Incidence and risk factors for postoperative posterior column fractures following periacetabular osteotomy

Periacetabular osteotomy (PAO) is a widely used surgical technique for symptomatic developmental dysplasia of the hip (DDH). However, the incidence of posterior column fractures after PAO and the risk factors are not adequately investigated. Identification rates have been improved by using oblique radiographs, but few reports have examined the incidence of posterior column fractures using early postoperative computed tomography (CT) scans. This study aimed to investigate the incidence and risk factors for postoperative posterior column fracture following PAO using early postoperative CT scans. This study included 80 hips from patients who underwent PAO for symptomatic DDH. Radiographic parameters such as lateral center-edge angle (LCEA), anterior center-edge angle (ACEA), acetabular roof obliquity (ARO), and the thickness of the posterior column before and after surgery were evaluated using preoperative and early postoperative (within 1 month) CT images. Statistical analyses were conducted to identify risk factors associated with postoperative posterior column fracture. Postoperative CT scans revealed that postoperative posterior column fracture occurred in 42% of cases. A preserved posterior column thickness of <13 mm was identified as a significant risk factor for postoperative posterior column fracture. In conclusion, Posterior column fractures are a relatively common complication following PAO, with a higher incidence than previously reported. A preserved posterior column thickness of <13 mm is a critical risk factor for postoperative posterior column fracture. These results suggest that early weight-bearing should be approached with caution and that accurate osteotomy techniques using computer-assisted surgery are needed.