Hip abductor strength-based exercise therapy in treating women with moderate-to-severe knee osteoarthritis: a randomized controlled trial.

Objective: To investigate whether hip abductor strength-based exercise therapy could result in further function improvement and more pain relief in women with knee osteoarthritis. Design: Randomized controlled trial. Settings: Rehabilitation department of Affiliated Hospital of Southwest Medical University from years 2016 to 2018. Subjects: In total, 82 women aged 50-70 years, with knee osteoarthritis grade II-IV on the Kellgren-Lawrence scale. Intervention: The experimental group engaged in hip abductor strength-based exercises under the supervision of physical therapists (once a day for six weeks), while the control group engaged in quadriceps femoris strength-based exercises. Main measures: Osteoarthritis severity measured by the Western Ontario and McMaster Universities Osteoarthritis Index, pain on a visual analogue scale and three objective functional tests were assessed at the sixth and 12th week. Repeated measures analysis of variance and multivariable analysis were applied. Results: Finally, 72 participants completed the study: 35 in the experimental group and 37 in the control group. The self-reported functional difficulties score in the experimental group was significantly lower than that in the control group both at the sixth week and at the 12th week (P < 0.001). There were significant differences between groups in the stair ascent/descent task and Figure of 8 Walk test, but not in the Five Times Sit-to-Stand Test. The pain in the experimental group decreased compared with that in the control group at the sixth week (P < 0.05), but not at the 12th week (P > 0.05). Conclusion: Hip abductor strength-based exercises could result in better performance and higher self-reported function in women with symptomatic knee osteoarthritis.