Recovery and Prediction of Physical Functioning Outcomes During the First Year After Total Hip Arthroplasty

Abstract

ObjectivesTo investigate recovery of physical functioning in patients during the first year after total hip arthroplasty (THA), and to predict postoperative walking distance outcomes from preoperative measures. DesignA longitudinal prospective design was used. Data were analyzed by repeated-measures analysis of variance and multivariate regression analyses. SettingTwo hospitals. ParticipantsPatients with hip osteoarthritis were consecutively included and assessed preoperatively (n=88), at 3 months (n=88), and at 12 months (n=64) after THA. InterventionsNot applicable. Main Outcome MeasuresPhysical functioning was assessed by objective measures—the 6-minute walk test (6MWT), stair climbing test, Index of Muscle Function, figure-of-eight, and active hip range of motion—and the subjective measures by Harris Hip Score and Hip dysfunction and Osteoarthritis Outcome Score. ResultsIn objective measures, improvements were found from preoperatively to 3 months in 6MWT (P<.01) and stair climbing test (P<.05) scores, while all measures had improved from 3 to 12 months (P≤.001). In contrast, all the subjective measures showed substantial improvements at 3 months, but small further improvements from 3 to 12 months (P<.001). Age, sex, preoperative 6MWT distance, and hip range of motion predicted 6MWT outcomes at 3 and 12 months (P≤.01). ConclusionsThe objective measures of physical functioning improved gradually during the first postoperative year, while the subjective measures showed large early improvements, but little further improvements. Younger age, male sex, and better scores of walking distance and hip flexibility before surgery predicted better score in walking distance at both 3 and 12 months after surgery.