Anshin Hospital, Kobe, Japan.
Department of Innovative Research and Education for Clinicians and Trainees (DiRECT), Fukushima Medical University Hospital, 1 Hikarigaoka, Fukushima City, Fukushima, 960-1295, Japan.
Clin Rheumatol. 2019 Mar;38(3):719-725. doi: 10.1007/s10067-018-4337-2. Epub 2018 Oct 19.
Quadriceps strength is important for maintaining functional movement in patients with knee osteoarthritis (OA). We aimed to examine whether knee OA severity weakened the magnitude of the associations between leg muscle mass, quadriceps strength, and functional movement. Screening for People Suffering Sarcopenia in Orthopedic cohort of Kobe study (SPSS-OK) was a single-center cross-sectional study. We recruited 611 patients with knee OA. Leg muscle mass was determined by bioimpedance and used as a proxy for quadriceps muscle mass. Quadriceps strength and indices of functional movement (assessed by the functional activities category of the new Knee Society Score questionnaire [KSS] and the Timed Up and Go [TUG] test) were measured. Knee OA severity was determined by the Kellgren-Lawrence radiographic grade. A series of general linear models was fitted with adjustment for confounding variables. The increase in quadriceps strength per leg associated with a 1-kg increase in leg mass per leg was 7.29 Nm, 5.43 Nm, and 3.77 Nm among patients with knee OA grade 1/2, 3, and 4, respectively (P for interaction = 0.003). A 1-Nm increase in quadriceps strength per leg was associated with both a 0.14 point increase in KSS movement score and a 0.05 s decrease in TUG, regardless of knee OA severity (P for interaction 0.430 and 0.323). Severe knee OA may reduce efficiency in the exertion of quadriceps strength by leg muscle mass even when the amount of muscle mass remains unchanged.
股四头肌力量对于维持膝骨关节炎（OA）患者的功能性运动很重要。我们旨在研究膝 OA 严重程度是否会削弱腿部肌肉质量、股四头肌力量和功能性运动之间关联的幅度。神户骨科人群肌少症筛查研究（SPSS-OK）是一项单中心横断面研究。我们招募了 611 名膝 OA 患者。腿部肌肉质量通过生物阻抗法确定，用作股四头肌质量的替代指标。股四头肌力量和功能性运动指标（通过新膝关节协会评分问卷的功能活动类别[KSS]和计时起立行走[TUG]测试评估）进行测量。膝关节 OA 严重程度由 Kellgren-Lawrence 放射学分级确定。在调整混杂变量后，使用一系列一般线性模型进行拟合。与每侧腿部质量增加 1 公斤相比，每侧腿部股四头肌力量增加 7.29 Nm、5.43 Nm 和 3.77 Nm，分别见于膝关节 OA 1/2 级、3 级和 4 级患者（P 交互=0.003）。每侧腿部股四头肌力量增加 1 Nm，与 KSS 运动评分增加 0.14 分和 TUG 时间减少 0.05 s 相关，无论膝关节 OA 严重程度如何（P 交互值为 0.430 和 0.323）。严重的膝关节 OA 即使肌肉质量保持不变，也可能降低腿部肌肉质量对股四头肌力量的发挥效率。
