Although guidelines do not recommend use of opioids to manage pain for individuals with knee osteoarthritis, a recent study published early online in Arthritis Care & Research, an official journal of the American College of Rheumatology and the Association of Rheumatology Professionals, estimates that 858,000 Americans use opioids such as tramadol and oxycodone for their knee pain, equating to $14 billion in lifetime opioid-related societal costs, or nearly $0.5 billion annually.