THE C B RATIO IN THE RADIOLOGICAL MONITORING OF THE HIP-JOINT IN CONGENITAL DISLOCATION OF THE HIP/

We report a method of monitoring hip joint development for congenital dislocation of the hip in children. The c/b ratio was measured on seri al radiographs of 41 hips in 38 patients. The measurement was compared to c/b ratio obtained from normal hips. It was used to detect concent ric reduction or its loss by migration of the femoral head during grow th. The age at diagnosis ranged from 8 months to 10 years 6 months. Th e normal c/b ratio was found to change little with age. Deviation of t he c/b ratio from normal in congenital dislocation of the hip resulted in a poor outcome and identified cases requiring further surgical int ervention. This measurement of c/b ratio is simple and accurate, using easily determined points. The graphic display promotes critical analy sis of situation and allows selection of cases at risk for treatment.