Güzel 2016.

Methods	Participants undergoing unilateral total knee arthroplasty (TKA) were randomised to one of three groups. The method of randomisation and allocation concealment is not described. The blinding status of participants, study personnel, and outcome assessors is not described. The study is described as randomised in both the abstract and methods; however, the discussion describes its retrospective nature as a limitation. We emailed the authors for clarification (5 December 2022).
Participants	176 people undergoing primary unilateral TKA were randomised to one of three groups: PAT group (Postoperative autologous transfusion) (Autotransfusion group): N = 50. M:F 8:42. Mean (SD) age 66.9 (5.1) Topical TXA group: N = 50. M:F 7:43. Mean (SD) age 66.5 (5.1) Routine drainage group (Control group): N = 50. M:F 10:40. Mean (SD) age 67 (4.5) The groups were comparable for age, gender, and preoperative haemoglobin level at baseline.
Interventions	PAT group (Postoperative autologous transfusion) (Autotransfusion group): the CellTrans (SUMMIT, Gloucestershire, UK) autologous transfusion drain was used. A drain was inserted into the knee joint at the end of TKA, and low suction drainage was started 30 minutes later. If more than 150 mL of blood had accumulated within 6 hours, it was re‐infused into the patient. After that, the system was used as a normal closed drain system. Topical TXA group: a drain and injector tip were placed within the joint before closing the arthrotomy. The drain was clamped and 12.5g TXA (Transamine, FAKO, Istanbul, Turkey) diluted in 100 mL normal saline was injected intra‐articularly via the injector tip. The drain was released after 1 hour. Routine drainage group (Control group): a low‐suction drain was placed in the knee joint and removed after 24 hours. The relevant group comparison eligible for inclusion in this review is PAT group versus routine drainage group.
Outcomes	Outcomes reported: lowest postoperative haemoglobin concentration, drain volume, number of participants who received allogeneic blood transfusion, total transfusion cost, acute infection, deep venous thrombosis, pulmonary embolism, myocardial infarction, stroke
Notes	Transfusion protocol: blood transfusion was indicated when the haemoglobin level fell below 8 g/dL (80 g/L) or the patient was symptomatic of anaemia. Prospective registration status: the registration status of the study is not known. Ethical approval: the study was approved by the ethics committee associated with Ordu University Medical School, Turkey. Language: the study is published in English. Reason for awaiting classification status: the study is described as randomised in both the abstract and methods; however, the discussion describes its retrospective nature as a limitation. We emailed the authors for clarification (5 December 2022).