Preoperative two-step test predicts independent ambulation one week after total hip arthroplasty.

PURPOSE: To identify preoperative physical performance and muscle quality factors associated with independent ambulation one week after total hip arthroplasty (THA).

METHODS

This retrospective study included 102 patients (102 hips) who underwent primary unilateral THA via a posterior approach between June 2024 and June 2025. Patients were classified into independent (n = 54) and dependent (n = 48) ambulation groups according to their ability to walk 50 m without walking aids one week after THA. Preoperative assessments included the 30-s chair-stand test, two-step test, one-leg stance time, and Timed Up and Go test, as well as computed tomography-derived muscle attenuation values. Multivariable logistic regression was performed to identify independent predictors of independent ambulation.

RESULTS

The independent ambulation group was younger and performed better on all four physical function tests (all p < 0.05). Muscle attenuation values differed only for the rectus femoris (p = 0.003). In multivariable analysis, the two-step value was the sole independent predictor of independent ambulation (per 0.1-unit increase: OR 1.33; 95% CI 1.02-1.74; p = 0.026). The optimal cutoff value was 0.95, with a sensitivity of 75%, specificity of 76%, and area under the receiver operating characteristic curve of 0.81.

CONCLUSION

Preoperative two-step test performance independently predicted independent ambulation one week after THA. A two-step value of 0.95 may help identify patients at risk of delayed walking recovery and facilitate preoperative risk stratification.