Thumb function and appearance following treatment of Wassel type III duplication thumbs

•Our reconstructive technique could restore thumb function and appearance to a large extent.•Nail lengthening surgery is used to augment the nail size with Wassel type III thumb duplication for the first time.•Other kinds of thumb duplication can be operated by nail lengthening surgery to improve the appearance.

ObjectiveThe purpose of our study is to evaluate thumb function and appearance after surgical correction of Wassel type III thumbs polydactyly.MethodsWe have reconstructed 28 cases of Wassel type III duplication thumbs, in which the duplicated digits were equal or almost equal in size by ablation of a radial digit. The extra thumb is osteotomized at the bifurcation level and excised except for the distal bone fragment supporting the nail bed and fillet flap. Meanwhile, the nail of the retained thumb should be reserved completely, and if the nail has relatively poor appearance it should be repaired by nail lengthening surgery. Eighteen cases were followed up for more than 3 years and were available for assessment using the Japanese Society for Surgery of the Hand evaluation form. The average age at follow-up was 5 years. The size of the nail and distal phalanx was measured to assess the growth of the thumb.ResultsAn average functional point was 12 points (maximum 14 points) and the cosmetic score averaged 3.6 (maximum 4 points) after the assessment. Slightly small nails without a central ridge were deemed acceptable. Second revision surgery is seldom. Long-term results after surgical reconstruction for duplication thumbs were excellent, and all patients and parents were satisfied with the cosmetic and functional results.ConclusionsThis procedure is a helpful and effective way to provide functional and aesthetical thumb for Wassel type III duplication thumbs.