“…Although open synovectomy is still a valuable option for the treatment of rheumatoid patients, arthroscopic synovectomy is becoming popular for many large joints, including shoulder [5], elbow [6], wrist [7], hip [8], knee [2] and ankle [9]. Arthroscopic synovectomy of the knee in RA is a relatively common procedure and different studies report good outcomes [10][11][12][13][14][15][16][17][18][19]. However, most of the papers available in the literature that include heterogeneous groups of patients (grouping RA, psoriatic arthritis, pigmented villonodular synovitis, chondromatosis, non-specific, seronegative, and post-traumatic synovitis), do not specify the diagnostic criteria for RA, or use the American College of Rheumatology (ACR) 1987 criteria [20].…”