Aims: Using 90% of final height as a benchmark, we sought to develop a quick, quantitative and reproducible method of estimating skeletal maturity based on topographical changes in the distal femoral physis.
Patients and methods: Serial radiographs of the distal femoral physis three years prior to, during, and two years following the chronological age associated with 90% of final height were analyzed in 81 healthy children. The distance from the tip of the central peak of the distal femoral physis to a line drawn across the physis was normalized to the physeal width.
Results: A total of 389 radiographs of the distal femur with corresponding Greulich and Pyle bone ages and known chronological ages were measured. Children reached 90% of final height at a mean age of 11.3 years (sd 0.8) for girls and 13.2 years (sd 0.6) for boys. Linear regression analysis showed higher correlation coefficent in predicting the true age at 90% of final height using chronological age + gender + central peak value (R2 = 0.900) than chronological age + gender (R2 = 0.879) and Greulich and Pyle bone age + gender (R2 = 0.878).
Conclusion: Chronological age + gender + central peak value provides more accurate prediction of 90% of final height compared with chronological age + gender and Greulich and Pyle bone age + gender. Cite this article: Bone Joint J 2018;100-B:1106-11.
Keywords: Chronological age; Distal femur; Peak height velocity; Skeletal maturity.