Transfer of the Fifth Finger to Replace an Amputated Thumb: A Preliminary Study.

Amputation of the thumb causes not only loss of significant functional use of the hand but also psychological and social problems. The procedures of toe-to-thumb transfer, pollicization, or metacarpal extension are recognized and well-documented options in thumb reconstruction. Although these techniques have been successfully applied, they have some disadvantages. This study aims to test the feasibility of the fifth finger for thumb reconstruction. The fifth finger was released following exploration of the digital artery, vein, nerve, and flexor and extensor tendons, including the flexor retinaculum. The digital vein and the extensor tendon of the fifth finger were separated at the level of the metacarpophalangeal joint. The proximal phalanx of the fifth finger was cut smoothly at the level of the metacarpophalangeal joint with a saw. The deep flexor tendons, digital arteries, and nerves were preserved. The proximal phalanx of the released fifth finger was fixed to the first metacarpal bone. The digital vein of the first finger was anastomosed to the digital vein of the fifth finger by microsurgery. Angiography was done after the transfer. Exploration till the flexor retinaculum enabled thumb transfer without any restriction of movement in all 10 cadaver fingers. The average total surgical time was 135 ± 12 minutes. Flow from both radial and ulnar arteries was demonstrated in the transferred fifth finger by angiography. The technique appears to be feasible for thumb reconstruction by preserving digital arteries and nerves in a relatively short time, but further important aspects have to be assessed in further clinical studies.