Background

The innate shape characteristics of the hindfoot bones alter the loading conditions of the foot and thus may be associated with an increased risk of developing varus ankle osteoarthritis (OA). This study aimed to clarify the innate morphological patterns of the hindfoot bones that may be associated with ankle OA by analyzing the differences between the bone morphology of the non-affected side of patients with unilateral varus ankle OA and that of healthy participants.

Methods

In this case-control study, computed tomography images were used to develop three-dimensional models of three hindfoot bones (distal tibia with fibula, talus, and calcaneus) from 23 non-affected sides of patients with radiography-diagnosed unilateral ankle OA and 22 healthy control participants. Anatomical and sliding landmarks were placed on the surface of each bone, and the principal components (PCs) of shape variation among specimens were independently calculated for each bone, preserving homology between individuals. The PC modes representing 5% or more of the overall variation were statistically compared between the ankle OA and control groups.

Results

Significant differences were identified between the OA and control groups in the fifth PC mode for the tibia with fibula (proportion of variance, 5.1%; p =.025), fifth PC mode for the talus (6.7%, p =.031), and third PC mode for the calcaneus (7.4%, p =.001). The hindfoot bones of the participants who developed ankle OA had the following innate morphological characteristics: the lateral malleolar articular surface of the fibula was shifted superiorly, tibial plafond was enlarged posteroinferiorly, posterior width of the talar trochlea was narrower, talonavicular articular surface of the talus was oriented more frontally, anterior-middle talocalcaneal articular surfaces of the talus were more medially shifted and those of the calcaneus were flatter, calcaneal sustentaculum tali was less protruding, and lateral plantar process of the calcaneus was more superiorly positioned.

Conclusions

These distinctive morphological alterations may increase the incidence and progression of varus ankle OA through aberrant anterior translation, internal rotation, and varus tilting of the talus.

中文翻译：

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单侧内翻踝骨关节炎患者后足健侧形态特征

背景

后足骨的先天形状特征改变了足部的负荷条件，因此可能与发生内翻踝骨关节炎（OA）的风险增加有关。本研究旨在通过分析单侧内翻踝关节 OA患者非患侧骨形态与健康参与者之间的差异，阐明可能与踝关节 OA 相关的后足骨先天形态模式。

方法

在这项病例对照研究中，使用计算机断层扫描图像开发了 3 个后足骨（远端胫骨、腓骨、距骨和跟骨）的三维模型，这些骨来自放射线检查诊断的单侧踝关节 OA 患者的 23 个非受影响侧和 22 个后足骨。健康对照参与者。在每块骨头的表面放置解剖和滑动标志，并独立计算每块骨头样本之间形状变化的主成分（PC），保留个体之间的同源性。对踝关节 OA 组和对照组之间代表 5% 或更多总体变异的 PC 模式进行统计比较。

结果

在胫骨和腓骨的第五种 PC 模式（方差比例，5.1%；p =.025）、距骨的第五种 PC 模式（6.7%，p =.031）中，OA 组和对照组之间存在显着差异。第三种 PC 模式为跟骨 (7.4%, p =.001)。发生踝关节OA的参与者的后足骨具有以下先天形态特征：腓骨的外踝关节面向上移位，胫骨平台向后下方扩大，距骨滑车的后部宽度变窄，距骨的距舟关节面距骨的前中距跟关节面更向内移动，跟骨的距跟关节面更平坦，跟骨支撑距骨的突出程度更小，跟骨的外侧跖突位置更靠前。

结论

这些独特的形态改变可能会通过距骨的异常前平移、内旋和内翻倾斜而增加踝关节内翻骨关节炎的发生率和进展。