Isolated Unilateral Heptadactyly With Combined Preaxial and Postaxial Polydactyly of the Foot in a 9-Month-Old Infant.

BACKGROUND: Polydactyly is a common congenital limb anomaly characterized by supernumerary digits, most frequently involving the hands or feet. Foot polydactyly is traditionally classified into preaxial, postaxial, and central types, with postaxial forms being the most common and central forms the rarest. Heptadactyly, defined as the presence of seven digits in a single limb, represents an exceptionally rare and severe expression within this spectrum, most often described as central duplication. Isolated unilateral heptadactyly of the foot with combined preaxial and postaxial duplication is exceedingly rare, with very few cases reported in the literature.

CASE PRESENTATION: We report the case of a 9-month-old female infant who presented with a congenital deformity of the right foot noted at birth. Clinical examination revealed unilateral heptadactyly with seven well-formed toes involving both preaxial and postaxial duplication, resulting in medial and lateral widening of the forefoot. The contralateral foot, upper limbs, and systemic examination were normal, and there was no family history of congenital anomalies. Radiographic evaluation confirmed complete duplication of the medial and lateral rays without central ray involvement, tarsal abnormalities, or syndactyly, consistent with isolated mixed-pattern preaxial-postaxial heptadactyly. Given concerns regarding footwear and future gait function, elective surgical correction was performed at 9 months of age. The procedure involved excision of the most medial and lateral supernumerary rays with meticulous preservation of neurovascular structures and reconstruction of soft tissues to restore a narrowed, stable, plantigrade foot. No internal fixation or ligament reconstruction was required due to preserved postoperative stability. The postoperative course was uneventful, with satisfactory wound healing, improved cosmetic appearance, and symmetric early functional use of the limb.

CONCLUSION: This case highlights an exceptionally rare presentation of isolated unilateral heptadactyly with combined preaxial and postaxial duplication. It expands the phenotypic spectrum of foot polydactyly and emphasizes the importance of detailed clinical and radiological assessment for accurate classification and surgical planning. Early individualized surgical management can achieve favorable functional and cosmetic outcomes, while long-term follow-up remains essential to monitor gait development and detect late deformities.