Polydactyly of the thumb: abnormal anatomy and treatment.

In nine years 26 duplicated thumbs were seen in the hand clinic of a hospital for crippled children. Using a classification based on the level and degree of duplication and a knowledge of the abnormal anatomy, reconstruction was done. This surgery was done with proper skin incisions, reconstructions of the collateral ligaments, centralization of the flexor and extensor tendons, and alignment of the bones and joints by corrective osteotomies. Simple ablation or incomplete correction produced complications such as skin contractures, increased angular deformities, unstable joints, and intrinsic weakness. In all of the patients, the appearance was improved, opposition was maintained, and postoperative function was not impaired.