Bone age assessment: a large scale comparison of the Greulich and Pyle, and Tanner and Whitehouse (TW2) methods

Purpose-Comparison of bone age assessed using either the "atlas matching" m ethod of Greulich and Pyle or the "point scoring system" of Tanner and Whit e-house (TW2). Materials and methods-362 consecutive "bone age" radiographs of the left ha nd and distal radius performed in a large provincial teaching hospital. Dat a were analysed using the "method comparison" statistical technique. Ten pe r cent of the radiographs were re-analysed to assess intra-observer variati on. Results-The 95% confidence interval for the difference between the two meth ods was 2.28 to -1.52 years. Intra-observer variation was greater for the G reulich and Pyle method than for the TW2 method (95% confidence limit, -2.4 6 to 2.18 upsilon -1.41 to 1.43). Conclusion-The two methods of bone age assessment as used in clinical pract ice do not give equivalent estimates of bone age and we suggest that one me thod only (preferably the TW2) should be used when performing serial measur ements on an individual patient.