Abstract Objective To identify an assessment tool and its cut-off point for indicating ambulatory status 6 months after total hip arthroplasty (THA). Design Cross-sectional study. Setting Kyoto University Hospital. Participants Eighty-eight patients who underwent unilateral THA. Main outcome measure Lower-extremity muscle strength, hip range of motion and hip pain were measured 6 months after THA. The patients were divided into two groups according to their ability to walk 6 months after THA: an independent ambulation group and a cane-assisted ambulation group. Results A stepwise multiple logistic regression analysis indicated that age and lower-extremity maximal load were significant variables affecting mid-term ambulatory status following THA. Receiver operating characteristic curve analyses revealed that ambulatory status following THA was indicated more accurately by leg extension strength (cut-off point=8.24N/kg, sensitivity=92%, specificity=82%, area under the curve=0.93) than age. Conclusion Lower-limb load force with a cut-off point of 8.24N/kg is a reliable assessment tool for indicating ambulatory status 6 months after primary THA.