Osteoarthritis (OA) also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion. Psoriatic arthritis is a type of inflammatory arthritis that will develop in up to 30 percent of people who have the chronic skin condition psoriasis. This book presents topical research on both these topics including the pharmacological treatment of osteoarthritis; the health effects and current treatment of psoriasis and psoriatic arthritis; the role of aquaporins in human synovitis and subclinical atherosclerosis in patients with psoriatic arthritis.