Publication 2026 Recently added
A Comparison of the Outcomes of Simultaneous Bilateral and Unilateral Mobile-Bearing Unicompartmental Knee Arthroplasties: An Analysis of Data from the National Joint Registry of England, Northern Ireland and Isle of Man
Citation
Mohammad, H. R., A. Judge and D. W. Murray (2026). JB JS Open Access 11(1)
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Background
Unicompartmental knee arthroplasty (UKA) is an effective treatment for unicompartmental end-stage knee arthritis. Simultaneous bilateral UKAs for patients with bilateral knee arthritis can reduce costs, number of anesthetics, and overall rehabilitation time. It is unknown how the long-term outcomes of unilateral and simultaneous bilateral UKAs compare.
Methods
In total, 1,939 unilateral and 1,939 simultaneous bilateral medial mobile-bearing UKAs (n = 3,878) from the National Joint Registry were propensity score matched. Kaplan-Meier and Cox regression were used to compare implant survival, revision indications, and mortality.
Results
The 10-year implant survival in the simultaneous bilateral group was 92% (95% confidence interval [CI] 90-94) and in the unilateral group was 90% (95% CI 88-92). The simultaneous bilateral group had a lower revision risk (hazard ratio [HR] 0.73, p = 0.01). Revisions for pain were lower in the bilateral group (0.5% vs. 1.2%, p = 0.01). There were no differences in patient mortality. Subgroup analyses found similar trends in 10-year implant survival and revision risk with both cementless (simultaneous bilateral 98% CI 95-99; unilateral 95% CI 91-98; HR 0.66, p = 0.27) and cemented fixation (simultaneous bilateral 91% CI 89-93; unilateral 90% CI 88%-92%; HR 0.85, p = 0.28).
Conclusions
Simultaneous bilateral UKAs had better 10-year implant survival and similar mortality to compared with single-unilateral UKAs. For patients with severe symptomatic bilateral unicompartmental knee osteoarthritis, simultaneous bilateral UKAs could be considered to be a safe and effective procedure, particularly as only one operation and postoperative recovery is required. LEVEL OF EVIDENCE: Level IV. See Instructions for Authors for a complete description of levels of evidence.