Thumb Arthritis

Healthy joints have smooth cartilage, which acts as a shock absorber allowing pain-free movement. The thumb basal joint (CMC or carpometacarpal joint) is a saddle-shaped joint that is formed by the wrist bone (carpal trapezium bone) and the first metacarpal thumb bone. The thumb basal joint is responsible for the thumb's extensive range of motion, which allows firm grasping and pinching (see Figure 1).

The most common type of arthritis that affects the thumb joint is osteoarthritis. Less common causes of basal joint arthritis are post-traumatic arthritis, reactive joint arthritis due to infection, rheumatoid arthritis, gout arthritis, and psoriatic arthritis.

In osteoarthritis, the cartilage wears out, resulting in direct contact of joint bones and producing pain and deformity. Thumb basal joint is one of the most common places in the hand where degenerative arthritis occurs.

Basal thumb arthritis is more commonly seen in women over 40. Previous thumb injuries and joint laxity may predispose towards the development of basal thumb arthritis.

Symptoms of Thumb Arthritis

The most common symptom of thumb arthritis is pain at the base of the thumb joint. The pain can be aggravated by daily activities such as opening jars, turning doorknobs or keys, and writing. Patients with advanced basal thumb arthritis have pain at rest and night. In severe cases of thumb basal joint arthritis, a bony bump develops over the joint space at the base of the thumb as the joint subluxation forces its collapses into the palm, causing a zig-zag deformity.

Thumb Arthritis Diagnosis

The diagnosis of thumb arthritis is made by history and physical evaluation. Frequently, people with thumb arthritis have decreased grip strength, loss of strength, limited motion, pain with activity such as twisting, all of which cause joint pain in the carpometacarpal joint. A grinding sensation and grinding sound may also be present at the carpometacarpal joint (see Figure 3). X-rays are used to confirm the diagnosis, but symptom severity often does not correlate with x-ray findings.

Treatment For Thumb Arthritis

Less severe thumb arthritis will usually respond to conservative management and nonsurgical treatment such as anti-inflammatory medication. Arthritis medication, splinting, and limited corticosteroid injections are treatment options that may provide pain relief. A physical therapist or an occupational therapist may recommend activity modifications and provide a variety of rigid and non-rigid splints which can be used while sleeping or during activities.

Patients with advanced disease, severe pain, or who fail conservative measures and conservative treatment have surgical options. Various surgical options and surgical techniques can successfully reduce or eliminate pain, including surgical reconstruction and joint replacement. Surgical procedures include removing arthritic bone and joint reconstruction (arthroplasty), joint fusion, bone realignment, and even arthroscopy. Your hand surgeon can help you decide the best option for you.