Could the evaluation of muscle strength imbalances be used as a predictor of total hip arthroplasty?

Abstract

Loss of muscle strength characterizes the period before total hip arthroplasty (THA). Little is known about whether muscle strength imbalances caused by muscle strength decline could be considered another clinical predictor for THA. This study aimed to determine whether muscle imbalances may be used as a clinical predictor for THA surgery. Thirty-six participants were enrolled in the study. Eighteen patients had THA (THA group), while 18 were healthy elders (CON group). Ipsilateral (H/Q) and bilateral (% Def) muscle imbalances of the knee were assessed. THA patients showed impairment of the extensors on the affected extremity compared to those unaffected. A comparison between the groups proved there were weakened flexors in the THA group on both extremities. A comparison of the imbalances revealed a significant bilateral imbalance of the extensors and ipsilateral imbalance of both extremities in the THA group. We computed two logistic regressions using bilateral and ipsilateral imbalance as the predictors of THA surgery. We found that bilateral extensor imbalance may be used as a predictor for THA (Nagelkerke R2 = 0.22). A decrease of the bilateral extensors imbalance by 8% decreases the probability of THA by 8%. The most interesting finding is that the evaluation of the bilateral extensor imbalance may be used as another clinical predictor for THA.