Is the Rate of Change in Posterior Pelvic Tilt After Total Hip Arthroplasty Constant?

BACKGROUND: The purpose of this study was to evaluate the age-related change in pelvic sagittal inclination in the standing position after total hip arthroplasty (THA). This study hypothesized that the rate of progression of posterior tilt is not constant. MATERIAL AND METHODS: We measured sacral slope and pelvic tilt in 36 patients who were followed up for more than 10 years after unilateral primary THA. RESULTS: The posterior pelvic tilt in the standing position progressed significantly in the first year after THA and then progressed slowly. However, there was a tendency to accelerate again for those older than 75 years. Posterior pelvic tilt tended to progress rapidly after surgery in patients with femoral neck fractures and subchondral fractures of the femoral head. CONCLUSIONS: In patients older than 75 years and those with fragility fractures, postoperative pelvic tilt in the standing position tends to be greater, suggesting that the use of a large head or dual mobility system should be considered.