A simple method for bone age assessment: the capitohamate planimetry.

OBJECTIVES: To determine if the capitohamate (CH) planimetry could be a reliable indicator of bone age, and to compare it with Greulich-Pyle (GP) method.

METHODS: This retrospective study included 391 children (age, 1-180 months). Two reviewers manually measured the areas of the capitate and hamate on plain radiographs. CH planimetry was defined as the measurement of the sum of areas of the capitate and hamate. Two reviewers independently applied the CH planimetry and GP methods in 109 children whose heights were at the 50th percentile of the growth chart.

RESULTS: There was a strong positive correlation between chronological age and CH planimetry measurement (right, r = 0.9702; left, r = 0.9709). There was no significant difference in accuracy between CH planimetry (84.39-84.46 %) and the GP method (85.15-87.66 %) (p ≥ 0.0867). The interobserver reproducibility of CH planimetry (precision, 4.42 %; 95 % limits of agreement [LOA], -10.5 to 13.4 months) was greater than that of the GP method (precision, 8.45 %; LOA, -29.5 to 21.1 months).

CONCLUSIONS: CH planimetry may be a reliable method for bone age assessment.

KEY POINTS: • Bone age assessment is important in the work-up of paediatric endocrine disorders. • Radiography of the left hand is widely used to estimate bone age. • Capitatohamate planimetry is a reliable and reproducible method for assessing bone age.