Comparison of bone age delay and recovery in Meyer dysplasia and Legg-Calv,-Perthes disease: a pilot study

Meyer dysplasia (MD) is a rare disease but readily mistaken for Legg-Calv,-Perthes disease (LCPD). Although most published studies on MD have characterized and differentiated it from LCPD radiologically and clinically, differences with regard to bone age delay and recovery have not been sought. We deemed it necessary to distinguish bone age delay and recovery patterns between the two entities for better differentiation, prognostication, and parental advice. Bone age delay and recovery of eight patients who were initially diagnosed with LCPD but were found to have MD were retrospectively reviewed and compared with those of age-matched patients with LCPD. Based on hand radiographs, the radius-ulna-short bones (RUSs) and carpal bone ages were determined using the Tanner and Whitehouse 3 (TW3) method. Minimum follow-up was 2 years (range 2-5 years). Differences in RUS and carpal bone ages and recovery patterns between the two entities were analyzed using trend lines in scatter plots. The mean delay of RUS bone age was significantly less in MD (0.52 +/- 0.87 years) than in LCPD (1.11 +/- 0.99 years). However, the difference between the mean carpal bone age delay in MD (1.13 +/- 1.28 years) and LCPD (1.47 +/- 1.19 years) was not significant. Trend lines showed faster bone age recovery patterns in MD than in LCPD. Bone age was delayed in both MD and LCPD but was less delayed in the former. RUS bone age showed more significant differences than carpal bone age when comparing the two entities and hence might be more useful for differentiating the two. Earlier bone age recovery patterns may be anticipated in patients with MD.