Chang Alison, Hurwitz Debra, Dunlop Dorothy, Song Jing, Cahue September, Hayes Karen, Sharma Leena
Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
Ann Rheum Dis. 2007 Oct;66(10):1271-5. doi: 10.1136/ard.2006.062927. Epub 2007 Jan 31.
A greater knee adduction moment increases risk of medial tibiofemoral osteoarthritis (OA) progression. Greater toe-out during gait shifts the ground reaction force vector closer to the centre of the knee, reducing the adduction moment. The present study was designed to test whether greater toe-out is associated with lower likelihood of medial OA progression.
Baseline assessments included: kinematic/kinetic gait parameters using an optoelectronic camera system, force platform and inverse dynamics to calculate three-dimensional external knee moments; toe-out angle (formed by the line connecting heel strike and toe-off plantar surface centres of pressure and the forward progression line; knee pain; and full-limb alignment. Knee x-rays (semi-flexed) were obtained at baseline and at 18 months, with progression noted as medial joint space grade worsening. With logistic regression, odds ratios (ORs) for progression/5 degrees toe-out were estimated.
In the 56 subjects (59% women, mean age 66.6 years, body mass index (BMI) 29), baseline toe-out angle was less in knees with than without progression (difference -4.4, 95% CI -8.5 to -0.3). Greater toe-out was associated with reduced likelihood of progression (OR 0.60, 95% CI 0.37 to 0.98). Adjusting for age, gender, BMI, pain severity and disease severity, the OR was 0.62, 95% CI 0.36 to 1.06. Adjusting for adduction moment (second peak), the OR was 0.72, 95% CI 0.40 to 1.28.
Osteoarthritic knees that progressed had less toeing-out than knees without progression. Greater toe-out was associated with a lower likelihood of progression. Adjustment for covariates did not alter the OR, although the 95% CI included 1. Further adjustment for adduction moment did alter the OR, consistent with the possibility that a mechanism of the effect may be via lowering of the adduction moment.
更大的膝关节内收力矩会增加胫股内侧骨关节炎（OA）进展的风险。步态期间更大的足外旋角度会使地面反作用力矢量更靠近膝关节中心，从而减小内收力矩。本研究旨在测试更大的足外旋角度是否与内侧OA进展的可能性降低相关。
基线评估包括：使用光电摄像系统、测力平台和逆动力学计算三维膝关节外部力矩的运动学/动力学步态参数；足外旋角度（由连接足跟触地和足趾离地时足底压力中心的线与向前行进线形成）；膝关节疼痛；以及全下肢对线情况。在基线和18个月时获取膝关节（半屈曲位）X线片，进展情况记录为内侧关节间隙分级恶化。通过逻辑回归，估计进展/足外旋角度每增加5度的比值比（OR）。
在56名受试者（59%为女性，平均年龄66.6岁，体重指数（BMI）为29）中，进展的膝关节基线足外旋角度小于未进展的膝关节（差值 -4.4，95%置信区间 -8.5至 -0.3）。更大的足外旋角度与进展可能性降低相关（OR 0.60，95%置信区间0.37至0.98）。在调整年龄、性别、BMI、疼痛严重程度和疾病严重程度后，OR为0.62，95%置信区间0.36至1.06。在调整内收力矩（第二个峰值）后，OR为0.72，95%置信区间0.40至1.28。
进展的骨关节炎膝关节的足外旋角度小于未进展的膝关节。更大的足外旋角度与进展可能性降低相关。对协变量进行调整并未改变OR，尽管95%置信区间包含1。对内收力矩进行进一步调整确实改变了OR，这与该效应的机制可能是通过降低内收力矩的可能性一致。
