Skane University Hospital, Department of Clinical Sciences Lund, Orthopaedics, Lund University, 221 85, Lund, Sweden.
Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Motoriklab, Q2:07, 171 76, Stockholm, Sweden.
J Orthop Surg Res. 2020 Apr 16;15(1):151. doi: 10.1186/s13018-020-01663-0.
Methods to quantify and evaluate function are important for development of specific rehabilitation interventions. This study aimed to evaluate functional movement compensation in individuals with hip osteoarthritis performing the five times sit-to-stand test and change following total hip arthroplasty. To this end, trajectories of the body's center of mass in the medial-lateral and anterior-posterior dimensions were quantified prior to and 1 year after total hip arthroplasty and compared to a healthy control group.
Twenty-eight individuals with hip osteoarthritis and 21 matched healthy controls were enrolled in this prospective study. Within 1 month prior to and 1 year after total hip arthroplasty, performance on the five times sit-to-stand test was evaluated using three-dimensional motion analysis and perceived pain using a visual analog scale. The center of mass trajectories for the medial-lateral and the anterior-posterior dimensions were identified, and the area under the curve was calculated, respectively. Repeated measures ANOVA were used to evaluate differences in the area under the curve, between pre- and postoperative performance, and between participants with hip osteoarthritis and controls.
Preoperatively, individuals with hip osteoarthritis displayed a larger contralateral shift (p < 0.001) and forward displacement of the center of mass (p = 0.022) compared to controls. After surgery, deviations in both dimensions were reduced (medial-lateral p = 0.013; anterior-posterior p = 0.009). However, as compared to controls, the contralateral shift of the center of mass remained larger (p = 0.010), indicative of persistent asymmetric limb loading. Perceived pain was significantly reduced postoperatively (p < 0.001).
By quantifying the center of mass trajectory during five times sit-to-stand test performance, functional movement compensations could be detected and evaluated over time. Prior to total hip arthroplasty, individuals with hip osteoarthritis presented with an increased contralateral shift and forward displacement of the center of mass, representing a strategy to reduce pain by unloading the affected hip and reducing required hip and knee extension moments. After surgery, individuals with total hip arthroplasty displayed a persistent increased contralateral shift as compared to controls. This finding has implications for rehabilitation, where more focus must be directed towards normalizing loading of the limbs.
量化和评估功能的方法对于特定康复干预措施的发展很重要。本研究旨在评估髋关节炎患者在进行五次坐站测试时的功能运动补偿，并评估全髋关节置换术后的变化。为此，在全髋关节置换术前和术后 1 年，分别对患者和健康对照组的身体质心在横向和前后方向上的轨迹进行了量化。
本前瞻性研究共纳入 28 例髋关节炎患者和 21 名匹配的健康对照组。在全髋关节置换术前 1 个月内和术后 1 年内，使用三维运动分析评估五次坐站测试的表现，使用视觉模拟量表评估疼痛感知。分别确定横向和前后方向的质心轨迹，并计算曲线下面积。使用重复测量方差分析评估曲线下面积在术前和术后、髋关节炎患者和对照组之间的差异。
术前，髋关节炎患者的质心向对侧的偏移较大（p < 0.001），向前的位移较大（p = 0.022），与对照组相比。术后，两个方向的偏差均减小（横向 p = 0.013；前后向 p = 0.009）。然而，与对照组相比，质心向对侧的偏移仍然较大（p = 0.010），表明存在持续的不对称肢体负荷。术后疼痛明显减轻（p < 0.001）。
通过量化五次坐站测试过程中质心轨迹，可以随时间检测和评估功能运动补偿。在全髋关节置换术前，髋关节炎患者的质心向对侧的偏移和向前的位移增加，这是一种通过减轻患髋的负荷和减少所需的髋关节和膝关节伸展力矩来减轻疼痛的策略。术后，与对照组相比，全髋关节置换术后患者的质心向对侧的偏移仍然持续增加。这一发现对康复治疗具有重要意义，需要更加关注肢体负荷的正常化。
