The association between foot morphological development and bone maturation in children: a cross-sectional study

Accurate assessment of pediatric foot development is essential for guiding clinical interventions. While chronological age (CA) is commonly used, it may not account for individual variations influenced by skeletal maturity. This study hypothesizes that bone age (BA) correlates more strongly with foot morphology than CA, particularly in predicting pediatric flatfoot progression.

A retrospective cross-sectional study was conducted with 141 healthy children aged 9-13 years. BA was assessed via hand-wrist X-rays (China 05 RUS-CHN method), and 3D foot parameters were measured using laser scanning. Participants were categorized into delayed, normal, and advanced maturity groups based on BA-CA differences. Correlation analyses and principal component analysis (PCA) were performed to evaluate associations between BA, CA, and foot morphology.

BA exhibited stronger correlations with foot length (FL), outer ankle height (OAH), ball width (BW), and ball girth (BG) compared to CA. Stratified analyses revealed sex-specific differences, with BA-FL correlations in males (r = 0.722) surpassing females (r = 0.572). However, BA showed limited associations with arch morphology parameters (KY index [KYI] and arch height [AH]; |r| < 0.3). PCA further demonstrated that general foot size (PC1) correlated robustly with BA (r = 0.671), while arch morphology (PC2) remained independent of both BA and CA (r = -0.113).

BA is a superior predictor of foot size growth (e.g., FL, BW) compared to CA, particularly in males, but offers limited utility in assessing arch maturation. These findings suggest BA may enhance clinical foot size predictions, yet arch development likely depends on other factors beyond skeletal maturity. Integrating BA into pediatric flatfoot management requires careful consideration of its context-specific benefits and limitations.