Pigmented villonodular synovitis (PVNS) is a relatively rare invasive disease occurring in the synovial membrane, tendon sheath and bursa of the joint, divided into nodular and diffuse types, with an incidence of 1~2/1000000, characterized by atypical hyperplasia of the synovial membrane swelling in the tendon sheath and synovial membrane of the joint. The cause of the disease is not clear, and it is characterized by abnormal proliferation and easy recurrence. The lesions are mainly unilateral, commonly found in the knee (about 80%), hip (about 15%), shoulder, ankle and other joints, and in a few cases in the finger joints and temporomandibular joints. The patient’s symptoms are mostly swelling, pain, limited joint movement, and bloody fluid or coffee-colored puncture fluid can be seen in joint aspiration. Typical case: Patient Zhang XX, female, 24 years old, had recurrent swelling and discomfort in the right knee joint for more than 1 year. She was considered to have “hyperpigmented villous nodular synovitis” and underwent arthroscopic subsurface total synovectomy. The surgery was performed through several incisions of a few millimeters on the skin surface, and the diseased synovial tissue was completely removed under direct arthroscopic vision, minimizing recurrence after surgery. The procedure is minimally invasive, with beautiful incisions, minimal pain, rapid recovery and satisfactory results. In the treatment of dysplastic villous nodular synovitis, there is a consensus that surgery is preferred to completely remove the diseased synovial tissue and block its further invasion and damage to the articular cartilage, ligaments and surrounding normal tissues, and open incision often requires two incisions to completely remove the diseased synovial membrane, which has the advantage of clear exposure and complete cleanup, but at the same time, it is also traumatic, the incision affects the aesthetics, the patient suffers a lot, and the postoperative recovery and The advantages are clear exposure, complete debridement, but at the same time, the incision is very traumatic, the patient suffers a lot of pain, and postoperative recovery and rehabilitation are difficult. In medical centers, more and more surgeons prefer to use arthroscopic techniques for synovial resection, which can be done through anterior-external, superior-external, anterior-internal, posterior-external, and posterior-internal approaches, providing a clear and precise synovial resection with less injury, less pain, faster recovery of joint mobility, and satisfactory results.