HIGHER REVISION RATES AND ASEPTIC LOOSENING WITH POSTERIOR-STABILISED TOTAL KNEE ENDOPROSTHESIS COMPARED TO THE CRUCIATE-RETAINING TYPE OF THE SAME IMPLANT MODEL- A SINGLE-CENTRE RETROSPECTIVE STUDY ANALYSING 580 TOTAL KNEE ARTHROPLASTIES.

The purpose of this study was to evaluate the 4-year survivorship of total knee arthroplasty (TKA) of a single manufacturer and determine whether failure rates differ between the cruciate-retaining (CR) and the posterior-stabilised (PS) type of implant. In addition, possible causes of revision were analysed as well. A retrospective analysis of 580 TKAs, with either the CR or the PS type of the Biotech Future Knee endoprosthesis (BIOTECH GmbH, Garbsen-Berenbostel, Germany) was performed. The 4-year survivorship for revision of any cause in all cases was 89.14%, with aseptic loosening being the most common cause of revision (53.9%). Regarding the type of implant model, the revision rate was higher in the PS group compared to the CR group (13.7% to 8.0%, respectively, p=0.027). The Cox regression models suggested that the type of prosthesis was a significant predictor of the need for revision (HR, 0.442; 95% CI, 0.234-0.833). In conclusion, our study has shown higher revision rates with the PS implant type when compared to the CR implant type with a higher rate of aseptic loosening in the PS group. Further studies are needed to determine the cause of these results and to investigate whether the problem is specific to the implant.