The 1st Metacarpal Osteotomy for Basilar (Basal) Thumb Pain in Young Adults

Arthritis commonly affects the base of the thumb. Older patients, or those with more advanced arthritis, are well-treated by the LRTI procedure, which is well-covered in this website. While the LRTI is extremely effective, it may be more surgery than a younger patient with less-advanced arthritis requires.

If nonoperative management, including activity modification, a splint and an injection fail to provide acceptable pain relief, younger patients may desire surgical treatment.

The first metacarpal osteotomy is a simple procedure that provides predictable pain relief for young adults with less-advanced basilar thumb arthritis. First metacarpal osteotomy involves cutting the first metacarpal (the long bone of your thumb) and extending it 30°. It is then fixed in its new position with 2 wires, one that stays inside and one that protrudes through the skin and is removed after five weeks (which doesn’t hurt much at all). After surgery, a cast is worn for five weeks. Throughout this time it is important to move the tip of the thumb at least 3 times a day to prevent the thumb’s tendons from scarring down.

This surgery has passed the test of time and is very effective. It transfers stress from the arthritic areas of the basilar joint to areas of the basilar joint that are still normal, or have only mild arthritis. This decreases the stresses going through the most arthritic areas of the basilar joint, decreasing pain. The first metacarpal osteotomy does not remove any arthritis already present. Therefore, activities that are very stressful on the thumb (massage, forceful use of certain tools, etc) often have to be avoided indefinitely. Many people often have one activity that they have to ‘give up’. Following first metacarpal osteotomy, any given stress on the basilar joint will lead to less pain. Another way to say this is that more stress can be placed on the thumb before pain occurs. Any arthritis present will still continue to progress, but probably at a slower pace. Therefore, this surgery probably helps to delay the need for future surgery. The first metacarpal osteotomy will not be effective in cases of more advanced arthritis because, in advanced cases, there’s no remaining normal joint to ‘off-load’ stresses onto.

Because the thumb’s metacarpal bone is extended, thumb flexion will be decreased a little, but this is rarely a problem. Close inspection of the thumb will detect a slight angle to it, but this is rarely noticed unless actually looked for, ie. the angulation is not usually ‘obvious’. There is some, but usually not a lot, of hand therapy required once the cast is removed. A removable splint is then used as needed.

In summary, basilar thumb pain can usually be successfully treated in young patients without advanced arthritis by a first metacarpal osteotomy, an outpatient procedure that ‘burns no bridges’ and still allows for an LRTI, or any other needed procedure, to be performed in the future.