Treatment of the triphalangeal thumb.

The triphalangeal thumb is a rare congenital malformation, but not as rare as the literature would imply. Forty-two patients with 68 triphalangeal thumbs, represent an incidence of about 3 per cent of a population of upper extremity abnormalities. Although little is written about the details of treatment, surgery is frequently necessary. Age makes a great difference as to hom the extra phalanx should be treated. The associated abnormalities present major surgical problems that must be treated early.