Repetitive thumb deformity is one of the most common congenital malformations of the hand in children, manifesting as a split-thumb deformity of the thumb of the hand, with an incidence of approximately 1 in 3,000, which may be related to genetics and environmental pollution. Diagnosis Diagnosis is relatively simple and relies on physical examination, but X-ray examination is often required to clarify the developmental differentiation of the phalanges and metacarpals. Treatment The main reliance is on surgical treatment. Surgical treatment involves removing the duplicated parapodial thumb while using each duplicated portion to reconstruct a thumb with normal force lines and function whenever possible. The main surgical considerations are to align the long axis of the thumb, stabilize the joint, balance the muscles, form a nail that is large enough and free of deformities, and reconstruct the shape of the thumb of adequate size. Surgery is often performed around one year of age. Case presentation: Pre-operative appearance photo Post-operative appearance photo