Dr. Adachi has received consultant fees, speaking fees, and/or honoraria (less than $10,000 each) from Merck and Novartis, and (more than $10,000 each) from Amgen and Eli Lilly.
Knee Power Is an Important Parameter in Understanding Medial Knee Joint Load in Knee Osteoarthritis
Article first published online: 22 APR 2014
© 2014 The Authors. Arthritis Care & Research is published by Wiley Periodicals, Inc. on behalf of the American College of Rheumatology.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Arthritis Care & Research
Volume 66, Issue 5, pages 687–694, May 2014
How to Cite
Calder, K. M., Acker, S. M., Arora, N., Beattie, K. A., Callaghan, J. P., Adachi, J. D. and Maly, M. R. (2014), Knee Power Is an Important Parameter in Understanding Medial Knee Joint Load in Knee Osteoarthritis. Arthritis Care Res, 66: 687–694. doi: 10.1002/acr.22223
- Issue published online: 22 APR 2014
- Article first published online: 22 APR 2014
- Accepted manuscript online: 31 OCT 2013 01:16PM EST
- Manuscript Accepted: 22 OCT 2013
- Manuscript Received: 10 MAY 2013
- Canadian Institutes of Health Research. Grant Number: 102643
- Canadian Institutes of Health Research Joint Motion Program Postdoctoral Fellowship
- Network Scholar Award through The Arthritis Society/Canadian Arthritis Network
- Tier I Canada Research Chair in Spine Biomechanics and Injury Prevention
- Alliance for Better Bone Health Chair in Rheumatology
- New Investigator Award from the Canadian Institutes of Health Research
To determine the extent to which knee extensor strength and power explain variance in knee adduction moment (KAM) peak and impulse in clinical knee osteoarthritis (OA).
Fifty-three adults (mean ± SD age 61.6 ± 6.3 years, 11 men) with clinical knee OA participated. The KAM waveform was calculated from motion and force data and ensemble averaged from 5 walking trials. The KAM peak was normalized to body mass (Nm/kg). The mean KAM impulse reflected the mean total medial knee load during stride (Nm × seconds). For strength, the maximum knee extensor moment attained from maximal voluntary isometric contractions (MVIC) was normalized to body mass (Nm/kg). For power, the maximum knee extensor power during isotonic contractions, with the resistance set at 25% of MVIC, was normalized to body mass (W/kg). Covariates included age, sex, knee pain on the Knee Injury and Osteoarthritis Outcome Score, gait speed, and body mass index (BMI). Relationships of the KAM peak and impulse with strength and power were examined using sequential stepwise forward linear regressions.
Covariates did not explain variance in the KAM peak. While extensor strength did not, peak knee extensor power explained 8% of the variance in the KAM peak (P = 0.02). Sex and BMI explained 24% of the variance in the KAM impulse (P < 0.05). Sex, BMI, and knee extensor power explained 31% of the variance in the KAM impulse (P = 0.02), with power contributing 7% (P < 0.05).
Knee extensor power was more important than isometric knee strength in understanding medial knee loads during gait.