- Will be included patients older than 18 years, who have moderate to strong chronic pain in knee on most of the days days for at least 3 months, with osteoarthritis of the knee documented by graded radiologically at 3 to 4 in Kellgren-Lawrence rating, refractory to medical treatment (physical therapy, oral analgesics, intra-articular injections of hyaluronic acid or corticosteroids).