Arthroscopy of the osteoarthritic knee is a common and costly practice with limited and specific indications. The extent of osteoarthritis (OA) is determined by joint space narrowing, which is best measured on a weight-bearing radiograph of the knee in 30° or 45° of flexion. The patient older than 40 years with a normal joint space should have a magnetic resonance image taken to rule out focal cartilage wear and avascular necrosis before recommending arthroscopy. Randomized controlled trials of patients with joint space narrowing have shown that outcomes after arthroscopic lavage or debridement are no better than those after a sham procedure (placebo effect), and that arthroscopic surgery provides no additional benefit to physical and medical therapy. The American Academy of Orthopedic Surgeons guideline on the Treatment of Osteoarthritis of the Knee (2008) recommended against performing arthroscopy with a primary diagnosis of OA of the knee, with the caveat that partial meniscectomy or loose body removal is an option in patients with OA that have primary mechanical signs and symptoms of a torn meniscus and/or loose body. There is no evidence that removal of loose debris, cartilage flaps, torn meniscal fragments, and inflammatory enzymes have any pain relief or functional benefit in patients that have joint space narrowing on standing radiographs. Many patients with joint space narrowing are older with multiple medical comorbidities. Consider the complications and consequences when recommending arthroscopy to treat the painful osteoarthritic knee without mechanical symptoms, as there is no proven clinical benefit.