Hip Abductor Strength and Lower Limb Load on Nonoperating Predict Functional Mobility in Women Patients With Total Hip Arthroplasty

Objective: The aim of this study was to identify which aspect of the preoperative lower limb functions is most likely to affect the functional mobility at 6 mos after total hip arthroplasty.

Design: The study subjects included 125 women who underwent total hip arthroplasty. Hip flexion and abduction angles, hip abductor and knee extensor strengths, and lower limb load were measured preoperatively. The Timed Up and Go test was performed 6 mos postoperatively. Then, patients were divided into fast or slow groups as per the comparison with the Timed Up and Go score of healthy women.

Results: Hip abductor strength and lower limb load on the nonoperative side were revealed as significant measurements that affected functional mobility after total hip arthroplasty according to stepwise multiple logistic regression analysis. Moreover, receiver operating characteristic curve analyses showed that the postoperative functional mobility was predicted by the lower limb load of the nonoperative side (cutoff point, 8.97 N/kg; sensitivity, 62.3%; specificity, 82.8%; and area under the curve, 77.5%).

Conclusions: This study revealed that patients with preoperative hip abductor strength of greater than 0.66 Nm/kg and lower limb load of greater than 8.97 N/kg on the nonoperative side could achieve better functional mobility at 6 mos postoperatively than healthy women of the same age group.