Table 10.4 summarises the studies of UKA other than the Oxford Knee that give 10-year survival or longer. Argenson reports a 20-year survival in a series of 160 Miller-Galante of 74% (95% CI 67 – 81) (Argenson et al, 2013). This series is independent. In the designer series of 68 reported by Foran, the survival was 90% (Foran et al, 2013). A single large series of St Georg Sled from Bristol has been reported at various time intervals. The 10-year survival was 88% and, of those reaching 10 years, 86% survived to 20 years. This suggests the overall survival at 20 years was 75% (Steele et al, 2006).
Table 10.4
Six studies report the results of the Marmor with 10-year survival ranging from 70% – 93%. The majority of revisions (42/70, 60%), were for loosening or subsidence with a particular problem reported for smaller sizes. Of the remaining reasons for revision, the commonest was disease progression. Five 10-year studies exist on the Miller-Galante with survival ranging from 74% – 95%. The commonest reason for revisions (25/47, 53%) was disease progression either in the lateral or patellofemoral joint. Wear (17%) and loosening (13%) are other major reasons for revision.
Parratte et al. (2012) compared the long-term survival and function of 79 fixed and 77 Phase 2 mobile bearing UKAs implanted between 1989 and 1992 (mean age was 63 years). The mean Knee Society Scores and range of movement were not significantly different in the two groups. At final follow up, considering revision for any reason, 12 of 77 (15%) UKAs were revised (for aseptic loosening, dislocation, and arthritis progression) in the mobile-bearing group and 10 of 79 (12%) in the fixed-bearing group (for wear and arthritis progression). The authors concluded that although there were no differences in the outcome or survivorship between fixed and mobile bearing UKAs, the failure mechanisms were different (wear for fixed bearing and progression of arthritis for the mobile bearing).
