Bone age estimation and prediction of final height in patients with β-thalassaemia major:: a comparison between the two most common methods

Background Thalassaemic patients are in need of frequent assessment of bone age because of growth failure and pubertal disorders. Objective To compare the "rapid" Greulich and Pyle (G&P) method with the third edition of the Tanner and Whitehouse (TW3) method for determining skeletal maturity and predicting final height in thalassaernic patients. Materials and methods A total of 191 radiographs from 58 patients (28 male, 30 female) were retrospectively evaluated by two investigators, one for each method. In 47 radiographs from 15 patients having attained their adult height, predicted final height was calculated according to each method. Results The mean bone ages determined by both the G&P and TW3 methods were lower than mean chronological age, although the differences were not statistically significant (10.04 +/- 3.69 years and 9.98 +/- 3.39 years vs. 10.78 +/- 3.96 years, respectively). Both methods had a tendency to over-estimate final height. Overall, the TW3 method seemed to be more accurate than the G&P method (mean absolute error 3.21 +/- 2.51 years vs. 3.99 +/- 2.99 years, respectively, P=0.048). Conclusions The same method should be used when serial assessments are performed, as both methods provide similarly reliable, although not equivalent, results. The TW3 height prediction method seemed to be more accurate in patients with beta-thalassaemia major than the G&P method, albeit with a large confidence interval.