Osteoarthritis : Definition, Pathophysiology, Diagnosis and Treatment
Osteoarthritis (OA) is a common, slowly progressive disorder affecting primarily the weight-bearing diarthrodial joints of the peripheral and axial skeleton. It is characterized by progressive deterioration and loss of articular cartilage resulting in osteophyte formation, pain, limitation of motion, deformity, and progressive disability. Inflammation may or may not be present in the affected joints.
Early in OA, cartilage water content increases, possibly as a result of a damaged collagen network that is unable to constrain proteoglycans, which subsequently gain water. As OA progresses, cartilage proteoglycan content decreases, possibly through the action of metalloproteinases.
Changes in glycosaminoglycan composition also occur, with decreased keratan sulfate and an increased ratio of chondroitin 4-sulfate to chondroitin 6-sulfate. These changes may interfere with proper collagen-proteoglycan interaction in cartilage. The collagen content does not appear to change until severe disease is present. Increases in collagen synthesis and altered distribution and diameter of the fibers are seen.
Inflammation, noted clinically as synovitis, occurs and may result from release of inflammatory mediators such as prostaglandins from chondrocytes.
The prevalence and severity of OA increase with age. Potential risk factors include obesity, repetitive use through work or leisure activities, joint trauma, and heredity.
The diagnosis of OA is dependent on patient history, clinical examination of the affected joint(s), and radiologic findings.
Primary (idiopathic) OA, the most common type, has no known cause. Subclasses of primary OA are localized OA (involving one or two sites) and generalized OA (affecting three or more sites. The term erosive OA indicates the presence of erosion and marked proliferation in the proximal and distal interphalangeal hand joints.
Secondary OA is associated with a known cause such as rheumatoid arthritis or another inflammatory arthritis, trauma, metabolic or endocrine disorders, and congenital factors.
The treatment of Osteoartritis (OA) :
The first step is to educate the patient about the extent of the disease, prognosis, and management approach. Dietary counseling for overweight OA patients is warranted.
Physical therapyâ€”with heat or cold treatments and an exercise program helps to maintain and restore joint range of motion and reduce pain and muscle spasms. Exercise programs using isometric techniques are designed to strengthen muscles, improve joint function and motion, and decrease disability, pain, and the need for analgesic use.
Assistive and orthotic devices such as canes, walkers, braces, heel cups, and insoles can be used during exercise or daily activities.
Surgical procedures (e.g., osteotomy, joint debridement, osteophyte removal, partial or total arthroplasty, joint fusion) are indicated for patients with severe pain unresponsive to conservative therapy or pain that causes substantial functional disability and interference with lifestyle.