Long-term results of fixed and mobile bearing designs in total KNEE arthroplasty

Total knee arthroplasty (TKA) procedure is being applied increasingly all over the world and in our country with high success rate in knee osteoarthritis. With decrease in the average age of individuals undergoing knee arthroplasty, patient expectations for prolonged survival of the prosthesis and clinical outcomes of surgery have recently increased substantially. In this study, we aimed to analyze long-term survival rate, clinical and radiological outcomes of posterior stabilized knee system. Between June 2002 and January 2010, 328 knees of 248 patients who underwent total knee arthroplasty with Nexgen LPS-Flex knee system in our department with a minimum 10 years of follow-up period were evaluated. The mean follow-up was 13.2± 2.1 years and 16.9% of the patients were men. The mean age was 67.2 years (25y-81y). In the majority of patients, the etiology was primary knee osteoarthritis (273 knees.) and rheumatoid arthritis (43 knees). Mobile insert was preferred in 69 knees while fixed insert was preferred in 259 knees. Clinical and functional evaluation of the patients was performed by using the American Knee Society Score and Turkish Adaptation of the Forgotten Joint Score (FJS). American Knee Society Knee and Function Scores, as well as ROM and tibiofemoral alignment, significantly improved at the latest follow-up compared to the preoperative period (p<0.05). Although there was no significant difference between fixed and mobile insert groups in terms of clinical parameters, there was a significant difference in terms of the Forgotten Joint Score applied at the latest follow-up period (p: 0.026). 17 patients required revision surgery and overall survival rate was 94.8% at the last follow-up. Conclusion: NexGen LPS-Flex knee system allows for satisfactory clinical and radiological results with 94.8% implant survival rate in 13.2 years. When the fixed group compared to mobile bearing counterpart at the end of the long follow-up period, there is a statistically significant difference in favor of the fixed insert group according to the Forgotten Joint Score.