Evaluate Treatment Options for Basal Joint Arthritis 

by Rosemary Buckle, M.D.

Board-Certified Orthopedic Surgeon

Arthritis is a disease that causes inflammation and stiffness in the joints. It often affects the joint at the base of the thumb, called the basal joint, which allows for the swivel and pivoting motions of the thumb. It is also referred to as thumb CMC (carpometacarpal) joint. Because of its design, it tends to wear out and develop arthritis early in life. Basal joint arthritis is also common in people who have osteoarthritis. It is most common in women over 40, but anyone can get it, and it often happens in both thumbs.

What causes Basal Joint Arthritis?

Basal joint arthritis occurs as a result of wear and tear on the joint. It is more likely to occur if you have fractured or injured your thumb, and at a young age. Repeatedly gripping, twisting or turning objects with the thumb and fingers may make the arthritis worse. It causes pain at the base of the thumb, particularly during pinching or gripping, and also results in weakness of pinch. 

Inside the Thumb

The basal joint is formed by one of the wrist bones and the first of the three bones in the thumb. This joint allows the thumb to move and to pinch with the fingers. When arthritis occurs in the basal joint, it slowly destroys the joint.

The ends of the bones are covered with cartilage. This covering acts like a cushion, allowing the bones to move smoothly. Arthritis wears away or destroys the cartilage. Then the bones rub against each other when you move your thumb. This causes the joint to become stiff, inflamed and painful. With time, the bone in the thumb may collapse and then you will no longer be able to straighten your thumb.

Basal Joint Arthritis Symptoms

The most common symptom is pain in the lower part of the thumb. You may feel pain when you lift something with the thumb and fingers, unscrew a jar lid, grip an object, or turn a door handle or a key. You may find yourself dropping things. Weather may also make the thumb hurt. The joint may swell, and with time, the thumb may become stiff or deformed.

Treating Basal Joint Arthritis

Treatment will depend on how severe the pain is and also if the joint is exceptionally worn. There are nonsurgical and surgical treatments to consider. If arthritis is diagnosed early, it often responds to treatment without surgery. Your doctor may put a splint on your thumb for three to six weeks. This limits movement and helps reduce the inflammation. You may be given a pain medicine such as acetaminophen. You may also be given oral anti-inflammatory medication, such as ibuprofen or aspirin. If your symptoms don’t improve, your doctor may give you injections of an anti-inflammatory, such as cortisone, right into the joint.

If nonsurgical treatment does not relieve the pain and stiffness, or if arthritis has destroyed the joint, your doctor may recommend surgery where the diseased joint is removed. Then the joint is rebuilt, usually with a piece of tendon (graft) taken from your arm or wrist. Your arm, or sometimes your entire body, is anesthetized so you don’t feel anything during surgery. You can probably go home the day of surgery with your hand wrapped in a dressing, then you will have a cast or a splint on your thumb for 3–6 weeks to keep it stable during healing.

Once you can move your thumb, your doctor will give you exercises, or refer you to a physical therapist, to help strengthen the muscles and make the joint more flexible. Regaining use of your thumb will take time. Surgery helps more than four out of five people with this problem, but as many as one out of five will have numbness on the back of the hand or tenderness of the scar following surgery.

Treatment really depends on how much the basal joint is bothering you. The good news: it does not spread to other parts of the body. Many people have thumb pain that subsides after a few years, when the arthritis and irritation in this joint "burns out." However, there is a limited period of time during which surgery can provide the best result. After a period of years, the thumb weakness and the loss of motion of the thumb may not be reversible even with surgery.

Dr. Rosemary Buckle is a board-certified orthopedic surgeon who sees patients at St. Joseph Medical Center.