title: Muscle power is an important measure to detect deficits in muscle function in hip osteoarthritis: a cross-sectional study.
abstract: To investigate between-leg differences in hip and thigh muscle strength and leg extensor power in patients with unilateral hip osteoarthritis. Further, to compare between-leg differences in knee extensor strength and leg extensor power between patients and healthy peers.
  
  
  
  Seventy-two patients (60-87 years) with radiographic and symptomatic hip osteoarthritis not awaiting hip replacement and 35 healthy peers (63-82 years) were included. Hip and thigh muscle strength and leg extensor power were measured in patients and knee extensor strength and leg extensor power in healthy.
  
  
  
  The symptomatic extremity in patients was significantly (p < 0.05, paired t-test) weaker compared with the non-symptomatic extremity for five hip muscles (8-17%), knee extensors (11%) and leg extensor power (19%). Healthy older adults had asymmetry in knee extensor strength (6%, p < 0.05) comparable to that found in patients, but had no asymmetry in leg extensor power.
  
  
  
  Patients had generalized weakening of the affected lower extremity and numerically the largest asymmetry was evident for leg extensor power. In contrast, healthy peers had no asymmetry in leg extensor power. These results indicate that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with hip osteoarthritis. Implications for Rehabilitation Even in patients with mild symptoms not awaiting hip replacement a generalized muscle weakening of the symptomatic lower extremity seems to be present. Between-leg differences in leg extensor power (force × velocity) appears to be relatively large (19%) in patients with unilateral hip osteoarthritis in contrast to healthy peers who show no asymmetry. Compared to muscle strength the relationship between functional performance and leg extensor power seems to be stronger, and more strongly related to power of the symptomatic lower extremity. Our results indicate that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with mild symptoms not awaiting hip replacement.
authors.affiliation: a Musculoskeletal Rehabilitation Research Unit, Department of Physical & Occupational Therapy, Bispebjerg and Frederiksberg Hospitals , University of Copenhagen , Copenhagen , Denmark.|b Institute of Sports Medicine Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen , Copenhagen , Denmark.|c Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark.
authors.forename: Theresa
authors.initials: T
authors.lastname: Bieler
authors.affiliation: a Musculoskeletal Rehabilitation Research Unit, Department of Physical & Occupational Therapy, Bispebjerg and Frederiksberg Hospitals , University of Copenhagen , Copenhagen , Denmark.|b Institute of Sports Medicine Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen , Copenhagen , Denmark.|c Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark.
authors.forename: Stig Peter
authors.initials: SP
authors.lastname: Magnusson
authors.affiliation: d Department of Radiology Bispebjerg and Frederiksberg Hospitals , University of Copenhagen , Copenhagen , Denmark.
authors.forename: Helle Elisabeth
authors.initials: HE
authors.lastname: Christensen
authors.affiliation: b Institute of Sports Medicine Copenhagen, Bispebjerg and Frederiksberg Hospitals, University of Copenhagen , Copenhagen , Denmark.|c Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Kjaer
authors.affiliation: a Musculoskeletal Rehabilitation Research Unit, Department of Physical & Occupational Therapy, Bispebjerg and Frederiksberg Hospitals , University of Copenhagen , Copenhagen , Denmark.
authors.forename: Nina
authors.initials: N
authors.lastname: Beyer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006615:Hip / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D015207:Osteoarthritis, Hip / Q000503:physiopathology* / Q000534:rehabilitation*; D057566:Self Report
keywords: Hip osteoarthritis; muscle weakness; outcome measures