[Ultrasound of the neonatal hip: initial evaluation and follow-up].

Developmental dysplasia of the hip can arise in utero due to a dislocating posture, sometimes associated with predisposing genetic factors. The ideal time for diagnosis is during the neonatal period and adequate screening procedures must be in place. Indeed, the plasticity of hyaline cartilage and fibrocartilage combined with the growth potential at this age nearly always result in rapid complete resolution of the deformity. Ultrasound, when indicated, is the best imaging modality for diagnostic confirmation. It allows evaluation of the osteocartilaginous structures, joint space and soft tissues. Ultrasound provides the clinician with a reliable morphologic and dynamic evaluation tool improving the diagnostic accuracy and guiding orthopedic treatment. Our experience, dating back to 1985, is based on a population imaged between 2007 and 2009. From a total of 2480 neonates screened because of abnormal finding or risk factors, we identified 257 cases of dislocation (10%) in 191 neonates : 14 cases of nonreducible dislocation (10 neonates), 30 cases of reducible hip dislocation (24 neonates), 97 cases of dislocatable hip (73 neonates) and 116 cases of subluxable hip (84 neonates). Clinical and sonographic follow-up demonstrated therapeutic success in 237 cases (93%) and failure in 20 cases (one case of subluxable hip, two cases of dislocatable hip, three cases of dislocated hip, 14 cases of nonreducible hip dislocation). Imaging follow-up (6 to 24 months) showed asymmetry in the size of the proximal femoral epiphyses in 20 cases (with resolution in 10 cases), three cases of dysplasia and one case of post-reduction osteochondritis.