Combined reduction osteotomy for triphalangeal thumb.

Triphalangeal thumb is an uncommon congenital deformity. The thumb is long, awkward, frequently angulated, and may have a broad, unsightly nail. When the middle phalanx has an abnormal C-shaped ("delta") epiphysis, the deformity worsens if untreated. Three triphalangeal thumbs in two patients who were 2 1/2 and 8 1/2 years of age were treated with single-stage combined longitudinal and transverse reduction osteotomy, which included narrowing, shortening, and deangulation by ablating the extra joint and abnormal epiphysis. The patients were followed 48 to 59 months after surgery. Realignment, corrected relative length, and interphalangeal motion have been preserved in all thumbs. Neither patient has developed instability or angulation or had a recurrence after surgery.