Recently, our joint surgery department successfully managed a patient with pigmented villous nodular synovitis of the knee using arthroscopy. The patient was a local patient surnamed Huang, female, 89 years old, from Gaoming. She complained of pain due to an accidental sprain of her right knee more than 10 years ago, which was not taken seriously. After rest, the pain gradually improved, but later the right knee became swollen and painful with recurrent attacks. After MRI examination, the synovial membrane in the knee was significantly hyperplastic and thickened, which was consistent with the nuclear magnetic manifestation of pigmented nodular villous synovitis. After preoperative preparation and with the patient’s consent, we operated on the patient using arthroscopy, which confirmed the preoperative judgment, and then performed a total synovectomy of the right knee. The patient recovered well after surgery and started to walk off the bed on the first day after surgery. Pigmented villonodular synovitis (PVS) is a benign but rare disease with a tendency to localized infiltration and erosion. Traditional treatment requires arthrotomy and removal of most of the synovium; arthroscopy has the advantages of less damage, faster recovery, and accurate diagnosis. Figure 1: Pre-operative knee puncture was a bloody effusion. Figure 2: The intra-articular synovial membrane was yellowish-brown fluffy and nodule formation was visible Figure 3: The cartilage of the patellofemoral articular surface was eroded and destroyed, and postoperative pathological examination confirmed the pigmented fluffy nodular synovitis.