Introduction In hip osteoarthritis, hip flexion contracture can severely alter the patient’s alignment, and, therefore, affect the patient’s quality of life (QOL). Hip contracture is not well-studied, partly because of the difficulties of its diagnosis. The aim of this study was to propose a quantitative definition of hip flexion contracture, and to analyse sagittal alignment in these patients compared to non-contracture ones, before and 12 months after total hip arthroplasty (THA). Materials and methods Consecutive patients with hip arthrosis and an indication for THA were included (N = 123). Sagittal full-body radiographs were acquired in free standing position and in extension. QOL questionnaires were administered before and after surgery. Spinopelvic parameters were measured, including the pelvic–femur angle (PFA). Patients with low pelvic incidence ( 5°, or PFA > -5° when pelvic incidence ≥ 45°. Results 29% of patients were in the hip flexion contracture group, and they showed lower pelvic tilt than the no-contracture group (p
