title: Skeletal and chronological ages in American adolescents: current findings in skeletal maturation.
abstract: OBJECTIVE
  This study was designed to assess the relationship between skeletal and chronological ages among current American adolescents using the Greulich and Pyle atlas for skeletal age determination.
  
  
  METHODS
  We used the Greulich and Pyle atlas to prospectively determine skeletal age in a group of 138 otherwise healthy American adolescents from 12 to 18 years of age. 62 males and 76 females were enrolled in this cohort. Paired Student t-tests were used to statistically compare the skeletal and chronological ages in this population. Subgroup analysis examined the effect of gender on differences between chronologic age and skeletal age.
  
  
  RESULTS
  For the entire cohort, mean skeletal age was significantly greater than chronological age (mean 0.80 years, P < 0.01). In 29 cases (21%) the skeletal age was at least 2 years greater than the chronologic age. Among females, such cases with marked discrepancy occurred exclusively in those chronologically between 12 and 15 years of age (P < 0.01). Males demonstrated a 2-year or greater discrepancy more commonly than females (26 vs. 17%). In males, 2-year discrepancies were equally likely across chronologic ages (P = 0.82).
  
  
  CONCLUSIONS
  Current American adolescents are significantly more mature by skeletal age, as determined by the Greulich and Pyle method, than their chronological age would suggest. The skeletal ages of females are most likely to markedly exceed chronologic age between the ages of 12-15 years.
authors.affiliation: Department of Orthopaedic Surgery, Shriners Hospital for Children, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8233, St. Louis, MO 63110 USA.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Calfee
authors.forename: Melanie
authors.initials: M
authors.lastname: Sutter
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Steffen
authors.forename: Charles A
authors.initials: CA
authors.lastname: Goldfarb