Comparison of Ultrasonography with CT-Scan in the Evaluation of Femoral Head Position after DDH Reduction

Developmental dysplasia of the hip (DDH) is a common problem and inappropriate treatment may result in serious complications. Several techniques have been used to monitor the status of the hip after reduction. Each has its own problem so that ultrasound found a special place where the assessment is needed. The aim of this study was to determine the diagnostic value of transinguinal and transgluteal ultrasound in comparison to CT scan in the evaluation of femoral head position in acetabulum in DDH treatment in spica cast. A cross-sectional study was performed on 37 affected hips in 24 infants at the age of 9 to 36 months during one year in a teaching hospital in Tehran، Iran. After close or open reduction and applying spica cast، an opening was made over the anterior edge of the inguinal region and transinguinal and transgluteal ultrasound was performed to confirm the quality of reduction in the acetabulum. The sensitivity، specificity، positive and negative predictive values of the postoperative ultrasonography was compared with CT scan. Data analysis was done by statistical tests. The rate of agreement between ultrasonography and CT scan results was 91% (p<. 001). The sensitivity of 87%، specificity of 100%، accuracy of 97%، PPV of 100% and NPV of 96% were reported for ultrasound in comparison to CT scan. Ultrasound could be applied after closed or open reduction for determination of the femoral head position in spica casts in the management of DDH.