Survival analysis of total knee arthroplasty at a minimum 10 years' follow-up: A multicenter French nationwide study including 846 cases

Introduction: Survivorship for modern total knee arthroplasties (TKA) is not precisely known from large series, other than registries. The present retrospective study therefore analyzed 846 TKAs at a minimum 10 years' follow-up. Hypothesis: Ten-year survivorship for TKAs in a multicenter study exceeds 90%, independently of design and level of prosthetic constraint. Materials and methods: Eight hundred and twenty-eight patients (846 TKAs) were assessed on the Knee Society score. Mean age was 71 years (range, 41-93 years); 274 males and 554 females (67%); 496 patients (60%) were active; diagnosis was principally osteoarthritis (n = 752 [89%]). Most TKAs were cemented (n = 704 [83%]), replacing the patella (n = 668 [79%]) and sacrificed the posterior cruciate ligament (PCL) (n = 707 [84%]), 65% being posterior-stabilized and 35% ultracongruent, with fixed (39%) or mobile bearing (61%). Results: At a minimum 10 years' follow-up, mean knee score rose from 35 (15-55) to 83 points (74-95), and functional score from 24 (5-45) to 74 points (60-90); mean flexion rose from 105 degrees (25-125 degrees) to 112 degrees (25-125 degrees). Mean hip-knee-ankle angle was 179.5 degrees (169-189 degrees). Sixty-three (7.5%) revision surgeries were required, mainly for loosening (n = 18 [2%]) or infection (n = 18 [1.8%]). Overall 10-year survivorship was 92% (95% CI: 0.90-0.94). There was no significant difference in survivorship according to implant design or PCL retention. Activity level correlated with revision rate; mechanical complications were more frequent in active and infectious complications in sedentary subjects. Revision was not more frequent in TKA aligned outside the 177-183 degrees range. Discussion: Ten-year TKA survivorship was 92%, independently of design and level of mechanical stress. Revision was mainly for infection or loosening, and not for greater than 3 degrees axis misalignment. Mechanical complications were more frequent in younger and more active subjects, for whom therefore other treatment options or technical improvements should be sought. Level of evidence: Level IV. Retrospective study. (C) 2013 Elsevier Masson SAS. All rights reserved.