Applicability of Shoulder, Olecranon, and Wrist-based Skeletal Maturity Estimation Systems to the Modern Pediatric Population

Background: The proximal humerus ossification system (PHOS), olecranon apophyseal ossification system (OAOS), and modified Fels wrist skeletal maturity system (mFWS) were recently developed or updated using a historical, mostly White, pediatric population. These upper extremity skeletal maturity systems have demonstrated skeletal age estimation performance superior or equivalent to Greulich and Pyle in historical patients. Their applicability to modern pediatric populations has not yet been evaluated.

Methods: We reviewed anteroposterior shoulder, lateral elbow, and anteroposterior hand and wrist x-rays of 4 pediatric cohorts: White males, Black males, White females, and Black females. Peripubertal x-rays were evaluated: males 9 to17 years and females 7 to 15 years. Five nonpathologic radiographs for each age and joint were randomly selected from each group. Skeletal age estimates made by each of the 3 skeletal maturity systems were plotted against the chronological age associated with each radiograph and compared between cohorts, and with the historical patients.

Results: Five hundred forty modern radiographs were evaluated (180 shoulders, 180 elbows, and 180 wrists). All radiographic parameters had inter- and intra-rater reliability coefficients at or above 0.79, indicating very good reliability. For PHOS, White males had delayed skeletal age compared with Black males (Δ-0.12 y, P =0.02) and historical males (Δ-0.17 y, P <0.001). Black females were skeletally advanced compared with historical females (Δ0.11 y, P =0.01). For OAOS, White males (Δ-0.31 y, P <0.001) and Black males (Δ-0.24 y, P <0.001) had delayed skeletal age compared with historical males. For mFWS, White males (Δ0.29 y, P =0.024), Black males (Δ0.58 y, P <0.001), and Black females (Δ0.44 y, P <0.001) had advanced skeletal age compared with historical counterparts of the same sex. All other comparisons were not significant ( P >0.05).

Conclusions: The PHOS, OAOS, and mFWS have mild discrepancies in skeletal age estimates when applied to modern pediatric populations depending on the race and sex of the patient.

Level of evidence: Level III - retrospective chart review.