Association of walking cadence with knee adduction angular impulse while controlling for speed in patients with knee osteoarthritis

Abstract

Purpose: Walking cadence and speed are correlated and may affect knee loading in different ways. Previous research suggests higher walking cadence at baseline is associated with less structural progression of knee osteoarthritis (OA), presumably due to lower cumulative knee loading. The knee adduction angular impulse during walking is a surrogate measure of medial compartment load throughout stance and is associated with greater knee OA progression and knee pain. Thus, we aimed to test the hypothesis that higher walking cadence is associated with lower knee adduction angular impulse, while controlling for walking speed, in patients with medial knee OA. Methods: We analyzed existing data from 691 patients with medial compartment knee OA and varus alignment who participated in studies investigating rehabilitative and surgical interventions. The mean age and body mass index were 47±9 years and 30±5 kg/m2, respectively. All patients had undergone a baseline 3D quantitative gait analysis at preferred walking speed and cadence. Analyses included spatiotemporal characteristics and external knee joint moments. We used multivariate linear regression to test the association of cadence with knee adduction angular impulse while controlling for walking speed. We repeated the regression analyses while sequentially replacing the dependent variable knee adduction angular impulse with the first peak knee adduction moment, second peak knee adduction moment, peak knee flexion moment and peak vertical ground reaction force. We also repeated these analyses separately for females (n=163) and males (n=528). Lastly, we split the cohort into higher (n=462) and lower (n=229) cadence groups based on a cut-point of 100 steps/min - the minimum recommended walking cadence for adults - and plotted their adjusted means using analysis of covariance controlling for walking speed. Results: Mean ± SD for cadence, speed and knee adduction angular impulse were 1.10±0.19 m/s, 103±10 steps/min, 1.59±0.56 %BW.Ht.s; respectively. While controlling for walking speed, cadence was negatively associated with knee adduction angular impulse (unstandardized B [95% CI], p-value = -0.020 [-0.027 to -0.015], p<0.001), suggesting every 1 step/min increase in cadence was associated with a 0.02 %BW.Ht.s decrease in knee adduction angular impulse. For example, an increase in cadence of 20 steps/min (e.g. from 100 to 120 steps/min) was associated with a decrease in knee adduction angular impulse of 0.4 %BW.Ht.s (e.g. from 1.6 to 1.2 %BW.Ht.s), and when described in terms of the percent changes from the present sample means, this translated to a 20% increase in cadence associated with a 25% decrease in knee adduction angular impulse. The association was slightly higher in females (-0.028 [-0.039 to -0.016], p<0.001) than males (-0.017 [-0.024 to -0.009], p<0.001). While controlling for walking speed, cadence was also negatively associated with other surrogate measures of knee loading (Table 1). Adjusted means for higher and lower cadence groups are shown in Figure 1, illustrating that patients with medial knee OA walking with higher cadence (109±6 steps/min) have lower knee adduction angular impulse than patients walking at the same speed but with lower cadence 92±7 steps/min) (adjusted knee adduction angular impulse mean difference [95% confidence interval]: -0.27 %BW.Ht.s [-0.37 to -0.16]). Conclusions: In patients with medial knee OA, when controlling for walking speed, higher walking cadence is associated with lower knee adduction angular impulse. Although lower in size, the negative association of cadence remained with other surrogate measures of knee loading while controlling for walking speed. Future prospective studies should investigate the hypothesis that gait retraining to increase cadence at a given walking speed has beneficial biomechanical and clinical effects in patients with knee OA.View Large Image Figure ViewerDownload Hi-res image Download (PPT)