Steidle-Kloc Eva, Wirth Wolfgang, Glass Natalie A, Ruhdorfer Anja, Cotofana Sebastian, Eckstein Felix, Segal Neil A
From the Institute of Anatomy, Paracelsus Medical University, Department Salzburg, Austria (ES-K, WW, AR, SC, FE); Department of Orthopaedics & Rehabilitation, University of Iowa, Iowa City, Iowa (NAG); and Department of Rehabilitation Medicine, University of Kansas, Kansas City, Kansas (NAS).
Am J Phys Med Rehabil. 2015 Oct;94(10):792-803. doi: 10.1097/PHM.0000000000000262.
Knee pain and muscle weakness confer risk for knee osteoarthritis incidence and progression. The purpose of this study was to determine whether unilateral knee pain influences contralateral thigh muscle strength.
Of 4796 Osteoarthritis Initiative participants, 224 (mean ± SD age, 63.9 ± 8.9 yrs) cases could be matched to a control. Cases were defined as having unilateral knee pain (numerical rating scale, ≥ 4/10; ≥infrequent pain) and one pain-free knee (numerical rating scale, 0-1; ≤infrequent pain; Western Ontario and McMaster Universities Arthritis Index, ≤ 1). Controls were defined as having bilaterally pain-free knees (numerical rating scale, 0-1; ≤infrequent pain; Western Ontario and McMaster Universities Arthritis Index, ≤ 1). Maximal isometric muscle strength (N) was compared between limbs in participants with unilateral pain (cases) as well as between pain-free limbs of cases and controls.
Knee extensor/flexor strength in pain-free limbs of the cases was lower than that in bilaterally pain-free controls (-5.5%/-8.4%; P = 0.043/P = 0.022). Within the cases, maximum extensor/flexor strength was significantly lower in the painful limb than in the pain-free limb (-6.3%/4.1%; P < 0.0001/P = 0.015).
These results suggest that strength in limbs without knee pain is associated with the pain status of the contralateral knee. The strength difference between unilateral pain-free cases and matched bilateral pain-free controls was similar to that between limbs in persons with unilateral knee pain. Lower strength caused by contralateral knee pain might be centrally mediated.
膝关节疼痛和肌肉无力会增加膝关节骨关节炎发病和进展的风险。本研究的目的是确定单侧膝关节疼痛是否会影响对侧大腿肌肉力量。
在4796名骨关节炎倡议参与者中，224例（平均±标准差年龄，63.9±8.9岁）可与对照匹配。病例定义为有单侧膝关节疼痛（数字评分量表，≥4/10；≥不频繁疼痛）且一个膝关节无疼痛（数字评分量表，0 - 1；≤不频繁疼痛；西安大略和麦克马斯特大学骨关节炎指数，≤1）。对照定义为双侧膝关节无疼痛（数字评分量表，0 - 1；≤不频繁疼痛；西安大略和麦克马斯特大学骨关节炎指数，≤1）。比较了单侧疼痛参与者（病例）肢体之间以及病例和对照的无疼痛肢体之间的最大等长肌肉力量（N）。
病例的无疼痛肢体的膝关节伸肌/屈肌力量低于双侧无疼痛对照（-5.5%/-8.4%；P = 0.043/P = 0.022）。在病例组中，疼痛肢体的最大伸肌/屈肌力量明显低于无疼痛肢体（-6.3%/4.1%；P < 0.0001/P = 0.015）。
这些结果表明，无膝关节疼痛肢体的力量与对侧膝关节的疼痛状态有关。单侧无疼痛病例与匹配的双侧无疼痛对照之间的力量差异类似于单侧膝关节疼痛患者肢体之间的差异。对侧膝关节疼痛导致的力量降低可能是由中枢介导的。
