Juvenile Idiopathic Arthritis (JIA) is a paediatric musculoskeletal disease of unknown aetiology, leading to walking alterations when the lower-limb joints are involved. Diagnosis of JIA is mostly clinical. Imaging can quantify impairments associated to inflammation and joint damage. However, treatment planning could be better supported using dynamic information, such as joint contact forces (JCFs). To this purpose, we used a musculoskeletal model to predict JCFs and investigate how JCFs varied as a result of joint impairment in eighteen children with JIA. Gait analysis data and magnetic resonance images (MRI) were used to develop patient-specific lower-limb musculoskeletal models, which were evaluated for operator-dependent variability (< 3.6°, 0.05 N kg-1 and 0.5 BW for joint angles, moments, and JCFs, respectively). Gait alterations and JCF patterns showed high between-subjects variability reflecting the pathology heterogeneity in the cohort. Higher joint impairment, assessed with MRI-based evaluation, was weakly associated to overall joint overloading. A stronger correlation was observed between impairment of one limb and overload of the contralateral limb, suggesting risky compensatory strategies being adopted, especially at the knee level. This suggests that knee overloading during gait might be a good predictor of disease progression and gait biomechanics should be used to inform treatment planning.

中文翻译：

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将幼年特发性关节炎患者的关节损伤与步态生物力学联系起来。

幼年特发性关节炎 (JIA) 是一种病因不明的儿科肌肉骨骼疾病，当下肢关节受累时会导致行走改变。JIA 的诊断主要依靠临床。成像可以量化与炎症和关节损伤相关的损伤。然而，使用动态信息（例如联合接触力（JCF））可以更好地支持治疗计划。为此，我们使用肌肉骨骼模型来预测 JCF，并研究 18 名 JIA 儿童的 JCF 如何因关节损伤而变化。步态分析数据和磁共振图像 (MRI) 用于开发患者特异性下肢肌肉骨骼模型，并评估操作者相关的变异性（关节角度、力矩< 3.6°、0.05 N kg-1 和 0.5 BW）和 JCF）。步态改变和 JCF 模式显示出受试者间的高度变异性，反映了队列中病理学的异质性。通过基于 MRI 的评估进行评估，较高的关节损伤与整体关节超负荷关联较弱。在一侧肢体损伤与对侧肢体超负荷之间观察到更强的相关性，这表明所采用的补偿策略存在风险，尤其是在膝盖水平。这表明步态期间膝关节超负荷可能是疾病进展的良好预测因子，并且应使用步态生物力学来指导治疗计划。