Attritional rupture of the flexor digitorum profundus tendon to the index finger caused by accessory carpal bone in the carpal tunnel: a case report.

We describe a case of attritional rupture of a flexor digitorum profundus tendon to the right index finger in a 73-year-old man by an accessory carpal bone located on the palmar side of the capitate and triquetrum. The radial edge of the accessory carpal bone appeared to be the cause of the rupture. Excision of the accessory carpal bone, bridge tendon graft using the palmaris longus tendon, and early controlled mobilization after surgery led to a successful outcome.