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Arthritis of the Thumb
(Basal Joint Arthritis)
General Information:
Arthritis of the thumb, or basal joint arthritis, is a form of osteoarthritis, also known as degenerative joint disease. It affects the basilar joint at the base of the thumb, formed by the thumb metacarpal bone and a small wrist bone called the trapezium. The ends of these bones are covered with cartilage, which acts as a cushion and allows them to move freely. Arthritis destroys the cartilage, causing the joint to become painfully inflamed.
Basal joint arthritis results in pain and restricts movement of the thumb across the palm. Far more common among women than men, it typically occurs after the age of forty. Both thumbs may be affected.
Causes of Arthritis of the Thumb:
Basal joint arthritis is caused by wear and tear on the joint at the base of the thumb, perhaps as the result of a fracture or injury. Repeated motions such as twisting, turning, or gripping objects with the thumb and fingers can worsen this condition.
Symptoms of Arthritis of the Thumb:
The earliest symptom of arthritis of the thumb is pain associated with activities involving pinching motions, such as unscrewing jar lids, gripping doorknobs, or turning keys. Prolonged or intense use of the thumb may produce an aching discomfort at the base of the thumb. Changes in the weather may also cause pain. Over time, pinch strength diminishes and less stress is required to cause pain; eventually, any motion of the thumb may cause discomfort.
The joint may begin to appear enlarged or deformed, and the thumb becomes increasingly stiff. Limited motion of the thumb is an eventual symptom, and it becomes increasingly difficult to pull the thumb away from the hand in order to reach around objects. It may be impossible to straighten the thumb.
In the most severe cases, the thumb metacarpal bone may collapse into the palm, causing other joints to compensate by assuming abnormal positions. There may be a tender prominence at the base of the thumb caused by inflammation or displacement of the thumb metacarpal.
Treatment:
Diagnosis of arthritis of the thumb is usually made on the basis of how your thumb looks and moves. Your doctor may order x-rays to examine how much of the joint has been destroyed. He or she may press the thumb metacarpal firmly against the trapezium in a grind test used to assess and reproduce the symptoms of pain. This test may result in a gritty sensation, called crepitance, which indicates bone contact against bone and the degeneration of cartilage.
Nonsurgical treatments for basal joint arthritis are often effective if the condition is diagnosed early. Oral anti-inflammatory medications, such as aspirin, may offer some relief from pain. Resting the hands may also help. Sometimes a splint is placed on the thumb for 3?6 weeks; this reduces inflammation by restricting movement in the sensitive area. Cortisone injections to the joint may also offer relief from painful symptoms.
Surgery may be warranted in cases where conservative methods of treatment no longer offer benefit. In order to relieve pain and restore movement to the thumb, all or part of the diseased trapezium is removed and the joint is rebuilt. A substitute joint is constructed (in an operation called an arthroplasty), using either a strip of tendon (a graft from your arm or wrist) or an artificial substance; this creates a sling suspension restoring movement. The reconstructed joint may be temporarily stabilized by means of a small stainless steel fixation pin. An "arthrodesis," or fusing the degenerated joint, may be another option that your surgeon may suggest.
Surgical procedures for arthritis of the thumb can be performed on an outpatient basis using a general anesthetic. A bulky compressive dressing and rigid splint are used after surgery to immobilize the thumb and restrict movement. The fingers and the tip of the thumb are usually left free, and movement of the fingers helps to prevent undesired swelling. It is important to elevate the entire upper extremity. Because of the bulky dressing, normal daily activities of the hand are usually not possible.
After 10?14 days, the postoperative dressing is changed and sutures are removed. A wrist and thumb splint or cast protects the hand for an additional 2?4 weeks of immobilization. A therapy program is initiated 4?6 weeks after surgery to help restore movement to the thumb. If the fixation pin has not been previously removed, it is taken out at this time. A small splint protects the thumb between exercises and maintains the web space between the thumb and index finger.
Over time, discomfort during therapy diminishes and the joint becomes more mobile. Unrestricted use of the thumb is usually possible at 12 weeks after surgery. Proper exercise of the hand strengthens the joint. It is also important to learn to avoid overuse of the thumb. While maximum benefits from surgery may take up to one year to achieve, patients should eventually be able to return to normal activities, experiencing little or no thumb pain. |
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Pain Medicine of York, LLC: Arthritis of the Thumb
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