77 patients with knee osteoarthritis underwent knee arthroscopy & joint lavage, followed by an intra-articular injection of corticosteroid (120mg methylprednisolone acetate) or placebo saline, assigned randomly. The outcomes assessed included patient-reported pain and function, response rate (minimum 30% reduction in pain from baseline), and relapse rate at 2, 4, 8, 12, and 24-week follow-ups. Results demonstrated no significant differences between groups in pain at rest, pain on movement, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Lequesne Functional Index scores over the duration of the follow-up. The response rate was not significantly different between groups at any time point during the follow-up, though a significantly longer mean time to relapse was observed in the IA corticosteroid group compared to the IA placebo group.