[P3-0783] Preoperative Predictors of Ambulation Ability at Different Time Points after Total Hip Arthroplasty in Patients with Osteoarthritis
Keywords:THA, Preoperative predictor, Ambulation ability
【Purpose】
The aims of this study were to identify the preoperative factors influencing ambulation ability at different postoperative time points after THA and to examine the cutoff values of predictive preoperative factors.
【Methods】
Forty-eight women with unilateral THA were measured for hip extensor, hip abductor, and knee extensor muscle strength in both legs；hip pain（VAS）；and the Timed Up and Go（TUG）test pre- and postoperatively. The levels of association between the TUG test score and clinical parameters were examined using Pearson’s rank correlation coefficients. When significant correlation coefficients were observed, stepwise multiple regression analysis was used to investigate the effect of the physical variables, while using the TUG test results at different postoperative time points as the dependent variable. Based on TUG test times, the patients were divided into the good（less than 13.5 s）and non-good（over 13.5 s）ambulation groups at 3 weeks, 4 months, and 7 months after THA. Subsequently, the discriminative properties of preoperative knee extensor strength, hip abductor strength, and age for ambulation ability were investigated by applying a receiver operating characteristic（ROC）curve.
【Results】
Multiple regression analysis indicated that preoperative knee extensor strength（β=－0.379）at 3 weeks, hip abductor strength（β=－0.572）at 4 months, and age（β=0.758）at 7 months were strongly associated with postoperative ambulation, measured using the TUG test. Optimal preoperative cutoff values for ambulation ability were 0.56 Nm/kg for knee extensor strength, 0.24 Nm/kg for hip abductor strength, and 73 years of age.
【Discussion】
Our results suggest that preoperative factors predicting ambulation ability vary by postoperative time point. Preoperative knee extensor strength, hip abductor strength, and age were useful predictors of ambulation ability at the early, middle, and late time points, respectively, after THA.
The aims of this study were to identify the preoperative factors influencing ambulation ability at different postoperative time points after THA and to examine the cutoff values of predictive preoperative factors.
【Methods】
Forty-eight women with unilateral THA were measured for hip extensor, hip abductor, and knee extensor muscle strength in both legs；hip pain（VAS）；and the Timed Up and Go（TUG）test pre- and postoperatively. The levels of association between the TUG test score and clinical parameters were examined using Pearson’s rank correlation coefficients. When significant correlation coefficients were observed, stepwise multiple regression analysis was used to investigate the effect of the physical variables, while using the TUG test results at different postoperative time points as the dependent variable. Based on TUG test times, the patients were divided into the good（less than 13.5 s）and non-good（over 13.5 s）ambulation groups at 3 weeks, 4 months, and 7 months after THA. Subsequently, the discriminative properties of preoperative knee extensor strength, hip abductor strength, and age for ambulation ability were investigated by applying a receiver operating characteristic（ROC）curve.
【Results】
Multiple regression analysis indicated that preoperative knee extensor strength（β=－0.379）at 3 weeks, hip abductor strength（β=－0.572）at 4 months, and age（β=0.758）at 7 months were strongly associated with postoperative ambulation, measured using the TUG test. Optimal preoperative cutoff values for ambulation ability were 0.56 Nm/kg for knee extensor strength, 0.24 Nm/kg for hip abductor strength, and 73 years of age.
【Discussion】
Our results suggest that preoperative factors predicting ambulation ability vary by postoperative time point. Preoperative knee extensor strength, hip abductor strength, and age were useful predictors of ambulation ability at the early, middle, and late time points, respectively, after THA.