Sex-Specific Difference in Dynamic Balance Following Total Hip Replacement

Total hip arthroplasty (THA) is a common surgical procedure in older adults (65 years or older). THA has high patient satisfaction, but little is known about balance and mobility limitations after surgery and if outcomes are sex-specific. This study was aimed to evaluate post-THA asymmetry during unilateral standing and a dynamic balance and reach test and test the hypotheses that balance performance would be decreased on the surgical limb and that balance deficits would be greater in women than in men.

Primary, unilateral THA (70 male, 57 female) patients completed a bilateral 10-s single-leg stance test. Sixty male but only 34 female participants could maintain unilateral balance for 10 s or greater. The cohort who successfully completed the 10-s single-limb stance test then completed a Lower Quarter Y-Balance Test in which the maximum anterior (ANT), posteromedial (PM), and posterolateral reach distances were obtained bilaterally and used to calculate the asymmetry score. All variables were compared using a mixed-model repeated-measures analysis of variance (sex by limb), while independent samples t tests were used to assess sex-specific asymmetry.

Women failed single-leg stance at a higher rate than men (85.7% vs 59.6%; p = .001). Reach distance was different between limbs for all reach directions (p < .004) with greater reach distance on the nonoperative limb for all patients. Men had a greater reach distance in the ANT (p = .004) and PM (p = .006) directions.

These results indicate that post-THA, the operative limb and female patients have greater balance limitations. These results are novel and reveal sex-specific patterns that emphasize the need for sex-specific postoperative rehabilitation programs to improve long-term outcomes, especially in older adults with muscle weakness and balance deficits.