Burn E, et al. - Authors attempted to estimate the value for money of unicompartmental knee replacement (UKR) compared with total knee replacement (TKR) using data from the National Joint Registry (NJR) for England and Wales. Better health outcomes and lower lifetime costs could be generated via UKR compared to TKR. Nevertheless, surgeon usage of UKR exerted a significant impact on the cost-effectiveness of the procedure. A sufficient proportion of knee replacements as UKR were required in order to achieve the best results. Hence, low usage surgeons would require a broadening of their indications for UKR.