Background As an antifibrinolytic agent, tranexamic acid (TXA) is increasingly used in total knee arthroplasty (TKA) to reduce blood loss. The administration of intravenous and intra-articular TXA has been well explored, but the most efficient way to administer TXA remains in question. Peri-articular injection (PAI) of TXA is a recently mentioned method. A meta-analysis of the efficacy of PAI TXA in patients after TKA should be performed. Methods A systematic search was performed within PubMed, Embase, and the Cochrane Library up to November 8, 2021. Two authors independently screened studies for eligibility and extracted data for analysis. The primary outcome was haemoglobin change. The secondary outcomes were haematocrit change, total drainage volume, thromboembolic events, and blood transfusion. Results A total of ten studies were included in this meta-analysis. The results indicated that there was a significant decrease in haemoglobin change when using PAI TXA compared with no TXA (mean difference − 1.05; 95% CI − 1.28 to − 0.81; P < 0.00001; I2 = 0%), but it had no significant differences compared with IA and IV (mean difference − 0.01; 95% CI − 0.17 to − 0.14; P = 0.85; I2 = 39%). There were no significant differences between the TXA < 1.5 g subgroup (0.10, 95% CI − 0.27 to 0.46; P = 0.60; I2 = 0%) and the TXA ≥ 1.5 g subgroup (0.18, 95% CI − 0.12 to 0.48; P = 0.24; I2 = 74%). In addition, the combined group (PAI plus IV or IA) was superior to the IV or IA group in terms of haemoglobin change (mean difference − 0.51; 95% CI − 0.76 to − 0.27; P < 0.0001; I2 = 19%). Regarding haematocrit change, the pooled result showed it was significantly less in the PAI group than the non-TXA group. Similarly, comparing it against the IV subgroup, the result revealed a difference in favour of the PAI group, with a mean difference of − 1.89 g/dL (95% CI − 2.82 to − 0.95; P < 0.0001; I2 = 67%). For total drainage volume, the pooled result was in favour of PAI TXA over no TXA (297 ml, 95% CI − 497.26 to − 97.23; P = 0.004; I2 = 87%), but it had no significant difference compared with IA and IV (mean difference − 37.98; 95% CI − 115.68 to 39.71; P = 0.34; I2 = 95%). There was no significant difference in thromboembolic events (OR 0.74; 95% CI 0.25 to 2.21; P = 0.59; I2 = 0%). Blood transfusion was not significantly different between the PAI group and the non-TXA group (OR 0.50; 95% CI 0.23 to 1.06; P = 0.07; I2 = 21%), and there was no significant difference between PAI and the other two TXA injection methods (OR 0.72; 95% CI 0.41 to 1.25; P = 0.24; I2 = 19%). Conclusion PAI has comparable effects to IV and IA injections. PAI is an alternative injection route of TXA for patients who have undergone TKA.

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