Methods of skeletal age assessment using hand and wrist radiographs in children and their applicability across different ethnicities: systematic review and meta-analysis protocol

BACKGROUND: Skeletal age assessment using hand and wrist X-rays is commonly used to determine the biological maturity of children. It is invaluable when the chronological age is not known or in diagnosing and treating various endocrine, genetic, and developmental disorders as well as in a forensic context. Skeletal age is affected by both internal and external factors, leading to differences in skeletal maturity between children of different ethnicities. Regional studies have even questioned the applicability of current international skeletal age references across ethnicities. METHODS: A comprehensive literature search will be conducted utilising the PubMed, Scopus, Web of Science, EMBASE, and Ovid online databases to identify existing publications. A combination of Medical Subject Headings (MeSH) terms and keywords, including "Skeletal age", "bone age", "radiograph", and "hand", will be used. Data screening and extraction will be done with Covidence software. Two independent reviewers will screen literature against predefined inclusion and exclusion criteria in abstract and full-text forms. A third reviewer will be consulted if consensus cannot be reached. The process will be reported in whole and presented in a PRISMA flow diagram. Study quality will be assessed by using the JBI critical appraisal tool. A meta-analysis will be conducted. DISCUSSION: This review will present a comprehensive analysis of existing literature on the applicability of skeletal age assessment methods using hand and wrist radiographs across different ethnicities. Further, this will be highlighting both strengths and gaps in existing knowledge. The inclusion of high-quality data will facilitate a quantitative meta-analysis for the exploration of ethnic differences in skeletal age assessments, ultimately laying the foundation for the development of population-specific reference standards. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration ID CRD42025646662.