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

Abstract

BackgroundUnicompartmental 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. MethodsA 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. ResultsThe 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). ConclusionYounger 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 evidenceIII.