Arthroscopic debridement is a reliable and effective treatment for knee arthritis in appropriately selected patients. Debridement may include lavage, loose body removal, partial meniscectomy, and/or chondroplasty. Patient selection criteria include acute effusion, well localized joint line tenderness, or catching or locking, often associated with a specific mechanism of injury, patients with imaging studies confirming loose bodies, patients with earlier stages of degenerative joint disease, and patients with realistic understanding that the goal of arthroscopy is to diminish pain and improve function and not to cure their arthritis. Surgeons are cautioned, in patients with an osteoarthritic knee, MRI may be overly sensitive and inadequately specific with regard to correlation between pathologic findings (with the exception of loose bodies) and predictably treatable disease. In conclusion, the authors cite the Arthroscopy Association of North America Position Statement on Osteoarthritis: "There is...sub-group of patients with knee arthritis that can be significantly helped with appropriate arthroscopic surgery."