Fregly Benjamin J, Reinbolt Jeffrey A, Rooney Kelly L, Mitchell Kim H, Chmielewski Terese L
Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611, USA.
IEEE Trans Biomed Eng. 2007 Sep;54(9):1687-95. doi: 10.1109/tbme.2007.891934.
Abstract-Gait modification is a nonsurgical approach for reducing the external knee adduction torque in patients with knee osteoarthritis (OA). The magnitude of the first adduction torque peak in particular is strongly associated with knee OA progression. While toeing out has been shown to reduce the second peak, no clinically realistic gait modifications have been identified that effectively reduce both peaks simultaneously. This study predicts novel patient-specific gait modifications that achieve this goal without changing the foot path. The modified gait motion was designed for a single patient with knee OA using dynamic optimization of a patient-specific, full-body gait model. The cost function minimized the knee adduction torque subject to constraints limiting how much the new gait motion could deviate from the patient's normal gait motion. The optimizations predicted a "medial-thrust" gait pattern that reduced the first adduction torque peak between 32% and 54% and the second peak between 34% and 56%. The new motion involved three synergistic kinematic changes: slightly decreased pelvis obliquity, slightly increased leg flexion, and slightly increased pelvis axial rotation. After gait retraining, the patient achieved adduction torque reductions of 39% to 50% in the first peak and 37% to 55% in the second one. These reductions are comparable to those reported after high tibial osteotomy surgery. The associated kinematic changes were consistent with the predictions except for pelvis obliquity, which showed little change. This study demonstrates that it is feasible to design novel patient-specific gait modifications with potential clinical benefit using dynamic optimization of patient-specific, full-body gait models. Further investigation is needed to assess the extent to which similar gait modifications may be effective for other patients with knee OA.
摘要——步态调整是一种用于降低膝骨关节炎（OA）患者膝关节内收扭矩的非手术方法。尤其是首次内收扭矩峰值的大小与膝骨关节炎的进展密切相关。虽然已表明向外撇脚可降低第二个峰值，但尚未发现能有效同时降低两个峰值的符合临床实际的步态调整方法。本研究预测了能在不改变足部轨迹的情况下实现这一目标的新型个性化步态调整方法。使用个性化的全身步态模型进行动态优化，为一名膝骨关节炎患者设计了改良步态运动。成本函数在限制新步态运动与患者正常步态运动偏离程度的约束条件下，将膝关节内收扭矩最小化。优化结果预测出一种“内侧推力”步态模式，该模式使首次内收扭矩峰值降低了32%至54%，第二个峰值降低了34%至56%。新的运动涉及三个协同的运动学变化：骨盆倾斜度略有降低、腿部屈曲略有增加以及骨盆轴向旋转略有增加。经过步态再训练后，患者第一个峰值的内收扭矩降低了39%至50%，第二个峰值降低了37%至55%。这些降低幅度与高位胫骨截骨手术后报告的幅度相当。除骨盆倾斜度变化不大外，相关的运动学变化与预测结果一致。本研究表明，利用个性化的全身步态模型进行动态优化来设计具有潜在临床益处的新型个性化步态调整方法是可行的。需要进一步研究来评估类似的步态调整方法对其他膝骨关节炎患者的有效程度。
