Assessing Muscle Strength Deficits in the Hip and Knee on Surgical and Non-Surgical Sides in Women Post 12 Months Total Hip Arthroplasty

Muscle Strength Deficits Post-THA in Women

Abstract

Background: THA is relevant in the intervention of end-stage hip osteoarthritis in relieving pain and improving function. It has been concluded that strength deficits in the surgical and nonsurgical limbs remain after surgery and affect gait, balance, and functional independence. This study was conducted to quantify hip and knee muscle strength deficits one-year post-THA in women and determine their association with functional performance.

Methods: A prospective cohort study was conducted on 30 women aged 50-75 years who had undergone unilateral THA due to primary osteoarthritis. They were assessed for muscle strength (hip abductors, hip extensors, knee extensor, and knee flexors) using hand-held dynamometry at 3, 6, and 12 months post-surgery. Functional performance was measured using Timed Up and Go (TUG), 30-second Chair Stand, and 6-minute Walk Test (6MWT) scores. Strength asymmetry was evaluated using mixed-model ANOVA, while the associations with function were determined using Pearson correlation.

Results: Strength deficits showed significant persistence for the surgical limb even at 3 months: hip abductor (-32.5%, p<0.001), hip extensor (-28.7%, p<0.001), knee extensor (-34.1%, p<0.001), and knee flexor (-26.4%, p<0.001). By 12 months, the deficits were still present but with less impact (-10.1 to -8.5, p = 0.07). Progressive improvement in functional performance with time correlated with recovery in strength (hip abductor strength vs. TUG: r=-0.72, p<0.001).

Conclusion: Post-THA, muscle strength asymmetry remains, especially in the hip abductors and knee extensors within the mobility context. Working toward extensive rehabilitation exceeding typical protocols but with a clear focus on strength training is mandatory for optimized recovery and functional results.

DOI: https://doi.org/10.59564/amrj/03.01/010