A practical classification of the distal radius and ulna radiograph for assessing skeletal maturity

Abstract

Accurate prediction of the pubertal growth spurt is critical to the management of adolescent idiopathic scoliosis (AIS). Menarche onset and Risser sign could not demonstrate peak growth accurately. The authors have noted that morphological changes in the distal radius and ulna parallel peak growth and the cessation of growth. This study aims to substantiate these observations by correlation with growth parameters. METHOD: Using a cohort of 145 females followed from age 10 to maturity with growth measurements and yearly hand radiographs, morphological changes in the distal radius were classified into 11 stages (R1-11) and ulna into 9 (U1-9). The radius and ulna classifications were correlated with bone age, standing height, sitting height and arm span. RESULTS: Peak growth velocity, significantly correlated with the stage R7, when the medial side of radial epiphysis form a cap covering the radial metaphysis, and U5, when distal ulna epiphysis has taken the shape of ulna head. These were equivalent to a chronologic age of 11.4 years +/- one year. Growth was complete at R10, when the junction of the radial epiphysis and metaphysis became a single sclerotic line. This was equivalent to a chronologic age of 15.6 +/- 1.3 years. DISCUSSION: The stages of R7, R10 and U5 are easily identifiable stages in the distal radius and ulna. They are easier to use than full bone age measurements, and can predict both peak growth and cessation of growth. These are simple and useful tools for spinal surgeons managing AIS.