and Stem Cell
Osteoarthritis, distinct from many other diseases, is amenable to local intra-articular injections, treatment as well as systemic treatment. Though most efforts so far have concentrated on development of systemic treatments, the agents used bear considerable risk of systemic side effects, such as the cardiovascular events and gastrointestinal adverse effects observed in association with most non-steroidal anti-inflammatory drugs and cyclooxygenase-2 inhibitors for treatment of joint pain (Petit-Zeman, 2004; Topol, 2004). The chronic nature of the disease requires development of drugs suitable for chronic systemic treatment with minimal side effects, which is a challenging goal. Local drug application, i.e., injection of drugs directly into the affected joint, is an option for treatment of osteoarthritis which is already frequently used and has the potential to deliver the desired profile. In summary, progression of knee osteoarthritis results from local factors, which include synovial membrane inflammation, chondrocyte activation, and bone remodeling. Therefore, it appears logical to favor an intra-articular route for treatment of knee (as well as hip) osteoarthritis.