Anatomical description and classification of hip dysplasia

Abstract

Developmental dysplasia of the hip (DDH) consists of several morphologic abnormalities caused by intrauterine mechanical factors leading to dysplastic changes of the femoral and acetabular sides that continue until the bones reach maturity. In the literature, many classification systems for hip dysplasia have been described. The goals of these classification systems are to better understand the pathology, to achieve better communication among physicians, to establish better treatment planning, and to evaluate better the results of various treatment options. The different classification systems described for hip dysplasia vary according to the radiological modality used, i.e., ultrasound, X-ray, and CT, according to the skeletal age and ossific center maturation. Classification systems for hip dysplasia could also be categorized either as those that grade the degree or direction of dysplasia or as those that grade the degree of displacement of the femoral head. Although a single classification system does not exist for DDH throughout all ages due to the vast spectrum of the disorder, familiarity of the aforementioned classifications is important.