Narrow window of bone age in children with slipped capital femoral epiphyses.

Pelvis radiographs of 30 children with slipped capital femoral epiphyses (SCFE) were reviewed by four readers to determine the skeletal age. The average chronologic age for girls was 12.1 +/- 1.0 years and that for boys was 14.4 +/- 1.3 years; the average pelvic bone age was 13.2 +/- 0.6 for girls and 15.1 +/- 0.6 years for boys. The chronologic age range was 98 months, and skeletal age range was only 50 months. Pelvis bone age was advanced in the youngest children, normal in most children, and mildly delayed in older children. We conclude that there is a uniform skeletal age or "narrow window" during which epiphyseal slipping occurs, regardless of the child's chronologic age.