On-Top Plasty in Post-Axial Polydactyly: A Case Report and Recommendation to Modify the Classifications

Post-axial polydactyly (PAP) is almost always treated by ablation of the sixth ray since the ulnar duplicate is universally inadequate and the radial one is normal. We report a patient with bilateral PAP with skeletal abnormalities in both radial and ulnar duplicates. This unusual presentation cannot be classified according to previous classifications of PAP and precludes simple ablation as the treatment of choice. Both hands of this patient were treated by on-top plasty with excellent functional and cosmetic results. A modification of the previous classifications is recommended at the end of this article. Level of Evidence: Level V (Therapeutic).