Mobile- versus fixed-bearing total knee arthroplasty: a prospective randomized controlled trial featuring 6-10-year follow-up

Objective: The purpose of this study was to compare long-term clinical and radiographic outcomes of mobile-(MB) and fixed-bearing (FB) total knee arthroplasties (TKA). Methods: A randomized controlled study was conducted to compare the clinical and radiographic outcomes of MB and FB prostheses in 93 consecutive patients who underwent primary TKA for knee osteoarthritis. Mean follow-up of the patients was 100.9 months in the MB group (range: 78-121 months) and 93.7 months (range: 78-120 months) in the FB group. The clinical results were graded according to the Knee Society Knee Score (KSKS) and the Knee Society Functional Score (KSFS). Secondary outcomes included pain, patellofemoral joint function, quality of life (QOL), and radiologic outcomes (Knee Society's roentgenographic evaluation system). Results: Although there was significant improvement in both groups, there were no significant differences between the groups with respect to mean KSFS and radiologic outcomes. However, mean pain score of the MB group was significantly higher than that of the FB group (48.83 +/- 0.62 vs 47.39 +/- 0.86, respectively, p=0.011), and mean KSKS was significantly higher than that of the FB group (93.5 +/- 6.2 vs 89.7 +/- 6.9, respectively, p=0.007). Conclusion: TKA clinical results were satisfactory in both the MB and FB groups. KSKS and pain scores were significantly better in the MB than in the FB group. However, no differences were found in other assessments. Thus, we conclude that the best design is the one with which the surgeon is most comfortable and most able to implant reproducibly.