Types V and VI are treated similarly to type IV, with the addition of a first web space Z-plasty or web widening if there is thenar eminence contracture. Acral transposition has also been described, with transposition of the tip of the ablated digit in place of the tip of the kept digit; this technique is ideal if one digit has a more normal proximal part while the other has a more normal distal part (Figure 13).35
Type VII thumb polydactyly, the type most likely inherited and associated with other disorders, should be treated like type VI. The nail should be preserved; amputation of the distal phalanx is not advised. Resection of the delta phalanx or 1 interphalangeal (IP) joint is an option. Articular surfaces will remodel if done before the age of 1 year. If the thenar eminence is hypoplastic, then Huber transfer of the abductor digiti minimi should be considered.37 Resection of the triphalangeal thumb is also advised, even if the biphalangeal thumb is more hypoplastic, with transfer of the ligaments and tendons, as described earlier.5,6,24,30,32,35
Thumb triphalangism, if isolated, and hyperphalangism in the other digits, can be treated with resection of the delta phalanx or one of the IP joints if it is affecting function or cosmesis.1,6 Wood and Flatt23 recommended early resection of a thumb delta phalanx because of the likelihood of deviation that impedes thumb function. For children, they recommended delta phalanx resection and Kirschner wire fixation for 6 weeks; for adults, they recommended resection or fusion of the joint, with osteotomy as needed for deviation.23,24 For thumb triphalangism, multiple surgeries are the norm, as Wood24 reported in his study of 21 patients who underwent 78 operations in total.
Index polydactyly may present as a simple pedunculated skin tag, which can be simply excised, or as a more complex musculoskeletal duplication. More complex presentations can be treated with procedures similar to those used for the thumb. Typically, the additional digit is radially deviated and angulated, eventually leading to impingement of thumb pinch and the first web space. Ray amputation is also an option if no reconstructive surgery will produce the stable, sensate radial pinch that is essential to hand function.32
Ring-finger polydactyly and long-finger polydactyly are often complicated by some element of syndactyly, resulting in a relative paucity of skin (Figure 14). There is failure of both formation (hypoplasia) and differentiation (syndactyly). The hypoplasia particularly affects the function of these digits by tethering them; multiple surgeries to restore proper hand function are the norm.1 Reconstructive surgery for these digits requires preoperative tissue inventory followed by resection and augmentation; as in syndactyly, skin for coverage is at a premium. Creation of a 3-fingered hand is an option.23
Temtamy and McKusick10 type A little-finger polydactyly is treated similarly to the thumb, with the caveat that hypothenar and intrinsic muscles that insert on the resected little finger are transferred to the remaining digit. In contrast to thumb polydactyly, the extrinsic musculature tends to be in good position. Suture ligation of type B polydactyly, as described by Flatt, is likely more common than orthopedists appreciate, as pediatricians and neonatal unit practitioners commonly perform this procedure in the nursery.1-3 It has been described with 2-0 Vicryl3 (Ethicon, Somerville, New Jersey) and 4-0 silk sutures,32 with the goal of necrosis and autoamputation. Parents should be told the finger generally falls off about 10 days (range, 4-21 days) after ligation.3 Multiple authors have cited a report of exsanguination from suture ligation, but we could not locate the primary source. It is advisable to wait until a patient is 6 months of age if planning to resect the nubbin in the operating room, given the anesthesia risk and the lack of functional impairment. Katz and Linder33 indicated they remove type B polydactyly in the nursery suite used for circumcisions; they use anesthetizing cream on the skin, and sharp excision with a scalpel, followed by direct pressure and Steri-Strip (3M, St. Paul, Minnesota) application. Suture ligation is recommended only if there is a narrow, thin (<2 mm) soft-tissue stalk; any broad or bony stalk necessitates surgical removal to avoid neuroma formation and failure of autonecrosis (Figure 15).27 Other options are a single swipe of a scalpel and elliptical excision; sharp transaction of the digital nerve with subsequent retraction is advised to avoid neuroma formation.2
Barton described ulnar dimelia operations as “spare parts surgery.”1 Extra digits are ablated and a thumb created (Figure 16). The hand might have a digit in relatively good rotational position for thumbplasty, or the principles of pollicization may need to be used. If the patient is already using the hand, the surgeon should note which finger the patient uses as a thumb.24 Any accompanying wrist flexion contracture must be corrected with careful attention to musculotendinous balancing. Because the forearm and elbow, and occasionally even the more proximal limb, will be abnormal in this disorder, multiple surgeries are again the norm.1
