Duplication of distal phalanx

Partial or complete duplication of the thumb distal phalanx can be treated in several ways:

• if the ulnar digit is dominant:
  • smaller radial digit is removed
  • head of the proximal phalanx may require contouring if the distal phalanx is completely duplicated
  • radial collateral ligament is repaired
• if the radial digit is dominant:
  • less frequent scenario
  • the ulnar-sided digit is removed and the ulnar collateral ligament is repaired
• if both digits are of similar size:
  • the ulnar thumb with the ulnar collateral ligament can be preserved; the bone from the smaller digit is excised but the residual soft tissue can be used to augment the ulnar thumb
  • alternatively, the Bilhaut-Cloquet procedure may be used:
    • both thumbs are divided into equal halves
    • the two halves nearest each other are discarded
    • the outer portions of each thumb are combined to create a new thumb
    • tends to give problems with cosmesis (central nail split, broad thumb) and function (stiffness)