EP1.72 Periacetabular Osteotomy in Older Children With Open Triradiate Cartilage: Does Premature Physeal Closure Affect Long-term Radiographic Outcomes?

Abstract

Abstract Background Periacetabular osteotomy (PAO) is generally considered contraindicated in patients with an open triradiate cartilage because of the risk of physeal injury and premature closure. However, older children with symptomatic hip disorders and limited remodeling potential may have few effective surgical options. The effect of PAO on triradiate cartilage closure and subsequent acetabular development remains unclear. Methods We retrospectively reviewed patients ≥8 years of age with an open triradiate cartilage who underwent PAO between 2014 and 2024. Inclusion criteria required unilateral surgery and follow-up to skeletal maturity. Radiographic parameters, including the lateral center-edge angle (LCEA), anterior center-edge angle (ACEA), and Tönnis angle, were measured postoperatively and at final follow-up. Paired comparisons were performed to evaluate maintenance of correction. Results Twenty patients (mean age, 10.7 years) were included, with a mean follow-up of 73.5 months. All patients demonstrated premature closure of the ilioischial limb of the triradiate cartilage at a mean of 4.8 months postoperatively. Despite this, all radiographic parameters improved to within normal ranges after surgery and were maintained at skeletal maturity. The LCEA and ACEA demonstrated slight increases over time, suggesting continued acetabular development. Conclusions In older children with an open triradiate cartilage, PAO resulted in consistent premature closure of the ilioischial limb but did not compromise acetabular development or the durability of correction. These findings suggest that PAO may be a reasonable surgical option in carefully selected patients.