Cementless versus cemented unicompartmental knee arthroplasty: a systematic review of comparative studies

There are still some controversies regarding the clinical use of cementless UKAs. The aim of this systematic review was to determine whether cementless medial UKA leads to similar outcomes compared to cemented medial UKA. This search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews guidelines (PRISMA). The random effects model with 95% confidence interval (CI) was applied to the analysis. The I² statistic was used to assess study heterogeneity. Six studies were eligible for inclusion (4784 UKAs, 4776 patients): 2947 cemented UKAs (61.6%) and 1837 cementless UKAs (38.4%). The overall mean follow-up was 4.9 years. The all-cause reoperation rate was 11.3% (80 of 706) at mean 5.7-year follow-up for cemented UKA and 6.9% (57 of 824) at mean 4.1-year follow-up for the cementless. The overall revision rate was 10.2% (303 of 2947) for the cemented and 5.8% (108 of 1837) for the cementless. Aseptic loosening was the most frequent reason of revision (2.3% cemented vs 0.5% cementless). The overall rate of radiolucent lines (RLL) was 28.3% (63 of 223) in the cemented cohort and 11.1% in the cementless (26 of 234). All the studies reported improved functional outcomes. Cementless UKA provides at least equivalent if not better results compared to cemented UKA. Despite the use of cemented UKA outnumber cementless fixation, available data shows that cementless UKA had a reduced midterm revision rate, while providing similar functional outcomes.