Prediction of ambulation ability following total hip arthroplasty

In early postoperative rehabilitation after THA, it is essential to clarify some factors related to future ambulation ability. The aim of this study was to examine whether it is possible to predict ambulation ability for patients with THA at 6 months postoperatively. The subjects of this study were 123 patients who had undergone unilateral THA. The hip abductor and knee extensor strength was assessed, and a timed up and go (TUG) test was performed at 4 weeks after the operation. Then, the patients were divided into two groups according to their ability to walk and to go up and down stairs at 6 months postoperatively: the good ambulatory group (n = 64) and the non-good ambulatory group (n = 59). The discriminating criteria between the two groups were 0.47 (Nm/kg) for hip abductor strength, 1.07 (Nm/kg) for knee extensor strength, and 10 s for TUG test. By multiple logistic regression, knee extensor strength and TUG test at 4 weeks were significantly associated with the categorization at 6 months. The results of this study suggest that the TUG test and knee extensor strength at an early stage after THA were useful indicators for predicting patients' ambulation ability at 6 months postoperatively.