Skeletal Maturity in Legg-Calve-Perthes Disease: Significant Discrepancy Present between the Hand and the Hip

Background: The concept of delayed skeletal maturity in Legg-Calve-Perthes Disease (LCPD) has been well identified with the Greulich and Pyle (GP) atlas showing 1 to 2 years delay. Recently the optimized Oxford hip skeletal age (Optimized Oxford) system has been developed and shown to have similar accuracy as the GP atlas for assessing skeletal maturity. However, this system has not been used to assess skeletal maturity in LCPD. Methods: A retrospective review of a prospective, multicenter study of patients with LCPD treated from 1984 to 1991 and followed to skeletal maturity was performed. We identified all patients who had a left-hand radiograph at the time of presentation with an accompanying anteroposterior pelvis radiograph including the contralateral hip. Patients were excluded if their age at presentation fell outside the validated range for the Optimized Oxford system. GP atlas was used to determine bone age using left-hand radiographs and the nonaffected hip radiographs were used to calculate the Optimized Oxford bone age. Skeletal maturity indices were compared with chronological age (CA) to determine the discrepancy between methodologies. Results: A total of 71 patients met inclusion criteria (mean 9.5 ± 1.2 y at presentation, 42.2% females). The mean GP bone age was 1.4 years younger than CA (95% CI: 1.01-1.76 y), with the discrepancy being greater for boys than girls (1.8 vs 0.86 y, P = 0.02). The mean Optimized Oxford bone age was 0.31 years older than CA (95% CI: 0.24-0.38 y) and correlated significantly with CA (R = 0.97, P < 0.001). There were no sex differences in the Optimized Oxford bone age relative to CA (P = 0.32). The GP bone age was a mean of 1.7 years younger than the Optimized Oxford bone age (95% CI: 1.35-2.05 y). Conclusion: Skeletal maturity assessment in children with LCPD varies according to the utilized maturity system. The Optimized Oxford bone age more closely mirrors the patient's CA and does not correlate with the GP bone age, which reveals a delayed maturation.