Pedicle complex tissue flap transfer for reconstruction of duplicated thumbs with unequal size.

Background: Thumb polydactyly is one of the most common congenital hand deformities, and the Bilhaut-Cloquet procedure or a modified one is often used. However, controversy remains over the rare instances in which both thumbs are not of similar length or far apart in distance.

Aim: To evaluate the clinical outcomes of pedicle complex tissue flap transfer in the treatment of duplicated thumbs with unequal size.

Methods: From January 2014 to December 2020, 15 patients underwent duplicated thumb reconstruction by pedicle complex tissue flap transfer at our hand surgery center. The technique was used when it was necessary to combine different tissues from both severed and preserved thumbs that were not of similar length or far apart in distance. Subjective parents' evaluations and functional outcomes (ALURRA and TATA criteria) were obtained. The alignment deviation, instability, range of motion (percent of opposite thumb) of the interphalangeal and metacarpophalangeal joints, and the aesthetic aspects, including circumference, length, nail size, and nail deformity, were used to assess the clinical outcomes.

Results: The average age of patients at the time of surgery was 13 mo, and the mean final follow-up occurred at 42 mo. An appropriate volume with a stable joint and good appearance was obtained in 14 reconstructed thumbs. An unstable interphalangeal joint occurred in one thumb. The flexion-extension arc at the metacarpophalangeal joint was good, while that at the interphalangeal joint was poor. Most of the parents were satisfied with the cosmetic and functional results of the reconstructed thumbs. The mean ALURRA score was 21.8 (range: 20-24), and the Tada score was 6.9 (range: 5-8). Compared with the non-operated side, the length of the operated thumb was approximately 95%, the girth was 89%, and the nail width was 82.9%. The mean ranges of motion were 62.1% of that of the unaffected thumb in the interphalangeal joint and 78.3% in the metacarpophalangeal joint.

Conclusion: Harvesting a pedicle flap from a severed thumb is a safe and reliable procedure. Defects of the preserved thumb, such as the skin, nail, and bone, can be effectively restored using the complex tissue flap.