"Immunity" of Ethiopian Jews to developmental dysplasia of the hip: a preliminary sonographic study.

Developmental dysplasia of the hip (DDH) is one of the most common problems affecting the pediatric musculoskeletal system. The condition represents a broad spectrum of sonographic (anatomic) pathoanatomical situations, ranging from very mild dysplasia to full dislocation, manifesting clinically as stable or unstable hip joints, particularly in the neonatal period. The cause of DDH is unclear. Various theories suggest genetic, hormonal, mechanical, and geographic factors, along with hemotypology and a great variety of other factors, as causes for this condition. In the present study, sonographic criteria for diagnosing DDH according to Graf were used. Although the overall incidence of DDH was 5.9% in white neonates, it was only 0.44% (two hips, one stable and one unstable) among 450 hips of black Ethiopian newborns. Left untreated, these hips became clinically and sonographically normal. Our results could be considered to indicate a zero incidence of DDH among Ethiopian Jews in this series.