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What is Arthritis of the Base of the Thumb?

 

In the normal joints of your body, cartilage covers the end of the bones serving as a shock absorber to allow smooth, pain-free movement. In osteoarthritis (OA) or “degenerative arthritis,” the cartilage layer wears out.  This results in direct contact between bones, producing pain and deformity.   One of the most common joints to develop OA in the hand is the base of the thumb. The basal joint of the thumb, also called the carpometacarpal or CMC joint, is a specialized saddle shaped joint that is formed by a small bone of the wrist known as “trapezium” and the first bone of the thumb called “metacarpal”. The saddle shaped joint allows the thumb to have a wide range of motions, including up, down, across the palm, and the ability to pinch.

 

Who Gets It?

 

Osteoarthritis at the base of the thumb is more commonly seen in women over the age of 40. Genetics, previous injuries such as fractures or dislocations, and generalized joint laxity may predispose toward development of this type of arthritis.  However, the exact cause is unknown.

 

What are the Symptoms and Signs?

 

The most common symptom of OA is pain at the base of the thumb. This pain can intensify by activities that require pinching, such as opening jars, turning door knobs or keys, and writing. Depending on the severity, pain can also appear at rest or at night. In more severe cases, progressive destruction and mal-alignment of the joint occurs, and a bump develops at the base of the thumb as the metacarpal moves out of the saddle joint. The shift in the joint can cause limited motion and weakness, making pinching difficult. The joint above the CMC may compensate by loosening, causing it to bend further back.  This is known as hyperextension.

 

How is the Diagnosis Made?

 

The diagnosis is made by a history and physical evaluation. Pain at the joint will occur from pressure and movement, such as twisting. A grinding sensation may also be present at the joint. X-rays are used to confirm the diagnosis, although symptom severity often does not correlate with x-ray findings.

 

What are the Treatment Options?

 

Arthritis in the thumb that is less severe will usually respond to non-surgical care. Arthritis medication, splinting, and limited cortisone injections may help alleviate pain. A hand therapist may provide a variety of rigid and non-rigid splints which can be used while sleeping or during activities.

 

Patients who have advanced disease or who fail non-surgical treatment may be candidates for surgical reconstruction. A variety of surgical techniques are available that can successfully reduce or eliminate pain. Removal of arthritic bone and joint reconstruction (arthroplasty), joint fusion, bone realignment, and even arthroscopy are some of the surgical procedures done in select cases. A consultation with

your hand surgeon can help decide the best option for you before having any kind of surgical treatment.

 

For more information about simple, safe, and effective treatments for Arthritis of the thumb, or any other conditions of the hands or upper extremities, schedule an appointment with Dr. Sagini by calling 239-337-2003.