OBJECTIVE:To investigate the effects of intra-articular injection of tranexamic acid on joint swelling,pain and recovery of joint function in patients with simple meniscus injury. METHODS:A total of 62 patients with simple meniscus injury receiving arthroscopic surgery of the knee in orthopedics department of Chongqing people's hospital during Oct. 2016-Apr. 2017 were selected and divided into control group and observation group according to random table,with 31 cases in each group. Both groups received meniscus excision or trimming under knee arthroscopy. Control group was given intra-articular injection of 0.9%Sodium chloride injection 10 mL after wound suture. Observation group was given intra-articular injection of Tranexamic acid for injection 2.0 g added into 0.9% Sodium chloride injection 10 mL after wound suture. The drainage tube was not placed in all the patients,The tourniquet was loosened after the pressurized dressing of wound. Circumferential diameter of the knee and VAS scores of 2 groups were observed before surgery,1,3,5 and 7 d after surgery. Lysholm scores were observed before and one month after surgery. The occurrence of ADR was recorded. RESULTS:There was no statistical significance in circumferential diameter of the knee,VAS score or Lysholm score between 2 groups before surgery(P>0.05). 1,3,5 and 7 d after surgery,circumferential diameter of the knee in 2 groups was significantly bigger than before surgery,but the observation group was significantly smaller than the control group 1,3 d after surgery,with statistical significance(P<0.05). There was no statistical significance in circumferential diameter of the knee between 2 groups 5 and 7 d after surgery(P>0.05). VAS score of observation group 1,3 d after surgery and control group 1,3 and 5 d after surgery were significantly higher than before surgery,but the observation group was significantly lower than the control group 1,3,5 d after surgery,with statistical significance(P<0.05). There was no statistical significance in observation group 5,7 d after surgery and control group 7 d after surgery,compared to before surgery and 7 d after surgery(P>0.05).One month after surgery,Lysholm scores of 2 groups were significantly higher than before surgery,and the observation group was significantly higher than the control group,with statistical significance(P<0.05). No severe ADR was found in 2 groups during medication,and there also was not deep venous thrombosis after surgery. CONCLUSIONS:Intra-articular injection of tranexamic acid can effectively reduce the degree of early knee swelling after knee arthroplasty,relieve postoperative early pain.It promotes the recovery of knee function with good safety.