Background: Most previous studies on the effects of therapeutic exercise on osteoarthritis (OA) of the hip joint included participants with knee OA or postoperative participants. Moreover, although some systematic reviews recommend therapeutic exercise for hip OA, a consensus on the effective interventional frequency has not been reached. This study aimed to investigate the effects of therapeutic exercise performed at different frequencies on physical function and health-related quality of life in participants with hip OA.
Methods: Individuals diagnosed with hip OA (36 women, age 42-79 years; 19 in 2009 and 17 in 2010) were recruited from the cooperating medical institutions. They were divided into two groups depending on the frequency of therapeutic exercise: fortnightly in 2009 (fortnightly group) and weekly in 2010 (weekly group). Participants in each group performed the same land-based and aquatic exercises on the same day for a total of ten sessions. Muscle strength of the lower extremity, "timed up and go" (TUG), time of one-leg standing with open eyes (TOLS), Harris Hip Score, and scores of the Medical Outcomes Survey Short Form-36 questionnaire, were measured before and after interventions.
Results: The fortnightly group had no significant changes in lower-extremity muscle strength following intervention, but the strength of all muscles in the weekly group improved significantly after intervention. Further, in both groups, TUG and TOLS of the worse side of the hip joint significantly improved after interventions.
Conclusions: Weekly exercise improves muscle strength of the lower extremity and may therefore be an effective interventional technique for managing hip OA. In addition, in persons with hip OA, therapeutic exercise consisting of both land- and water-based exercises markedly improved physical function.