Fluid accumulation one month after minimally invasive meniscus surgery may be caused by improper postoperative care, septic arthritis, proliferative arthritis and other factors. 1. Improper postoperative care: When patients fail to take good care of themselves after minimally invasive meniscus surgery, they have to do physical labor for a long time. This can lead to the emergence of effusion one month after the meniscus minimally invasive surgery. 2. septic arthritis: If the patient is not properly operated during the minimally invasive meniscus surgery, the bacteria and viruses will invade the affected area and induce septic arthritis. The condition will be aggravated, which will lead to the accumulation of fluid one month after the minimally invasive meniscus surgery. 3. Proliferative arthritis: in daily life, if the patient’s meniscus is seriously damaged, one month after the minimally invasive meniscus surgery, he fails to strictly follow the doctor’s instructions for maintenance. It induces hyperplastic arthritis disease, which stimulates the affected area, making the meniscus minimally invasive surgery one month with fluid accumulation. It is recommended to seek medical attention for a comprehensive examination to avoid self-diagnosis and treatment and delaying the treatment time if there is fluid accumulation one month after minimally invasive meniscus surgery.