Diagnostic yield of sonography in infants with suspected hip dysplasia: diagnostic thinking efficiency and therapeutic efficiency.

OBJECTIVE

The purpose of this study is to determine the impact of sonographic information on surgeons' diagnostic thinking and decision making in the management of infants with a possible diagnosis of developmental dysplasia of the hip (DDH).

SUBJECTS AND METHODS

Five experienced orthopedic surgeons examined 66 hips of infants who were referred for a possible diagnosis of DDH and reported for each hip a confidence level about the diagnosis of DDH using a visual analog scale (VAS) before and after hip sonography was obtained. In addition, they reported a management plan. We determined the efficiency in diagnostic thinking by calculating the mean gain in diagnostic confidence as the percentage change in VAS scores and the impact of sonography on the management plan (therapeutic efficiency).

RESULTS

Sonography led to a change in diagnosis in 52% (34/66) of hips. The management plan changed in 32% (21/66) of hips. The mean gain in reported diagnostic confidence was 19.4% (95% CI, 17.3-21.5%), but it was 46.0% (95% CI, 30.5-60.8%) in cases where the management changed as a result of sonography (difference, 37.7%; p < 0.0001). The greatest yield of sonography was found in hips showing limited abduction. Sonography obviated further follow-up in 23% (15/66) of cases.

CONCLUSION

Sonography refined the diagnostic thinking of clinicians and led to a change in diagnosis in 52% of cases. Management plans changed in 32% of cases.