The interaction of functional and mechanical deficits in chronic ankle instability remains a major issue in current research. After an index sprain, some patients develop sufficient coping strategies, while others require mechanical support. This study aimed to analyze persisting functional deficits in mechanically unstable ankles requiring operative stabilization. We retrospectively analyzed the functional testing of 43 patients suffering from chronic, unilateral mechanical ankle instability (MAI) and in which long-term conservative treatment had failed. Manual testing and arthroscopy confirmed mechanical instability. The functional testing included balance test, gait analysis, and concentric-concentric, isokinetic strength measurements and was compared between the non-affected and the MAI ankles. Plantarflexion, supination, and pronation strength was significantly reduced in MAI ankles. A sub-analysis of the strength measurement revealed that in non-MAI ankles, the peak pronation torque was reached earlier during pronation (maximum peak torque angle at 20° vs. 14° of supination, p < 0.001). Furthermore, active range of motion was reduced in dorsiflexion and supination. In balance testing, patients exhibited a significant increased perimeter for the injured ankle (p < 0.02). During gait analysis, we observed an increased external rotation in MAI (8.7 vs. 6.8°, p<0.02). This study assesses functional deficits existent in a well-defined population of patients suffering from chronic MAI. Impairments of postural sway, gait asymmetries, and asymmetric isokinetic strength can be observed despite long-term functional treatment. The finding that pronation strength is particularly reduced with the foot in a close-to-accident position indicates potential muscular dysfunction in MAI. Possibly, these deficits alongside the underlying mechanical instability characterize patients requiring mechanical stabilization.

中文翻译：

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慢性机械性踝关节不稳定的功能缺陷。


慢性踝关节不稳定中功能和机械缺陷的相互作用仍然是当前研究的一个主要问题。索引扭伤后，一些患者会制定足够的应对策略，而另一些患者则需要机械支持。本研究旨在分析需要手术稳定的机械不稳定脚踝的持续功能缺陷。我们回顾性分析了 43 例患有慢性单侧机械性踝关节不稳定 (MAI) 且长期保守治疗失败的患者的功能测试。手动测试和关节镜检查证实了机械不稳定。功能测试包括平衡测试、步态分析和同心-同心、等速力量测量，并在未受影响的脚踝和 MAI 脚踝之间进行比较。 MAI 踝关节的跖屈、旋后和旋前力量显着降低。力量测量的子分析显示，在非 MAI 踝关节中，在内旋期间较早达到峰值内旋扭矩（最大峰值扭矩角度为 20° 与 14° 旋后，p < 0.001）。此外，背屈和旋后的主动运动范围减少。在平衡测试中，患者受伤脚踝的周长显着增加（p < 0.02）。在步态分析过程中，我们观察到 MAI 的外旋增加（8.7 与 6.8°，p<0.02）。这项研究评估了明确的慢性 MAI 患者群体中存在的功能缺陷。尽管进行长期功能治疗，仍可观察到姿势摇摆、步态不对称和不对称等速力量的损害。 足部处于接近事故位置时，内旋力量尤其降低，这一发现表明 MAI 中存在潜在的肌肉功能障碍。这些缺陷以及潜在的机械不稳定性可能是需要机械稳定的患者的特征。