The Proportion of Normalized Hips with Growth in Japanese Adolescents Aged > 10 years with Acetabular Dysplasia who Presented with Suspected Scoliosis

Abstract

Background If asymptomatic acetabular dysplasia (AD) is incidentally identified in adolescence, it is difficult to determine the appropriate follow-up or treatment strategy because the acetabulum is still developing. We investigated the rate of AD normalization at the end of acetabular growth. Methods This cross-sectional study involved 653 patients (1306 hips) aged 10–14 years with scoliosis or suspected scoliosis. All patients underwent plain standing whole-spine radiography (with the pelvis included) at the first visit. We measured the lateral center–edge angle, Sharp angle, Tönnis angle, and acetabular head index on radiographs. The criterion for AD was a lateral center–edge angle of < 20°. We extracted the data of patients aged < 12 (10–11) years and ≥ 12 (12–14) years with AD. Furthermore, we analyzed the radiographic follow-up data at 15 years of age to identify the AD normalization rate. Results AD was diagnosed in 19 hips from patients aged < 12 years and in 36 hips from patients aged ≥ 12 years. The AD normalization rate at 15 years of age was 31.6% in those diagnosed at < 12 years of age and 5.6% in those diagnosed at ≥ 12 years of age. Conclusion AD in adolescence was predictive of AD at the end of growth in 95% of cases diagnosed at ≥ 12 years of age compared with approximately 70% of cases diagnosed at < 12 years of age. Surgical treatment before completion of acetabular growth is beneficial for acetabular remodeling, but the decision to operate should be carefully evaluated in patients aged < 12 years. Graphical Abstract