This swelling over the dorsum of the interphalangeal joint (IPJ) of the thumb appears to be a mucous cyst. A mucous cyst is a fluid-filled balloon arising from the IPJ of the thumb. It is commonly associated with wear-and-tear, or osteoarthritis, of the IPJ of the thumb. Overuse and increased motion in the IPJ may cause more joint fluid to fill this cyst, which in turn causes an increase in:
- pain,
- redness and
- swelling at this site.
Unfortunately, the only effective treatment for a mucous cyst is surgery. My preferred approach to treat a mucous cyst is decompression of the mucous cyst via a midlateral incision (not directly cutting into the cyst itself) and removing the osteophytes (bone protrusions as a result of the worn-out joint) which can cause irritation of the joint and recurrence of the mucous cyst.
This procedure avoids the complication of a skin defect resulting from directly excising the mucous cyst requiring a local flap procedure with additional scarring. A midlateral incision leaves a fine linear scar instead, and the skin overlying the mucous cyst remains intact and in original condition.
One may consider seeking treatment from a hand & wrist specialist to perform this delicate operative procedure.
