Mid-term results after implantation of rotating-hinge knee prostheses: primary versus revision

The aim of the study was to evaluate the mid-term clinical results and survivorship of a rotating-hinge knee prosthesis (LINK (R) EndoModel) in difficult primary and complex revision situations. Results after primary implantation were compared with those of revision procedures. Forty-nine prostheses in 45 patients were reviewed clinically during follow up. Twenty-one of these were implanted in primary and 28 in revision situations. Outcome was evaluated using commonly used scores (Knee Society, UCLA Activity, Lequesne) and a visual analog scale after a mean follow up of 56 +/- 37 months for 49 prostheses. Implant survival was analyzed using the Kaplan-Meier method. There were no significant differences in clinical examination and evaluation scores between the two groups (P> 0.05). Survival rates at final follow up were 95% after primary implantation and 76% in revision procedures. The risk of prosthesis loss (odds ratio 5.7) was significantly higher after revision procedures (P= 0.004). These data suggest that rotatinghinge knee prostheses provided good clinical and functional results in selected cases of advanced primary gonarthrosis associated with severe bone loss, ligamentous instability or comminuted fractures. They also provide good results in revision situations. However, the failure rate was significantly higher in cases of revision surgery.