Citation

de Zwart AH, van der Esch M, Pijnappels MA, Hoozemans MJ, van der Leeden M, Roorda LD, Dekker J, Lems WF, van Dieen JH. J. Rheumatol. 2015; 42(7): 1218-1223.

Affiliation

From the Amsterdam Rehabilitation Research Center/Reade; MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam; Department of Rehabilitation Medicine, and Department of Psychiatry, and Department of Rheumatology, VU University Medical Center; Jan van Breemen Research Institute/Reade, Amsterdam, the Netherlands; King Abdulaziz University, Jeddah, Saudi Arabia. A.H. de Zwart, MSc, Amsterdam Rehabilitation Research Center/Reade; M. Pijnappels, PhD, MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam; M. van der Esch, PhD, Amsterdam Rehabilitation Research Center/Reade; M.J. Hoozemans, PhD, MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam; M. van der Leeden, PhD, Amsterdam Rehabilitation Research Center/Reade, and Department of Rehabilitation Medicine, VU University Medical Center; L.D. Roorda, MD, PT, PhD, Amsterdam Rehabilitation Research Center/Reade; J. Dekker, PhD, Amsterdam Rehabilitation Research Center/Reade, and Department of Rehabilitation Medicine and Department of Psychiatry, VU University Medical Center; W.F. Lems, MD, PhD, Department of Rheumatology, VU University Medical Center, and Jan van Breemen Research Institute/Reade; J.H. van Dieën, PhD, MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, and King Abdulaziz University. Address correspondence to Dr. A.H. de Zwart, Amsterdam Rehabilitation Research Center/Reade, Amsterdam, the Netherlands. E-mail: a.d.zwart@reade.nl. Accepted for publication March 9, 2015.

Copyright

(Copyright © 2015, Journal of Rheumatology Publishing)

DOI

10.3899/jrheum.140517

PMID

25934818

Abstract

OBJECTIVE: We aimed to evaluate the associations between knee muscle strength (MS) and falls, controlling for knee joint proprioception, varus-valgus knee joint laxity, and knee pain, among patients with knee osteoarthritis (OA) reporting knee instability.

METHODS: A sample of 301 subjects (203 women, 98 men, 35-82 yrs) with established knee OA and self-reported knee instability was studied. The occurrence of at least 1 fall in the previous 3 months was assessed by questionnaire. Maximum knee extension and flexion strength were measured isokinetically. Additionally, proprioception, varus-valgus laxity, and pain were assessed. Student t tests were used to assess differences between subgroups. The association of muscle strength and falls was calculated using univariate and multivariate logistic regression analysis.

RESULTS: Over 10% of the subjects (31 out of 301) reported a fall in the previous 3 months. High knee extension muscle strength (crude OR 0.3, 95% CI 0.1-0.8, p = 0.022) and high knee flexion muscle strength (crude OR 0.2, 95% CI 0.0-1.0, p = 0.048) were associated with a lower risk of falls. Proprioception and laxity did not confound this relationship. After adjusting for pain, extensor strength had an adjusted OR of 0.5 (95% CI 0.2-1.4, p = 0.212) for falls and flexor strength had an adjusted OR of 0.4 (95% CI 0.1-2.3, p = 0.312).

CONCLUSION: High knee extension and flexion muscle strength decreased the risk of falls in patients with knee OA and self-reported knee instability. After considering the effect of pain, there was insufficient statistical power to detect an association between muscle strength and falls, which might be because of the low number of subjects who fell (n = 31).

Language: en