Effects of Sagittal Spinal Alignment on Postural Pelvic Mobility in Total Hip Arthroplasty Candidates

Recent research has demonstrated that patients with reduced pelvic mobility from standing to sitting have higher rates of dislocation after total hip arthroplasty (THA). This study evaluates the effect of sagittal spinal deformity, defined by pelvic incidence–lumbar lordosis mismatch (PI-LL), on postural changes in pelvic tilt (PT). A multicenter database of 1100 preoperative THA patients was queried. Anterior-pelvic-plane tilt (APPt), spinopelvic tilt (SPT), and LL were measured from radiographs of patients in supine, standing, flexed-seated, and stepping-up postures; PI was measured from computed tomography. Patients were separated into 3 groups based on PI-LL (10°) and propensity-score matched by PI. Lumbar flatback-deformity was defined as PI-LL > 10°, hyperlordosis: PI-LL