Iranian Journal of Orthopedic Surgery

Abstract Introduction: Hip dysplasia can be associated with early degenerative changes. Different values have been reported for incidence of hip dysplasia in different countries. In the current study, we are reporting on the incidence of hip dysplasia in a group of normal Iranians evaluated by measuring the morphologic parameters of acetabulum on radiographs. Materials and Method: 586 hips (293 person) were enrolled in this study. On anteroposterior hip radiographs, the following 5 parameters were measured: Central edge angle (CEA), acetabular angle (AA), acetabular depth (AD), acetabular roof obliquity (ARO) and roof angle (RA). The normal and abnormal values were obtained in different sexes and compared with the known normal values in orthopaedic literature. Furthermore, the correlation between the above measurements was investigated. Results: Based on CEA, 15 (2.6%) of hips were dysplastic:-0.7% definite and 1.9% mild. 19 hips (3.2%) were dysplastic when using AA values. AD and RA were significantly higher in males. Except for lack of correlation between AA and AD, the other parameters -in particular, CEA and AA- were closely correlated. CEA, AA, ARO and RA were significantly different between dysplastic and non-dysplastic hips. Conclusion: Definite or mild dysplasia was recognized in 0.7% and 1.9% of the “normal” population that was studied. Since CEA was the same between males and females and was correlated with all other morphologic parameters, it seems that CEA is a useful measurement to evaluate presence of hip dysplasia.