Rupture of the ulnar ligament of the metacarpophalangeal joint of the thumb.

We have operated on 51 old injuries with abduction instability of the metacarpophalangeal joint of the thumb. The time from injury to operation was 8 weeks to 5 years. Ligament repair was made in 29 cases. In 22 cases arthrodesis of the joint was performed because of primary unsuccessful operation or arthrosis of the joint. The patients were followed-up for 6.9 years on average. Twenty-three patients with ligament repair were satisfied, while 6 patients were not satisfied; 4 having a disabling instability and 2 complaining of pain and stiffness of the joint. By stress radiography only 15 of the 29 patients had a stable joint. All the patients with arthrodesis of the joint were satisfied, having a painless and well-functioning thumb.