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Femoroacetabular Impingement Syndrome (FAIS), a common and painful hip condition that affects active young adults, is associated with muscle weakness and altered movement patterns during common daily activities. FAIS is believed to be a precursor to osteoarthritis through disrupted loading patterns; thus, understanding how weakness affects joint loading may provide insights into the pathogenesis from FAIS to osteoarthritis. The aim of this study was to examine the impact of gluteus maximus strength on hip joint contact forces during gait using musculoskeletal modeling. Twelve individuals with FAIS and 13 healthy controls were included in the study and five conditions of gluteus maximus strength (50%, 75%, 100%, 125%, and 150% of the model’s default strength) were examined. Differences in the magnitude of the resultant joint contact force and directional components of the joint contact force between groups (FAIS vs controls) and between strength conditions were assessed with statistical nonparametric mapping. Joint contact forces were also used to determine the direction of hip loading in the sagittal and frontal planes and the center of the loading area was compared between groups and between strength conditions using independent t-tests and repeated measures analysis of variance, respectively. Joint contact force magnitude and direction did not differ between FAIS and control groups, aside from a brief period of larger medial force in the FAIS group. With both groups combined for remaining analyses, magnitude and direction of the joint contact force changed with the varied strength conditions; specifically, the 50 and 75% strength conditions demonstrated a lower magnitude joint contact force with a more anterior and medial direction. Importantly, these changes were small and of questionable clinical value. Future investigations should model movement changes alongside strength changes and use magnetic resonance imaging to examine a mechanistic link between load and intraarticular joint health.

股髋臼撞击综合征（Femoroacetabular Impingement Syndrome, FAIS）是一种常见且引发疼痛的髋关节疾病，好发于活跃的年轻成年人群，其与肌肉无力以及日常活动中运动模式的改变相关。现有研究认为，FAIS通过负荷模式紊乱进展为骨关节炎的前驱病变；因此，明确肌肉无力如何影响关节负荷，或可为阐释FAIS进展至骨关节炎的发病机制提供新思路。本研究旨在通过肌骨建模方法，探究步态过程中臀大肌力量对髋关节接触力的影响。本研究共纳入12名FAIS患者与13名健康对照者，并设置了5种臀大肌力量梯度（分别为模型默认力量的50%、75%、100%、125%与150%）进行测试。采用统计非参数映射法，对比分析组间（FAIS患者组与健康对照组）以及不同力量梯度下的髋关节接触力合力幅值与方向分量差异。同时通过髋关节接触力确定髋负荷在矢状面与冠状面的方向，并分别采用独立样本t检验与重复测量方差分析，对比组间及不同力量梯度下的负荷区域中心差异。FAIS患者组与健康对照组的髋关节接触力幅值与方向整体无显著差异，仅FAIS组在短暂时段内表现出更大的内侧方向力。将两组数据合并进行后续分析时，髋关节接触力的幅值与方向随力量梯度变化发生改变：具体而言，50%与75%力量梯度下的髋关节接触力幅值更低，且方向更偏前内侧。值得注意的是，上述变化幅度较小，临床价值存疑。未来研究可结合力量变化与运动改变构建模型，并采用磁共振成像技术探究负荷与关节腔内健康状态之间的潜在机制关联。