The aim of the study is a retrospective evaluation of our patients with a dysplastic acetabulum treated by total hip arthroplasty (THA), who were followed up for at least 5 years, and a comparison of our intermediate-term results with those in the relevant literature.
In the period from June 1995 to June 2005, a total of 1305 total hip replacements were performed. Of these 293 were done in patients (213 women and 48 men) with the diagnosis of a dysplastic acetabulum; bilateral total hip arthroplasty was carried out in 18 women and four men. The evaluation was based on the Harris scoring system. The condition of at least 5-year follow-up was met by 65 patients (54 women and 11 men; average age, 53 years; average follow-up, 82 months). Eventually, 63 patients were assessed, because one patient died and one moved away.
The Hartofilakidis radiological system was used for preoperative evaluation. In more severe cases, 3D CT and multiplanar reconstruction were used. Intraoperative findings were assessed by the AAOS classification, and postoperative radiograms were evaluated on the basis of Gruen's criteria. The Bauer transgluteal approach to the hip joint was used. Antibiotics in prophylactic doses and medication for prevention of thromboembolic disease were administered in all cases. The final assessment of Harris hip scores was carried out in 63 patients in September and October 2005. All underwent implantation of a Zweymüller Bicon-Plus acetabular component. As diagnosed according to the Hartofilakidis radiological system, 42 type I, 21 type II and two type III hips were operated on for a dysplastic acetabulum.
The average preoperative and postoperative Harris scores were 39 (range, 21-58) and 85 (range, 66-98) points. All patients reported satisfaction with the results; excellent outcomes were achieved in 41, good in 10 and satisfactory in six patients. No radiographic cup loosening was found at 3- and 6-month follow-up or at 1 year. None of the patients received a solid bone graft.
The crucial problem in treating hip arthritis due to acetabular dysplasia is precise surgical reconstruction of the acetabulum. This involves implantation of an acetabular component into the original anatomical position in order to sufficiently cover the cup and provide mechanical stability. Various operative procedures discussed in the literature include the use of a small cup placed into the original acetabulum, techniques of acetabular component medialization, with perforation or "controlled fracture" of the acetabular wall, when indicated, and involvement of bone grafts to repair the acetabular defect in both cemented and cementless acetabular components.
Our intermediate-term results with the use of Zweymüller Bicon-Plus acetabular components give support to the previous good experience with this prosthesis in the treatment of hip arthritis following acetabular dysplasia.