What is it?

Basilar joint arthritis affects the thumb and in severe cases can require joint replacement surgery (carpo metacarpal joint arthroplasty). The thumb basilar joint is located at the base of the thumb where it attaches to the wrist, and is the most mobile joint in the hand. Like other joints, it is normally covered with cartilage, a smooth coating which allows painless and smooth movement. Joint arthritis occurs when these smooth surfaces wear out. The initial symptom is a toothache-like pain in the wrist or thumb with activities that involve gripping, pinching, or twisting. Some patients notice pain with weather changes. Weakness and decreased flexibility occur as the arthritis progresses. Basilar joint arthritis can affect both thumbs.

What causes it?

Basilar joint arthritis is a result of thinning of the cartilage between the thumb and the wrist. The joint then becomes inflamed leading to pain and swelling. It is seen with all forms of arthritis including rheumatoid, osteoarthritis, and gout. It can occur after fractures or injuries to the thumb although most cases have no clear causes. Like other forms of arthritis, it is more common in women than men.

How is it diagnosed?

The diagnosis is made from the patient’s history of an ache or soreness in the thumb, followed by an examination and x-rays. The thumb mobility may be decreased and with manipulation of the thumb, the pain is reproduced. Eventually the base of the thumb may enlarge because of swelling in the joint or formation of bone spurs. Other conditions such as carpal tunnel syndrome or tendonitis should be excluded.

What are the treatments?

Although we currently have no cure for arthritis, the pain from basilar joint arthritis responds very well to treatment. The initial treatment is a steroid injection in conjunction with the use of a brace. We recommend a short period of activity modification after the injection to enhance its ability to work properly. Ice, heat or other topical medicines may also be helpful. These treatments are the most effective non-surgical treatments for this condition and will usually be offered to you at your initial visit. This will often lead to significant improvement, and in most cases surgical treatments, such as  carpal metacarpal joint arthroplasty, are not necessary. If non-surgical treatment is unsuccessful, surgery may be suggested.

The surgical procedure Dr’s. Helgemo & Olarte perform, carpal metacarpal arthroplasty with tendon transfer, is the “gold standard” for arthritis at the base of the thumb. They perform this surgery an average of 50 times per year. Surgery involves making two small incisions— one over the basilar joint, and one in the anterior forearm– removing the trapezium bone to create a “scar tissue” joint (carpal metacarpal joint arthroplast) and reconstructing it with an expendable tendon from your forearm (tendon transfer). The tendon removed does not lead to any loss of arm or hand function. The surgery generally takes about 30 minutes and is usually done in an ambulatory surgery center. General anesthesia is not usually necessary.