School of Rehabilitation Science, McMaster University, Hamilton, Ontario, Canada.
School of Rehabilitation Science, McMaster University, Hamilton, Ontario, Canada; Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
Osteoarthritis Cartilage. 2018 Feb;26(2):220-226. doi: 10.1016/j.joca.2017.11.003. Epub 2017 Nov 9.
Biomechanical factors are important treatment targets in knee osteoarthritis. The knee adduction (KAM) and flexion (KFM) moments, quadriceps strength and power, load frequency, and body mass index (BMI) all have the potential to affect knee articular cartilage integrity by modulating forces across the joint. To identify clinically meaningful change, however, these measurements must be reliable and sensitive to change. This study estimated relative and absolute test-retest reliabilities over long periods of biomechanical risk factors for knee osteoarthritis progression.
Data from a longitudinal, observational study were analyzed for knee osteoarthritis patients with data at baseline, 6-month and 24-month follow-ups. Gait kinematics and kinetics, quadriceps strength and power, daily load frequency and BMI were collected. Relative and absolute test-retest reliabilities of these measures were estimated using intraclass correlation coefficients (ICCs) and standard errors of measurement (SEMs), respectively. Minimal detectable change at the 95% confidence level (MDC95) was also calculated.
Data from 46 participants [36 women; age 61.0 (6.6) years] were included. Good-to-excellent relative reliabilities (ICC ≥ 0.80) indicated that KAM peak and impulse, quadriceps strength and power, and BMI had a strong ability to discriminate amongst participants. Absolute reliabilities were high for quadriceps strength and BMI, which demonstrated reasonable within-participant variability (SEMs ≤ 11% of the mean). The MDC95 values supported use of clinical interventions effective in reducing BMI and KAM, and increasing quadriceps strength.
These data are useful in interpreting findings from interventional or longitudinal investigations by determining whether observed changes are beyond measurement error and interpretable as true change.
生物力学因素是膝骨关节炎的重要治疗靶点。膝关节内收（KAM）和弯曲（KFM）力矩、股四头肌力量和功率、负荷频率以及体重指数（BMI）都有可能通过调节关节力来影响膝关节关节软骨的完整性。然而，为了确定具有临床意义的变化，这些测量必须具有可靠性并且对变化敏感。本研究评估了膝关节骨关节炎进展的长期生物力学危险因素的相对和绝对测试-重测可靠性。
对基线、6 个月和 24 个月随访时存在膝关节骨关节炎数据的纵向观察性研究的数据进行了分析。收集了步态运动学和动力学、股四头肌力量和功率、日常负荷频率和 BMI。使用组内相关系数（ICC）和测量误差（SEM）分别估计这些测量的相对和绝对测试-重测可靠性。还计算了 95%置信水平下的最小可检测变化（MDC95）。
纳入了 46 名参与者的数据[36 名女性；年龄 61.0（6.6）岁]。良好到优秀的相对可靠性（ICC≥0.80）表明 KAM 峰值和冲量、股四头肌力量和功率以及 BMI 具有很强的区分参与者的能力。股四头肌力量和 BMI 的绝对可靠性较高，表明参与者的个体内变异性合理（SEM≤均值的 11%）。MDC95 值支持使用有效的临床干预措施来降低 BMI 和 KAM，以及增加股四头肌力量。
这些数据有助于通过确定观察到的变化是否超出测量误差并且可解释为真实变化来解释干预或纵向研究的结果。
