Carpal Metacarpal (CMC) or Basal Joint Arthritis:

UW Medicine Hand Center
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Carpal Metacarpal (CMC) or Basal Joint Arthritis:

CMC arthritis is a very common condition that affects about 1 in every four women and 1 in every twelve men. Symptoms include pain at the base of your thumb especially with activities such as pinching or opening jars. A palpable bump may be felt at the base of the thumb (Figure 1). This condition occurs because a ligament at the base of the thumb wears out or stretches out. The loose ligament then allows abnormal rotation of the joint causing increased wear and tear or arthritis.

CMC arthritis can be diagnosed by x-rays (Figure 1). Additionally, pushing the thumb towards the base and rotating it can recreate the symptoms. Non surgical treatments consist of anti-inflammatory medications (NSAID's), splinting and steroid injections into the joint. While these options may help relieve some of the symptoms, they will not cure or reverse the arthritis. Surgical options include several different options. Most options included resection of the arthritic joint and reconstruction of the lax ligament. In some cases, a cartilage spacer or even prosthetic joint may be indicated to maintain the normal height of the thumb (Figure 2).

Postoperative course requires a cast for approximately six weeks followed by a home course of hand exercises for an additional six weeks. While pain should be relieved with any procedure, some decreases in strength and motion should be expected.

CMC arthritis can be diagnosed by x-rays Figure 1 CMC arthritis can be diagnosed by x-rays Figure 2