An integral analysis of the acetabular parameters for the pathomorphological evaluation of dysplastic hip arthritis.

Abstract

integral analysis of the acetabular parameters for the pathomorphological evaluation of dysplastic hip arthritis. ABSTRACT. Background. Despite the successes in the hip arthroplasty the incidence of complications in cases of dysplastic hip arthritis remains higher then after other forms of hip arthritis. Objective. To pick up the anthropometric criteria of dysplastic acetabulum that determine the correct implantation of the hip implant's cup. Methods. X-ray anthropometric analysis was carried out for 194 dysplastic acetabula, which were divided into 4 groups according to classification by Eftekhar N.S. The same parameters of 70 normal acetabula are studied. Results. Petal diagrams with 4 axes were constructed to visualize the changes in the shape of the dysplastic acetabulum. On each axis of the diagram one of next parameters was deposited: the acetabular width and depth, the thickness of acetabular bottom and the index of the acetabulum, which is calculated as the ratio of depth to width. The indices of the normal acetabular parameters were taken as 1, and the dysplastic indices were expressed as fractions of 1. Variations in the shape of the acetabulum according to Eftekkar's classification are described. An algorithm of action for the implantation of the endoprosthetic cup is proposed for each type of deformation. Also the sketches of preoperative planning for each type of the deformation are presented. Discussion. The ratio of the depth of the acetabulum and the thickness of its bottom is the most significant for the correct implantation of the cup. This indicator enables to surgeon to make the decision about resection of the acetabular bottom during the preparing of the implant's bed. The acetabular width becomes the determining criterion for the dicision on requarment for bone grafting of acetabular roof only for types C and D by Eftekhar. Conclusion. The proposed technique allows to visualize the acetabular deformation from the position of hip replacement in cases of dysplastic hip arthritis. Also this one is suitable for other nosological forms of hip arthritis.