Reliability and normative values of common adult radiographic parameters for hip preservation in the developing pelvis

Abstract

AbstractAnterior–posterior (A/P) radiography of the pelvis is essential to the diagnosis and treatment of developmental dysplasia of the hip (DDH). Multiple well-defined parameters of adult hip morphology with good reliability are readily available. The purpose of this study was to determine normative values and observed reliability for 10 common adult hip parameters in the developing pelvis of male and female patients aged 6 months–16 years. One hundred and fifty-eight standardized A/P pelvic radiographs were randomly selected from an existing trauma patient database and stratified into five age groups. Mean values or presence of categorical values and the observed reliability of 10 adult hip parameters (acetabular index/angle, pelvic width index, lateral center edge angle, Tonnis angle, acetabular to femoral head distance, femoral head diameter, coxa profunda/protrusio, ischial spine sign, crossover sign and posterior wall sign) were determined. Minimal differences in all parameters were observed between male and female patients. The observed inter-rater reliability of continuous parameters was 0.77–0.99. The observed intra-rater reliability was 0.7–0.99 with a combined intra-rater reliability of 0.88–0.99. The observed inter-rater reliability of categorical variables was 0.64–1.0. The intra-rater reliability of categorical variables was 0.83–1.0. Normative values for 10 common adult hip parameters were determined for male and female patients in the developing pelvis. Reliable knowledge of these values and their relationship to the age of the patient and/or stage of pelvic development associated may provide additional information to aid the treatment of DDH.