Percent Final Height Is a Novel Method That Identifies Differences Between the Rate of Development in American Children of Different Races

Abstract

Introduction: The Greulich & Pyle (G&P) Radiographic Atlas of Skeletal Development uses hand x-rays obtained between 1926 and 1942 on children of Caucasian ancestry. Our study uses modern Caucasian, Black, Hispanic, and Asian children to investigate patterns of development as a function of percent final height (PFH). Methods: A retrospective review, at a single institution, was conducted using children who received a hand x-ray, a height measurement taken within 60 days of that x-ray, and a final height. BA and CA were compared between races. PFH was calculated by dividing height at the time of the x-ray by their final height. To further evaluate differences between races in CA or BA, PFH was then modeled as a function of CA or BA using a fifth-degree polynomial regression, and mean ages at the 85th PFH were compared. Patients were then divided into Sanders stages 1, 2-4, and 5-8 and the mean PFH, CA, and BA of the Asian, Black, and Hispanic children were compared with the White children using Student t test. P values less than 0.05 were considered significant. Results: We studied 498 patients, including 53 Asian, 83 Black, 190 Hispanic, and 172 White patients. Mean BA was significantly greater than CA in Black males (1.27 y) and females (1.36 y), Hispanic males (1.12 y) and females (1.29 y), and White females (0.74 y). Hispanic and Black patients were significantly more advanced in BA than White patients (P<0.001). At the 85th PFH, White and Hispanic males were older than Black males by at least 7 months (P<0.001), and White females were significantly older than Hispanic females by 6.4 months (P<0.001). At 85th PFH for males, Hispanic and Black males had greater BA than White males by at least 5 months (P<0.001), and Asian females had a greater BA than Black females by at least 5 months (P<0.001). Compared with White children, Hispanic children were significantly younger at Sanders 2-4 than White children, and Black children were skeletally older at Sanders 5-8. Conclusions: BA was greater than CA by ≥1 year in Black and Hispanic children, and that these children had a significantly greater BA than their White counterparts. Black males and Hispanic females reached their 85th PFH at younger ages, and Hispanic males and Asian females were the most skeletally mature at their 85th PFH. Our results suggest that BA and CA may vary as a function of race, and further studies evaluating growth via the 85th PFH may be necessary. Level of Evidence: Therapeutic Study – Level IV