title: Stiffness, pain, and hip muscle strength are factors associated with self-reported physical disability in hip osteoarthritis.
abstract: BACKGROUND
  Physical disability (PD) is common among patients with osteoarthritis (OA) of the hip. Exercise therapy is proposed to be a potential intervention to reduce PD. However, the optimal targets of an exercise program are not known.
  
  
  OBJECTIVE
  The aim of the present study was to identify factors that explain the level of self-reported PD in patients with hip OA. Knowledge of these factors will help develop specific and effective exercise programs.
  
  
  METHODS
  Data from 149 patients with hip OA (85 men and 64 women) were analyzed. Self-reported PD was quantified using the physical function subscale of the Western Ontario and McMaster index. A stepwise regression analysis was conducted to identify significant factors associated with self-reported PD.
  
  
  RESULTS
  Stiffness, pain, and hip muscle strength were found to be significant factors related to the level of self-reported PD in hip OA. These factors explained 59% (r adjusted = 0.59) of the variance. Body mass index, gender, age, and passive internal hip rotation and flexion range of motion explained only minor parts of the dependent variable self-reported PD.
  
  
  CONCLUSIONS
  Stiffness, pain, and hip muscle strength are associated with self-reported PD in hip OA. It is imperative that exercise treatments for hip OA include strategies to modify these factors. Further research should evaluate their role in preventing hip OA.
authors.affiliation: 1Medical Clinic, Department of Sports Medicine, University of Tübingen, Tuebingen, Germany. 2University of Gothenburg, Department of Food and Nutrition, and Sport Science Biomechanics, Göteborg, Schweden.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Steinhilber
authors.forename: Georg
authors.initials: G
authors.lastname: Haupt
authors.forename: Regina
authors.initials: R
authors.lastname: Miller
authors.forename: Stefan
authors.initials: S
authors.lastname: Grau
authors.forename: Pia
authors.initials: P
authors.lastname: Janssen
authors.forename: Inga
authors.initials: I
authors.lastname: Krauss
mesh_terms: D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000523:psychology / Q000534:rehabilitation; D005081:Exercise Therapy; D005260:Female; D006621:Hip Joint; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D063806:Myalgia / Q000175:diagnosis* / Q000209:etiology; D015207:Osteoarthritis, Hip / Q000175:diagnosis* / Q000534:rehabilitation; D010147:Pain Measurement / Q000379:methods; D057566:Self Report