对于跟骨的位置差异在负重状态下为外翻 2.3 度（p = 0.0034）。跟距关节距骨相对于跟骨的位置差异在负重状态下为背屈 1.1 度（p = 0.0060）和外翻 1.7 度（p = 0.0018）。
参考以前的尸体研究，不仅在尸体足，而且在活体足中，扁平足患者在负重时后足关节不稳定。
本研究中使用的方法将来可应用于扁平足等足部疾病的临床分析和生物力学分析，以评估足部手术的效果。
