Polydactyly is quite common and is caused by genetic predisposition. Polydactyly can be classified as radial polydactyly, ulnar polydactyly and central polydactyly. It can be a single finger polydactyly or multiple fingers polydactyly. It is usually found on the radial side of the thumb and on the ulnar side of the little finger. Polydactyly can occur at the end of the finger, proximal phalanges, attached to the normal phalanges, or at the interphalangeal and metacarpophalangeal joints. Some polydactyly can be the result of repetitive development of one finger with corresponding long bones, resulting in a deformity of six fingers in one hand or even a heavy hand, but it is less common. The shape of the polydactyly can vary widely, from a dermatome attached to a complete finger, making it difficult to distinguish a normal finger from a polydactyly. The angle of growth of the polydactyly varies, and some polydactyly is at a right angle to the radial or ulnar margin of the hand. X-rays should be performed to clarify the morphology and structure of the osteoarthritis and to provide a basis for surgery. Treatment: The surgical treatment of radial polydactyly should vary according to its type. Commonly used surgical methods include: excision of the extra finger, repair of the soft tissue of the preserved finger, repair of the stenosis of the first web, reconstruction of the tendon and muscle stop, correction of the deformity of the joint, reconstruction of the joint capsule and lateral collateral ligament and osteotomy to correct the deformity of the deviated finger.