Usually, the recurrent swelling of rheumatoid monoarticular joints is mainly due to joint cavity effusion, synovial hyperplasia, soft tissue edema and osteophytes. Joint fluid: Due to repeated inflammatory reactions in the soft tissues around the monoarticular joint, a large amount of joint fluid occurs, which may cause recurrent swelling of the monoarticular joint, accompanied by pain. Synovial lesions: Synovial lesions of the unicompartmental joint may occur, including synovial inflammation, intrasynovial tissue hyperplasia, and synovial fibrous tissue hyperplasia. In the early stages, synovial inflammatory changes may resolve or disappear after the inflammation subsides and the joint swelling resolves. Soft tissue edema and osteophytes: As the disease progresses, soft tissue edema and osteophytes can occur, resulting in recurrent swelling of a single joint. It is recommended that patients with rheumatoid monoarticular recurrent swelling go to the hospital in time and follow the doctor’s instructions for treatment to avoid delaying the condition.