Impaired Hip Muscle Strength, Function, and Patient-Reported Outcomes in Women With Hip Abductor Tendon Tears: A Cross-sectional Study of 62 Patients and 24 Healthy Volunteers

Abstract

OBJECTIVE: The impact of hip abductor tendon tears on hip muscle strength in women is unknown. We described maximal isometric hip muscle strength in women with magnetic resonance imaging–verified hip abductor tendon tears who were scheduled for surgery and compared to age-matched healthy volunteers, and evaluated whether strength was correlated with patient-reported and function outcomes. DESIGN: Cross-sectional, comparative study. METHODS: Strength was assessed using a handheld dynamometer in 62 patients and 24 healthy volunteers (100% females) with mean ± SD age of 55 ± 12 and 53 ± 6 years. The self-reported outcomes were Hip and Groin Outcome Score and Oxford Hip Score. Lower-limb functional capacity was assessed using the sit-to-stand (STS) test. RESULTS: Compared to healthy volunteers, patients (1) had lower maximal isometric hip abduction strength (mean difference, −0.41; 95% confidence interval [CI]: −0.52, −0.29), extension strength (mean difference, −0.36; 95% CI: −0.47, −0.25), and external rotation strength (mean difference, −0.24; 95% CI: −0.32, −0.17) ( P<.001); (2) reported 53 to 87 points lower in all Hip and Groin Outcome Score subgroups and 26 points lower on Oxford Hip Score ( P<.001); (3) completed fewer STS test repetitions (12 ± 4 vs 18 ± 5 repetitions, P<.001). There was a significant correlation between STS test performance and maximal isometric hip abduction (r = 0.47, P<.001), extension (r = 0.41, P = .005), and external rotation (r = 0.49, P<.001) strength. CONCLUSION: Women with magnetic resonance imaging–verified hip abductor tendon tears, who were scheduled for surgery, had substantial impairments in lower-limb strength, function, and self-reported outcomes compared to healthy volunteers. JOSPT Open 2023;1(1):70-77. Epub 15 August 2023. doi:10.2519/josptopen.2023.0012