Abstract
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.