Osteoarthritis is the most common type of joint disease where it results in histopathologic and radiologic changes. It generally affects the weight-bearing joints such as the cervical spine, lumbosacral spine, hips, knees, and feet. Other joints that are commonly affected are the joints in the fingers.
Although once thought to be predominantly caused by excessive wear and tear, there is increasing literature and evidence pointing to the contributions of inflammation and abnormal mechanics. Generally, it can be divided into the primary and secondary forms. Since it is a common condition, it is costly due to visits, medications, therapy, and surgery. There is also indirect costs due to absence from work and decreased productivity.
In early stages of the disease, osteoarthritis can cause subtle biochemical changes. As the disease progresses, it can cause gross cartilage loss and damage to the joint tissues. In osteoarthritis, the collagen matrix is disorganized and the proteoglycan content in the cartilage decreases. As the collagen fibers break down, the water content increases. Without the proteoglycan’s protective effects, the collagen fibers are susceptible to degradation and results in degeneration. Inflammation of the joint capsule and synovium can also occur as products from the breakdown are released into the synovial space. In the joint, the ligaments thicken and become fibrotic while the damaged menisci is damaged and worn. Bony growths known as osteophytes or spurs can also form on the joint margins causing more issues.