Osteoarthritis is usually regarded as a localized disease whose optimal treatment is a therapy applied directly to the affected joint. Unfortunately, current local therapies such as repeated intraarticular injections or constant infusions are associated with a higher risk of infection. One way to overcome this would be to transfer substances made locally by cells within the joint. However, attempts using direct vector transfers or intraarticular injections of ex vivo modified cells could not achieve a sustained protein secretion over several months. Another method of delivering biological factors (i.e.growth hormones) intraarticularly is to transplant an artificial organ, capable of supporting the regeneration of natural cartilage, directly into the affected joint The main difficulty of having to produce bioactive factors over a long period of time is overcome by implanting a chamber-like system filled with either genetically modified cells or a drug-releasing matrix. This drug delivery system would be located at a peripheral site of the joint and could release substances directly into the joint cavity which would be transported via the synovial fluid and/or diffused to the chondrocytes or synoviocytes.
Keywords: Cartilage, osteoarthritis, therapy, drug delivery, artificial organ