Knee joint 1, knee joint diagnostic examination: including examination of knee joint disorders with unclear clinical diagnosis, biopsy of intra-articular lesions, diagnostic confirmation before open surgery, preoperative evaluation of total knee replacement or high tibial osteotomy in single-compartment osteoarthritis, etc., so as to obtain intuitive information about the condition; 2, total resection, subtotal resection, partial resection, suture and discoidal chondroplasty for meniscal or discoidal cartilage injury and degeneration; 3, synovitis of different types, including rheumatoid arthritis and other synovial lesions Disc cartilage forming; 3, synovial biopsy and synovectomy for different types of synovitis, including rheumatoid arthritis and other synovial lesions; 4, joint debridement and irrigation and drainage for septic arthritis; 5, removal of foci of tuberculosis of the knee; 6, resection of wrinkles and splits of synovial strangulation syndrome, and 7, resection of fat pads of hyperplasia and thickening; 8, removal of synovial chondroma and other causes of intra-articular fossilized or intra-articular Removal of foreign body; 9, joint flushing and joint cleaning and cartilage scratching, drilling and shaping of osteoarthritis; 10, repositioning and internal fixation of exfoliative osteochondritis or intra-articular fracture; 11, repair or reconstruction of cruciate ligament injuries; 12, release of the lateral support band and tightening and suturing of the medial support band of patellofemoral arthropathy due to patellar subluxation or subluxation; 13, crystal removal of gout of knee joint. Removal. With the increase of knowledge of shoulder joint pathology and mechanics, in the past, with the traditional method of open surgery, the structural damage to the shoulder joint may be missed, and arthroscopy can be clearly diagnosed. In the early stage of mild shoulder instability (shoulder instability can cause superior glenoid labral injury, anterior and posterior superior glenoid labral injury, and secondary rotator cuff injury), shoulder arthroscopy can be used to directly target the cause of the injury for etiologic treatment, especially in the case of rotator cuff injuries due to shoulder instability. 2. Arthroscopy can also be used to diagnose the posterior free body of the shoulder, which is often missed by incisional surgery, and can also be used to evaluate the original damage of the rotator cuff. The arthroscope can also be used to confirm the diagnosis of the posterior free body of the shoulder, which is often missed by the incision surgery, and to evaluate the original damage of rotator cuff. Arthroscopy prior to incision can determine the quality of the rotator cuff to determine the likelihood of reparative surgery; 3. Arthroscopic debridement and acromioplasty may be used as an alternative to incision for some rotator cuff tears; 4. Arthroscopic debridement may also be performed for calcific tendonitis or septic arthritis; 5. Arthroscopic indications include the diagnosis and treatment of anterior instability with glenoid labral tearing; 6. Biopsy and synovectomy in case of infection, diagnosis and treatment of osteochondral injury; 7. Treatment of frozen shoulder. We believe that it is easier to first perform gentle manipulation on frozen shoulder and then perform arthroscopic examination to further understand the partial tear injury of rotator cuff. If a partial tear of the rotator cuff is found, debridement can be performed. In frozen shoulder syndrome, extensive shoulder arthroscopy should be avoided to avoid increasing the chance of adhesions; 8. Traumatic shoulder dislocation combined with Bankart injury. Third, elbow joint 1, examination and removal of free body; 2, examination and treatment of humeral tuberosity exfoliative osteochondritis; 3, examination and treatment of radial head cartilage and osteochondral injuries; 4, excision of humeral or ulnar hawksbill fossa osteochondrosis; 5, partial synovial membrane excision, especially rheumatoid; 6, traumatic or degenerative elbow adhesion debridement and laxity; 7, painful elbow examination (when other diagnostic examinations When other diagnostic tests cannot confirm the diagnosis), elbow arthroscopy can be applied for debridement of ulnar falciform bursa. IV. Carpal joint 1, carpal arthritis; 2, carpal joint free body; 3, triangular fibrocartilage complex injury. V. Ankle joint 1, synovectomy:Conservative treatment is ineffective synovitis, including rheumatoid arthritis, pigmented choriocapillaris nodular synovitis and synovial chondromatosis, arthroscopic synovectomy can be used. This procedure is technically demanding, and limited arthrotomy synovectomy may be a better choice for some patients; 2, septic arthritis debridement: septic arthritis can be treated by arthroscopic debridement and thorough flushing with 8~10 liters of saline. Cultures should be done before flushing. Drainage tubes are retained in the via for 36~48 hours, during which time the ankle joint is immobilized with a splint. If the inflammation subsides, active mobility exercises should be started; if it does not subside then re-flushing and debridement should be considered; 3. Ligament reconstruction for ankle injuries; 4. Drilling, resection or pinning fixation for exfoliative osteochondritis:Berndt and Harty divided osteochondral injuries to the talar dome into four phases: phase Ⅰ, compression of the subchondral bone; Ⅱ, partial separation of the osteochondral fragments; Ⅲ, complete separation of the fragments but still in the bone Stage Ⅰ, the osteochondral fragments are partially separated; Stage Ⅲ, the fragments are completely separated but still in the bone defect; Stage Ⅳ, the osteochondral fragments are free. Highly resolved CT scan and MRI are helpful for the correct staging and treatment; 5. Bone resection of anterior impingement syndrome: Anterior impingement that causes pain, swelling, and limitation of activities can be treated by arthroscopic resection of bone fragments. Impact injuries can be excised with a bone cutter or grinding drill. Inflammatory soft tissue around the injury is carefully removed with a razor-like planer to improve visualization of the lesion; 6. Ankle fusion. Sixth, hip joint 1, the most common indication is free body removal; 2, including synovial biopsy or synovectomy for rheumatoid arthritis or pigmented villous nodular synovitis; 3, arthroscopy can also be used to check the unexplained painful hip that is ineffective for conservative treatment; 4, removal of the intra-articular bone cement; 5, removal of torn acetabular rims and round ligament insertion has been reported; 6, can be used arthroscopically for the early stage of Arthroscopic irrigation and debridement of early septic arthritis.