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

## TL;DR

This study examines how often acetabular dysplasia normalizes in Japanese adolescents with suspected scoliosis, finding higher normalization rates in younger patients.

## Contribution

The study provides new insights into acetabular dysplasia normalization rates in adolescents based on age at diagnosis.

## Key findings

- 31.6% of acetabular dysplasia cases diagnosed before age 12 normalized by age 15.
- Only 5.6% of cases diagnosed at or after age 12 normalized by age 15.
- AD in adolescence predicted AD at growth completion in 95% of cases diagnosed at ≥12 years.

## Abstract

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.

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.

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.

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.

The online version contains supplementary material available at 10.1007/s43465-023-01065-4.