Osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis. Also known as degenerative jointdisease, OA is characterized by loss of articular cartilage within a joint resulting in chronicpain, stiffness, deformity, and subsequent functional disability. Osteoarthritis may beclassified as primary/idiopathic, for which the cause is unknown, or secondaryosteoarthritis,which occurs as a result of trauma, infection, neuropathy, bone ischemia, congenitalabnormality, chronic inflammatory arthropathy, or other cause. The prevalence of thedisease has been increasing in recent years:an estimated ۲۱ million suffered from the disease in ۱۹۹۰ compared with ۲۶.۹ million in۲۰۰۵.۱ The incidence of osteoarthritis increases with age; however, there has been arecent increase in patients presenting with symptoms earlier in adulthood, prior to the ageof ۶۵. The precise etiology of osteoarthritis is unknown. A number of biomechanical andbiochemical causes have been implicated to suggest that the etiology is multifactorial.Although older age is associated with OA, the changes in osteoarthritic cartilage arepathologic and distinct from those of normal senescence.In healthy cartilage, thechondrocytes maintain a balance between synthesis and regeneration of hyaline cartilageby producing the proteoglycans and collagen that form the matrix. In OA, this balance isinterrupted and chondrocytes do not synthesize a sufficient matrix.