Increased Risk of Stress Fractures Following Second-Side Periacetabular Osteotomy: A Retrospective Cohort Study.

Abstract

Postoperative stress fractures following periacetabular osteotomy can prolong the healing process, with some cases resulting in non-union. The purpose of this study was to characterize the incidence of stress fracture following periacetabular osteotomy (PAO) in a cohort of patients who underwent bilateral PAO and identify the subsequent risk of second-side stress fracture if there had been a stress fracture on the first side. A total of 112 patients (224 procedures) who underwent bilateral PAO between 2013 and 2023 to treat symptomatic acetabular dysplasia or retroversion were identified from the Northumbria Hip Preservation Unit patient database. In addition to demographic data and anatomical measurements (e.g., acetabular index, center edge angle, acetabular version, and femoral version), postoperative radiographs were reviewed for evidence of stress fractures. The risk of sustaining a stress fracture following a first-side procedure was 11.6% (13 of 112). The risk of sustaining a stress fracture following a side procedure was 25% (28 of 112). The risk of sustaining a stress fracture on the second side PAO after sustaining a stress fracture on the first side was in 10 of 13). The risk of sustaining a stress fracture on the second side after not sustaining it on the first was 18.2% (18 of 98). This study highlights that there is an increased risk of 25.0% of patients undergoing their second side periacetabular osteotomy having a stress fracture. If patients had a stress fracture following their first procedure, then this risk was even higher, with 79.6% patients having a further stress fracture. These findings should alert surgeons to the increased risk and seek to identify potentially modifiable risk factors before undertaking a second PAO and in cases where there has been a stress fracture following the first procedure.