[Congenital asymmetrical pelvis. Clinical, radiological study and outcome]

In congenital pelvic obliquity, there is a restricted abduction in one hip and an abduction contracture in the other. This association has been considered as a cause of acetabular dysplasia with progressive subluxation of the hip opposite to the abduction contracture. The clinical and radiological study of 120 children with an average follow-up of 3 years and 3 months permitted to demonstrate that two different types exist: the simple types (93 cases) without dysplasia, which never developed progressive subluxation and must not be treated, and the pelvic obliquities with dysplasia-subluxation-dislocation (27 cases) which have to be treated if the decentration of the hip opposite to the abduction contracture is marked. Distinguishing between these two types may be difficult because the X-ray is nearly never strictly correct because of the pelvic obliquity. This work leads to a better comprehension of the acetabular dysplasias who are subdivided into pseudodysplasias, secondary dysplasias and primary dysplasias. In the screening for the detection of congenital dislocation of the hip, it is essential that a pelvic obliquity be recognised because it constitutes a sign of hip at risk. Then, the clinical research of instability could be completed by echographic study in the two or three months or by radiographic study after 3 months in order to have a very precise diagnosis and apply the best treatment.