Osteoarthritis

DEFINITION: A degenerative joint disease that results from the deterioration of the cartilage of bones, causing inflammation, swelling, and pain in affected joints and eventually causing joint stiffness and limitation of movement, misalignment, and bone spurs

ANATOMY OR SYSTEM AFFECTED: Joints, musculoskeletal system

CAUSES: Old age, previous joint injuries, joint overuse, obesity, genetic or metabolic diseases, congenital bone deformities

SYMPTOMS: Joint pain (commonly in hands, hips, knees, spine); loss of flexibility; stiffness in morning or after long periods of immobility; development of bone spurs

DURATION: Chronic and progressive

TREATMENTS: Occupational therapy; physical therapy; moderate exercise; heat therapy (warm soaks, paraffin, mud treatments); pain medications such as topical analgesic ointments, acetaminophen, NSAIDs (ibuprofen, naproxyn); COX-2 inhibitors; injections of cortisone or hyaluronic acid; joint replacement surgery in severe cases

Causes and Symptoms

There are several causes of osteoarthritis (OA), including traumatic injuries, joint overuse or repetitive movement of a joint, obesity, congenital bone deformities, and genetic or metabolic diseases such as diabetes or Paget's disease of the bone. Other risk factors include old age and female gender. The most commonly affected joints are in the hands, hips, knees, and spine. An inherited genetic defect in the production of collagen can lead to defective cartilage and to more rapid joint deterioration. OA in the hands or hips may be hereditary. OA in the knees and hips is linked to excess weight, which puts added stress on these joints. Muscle weakness can also predispose one to OA; thigh strengthening exercises can reduce one's risk of developing OA in the knees.

In healthy joints, cartilage containing synovial fluid and elastic tissue reduces friction as joints move. Osteoarthritis develops when the cartilage wears away and bone rubs against bone. The most prominent symptom of osteoarthritis is joint pain. Other symptoms include morning stiffness or stiffness after long periods of immobility. Early in the disease, individuals may experience joint pain after strenuous exercise. As the disease progresses, joints stiffen and diminished joint mobility is experienced even with slight activity. As joint mobility decreases, the muscles surrounding the joint weaken, thereby increasing the likelihood of further injury to the joint. As the cartilage wears away, crepitus can often be heard and a grating sensation can be felt as bone moves against bone. The development of Heberden’s nodes on the distal interphalangeal joints and Bouchard’s nodes on the proximal interphalangeal joints of the hands is not uncommon.

Confirmation of osteoarthritis is based on a history of joint pain and physical findings that indicate arthritic changes in the joints. In a physical examination, a doctor may check for swelling and joint tenderness under pressure, as well as a loss of the joint's range of mobility. An X-ray can show a loss of joint space, osteophytes, bone cysts, and sclerosis of subchondrial bone. Sometimes, a computed tomography (CT) scan or magnetic resonance imaging (MRI) may be helpful in confirming the presence of osteoarthritis and can show the loss of cartilage.

Treatment and Therapy

The goal of treatment for OA is to preserve physical function and reduce pain. Education, physical therapy, and occupational therapy are instrumental in maintaining independence and improving muscle strength around affected joints. Pacing activities to avoid overexertion of the affected joints is an effective means to prevent further pain and injury. Heat therapies such as warm soaks, paraffin, and mud treatments may help to lessen the discomfort in tender joints. Moderate exercise such as walking, swimming, strength training, and stretching all may help to maintain mobility in arthritic joints and to improve posture and balance. Relaxation techniques, stress reduction activities, and biofeedback may also be helpful.

Over-the-counter topical analgesic ointments may help to reduce joint swelling and pain. Acetaminophen is very effective for controlling OA pain. However, persons who take blood-thinning medicines, have liver disease, or consume large amounts of alcohol should use acetaminophen with caution. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen are also effective for pain relief, but they may cause gastrointestinal bleeding. This class of drugs selectively blocks the enzyme COX-2, thus controlling the production of prostaglandins, natural chemicals that contribute to body inflammation and cause the pain and swelling of arthritis. Since they do not block the COX-1 enzyme cyclooxygenase-1, which is present in the stomach and inflammation sites, the natural mucous linings of the stomach and intestine are protected, thereby reducing the incidence of upset, ulceration, or bleeding; however, COX-2 selective inhibitors increase the rate of cardiovascular events such as heart attacks and stroke. Any medication used to treat OA should be taken under the direction of a healthcare provider.

Glucosamine and chondroitin naturally occur in the body. Both have been promoted for the treatment of OA. Glucosamine may promote the formation and repair of cartilage, while chondroitin may promote water retention and elasticity in cartilage and prevent cartilage breakdown. However, recent studies indicate that taking glucosamine for arthritis may increase a patient's risk of developing glaucoma.

When interventions to relieve symptoms of OA no longer work, an orthopedic surgeon may inject cortisone or hyaluronic acid into joint spaces. Hyaluronic acid is used to replace the synovial fluid that a joint has lost in order to maintain knee movement without pain. Cortisone may be injected into affected joint spaces to provide temporary relief of joint pain. Surgical intervention to trim torn and damaged cartilage from joint spaces, to partially or totally replace severely damaged joints in the knees and hips, or to fuse bones together are effective treatments in the most severe, debilitating stages of OA. Realignment of a joint (osteotomy) and joint replacement surgery other possible procedures.

Perspective and Prospects

Arthritis comprises more than one hundred diseases and conditions and is the major cause of disability in the United States. The incidence of OA increases with age, but it can affect individuals as young as eighteen. According to the Centers for Disease Control and Prevention, approximately 33 million people in the United States have OA, and it is the most common form of arthritis. The Global Burden of Disease 2019 study ranked hip and knee OA as the eighteenth highest contributor to global disability in persons age fifty to seventy-four. OA is three times more common among women, although before forty-five years of age, it is more common in men. There is no cure for OA, but a healthy diet, regular exercise and physical therapy, weight management, and the use of medications are measures that can slow its progress and maintain joint function.

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