Unicompartmental knee arthroplasty (UKA) has a long history and has many advantages in some aspects over total knee arthroplasty (TKA) for patients with suitable indications, but it has not been established as a treatment at the same level with TKA. Therefore, 80 members of the British Association for Surgery of the Knee (BASK) and the European Knee Society (EKS) were invited to attend a joint meeting with the aim of creating an evidence-based consensus statement on UKA, in London, UK (December 2019). A formal consensus process was undertaken at the meeting incorporating a multiple round Delphi exercise, with group discussion of areas of agreement and disagreement between rounds. Five consensus statements were issued: ① UKA should be offered as a successful alternative to TKA in patients undergoing arthroplasty who meet agreed indications. ② When consenting a patient for UKA, information including the benefits and risks that are specific to UKA, should be tailored to and discussed with the individual patient. ③ Evidence suggests that surgeons should avoid low-volume use of UKA to optimise outcomes for their patients. ④ Surgeons should use the contemporary evidence-based indications and contraindications for medial UKA. ⑤ Knee arthroplasty surgeons should have exposure to and training in UKA. On the basis of full study of the consensus, combined with the Expert Consensus on Perioperative Management of Unicompartmental Knee Arthroplasty in China in 2020, this paper elaborates the meaning of the final evidence-based consensus for clinicians’ reference.