Base of Thumb Arthritis

What is a Base of Thumb Arthritis?

Arthritis of the base of the thumb occurs when there is a loss of joint cartilage. This results in direct contact between bones producing pain and deformity. The thumb basal joint is also called the carpometacarpal joint (CMC joint). It is a specialised saddle-shaped joint that is formed by the trapezium and the base of the thumb metacarpal.


Thumb arthritis may cause severe pain, swelling and decreased range of motion. This may create difficulties on a daily basis eg opening jars, grasping small objects between the thumb and index finger or fastening buttons. Pain may be severe at night, causing difficulty sleeping. 


Initially, non surgical techniques should be trialled. Splinting may be helpful to both relieve pain and improve a patient’s ability to perform certain activities. Medications and steroid injections may also be useful to control the pain.

Surgery may be indicated when the pain is severe and daily function is impacted. One of the most commonly performed surgical procedures is removal of one of the carpal bones known as the trapezium. This provides very good pain relief, but there is a loss of strength in the thumb. Other surgical procedures include fusion and replacement.