Physical Medicine and Rehabilitation

Knee Arthritis

Description

The knee is one of the most commonly involved joints with arthritis. Arthritis is the loss of the normal protective cartilage that covers the bones. When this cartilage or "padding" of the bone breaks down and is lost, areas of raw bone become exposed. When large areas of bone are exposed, they grind against each other with standing and walking. This is "bone on bone" arthritis and is usually painful. Arthritis in the knee can be isolated to one part of the knee or be found through the entire knee. It can be isolated to the area under the knee cap (patella) or on the ends of the femur (thigh bone) and tibia (shin bone). It can be mostly on the inner side of the knee (medial side) or outer side (lateral side) of the knee. Medial sided (inner side) and patella femoral (under the knee cap) are the two most common areas for wear and tear of the cartilage (arthritis) to develop. When it develops, it frequently affects more than one part of the knee, though.

Symptoms

Swelling, pain, limited motion, and weakness are all common symptoms of arthritis. Other symptoms may also occur, depending on the type and severity of the disease, location in the body, and other factors. In osteoarthritis of the knee, the first sign may be pain and stiffness when getting out of a chair or standing or walking for long periods of time. Swelling is also common. Pain and stiffness in the morning is typical, and in advanced cases, joint pain may even wake you up at night. Adapting use of the knee can help to prevent pain.

Additional symptoms may include a sensation of grating or grinding (crepitation) that is felt in the affected joint as damaged surfaces of cartilage rub together. If the arthritis is caused by damaged ligaments, the joint may feel unstable or loose. In advanced cases, changes in the bone, loss of cartilage, and swelling may cause the joint to appear larger than normal (hypertrophic).

Causes

• Osteoarthritis—This progressive condition is caused by excessive use; wear and tear that occurs as part of the aging process; or fractures, sprains, dislocations or other traumatic injuries that damage or destroy the smooth articular cartilage covering the ends of bones. Even when properly treated, an injured joint is about seven times more likely to develop arthritis.
• Rheumatoid arthritis (RA)—This is a chronic, autoimmune disease that causes the immune system to attack and damage normal tissue, including many joints throughout the body. RA often begins in smaller joints, such as those found in the hand and wrist, and it is symmetrical, so it usually affects the same joint on each side of the body.

Diagnosis

To diagnose arthritis of the knee, and the category of disease, your physician may use a variety of diagnostic tools, including patient history, physical examination, blood tests, and X-rays. When X-rays appear normal but arthritis is still suspected, an MRI can show more detail. Arthroscopy may also be used to allow direct inspection of the joint. During this procedure, the surgeon inserts a small camera inside the joint, allowing the clearest view possible without requiring a large incision. This diagnostic tool is used only in certain situations however, because although the incision is small, it is an invasive procedure.

Nonsurgical Treatment

There are several options for nonsurgical treatment of arthritis, depending upon: how far the disease has progressed; how many joints are involved; your age, activity level and other medical conditions; whether or not the dominant hand is affected; your personal goals and home support structure; and your ability to understand your treatment and comply with a therapy program. Following a prescribed exercise program can also help improve strength and range of motion in the affected joint.

• Medications—Although they offer relief for symptoms, medications cannot restore joint cartilage or reverse damage. Anti-inflammatories are the most commonly used because they stop the body from producing chemicals that cause joint swelling and pain. These include over-the-counter options such as aspirin and ibuprofen, as well as certain prescription medications. Acetaminophen is not an anti-inflammatory, but it can be used to help relieve the pain of arthritis. When symptoms of RA are not adequately controlled by these therapies, additional disease-modifying, anti-rheumatic drugs may be prescribed. Specially designed to stop the immune system from destroying joints, these medications carry varying risks and benefits to be discussed with your physician.
• Glucosamine and Chondroitin—Dietary supplements or nutraceuticals such as these are also widely advertised. These compounds are the "building blocks" of cartilage, they are not drugs. Originally used by veterinarians to treat arthritic hips in dogs, these in most studies of these nutraceuticals, no difference between placebo and the nutraceutical has been found. (Note: The U.S. Food and Drug Administration does not test dietary supplements, and these compounds may cause negative interactions with your other medications. Always consult your doctor before taking dietary supplements.)
• Injections—These may be used when anti-inflammatory medication is not appropriate. Typically containing an anesthetic (similar to Novacaine) and a steroid, injections can offer pain relief for weeks or even months. Injections can be repeated, but only a limited number of times because of possible side effects, such as lightening of the skin, weakening of the tendons and ligaments, or infection. Other types of injections that can be used are Viscosupplementation. This is a substance called hyaluronic acid, and is a naturally occurring part of the joint fluid. Arthritic joints make less of this. For some people, this seems to help, though recent studies have shown that this may not be as effective as previously thought.
• Physical therapy—Your physician or physical therapist may prescribe specific exercises to help you improve strength and flexibility, restore movement, and provide relief from uncomfortable symptoms. Physical therapy is often a key factor in successfully recovering from a wide range of conditions and disorders.

Surgery

When nonsurgical treatment does not provide the desired outcome, a variety of surgical options may be considered. For knee arthritis, partial or total knee replacement surgery can greatly improve symptoms. The appropriate option will depend on a variety of factors, including: the severity of disease; other medical conditions; and your age, goals, activity level, and home support structure. Your orthopaedic surgeon will review surgical treatments with you, and discuss which ones offer the highest potential for long-term relief of pain and allowing you to return to normal activity.

Recovery

Following surgery, a trained therapist will help you maximize your recovery. The length of time needed for recovery varies, depending on the extent of the surgery and individual factors. Most people are able to return to most, if not all, of their daily activities about three months after major joint reconstruction.