Arthritis of the Knee

Abstract

Osteoarthritis (OA) of the knee is the most common form of degenerative joint disease, affecting 13.9% of adults age 25 years and older and 33.6% of those 65 years and older. Some predisposing risk factors include age, obesity, infection, repetitive use, occupation, and previous trauma. Mild OA usually presents as pain in the knee with difficulty bending or straightening the knee, swelling, weakness, instability, locking, and clicking or snapping of the knee. A diagnosis can be made clinically and confirmed by x-ray showing narrowing of the joint space in mild cases; however, bone changes, subchondral cysts, and formation of bony spurs can be seen in more advanced stages. Treatment of mild to moderate OA involves a multimodal approach that includes lifestyle modifications, physical therapy, and electrical stimulation with or without pharmacologic management. Interventional therapies such as intra-articular corticosteroid injections and viscosupplementation are usually reserved for severe symptoms. Pharmacologic modalities such as acetaminophen, nonsteroidal antiinflammatory drugs, weak opioids, and duloxetine can be used as a single agent or combination therapy. Novel approaches to the treatment of OA include nerve growth factor inhibitors, botulinum toxin type B injections, and intra-articular platelet-rich plasma but are not well supported due to a lack of sufficient evidence. Key words: arthritis, degenerative joint disease of the knee, diagnosis, etiology, guidelines, noninflammatory arthritis, osteoarthritis of the knee, treatment