Comparison of Early Postoperative Step and Stair Counts With the Direct Anterior Approach Versus the Posterior Approach for Total Hip Arthroplasty

Background: The purpose of this study was to evaluate the impact of direct anterior approach (DAA) or posterior approach (PA) on step and stair counts after total hip arthroplasty using a remotely monitored mobile application with a smartwatch while controlling for baseline characteristics.

Methods: This is a secondary data analysis from a prospective cohort study of patients utilizing a smartphone-based care management platform. The primary outcomes were step and stair counts and changes from baseline through one year. Step and stair counts were available for 1,501 and 847 patients, respectively. Longitudinal regression models were created to control for baseline characteristics.

Results: Patients in the DAA group had significantly lower body mass index (P = .049) and comorbidities (P = .028), but there were no significant differences in age (P = .225) or sex (P = .315). The DAA patients had a higher average and improvement from baseline in step count at 2 and 3 weeks postoperatively after controlling for patient characteristics (P = .028 and P = .044, respectively). The average stair counts were higher for DAA patients at one month postoperatively (P = .035), but this difference was not significant after controlling for patient demographics. Average stair ascending speeds and changes from baseline were not different between DAA and PA patients. Descending stair speed was higher at 2 weeks postoperatively for DAA patients, but was no longer higher after controlling for baseline demographics.

Conclusions: After controlling for baseline characteristics, DAA patients demonstrate earlier improvement in step count than PA patients after total hip arthroplasty. However, patient selection and surgeon training may continue to influence outcomes through a surgical approach.