Varus-valgus motion and functional ability in patients with knee osteoarthritis

Ann Rheum Dis. 2008 Apr;67(4):471-7. doi: 10.1136/ard.2007.071258. Epub 2007 Jun 29.

Abstract

Objective: To assess the relationship between knee varus-valgus motion and functional ability, and the impact of knee varus-valgus motion on the relationship between muscle strength and functional ability in patients with osteoarthritis (OA) of the knee.

Methods: Sixty-three patients with knee OA were tested. Varus-valgus motion was assessed by optoelectronic recording and three-dimensional motion analysis. Functional ability was assessed by observation, using a 100 m walking test, a Get Up and Go test, and WOMAC questionnaire. Muscle strength was measured by a computer-driven isokinetic dynamometer. Regression analyses were performed to assess the relationships between varus-valgus motion and functional ability, and to assess the impact of varus-valgus motion on the relationship between muscle strength and functional ability.

Results: In patients with high varus-valgus range of motion, muscle weakness was associated with a stronger reduction in functional ability (ie, longer walking time and Get Up and Go time) than in patients with low varus-valgus range of motion. A pronounced varus position and a difference between the left and right knees in varus-valgus position were related with reduced functional ability.

Conclusions: In patients with knee OA with high varus-valgus range of motion, muscle weakness has a stronger impact on functional ability than in patients with low varus-valgus range of motion. Patients with knee OA with more pronounced varus knees during walking show a stronger reduction in functional ability than patients with less pronounced varus knees or with valgus knees.

MeSH terms

  • Aged
  • Disability Evaluation
  • Female
  • Gait
  • Humans
  • Knee Joint / physiopathology*
  • Male
  • Middle Aged
  • Muscle Strength
  • Muscle Weakness / etiology
  • Muscle Weakness / physiopathology
  • Muscle, Skeletal / physiopathology
  • Osteoarthritis, Knee / complications
  • Osteoarthritis, Knee / physiopathology*
  • Range of Motion, Articular*
  • Severity of Illness Index
  • Walking
  • Weight-Bearing