Introduction/objectives: This study aimed to investigate the association between hip abductor muscle strength and knee pain in patients with early-stage knee osteoarthritis (OA) while ascending and descending stairs.
Method: This cross-sectional study included individuals with early-stage knee OA (Kellgren/Lawrence grades 1 or 2). Knee pain while ascending and descending stairs was evaluated using a knee OA-related health domain measure (Japanese Knee Osteoarthritis Measure). Knee extension and hip abductor muscle strength were also evaluated. The association between hip abductor muscle strength and knee pain while ascending and descending stairs was evaluated using multiple regression analysis.
Results: A total of 157 participants were included in the final analysis. After the adjustment for age, sex, and knee extension strength, those with knee pain while descending stairs showed significantly decreased hip abductor muscle strength (β, - 0.09; 95% confidence interval [CI], - 0.19 to - 0.003). In contrast, after the adjustment for age, sex, and knee extension muscle strength, those with knee pain while ascending stairs did not have significantly decreased hip abductor muscle strength (β, - 0.06; 95% CI, - 0.15 to 0.02).
Conclusions: Patients with early-stage knee OA and knee pain while descending stairs had significantly reduced hip abductor muscle strength.
Keywords: Early stage; Hip abductor muscle; Knee osteoarthritis; Pain; Stair descent.