The Effect of Age on the Relative Outcomes of Cemented and Cementless Mobile-Bearing Unicompartmental Knee Arthroplasty, Based on Data From National Databases.

ABSTRACT

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is an effective treatment for medial compartment arthritis. A challenge is that patients requiring knee arthroplasty are becoming younger. It is currently unknown what the relative performances of cemented and cementless UKAs are, in different age groups. METHODS: A total of 12,882 cemented and cementless UKAs from the National Joint Registry and Hospital Episodes Statistics databases were matched on patient and surgical factors. Patients were stratified into 3 groups (1) <60 years; (2) 60-69 years; and (3) ≥70 years. Revision and reoperation rates were compared using Cox regression analyses. RESULTS: The 10-year implant survival for the matched cemented and cementless UKAs for (1) <60 years were 81.4% (CI 73.6-87.0) and 86.7% (CI 80.7-90.9) (hazard ratio [HR] 0.73, CI 0.56-0.94, P = .02); (2) for 60-69 years were 91.8% (CI 88.9-94.0) and 94.5% (CI 92.9-95.7) (HR 0.90, CI 0.67-1.22, P = .51); and (3) ≥70 years were 93.5% (CI 91.1-95.3) and 94.2% (CI 92.0-95.8) (HR 1.0, CI 0.71-1.40, P = .99). The same trend was observed for reoperations. In the <60 years and 60-69 years groups there were significantly fewer revisions for aseptic loosening in the cementless group (0.5% versus 1.6% [P < .001] and 0.4% versus 1.3% [P = .002], respectively). CONCLUSION: Younger ages were associated with higher revision rates in both cemented and cementless UKA groups. Cementless fixation has reduced long-term revision rates compared to cemented fixation in the <60 years group with aseptic loosening rates 3 times lower. LEVEL OF EVIDENCE III.