[Congenital subluxation of the metacarpophalangeal joint of the thumb as the cause of writer's syndrome].

A 26-year-old male patient developed a writer's cramp syndrome, the underlying cause of which was shown to be a congenital subluxation of the first metacarpophalangeal joint. The clinical symptoms are presented, the indications for surgery reviewed and the operative technique in accordance with A.N. Witt described. Post-operatively, the pathological hypermobility of the first metacarpophalangeal joint has been eliminated, and global function of the hand has normalized.