I. Indications Arthroscopy can be performed for any intra-articular lesion. With the exception of skin infections and bony ankylosis of the joints, diagnostic arthroscopy can be considered if there is a suspicion that a lesion exists within the joint. Depending on the results of the diagnostic arthroscopy, a decision is then made as to whether the management of the lesion will be accomplished arthroscopically or by incisional joint surgery. In orthopedics, arthroscopy is mainly used for the surgical treatment of sports injuries and arthritis; in rheumatology, arthroscopy is mainly used for the diagnosis of various arthritis. Contraindications 1, local skin infection: local skin infection can be brought into the joint through the arthroscope, which is an absolute contraindication to arthroscopic surgery. 2, serious narrowing of the joint space: patients with serious narrowing of the joint space, arthroscopy is difficult to enter, and microscopic surgery is difficult. The effect of arthroscopic surgery on advanced lesions also needs to be considered. 3, bleeding disorders: patients with severe bleeding disorders or bleeding tendency should ensure that the bleeding tendency is controlled before surgery. 4, invasion of bone lesions: some chronic arthritis in the advanced stage, such as pigmented villous nodular synovitis and rheumatoid arthritis, the lesions have invaded the subchondral bone, arthroscopic surgery can not remove the lesions invading the bone.