Postural and Chronological Change in Pelvic Tilt Five Years After Total Hip Arthroplasty in Patients With Developmental Dysplasia of the Hip: A Three-Dimensional Analysis.

The pelvis generally tilts to the posterior with movement from the supine to standing position, and with time after total hip arthroplasty (THA). This study aimed to investigate changes in pelvic tilt from the preoperative supine position to the standing position at 5 years after THA (pelvic change, PC). We measured pelvic tilt using a 2D-3D matching technique in 77 unilaterally affected patients who underwent primary THA. PC in 8% of all patients was ≤-20°, and the greatest PC was -25°. In these patients, posterior pelvic tilt continued up to 5 years after THA. These patients were older, and their lumbo-lordotic angle was small. For such cases, cup orientation should be planned to account for continuous posterior change in pelvic tilt after THA.