Traumatic boutonniere deformity of the thumb.

We report three patients who presented 3 to 8 months after sustaining a closed injury to the dorsoradial aspect of the metacarpophalangeal joint of the thumb. All three patients had an extensor lag of the metacarpophalangeal joint and paradoxical hyperextension of the interphalangeal joint. There were no collateral ligament injuries. The patients required surgical treatment which included advancement and reattachment of the extensor pollicis brevis insertion and imbrication of the dorsoradial capsule to restore the anatomical alignment of the extensor pollicis longus. Surgical treatment of dorsoradial injuries to the thumb metacarpophalangeal joint may be required for injuries that result in subluxation of the extensor pollicis longus tendon and a boutonnière deformity of the thumb.