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Basal Thumb Arthritis

Other names: carpometacarpal joint (CMCJ) osteoarthritis


What is it?

Arthritis occurring at the base of the thumb       



Pain around the base of the thumb which can occur at rest or on movement. It may be worse in bad weather and it can keep you awake at night.

Reduced hand function, typically with difficulty undoing jars, turning keys and taps, pinching clothes pegs or gripping objects. Grip strength is weak due to the pain and the thumb may not be able to stretch away from the index finger as far as it used to.


What causes it?

All our joints eventually wear out, given enough time and use. The joint at the base of the thumb is a very common place to suffer arthritis, especially in women. The joint cartilage (lining) thins and ultimately can wear away completely. Bone then rubs on bone which is painful and may be felt as a grating sensation.



Pain relief – simple painkillers or pain-relieving gels may be enough to enable most functions to be performed with the hand.

Splints – a splint may be worn to help prevent movement of the painful joint at the base of the thumb. Many types of splints are available from chemists, doctors and on-line. Different splints suit different individuals. The splint does not need to be worn all the time, but may be used during periods of more severe symptoms, or to help perform certain tasks (eg gardening).

Steroid injections – a steroid injection into the arthritic joint may settle the pain for up to 6 months but will not cure the underlying arthritis. The extent and duration of pain relief is variable from patient to patient. Injections can be repeated several times, but tend to be progressively less effective.

Surgery  – There are several different surgical options depending on the pattern of the arthritis and the requirements of the patient. The most commonly performed operation is a trapeziectomy, which involves removal of the arthritic area. Thumb movement is maintained, grip strength and hand function improved and pain relieved in 90% of patients.

Most operations for thumb arthritis can be performed as daycase surgery. Most involve a period of six weeks in a thumb plaster after surgery and take several months to make a full recovery from.

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