RESUMO
Objective - to justify the use of hip endoprosthesis techniques in dysplastic coxarthrosis depending on the type of dysplasia according to Crowe JF. The study is based on the analysis of hip replacement in 390 patients with dysplastic coxarthrosis, who underwent 436 endoprosthetics. There were 192 patients with type 1 dysplasia according to Crowe, type II - 142, type III - 38 and type IV - 18 patients. The age of patients ranged from 15 to 61 years and averaged 43 years. Pathology was prevalent in women, which accounted for 90 %. Preference was given to prostheses with a cementless type of fixation, which accounted for 89 %. An important task of the surgeon during hip replacement in patients with dysplastic coxarthrosis is to install the acetabulum component of the prosthesis in an anatomical position in compliance with the recommendations of spatial location, especially in types III and IV of dysplasia. Endoprosthetics in types 1 and II of hip dysplasia did not present any difficulties. The amount of bone tissue of the acetabulum of the pelvis is sufficient for the use of cups with primary press-fit fixation. Usually, acetabular components of small size were used. In type III dysplasia, there was a significant deficit of bone tissue of the anterior, posterior columns and acetabular roof. In such cases, bone grafting is used. Shortening of the limb in type III dysplasia, as a rule, does not exceed 4 cm, so the surgery may be performed in one stage and without a shortening osteotomy. In type IV dysplasia with shortening of the lower limb to 4 cm, a single stage endoprosthetics is performed it is possible to perform a shortening osteotomy of the proximal femur. Ðn patients with a unilateral process and shortening of the limb more than 4 centimeters, we used the two-stage surgery method. At the first stage, we applied a rod device for external fixation with the introduction of rods into the pelvis and hip, then gradually performed hip traction in order to lower the femoral head to the level of the acetabulum, after which the device was dismantled and at the second stage hip replacement was performed. The acetabular component in hip replacement in Crowe type III or IV dysplasia should be placed in the anatomical position of the acetabulum. If the cranial displacement of the femoral head is less than 4 cm, hip replacement should be performed in one stage. In a unilateral cranial displacement of the femoral head of more than 4 cm, in order to avoid neurovascular bundle traction damage and facilitate the reduction of the prosthesis, preparation should be performed with the reduction of the femoral head to the level of the anatomical acetabulum using an external fixation rod device. It is possible to use a shortening osteotomy of the proximal femur, but then the length of the limb is not restored.
