The impact of the acetabular component position on the rate of the polyethylene liner wear and periprosthetic osteolysis: a clinical case

Introduction Osteolysis is a common problem in the long-term outcome after total hip arthroplasty, since the wear of a polyethylene liner is an inevitable process. However, its pace depends on many factors and not all of them have been proven. In particular, many studies do not find a connection between the wear rate of the liner and the position of the acetabular component. The purpose of this publication is to demonstrate the importance of correct acetabular component positioning. Methods A clinical case of bilateral total hip arthroplasty with follow-ups after 17 and 19 years is presented. The patient was operated being 31 and 33 years old, respectively, by one surgeon. The same type of the acetabular component was installed with the same type of polyethylene and friction pair diameter. It eliminates implant or surgical approach factors and patient characteristics. The position of the implant components is then remains the most important factor. For analysis, there were radiographs before the operation, at different times after it, CT data and intraoperative photos during the revision surgery. Results At the time of the last examination, there were minor manifestations of retroacetabular osteolysis that were better seen in CT and were more pronounced on the right. CT radiometry data on the angles of inclination of the acetabular components were 50.6° and 46.7° on the right and left, respectively, and the anversion was 40.3° and 25.4°. Revision of the right total hip arthroplasty was performed and it was found that the liner wear extended till the metal layer. Given good fixation of the cup, only the liner was exchanged and osteolytic cavities were filled with allogenic bone chips. Discussion The case can be considered a very good result of primary arthroplasty as revision surgery in this young patient was performed only after 17 years. However, in the contralateral joint the implant with the same pair of friction has survived for 19 years and at the moment it is early to decide on its revision. In our opinion, this case is an excellent illustration of the importance of the correct positioning of implant components.