距骨缺血性坏死的有限元分析

背景：对距骨缺血性坏死的具体临床治疗，目前仍有很大争议。 目的：观察不同程度距骨坏死时，距骨滑车关节面上的应力及其分布变化。 方法：利用8具踝关节标本建立踝关节三维有限元模型，通过改变各模型距骨坏死的体积分析距骨滑车关节面压应力与其分布的变化规律，计算出距骨缺血性坏死可能诱发踝足创伤性关节炎或出现距骨塌陷的临界坏死体积。 结果与结论：实验成功建立了踝关节三维有限元模型。分析发现距骨内、外侧坏死程度比较小时，距骨滑车关节面应力分布变化不大；当内侧距骨坏死体积达到(26.6±1.5)%，外侧距骨坏死体积达到(35.0±2.5)%时，距骨坏死组织与正常骨组织边界区域出现应力集中的现象，其应力区域呈不规则形，提示，此时诱发踝足创伤性关节炎或发生距骨体塌陷的危险性很高，应手术治疗。

Finite element analysis of talar ischemic necrosis

BACKGROUND:Precise clinical treatment of talar ischemic necrosis remains controversial at present. OBJECTIVE:To observe the changes in the stress and its distribution on talar trochlear articular surface in case of talar necrosis at different levels. METHODS:The present study adopted eight ankle specimens to establish the three-dimensional finite element model of ankle. Through changes in the talar necrosis volume of these models, this study analyzed the change law of talar trochlear articular surface stress and its distribution and calculated the critical necrosis volume of traumatic foot and ankle arthritis or talar collapse that may be induced by talar ischemic necrosis. RESULTS AND CONCLUSION:The experiment successfully established the three-dimensional finite element model of ankle. This study found that talar trochlear articular surface stress distribution showed little change in case of talar medial and lateral necrosis at a lower level; when medial talar necrosis volume reached (26.6±1.5)%, and lateral talar necrosis volume reached (35.0±2.5)%. Stress concentration phenomenon occurred in the boundary area between talar necrosis tissue and normal osseous tissue, and the stress area took the shape of irregular pattern. It is suggested that surgical treatment should be considered due to the high-risk induction of ankle-foot traumatic arthritis or talar collapse.