PERCENTILE-GRAPHS FOR DOCUMENTATION OF TH E ACETABULAR INDEX - A TOOLFOR THE RADIOLOGIC-DIAGNOSIS OF DEVELOPMENTAL DYSPLASIA OF THE HIP, AND FOR QUALITY-CONTROL OF ITS TREATMENT

The acetabular index (AI; Hilgenreiner 1925) has proven to be a reliab le parameter for the radiological diagnosis of developmental hip dyspl asia (DDH). Age-dependent normal values and ranges of the AI are well documented. These data, however, have so far not been presented graphi cally in a way which would have made them suitable for patient data do cumentation on a routine basis (calculation of percentiles, time-axis with log scale, smoothing). We have therefore created graphs meeting t hese requirements, based on a previous examination of the AI of 719 gi rls and 428 boys (Tonnis and Brunken 1968). These graphs have meanwhil e proven to be a useful and time-saving tool for the diagnosis as well as quality control of the treatment in children with DDH.