Background: Roughly one in ten persons in the industrialized world suffers from hip osteoarthritis, a disease for which there is no cure. The goal of conservative therapy is to relieve symptoms, preferably with methods that let patients assume responsibility for their own treatment, e.g., physical training.
Method: In a randomized controlled trial, we studied the effectiveness of twelve weeks of exercise therapy in patients with hip osteoarthritis (THüKo), compared to no treatment (control group) and placebo ultrasound treatment of the hip (placebo ultrasound group). The primary endpoint was a comparison of the pain scores of the intervention versus control groups on the generic SF-36 health questionnaire. Secondary endpoints included comparisons across all three study groups of scores on the 7 other scales of the SF-36 and on the pain, physical function, and stiffness scales of the osteoarthritis-specific WOMAC Index. The statistical analysis was performed with ANCOVA, with baseline values as a covariate. Between-group effects were subsequently tested pairwise (two-tailed t-tests, alpha = 0.05).
Results: As for the primary endpoint, pain reduction was significantly greater in the intervention than in the control group (mean difference 5.7 points, 95% confidence interval [CI] 0.4-11.1 points, p = 0.034). The comparisons across all three study groups (i.e., secondary endpoints, with 71 subjects in the intervention group, 68 in the control group, and 70 in the placebo group) revealed no significant between-group effects with respect to the SF-36. On the WOMAC Index, however, statistically significant differences were found for pain reduction between the intervention and control group (mean difference 7.4 points, 95% CI 3.0-11.8, p = 0.001) and between the intervention and placebo group (mean difference 5.1 points, 95% CI 0.7-9.4, p = 0.024). Comparable mean differences were also found for functional improvement.
Conclusion: Twelve weeks of exercise therapy in hip osteoarthritis patients of normal vitality reduced pain and improved physical function. No significant improvement was found in these patients' general health-related quality of life.