TY - CHAP T1 - Ulnar polydactyly T2 - Living Textbook of Hand Surgery AU - Smits, Ernst AU - ten Berge, Sterre ED - Böttcher, Richarda AD - Dr. Ernst Smits, Erasmus MC – University Medical Centre Rotterdam, Department of Plastic, Reconstructive and Hand Surgery, Rotterdam, Niederlande, E-mail: e.smits@erasmusmc.nl N2 - Ulnar polydactyly is among the most common congenital hand anomalies. According to Temtamy and McKusick, it is classified as type A, a well-formed digit with tendons, bones and neurovascular structures, or type B, a rudimentary pedunculated underdeveloped digit. The condition results from genetic mutations affecting the radial-ulnar axis, often due to GLI3-mutations. It can present as an isolated anomaly or as part of various syndromes. Epidemiological groups show different clinical aspects and type B is the prevalent form overall. The diagnosis is primarily clinical, however, it can be supported by radiological imaging and referral to a clinical geneticist if needed. The goal of therapy is removal of the extra digit while preserving the function and sensation to the remaining digit. Type A-digits are surgically treated via various approaches, depending on their articulation and anatomy, and current evidence reveals good outcomes. Type-B digits can be managed via ligation, via sutures or clips, or via surgical excision, under local or general anesthesia. Surgical excision shows the lowest complication rate, although high-level comparative evidence is still limited. PY - 2026 DA - 2026/09/18 DO - 10.5680/lhhs000034 LA - en L1 - https://books.publisso.de/de/system/getFile/74244 UR - https://dx.doi.org/10.5680/lhhs000034 L2 - https://dx.doi.org/10.5680/lhhs000034 PB - German Medical Science GMS Publishing House CY - Berlin ER -