Hunt LP, Blom AW, Matharu GS, et al. - This study was intended to ascertain unicompartmental (UKR) and total knee replacement (TKR) revision rates, compare UKR revision rates with what they would have been having they received TKR instead, subsequent re-revision and 90-day mortality rates. Researchers applied the National Joint Registry data to calculate UKR and TKR revision and mortality rates. They applied Flexible Parametric Survival modelling to model failure in TKR and make estimates for UKR. They applier Kaplan-Meier estimates to compare cumulative re-revision for revised UKRs and TKRs. In comparison with TKR, UKR revision rates were substantially higher even when demographics and caseload differences were accounted for, nevertheless fewer deaths occur after UKR. This should be recognized when forming treatment guidelines and commissioning services. They found similar re-revision rates between revised UKRs and TKRs, but considerably higher than for primary TKR, therefore UKR cannot be recognized as an intermediate procedure.