Surgical repair for deformities of the nail unit.

The nail apparatus is the largest and most complex skin appendage. Defects in this unit can result in significant functional insufficiency and cosmetic disfigurement. Common nail deformities include split nail, short nail, onycholysis, nail malalignment, hooked nail, and absent nail. Currently, surgical repair is the primary treatment for such deformities. Based on the etiological and anatomical classifications, one or more appropriate operations can be selected to repair nail unit deformities. These include autologous fat grafting, longitudinal cicatrectomy, Z-plasties, nail bed elongation, split-thickness sterile matrix grafting, volar V-Y advanced flap reconstruction, sterile matrix particle grafting, germinal matrix flaps, and germinal matrix grafting. This review discusses the fundamental classification of nail unit deformities, common reconstructive surgical techniques, and their features.