Cross-sectional association between muscle strength and self-reported physical function in 195 hip osteoarthritis patients.
This study aimed to evaluate associations between strength of selected hip and knee muscles and self-reported physical function, and their clinical relevance, in men and women with hip osteoarthritis (OA).



Cross-sectional data from 195 participants with symptomatic hip OA were used. Peak isometric torque of hip extensors, flexors, and abductors, and knee extensors were measured, along with physical function using the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire. Separate linear regressions in men and women were used to determine the association between strength and physical function accounting for age, pain, and radiographic disease severity. Subsequently, magnitudes of strength associated with estimates of minimal clinically important improvement (MCII) in physical function were estimated according to severity of difficulty with physical function.



For men, greater strength of the hip extensors, hip flexors and knee extensors were each associated with better physical function. For women, greater muscle strength of all tested muscles were each associated with better physical function. For men and women, increases in muscle strength between 17-32%, 133-223%, and 151-284% may be associated with estimates of MCII in physical function for those with mild, moderate, and severe physical dysfunction, respectively.



Greater isometric strength of specific hip and thigh muscle groups may be associated with better self-reported physical function in men and women. In people with mild physical dysfunction, an estimate of MCII in physical function may be associated with attainable increases in strength. However, in patients with more severe dysfunction, greater and perhaps unattainable strength increases may be associated with an estimate of MCII in physical function. Longitudinal studies are required to validate these observations.
Department of Physiotherapy, Centre for Health, Exercise and Sports Medicine, School of Health Sciences, Melbourne, The University of Melbourne, VIC, Australia.
Michelle
M
Hall
Department of Physiotherapy, Centre for Health, Exercise and Sports Medicine, School of Health Sciences, Melbourne, The University of Melbourne, VIC, Australia.
Tim V
TV
Wrigley
Department of Physiotherapy, Centre for Health, Exercise and Sports Medicine, School of Health Sciences, Melbourne, The University of Melbourne, VIC, Australia; Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, VIC, Australia.
Jessica
J
Kasza
Department of Physiotherapy, Centre for Health, Exercise and Sports Medicine, School of Health Sciences, Melbourne, The University of Melbourne, VIC, Australia.
Fiona
F
Dobson
Department of Physiotherapy, Singapore General Hospital, Singapore, Singapore.
Yong Hao
YH
Pua
Department of Physiotherapy, Centre for Health, Exercise and Sports Medicine, School of Health Sciences, Melbourne, The University of Melbourne, VIC, Australia.
Ben R
BR
Metcalf
Department of Physiotherapy, Centre for Health, Exercise and Sports Medicine, School of Health Sciences, Melbourne, The University of Melbourne, VIC, Australia. Electronic address: k.bennell@unimelb.edu.au.
Kim L
KL
Bennell
D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000503:physiopathology*; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000503:physiopathology; D011859:Radiography; D057566:Self Report; D012720:Severity of Illness Index; D012737:Sex Factors
Hip osteoarthritis; Muscle strength; Physical function