A Comparison of Mobile and Fixed-Bearing Unicompartmental Knee Arthroplasty at a Minimum 10-Year Follow-up

• Published in: The Journal of arthroplasty Vol. 33; no. 6; pp. 1713 - 1718
• Main Authors: Neufeld, Michael E., Albers, Anthony, Greidanus, Nelson V., Garbuz, Donald S., Masri, Bassam A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-06-2018
• Subjects: Adult; Aged; Aged, 80 and over; Arthroplasty, Replacement, Knee - instrumentation; Cohort Studies; Female; fixed-bearing; Follow-Up Studies; functional outcomes; Humans; implant survival; Knee Joint - surgery; Knee Prosthesis - statistics & numerical data; Male; Middle Aged; mobile-bearing; Osteoarthritis, Knee - surgery; Patient Reported Outcome Measures; Prosthesis Design; Prosthesis Failure; Radiography; Retrospective Studies; revision; Tibia - surgery; Treatment Outcome; unicompartmental knee arthroplasty; fixed-bearing; functional outcomes; mobile-bearing; implant survival; unicompartmental knee arthroplasty; revision
• ISSN: 0883-5403; 1532-8406
• DOI: 10.1016/j.arth.2018.01.001

The long-term survivorship and functional outcomes of the mobile-bearing (MB) compared to the fixed-bearing (FB) unicompartmental knee arthroplasty (UKA) implant design remain a topic of debate. The aim of the current study was to compare the survivorship and functional outcomes of MB and FB UKA at a minimum 10-year follow-up.
We retrospectively reviewed 106 consecutive medial UKAs (89 patients) from our institution with a minimum 10-year follow-up. The 38 MB and 68 FB knees had follow-up of 14.2 years (12.9-15.5) and 11.5 years (10.2-15.1), respectively. Validated patient-reported outcomes and radiographs were evaluated as were etiology, timing, and complexity of revision. Kaplan-Meier 10-year survival was calculated with revision to total knee arthroplasty as the end point.
The 10-year survival was 82.9% (95% confidence interval [CI] 65.8-91.9) for MB and 90.9% (95% CI 79.4-96.2) for FB UKA (P = .102), and 88.0% (95% CI 79.3-93.2) for the entire cohort. Patient outcomes were similar between groups, as were timing and etiologies for revision to total knee arthroplasty. One-third of revisions required either stems or tibial augments, and of these, all were of MB design.
Survival and functional outcomes were similar between MB and FB designs. One-third of revisions required either stems or augments, all were of MB design.