Total hip arthroplasty using cementless avantage cup in patients with risk of hip prosthesis instability.

BACKGROUND The aim of the study was to assess total hip arthroplasty procedures using the cementless Avantage cup in women with additional risk factors for postoperative hip instability. MATERIAL AND METHODS A total of 280 cementless Avantage and Avantage Reload cups were implanted in 260 women aged between 29 and 79 years (60.9 years on average) in the years 2004-2010. In 217 women, there was at least one additional risk factor for prosthesis dislocation. The survival of the cup was assessed by using the necessity of cup replacement as an endpoint of the study. The statistical analyses used the Fisher test to assess the difference in the necessity of revision surgery between the Avantage and Avantage Reload cups, and the Kaplan Meier method was used to evaluate the effective functioning time of the prosthesis. Additionally, tests were conducted on the surface layer of 2 not used and 4 removed cups. RESULTS 239 patients (259 arthroplasties) were subjected to the final examination. The follow-up period ranged from 2.7 to 9.7 years, 7.0 years on average. None of the patients demonstrated postoperative prosthesis instability. Aseptic loosening was observed in 19 cups in 18 women (7.3%). Intra-prosthetic dislocation occurred 4 times, and in two cases it was combined with loosening of the cup. Revision surgery was required more often in patients with the Avantage cup (9.5%, 17 out of 179) in comparison to the Avantage Reload (2.5%, 2 out of 80). However, the observed differences did not reach the level of statistical significance. The cumulative survival rate of the Avantage cup was 0.94 at 5 years and 0.86 at 8 years. CONCLUSIONS 1. Avantage cups reduce the risk of postoperative hip instability. 2. Patients with cementless Avantage cups should be closely monitored for signs of aseptic loosening.