When reading a bone age X-ray, should priority be given to carpal bones or the radial epiphysis (radius bone growth plate)?

Bone Age Assessment: Carpal Bones vs. Radial Epiphysis

When reading a bone age X-ray, priority should be given to the radial epiphysis over carpal bones for more accurate skeletal age assessment, particularly during the pubertal growth spurt. 1

Comparison of Assessment Methods

• The radial epiphysis provides more reliable information for bone age assessment compared to carpal bones, especially in patients with skeletal dysplasias or growth disorders 1
• Studies comparing different bone age assessment methods have found that techniques focusing on the radius-ulna-short bones (RUS) scoring system have higher interobserver and intraobserver reliability than methods focusing solely on carpal bones 1
• The Tanner-Whitehouse 3 (TW3) method using the radius-ulna-short bones (RUS) scoring system and the Greulich-Pyle (GP) atlas method both demonstrate superior reliability compared to carpal bone maturity scoring systems 1

Evidence Supporting Radial Epiphysis Priority

• Assessment of the distal radial epiphysis provides more accurate information on skeletal development, particularly during and after the pubertal growth spurt 2
• The olecranon method (focusing on epiphyseal development) offers more detailed information during the pubertal growth spurt compared to methods focusing primarily on carpal bones 2
• In patients with multiple epiphyseal dysplasia (MED), the TW3 RUS method (which prioritizes radial epiphysis) provided more accurate information on skeletal development than the TW3 carpal bone maturity scoring system 1

Limitations of Carpal Bone Assessment

• Carpal bone assessment alone may provide less accurate information in certain conditions, such as:
  • Patients with skeletal dysplasias 1
  • Children with growth disorders 1
  • During and after the pubertal growth spurt when epiphyseal changes are more significant 2
• The pattern of skeletal age delay when using carpal bone assessment methods can be significantly different from methods that include radial epiphyseal assessment 1

Clinical Considerations

• When assessing bone age, consider using a combination approach that prioritizes radial epiphysis but also includes carpal bones for a comprehensive evaluation 3
• The ratio between carpal bones and epiphyses of the ulna and radius can be used in Bayesian approaches for more accurate age estimation 3
• In certain specialized cases, such as forensic age estimation, both carpal bones and radial epiphysis should be considered, but with greater weight given to the radial epiphysis findings 4

Common Pitfalls to Avoid

• Relying solely on carpal bone assessment may lead to inaccurate bone age determination, especially in patients with skeletal dysplasias 1
• Failing to prioritize radial epiphysis assessment during the pubertal growth spurt when it provides more detailed and accurate information 2
• Not considering that carpal bones may complete ossification earlier than long bone epiphyses, potentially leading to overestimation of skeletal maturity if only carpal bones are assessed 2

Remember that while both anatomical areas provide valuable information, the radial epiphysis generally offers more reliable and accurate assessment of skeletal age, particularly during key developmental periods such as the pubertal growth spurt.