Bone Growth Estimation Using Radiology (Greulich–Pyle and Tanner–Whitehouse Methods)

Abstract

Skeletal maturation commences in embryonic life and is completed in early adulthood. Radiographic features of the hand and wrist first noted over a century ago formed the basis for estimation of bone age (BA) developed by Greulich and Pyle (GP). The method involves matching radiographic patterns to an atlas and remains widely used over 50 years later. The Tanner–Whitehouse (TW) method was developed almost two decades later and while other hand and wrist methods have been proposed none are used as widely. BA estimation is indicated for assessment and treatment of growth disorders, prediction of height, and management of childhood orthopedic disorders. Hand and wrist based methods offer a composite score for BA and therefore may not accurately discriminate variation throughout the growth period, between racial groups and as a result of change over successive generations. Variations are seen within the United States between Hispanic, African, and Caucasians using the GP system. Differences have been documented between European populations with the TW systems although specific standards have been devised for some population groups. Estimation of skeletal maturity may be less predictable with hand and wrist radiography in the very young and variable during adolescent growth, and additional skeletal radiographic sites may improve timing in the management of skeletal disorders. There are few data on methods for BA estimation outside of radiographic imaging and new developments have focused on computer-based analysis of radiographic images to improve reproducibility and potentially transform BA into a continuous variable. It remains to be seen whether new technologies will offer sufficient advantage over the GP and TW methods. At present the GP method can be recommended for its simplicity and reliability in clinical practice and modifications of the TW methods for accuracy and reproducibility.