Indications for knee arthroscopy include: First, knee arthroscopy is a diagnostic tool to diagnose and explore some knee diseases that are not diagnosed preoperatively. Secondly, it is used for meniscus molding or resection surgery. Third, it is used for the cleaning of various synovitis, such as rheumatoid, gout, etc. Fourthly, it is used for the cleaning of septic arthritis and the placement of tubes. Fifth, for the treatment of tuberculosis. Sixth, the free body in the joint is removed again. Seventh, for age-related osteoarthritis, it can also be cleaned up by arthroscopy. Eighth, adjuvant treatment of intra-articular fractures. Ninth, the treatment of intra-articular ligament injury, reconstruction and repair. Contraindications to arthroscopy are, first, systemic or local infection that may cause joint infection. Secondly, the joint space is particularly narrow and the arthroscope cannot be reached in.