Purpose of the study: The authors evaluated the mid-term results in 133 patients to whom 143 uncemented Beznoska (BMT) acetabular cups were implanted.
Material: A total of 143 acetabular cups were implanted to 133 patients in the period from 1994 to 2002. Thirteen patients died or dropped out of the study during follow-up.
Methods: The patients were followed up at 3, 6 and 12 months after surgery and then, according to their conditions, every one or two years. In each patient, the following information was recorded: age at the time of implantation, gender, pre-operative diagnosis, physical activity, body mass index, Harris hip score, acetabular cup size, stem type, cup and stem alignment immediately after arthroplasty, intra-operative complications, early complications during hospital stay, and late complications. Attention was paid to infection, aseptic loosening and polyethylene wear. Loosening of both the cup and the stem was evaluated in each zone, using the criteria of Krbec and Cech. Malalignment of the stem and cup as well as thinning of the acetabular wall, as signs of loosening, were also recorded.
Results: Of the 133 patients treated, 35 had poor results (24.5 %) and 17 of them underwent revision surgery. Deep wound infection was recorded in seven hips, the prosthesis was removed from six, and subsequently three of them had reimplantation. Loosening of the stem occurred in nine patients and two were revised. In three patients with a thin acetabular wall, indication for surgery was not correct; in another patient an operative fault occurred. All of them underwent revision arthroplasty. One hip showed asymmetric wear of the polyethylene liner without sings of acetabular cup loosening. Aseptic loosening was found in 15 patients (10.5 %), eight were revised. In the group of patients who had surgery 5 and more years before, 13 cups out of 81 implanted ones were loosened (16 %). In the group operated on at 8 and more years earlier, aseptic loosening was found in nine hips out of 49 (18.4 %). DISCUSSION The mid-term results of the use of uncemented Beznoska acetabular cups are fully comparable with those of cemented Beznoska acetabular cups. However, the outcomes initially hoped for in relation to this component have not been achieved.
Conclusions: The uncemented BMT acetabular cup cannot be recommended for the same indications as are those for which other uncemented components are used. It is not suitable for young and active patients under 70 years of age and for patients who have a thin wall of the acetabulum. Also, it is not recommended to combine this component with an uncemented femoral component. In our opinion, it is not suitable for revision hip arthroplasty, either.