In the current literature concerning arthroscopy in the osteoarthritic patient, there are few well-controlled studies with long-term follow-up that establish selection criteria. The effectiveness of abrasion arthroplasty has not been proved in prospective studies. Prospective factors that are associated with a better outcome include normal limb alignment, a history of mechanical symptoms, minimal roentgenographic degeneration, and a short duration of symptoms. Variables associated with poor outcomes include varus or valgus malalignment, loading symptoms, severe roentgenographic degeneration, previous surgeries, and chronic symptoms. Advanced age, per se, is not a contraindication to arthroscopy.