University of Western Ontario, London, Ontario, and Dalhousie University, Halifax, Nova Scotia, Canada.
Arthritis Care Res (Hoboken). 2011 Jul;63(7):991-7. doi: 10.1002/acr.20476.
Although the relationship between pain and the magnitude of medial knee loading has been previously studied, the contribution of frequency of loading has not. The objective of this study was to determine whether the addition of loading frequency (steps/day) to loading magnitude (knee adduction moment [KAM] impulse) helps explain variance in knee pain in people with knee osteoarthritis (OA).
Participants were adults with symptomatic knee OA with radiographic signs in the medial knee compartment (n = 38, 10 women). Pain was measured using the pain subscale of the Knee Injury and Osteoarthritis Outcome Score. Participants wore an accelerometer for 1 week to determine the average number of steps/day. The external KAM impulse was calculated from 3-dimensional gait analysis as participants ambulated at self-selected speeds. Knee extensor strength was measured with an isokinetic dynamometer. Linear regression was used to examine the relationship between pain and steps/day after controlling for the KAM impulse, knee extensor strength, and body mass index (BMI).
After controlling for BMI (R(2) = 0.02), knee extensor strength (R2 change = 0.26, P < 0.05), and KAM impulse (R2 change = 0.11, P < 0.05), steps/day contributed an additional 9% of variance in pain (P < 0.05). This model accounted for a total of 49% of the variance in pain (F[4,33] = 7.77, P < 0.05).
Increased knee loading frequency and magnitude were associated with increased pain. Objective measures of loading frequency should be considered when investigating the incidence and progression of knee OA.
虽然已经研究了疼痛与内侧膝关节负荷大小之间的关系，但尚未研究负荷频率的作用。本研究旨在确定在膝关节骨关节炎（OA）患者中，将负荷频率（步数/天）增加到负荷大小（膝内收力矩[KAM]冲量）是否有助于解释膝关节疼痛的差异。
参与者为有内侧膝关节间隙放射学征象的症状性膝 OA 成年患者（n=38，10 名女性）。疼痛使用膝关节损伤和骨关节炎结果评分的疼痛子量表进行测量。参与者佩戴加速度计一周以确定平均每天的步数。通过 3 维步态分析计算外部 KAM 冲量，当参与者以自选择速度行走时。使用等速测力计测量膝关节伸肌力量。线性回归用于检查在控制 KAM 冲量、膝关节伸肌力量和体重指数（BMI）后，疼痛与步数/天之间的关系。
在控制 BMI（R2=0.02）、膝关节伸肌力量（R2 变化=0.26，P<0.05）和 KAM 冲量（R2 变化=0.11，P<0.05）后，步数/天增加疼痛的差异增加了 9%（P<0.05）。该模型总共解释了疼痛变化的 49%（F[4,33]=7.77，P<0.05）。
膝关节负荷频率和大小的增加与疼痛增加有关。在研究膝关节 OA 的发生率和进展时，应考虑负荷频率的客观测量。
