Introduction to Osteoarthritis

Osteoarthritis, also known as hypertrophic osteoarthritis, osteoarthrosis, and degenerative joint disease, is the most common form of arthritis. A chronic disease, it causes deterioration of the joint cartilage and formation of reactive new bone at the margins and subchondral areas of the joints. This degeneration results from a breakdown of chondrocytes, usually in the hips and knees.

Causes
Osteoarthritis is widespread, occurring equally in both sexes until age 55. After age 55, incidence is higher in women. Incidence is after age 40; its earliest symptoms generally begin in middle age and may progress with advancing age.
The degree of disability depends on the site and severity of involvement; it can range from minor limitation of the fingers to severe disability in persons with hip or knee involvement. The rate of progression varies, and joints may remain stable for years in an early stage of deterioration.
Primary osteoarthritis, a normal part of aging, results from many things, including metabolic, genetic, chemical, and mechanical factors. Secondary osteoarthritis usually follows an identifiable predisposing event—most commonly trauma, congenital deformity, or obesity—and leads to degenerative changes.

Signs and symptoms
The most common symptom of osteoarthritis is a deep, aching joint pain, particularly after exercise or weight bearing, usually relieved by rest. Other symptoms include:

• stiffness in the morning and after exercise (relieved by rest)
• aching during changes in weather (joint pain in rainy weather)
• “grating” of the joint during motion
• altered gait contractures
• limited movement.

These symptoms increase with poor posture, obesity, and occupational stress.
Osteoarthritis of the interphalangeal joints produces irreversible changes in the distal joints (Heberden’s nodes) and proximal joints (Bouchard’s nodes). These nodes may be painless at first but eventually become red, swollen, and tender, causing numbness and loss of dexterity.

Diagnosis
A thorough physical examination confirms typical symptoms, and the absence of systemic symptoms rules out an inflammatory joint disorder. X-rays of the affected joint help confirm diagnosis of osteoarthritis but may be normal in the early stages. 

X-rays may require many views and typically show:

• narrowing of joint space or margin
• cystlike bony deposits in joint space and margins
• sclerosis of the subchondral space
• joint deformity due to degeneration or articular damage
• bony growths at weight-bearing areas
• fusion of joints.

No laboratory test is specific for osteoarthritis.

Treatment
The goal of treatment is to relieve pain, maintain or improve mobility, and minimize disability. Medications include various nonsteroidal, antiinflammatory drugs (NSAIDs).

In some cases, intra-articular injections of corticosteroids given every 4 to 6 months are used to reduce inflammation and pain. Artificial joint fluid, such as Synvisc and Hyalgan, can also be injected into the knee and can result in temporary relief of pain for up to 6 months.
Usually, a 2-week trial period is needed to evaluate the benefit of a particular medication.

Effective treatment also reduces stress by supporting or stabilizing the joint with crutches, braces, cane, walker, cervical collar, or traction. Other supportive measures include massage, moist heat, paraffin dips for hands, protective techniques for preventing undue stress on the joints, adequate rest (particularly after activity) and, occasionally, exercise when the knees are affected.

Surgical treatment, reserved for patients who have severe disability or uncontrollable pain, may include the following:

• arthroplasty (partial or total): replacement of the deteriorated part of the joint with a prosthetic appliance
• arthrodesis: surgical fusion of bones; used primarily in the spine (laminectomy)
• osteoplasty: scraping and lavage of deteriorated bone from the joint
• osteotomy: change in alignment of the bone to relieve stress by excision of a wedge of bone or cutting of bone.