Prediction of adolescent pelvis development using femoral head and acetabulum growth in a longitudinal radiographic study

Abstract Introduction Adolescent total hip arthroplasty (THA) is guarded partially due unclarity as to when pediatric hip joints reach full development. This study sought to identify when maximum acetabular and femoral head diameters are achieved with relation to chronological and skeletal age. Materials and Methods Consecutive femoral head and acetabular diameters were measured in a random sample of 54 female and 78 male subjects, which were queried from a historical collection of annual radiographs of children. Femoral head and triradiate physeal plates were scored according to Oxford bone parameters. Results At 14 years females had femoral diameters of 4.16 +/− 0.23 cm and acetabular diameters of 5.15 +/− 0.30 cm. At 16 years males had femoral diameters of 4.85 +/− 0.30 cm and acetabular diameters of 5.90 +/− 0.35 cm. In the year following maximal femoral Oxford scores, no significant change was seen in femur and acetabulum diameters in females and in femur diameters in males. In the year following maximal acetabular Oxford scores, there was a significant increase in both femur and acetabulum diameters in both females and males. Conclusions Females on average reach maximum pelvis maturity at 14 years and males reach maximum pelvis maturity at 16 years. A closed femoral head was found to be a good marker of full hip growth, while a closed triradiate was not. This study provides anatomical data for surgeons to consider in assessing risk factors of THA failure in adolescents.