Developmental dysplasia of the hip: current concepts about the imaging findings

The diagnosis of developmental dysplasia of the hip (DDH) is mainly depended on ultrasound (US) and plain radiography. The US is sensitive in detecting the dysplasia, however, it highly relies on personal experiences, over diagnosis may happen. The plain radiography is useful for evaluation of the osseous hip, but not for the cartilaginous component. Evidences have showed that the cartilaginous acetabular plays a major role in stabilizing the femoral head. MRI has high resolution and contrast at the interface between the osseous and cartilaginous component, and can provide quantitative measures. The soft tissues around the hip which serves as an obstacle to reduction can also be evaluated on MRI. In this article we reviewed the current concepts and interpretations about imaging findings on DDH, especially the studies about the value of MRI on the evaluation of the development of the hip. (authors)