Eighteen-Year Outcome of an Uncemented "Meniscal Bearing", Cruciate-Retaining Total Knee System

Background: The aim of this study is to evaluate the survival, radiographic, and functional outcomes of the uncemented "meniscal bearing" cruciate-retaining Low Contact Stress (LCS) (DePuy Synthes, War-saw, IN, USA) total knee system after a long-term follow-up period. Methods: A total of 56 patients (67 knees) who received an uncemented "meniscal bearing" cruciate-retaining LCS total knee system between 2000 and 2005 were retrospectively reviewed. Patients were 64 +/- 7 years old with osteoarthritis as the indication for arthroplasty. The survivorship, radiographs, and patient-reported outcome measures (PROMs) were analyzed. Results: The all-cause survival after 5, 10, 15, and 18 years was 97.0%, 93.8%, 92.0%, and 92.0%, respec-tively. Survival with revision for aseptic loosening as an end point was 98.4% at 5 years and 96.7% at 10, 15, and 18 years. Reasons of revisions and their interventions consisted of anterior knee pain requiring secondary patellar resurfacing (n = 3, 60%), polyethylene wear requiring an insert exchange (n = 2, 40%), and bearing spin-out requiring an insert exchange (n = 1, 20%). Two of the 5 revision cases developed aseptic loosening of the tibial component later on during the study period. A radiographic analysis demonstrated radiolucent lines in 14/47 implants (30%) after 12.0 +/- 3.8 years, but were not revised, respectively. After a mean follow-up of 18.5 years, PROMs (n = 20) were found comparable with the 1 -year postoperative PROMs of all implants reported by the LROI (Dutch Arthroplasty Register). Conclusion: This present study demonstrates good results of the uncemented "meniscal bearing" cruciate-retaining LCS total knee system toward survival and functional outcomes after a long-term median follow-up of 17.5 years. Level of Evidence: Therapeutic retrospective cohort study, LEVEL III. (c) 2022 Elsevier Inc. All rights reserved.