Reconstruction for Wassel type III radial polydactyly with two digits equal in size.

PURPOSE: To report the surgical outcomes for Wassel type III radial polydactyly thumbs of equal or nearly equal size treated by excising the radial thumb with augmentation.

METHODS: We have reconstructed 15 cases of Wassel type III radial polydactyly, in which the duplicated digits were equal or almost equal in size, by ablation of a radial digit. The distal articular surface of the radial proximal phalanx was preserved in order to maintain stability of the interphalangeal joint. The stability of the retained thumb was further augmented by tendon repositioning, restoration of the radial collateral ligament, and transfer of soft tissues from the radial digit. Eleven of 15 cases were followed up for more than 2 years and were available for assessment using the Japanese Society for Surgery of the Hand evaluation form. The average age at follow-up was 8 years and 3 months. The size of the nail and distal phalanx was measured to assess the growth of the thumb.

RESULTS: An average functional point was 12 points (maximum 14 points), and restricted interphalangeal joint motion and extension lag were the disadvantages of this technique. The width of the distal phalanx was increased from 62% of the size of the metacarpal before surgery to 78% at the final follow-up. The cosmetic score averaged 3.6 (maximum 4 points), and slightly small nails without a central ridge were deemed acceptable.

CONCLUSIONS: Our technique can provide a functionally good thumb for Wassel type III radial polydactyly.

TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.