ObjectiveTo investigate the effect of different saline irrigation volume under arthroscopy on early postoperative pain and swelling of the knee.MethodsThe clinical data of 539 patients with meniscus injury treated by arthroscopic menisci reformation who met the selection criteria between July 2016 and February 2020 were retrospectively analyzed. They were divided into three groups according to the continuous saline irrigation volume during the operation: 176 patients in the non-irrigation group (group A), 183 patients in the 1 liter-irrigation group (group B), and 180 patients in the 3 liters-irrigation group (group C). There was no significant difference in gender, age, cause of injury, sides of injury, body mass index, disease duration, smoking history, and classification of meniscus injury among 3 groups (P>0.05). At 6, 12, 24, 48, and 72 hours after operation, the patient’s pain level was evaluated by the visual analogue scale (VAS) score, and the knee swelling situation was evaluated by the swelling ratings (the difference between both sides in circumference of the 2 cm upper patella of the knee). Knee skin temperature (the difference of the skin temperature between both sides) and the C-reactive protein (CRP) level in serum were measured at the 1st and 3rd days after operation. Range of motion of the knee was measured at the 1st, 3rd, and 5th days after operation.ResultsAll incisions healed by first intention without any complication after operation. The VAS scores of each group showed a slow increase trend after operation, and gradually decreased to less than the VAS score of 6 hours at 48 hours after operation. There was no significant difference in VAS scores among the 3 groups at each time point after operation (P>0.05). The swelling ratings of the knee in each group showed a gradually decrease trend after operation. There was no significant difference in the swelling ratings of the knee among the 3 groups at each time point after operation (P>0.05). The skin temperature of the knee in each group decreased at the 3rd day after operation than the 1st day, and there was no significant difference in the skin temperature of the knee among the 3 groups at each time point after operation (P>0.05). There was no significant difference in CRP level within the group and among the 3 groups at each time point after operation (P>0.05). Range of motion of the knee in each group increased gradually at the 1st, 3rd, and 5th days after operation, and there was no significant difference among the 3 groups at each time point after operation (P>0.05).ConclusionThe different continuous saline irrigation volume would not affect the early postoperative pain, swelling, and inflammation of the knee during the arthroscopic menisci plasty.