BRITISH JOURNAL OF ~ PLASTIC SURGERY 1

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1 British Journal of Plastic Surgery (2001), 54, The British Association of Plastic Surgeons doi: 10,1054/bjps BRITISH JOURNAL OF ~ PLASTIC SURGERY 1 Polydactyly of the feet in children: suggestions for surgical management S. E. Morley and E J. Smith Department of Plastic Surgery, Great Ormond Street Hospital, London, UK SUMMARY. Polydactyly is the commonest congenital deformity of the foot, presenting as a range of defects from minor soft tissue duplications to major bony abnormalities. There is a relative paucity of information on the management of this condition in the literature compared to that concerning polydactyly of the hand. We present a consecutive series of 34 cases of polydactyly of the foot in 25 patients treated surgically at our unit and these are classified according to the protocol described by Blanth and Olason. We emphasise the importance of preoperative classification using radiographs and an individualised surgical approach giving consideration to aesthetic and functional outcome. In the literature a number of authors have expressed the view that in polydactyly of the fifth ray of the foot the most lateral digit should always be excised irrespective of whether this is the more fully formed digit. We believe this should not always be the case and we describe two cases of polysyndactyly where the more medial element of a fifth-ray polydactyly was excised to allow for better maintenance of the contour of the foot. This involved more complex surgery than excision of the lateral element but gave a superior cosmetic and functional result The British Association of Plastic Surgeons Keywords: polydactyly, congenital foot abnormalities, surgical management. Polydactyly of the foot accounts for 45% of congenital foot abnormalities and usually presents to the surgeon with the parents of a young child seeking surgical treatment either for cosmetic reasons or due to difficulty finding comfortable footwear. ~ We assessed the pattern of polydactyly presenting over a 10-year period to a Paediatric Plastic Surgery Service to compare the approaches used to address this problem in our unit with those of other units. We also wished to gauge the usefulness and ease of application of the classification system most commonly used to describe polydactyly in relation to the foot and to compare the patterns of abnormality found at our unit with those previously described. Patterns of polydactyly of the foot vary from an additional fully formed digit to vestigial soft tissue masses and can affect any of the digits, metatarsals or tarsal bones, although polydactyly of the fifth ray is the commonest. 2 The deformity can occur unilaterally or affect both limbs and polydactyly of the hand and other congenital abnormalities can co-exist) Polydactyly of the foot usually has little functional significance other than difficulty in shoe fitting. Many attempts to classify polydactyly have been described in past publications and we have chosen the method described by Blauth and Olason, which we feel is logical and simple allowing accurate, reproducible classification taking into account radiographic details. 4 The area of duplication is described in terms of the point of duplication along the longitudinal axis (distal phalanx to tarsal bone) and along the transverse axis from one (the hallux) to five (the little toe) as in describing a point using coordinates. The most proximal duplicated bone, for example the metatarsal, denotes the nature of the duplication and the transverse axis is given a number denoting which ray the duplication involves. Figure 1 demonstrates a third-ray duplication of middlephalanx type whilst Figure 2 shows a bilateral fifth-ray duplication of metatarsal type. Radiographs are vital in allowing accurate description of these defects preoperatively. We feel that this classification is to be recommended as it allows a precise, reproducible description of level of duplication and ray involvement relying on a description of the anatomical abnormality. Multiple polydactyly can easily be incorporated into the classification and a description of tri-phalangism can also be included if this affects the hallux. Previous descriptions of the treatment of fifth-ray polydactyly have emphasised that the lateral-most elements should always be excised even if these are not the most hypoplastic. 5,6 The policy at our unit is to consider each case separately and if the lateral element is the less hypoplastic then the medial elements are excised. Often the medial metatarsal is poorly formed and does not articulate with its metatarsophalangeal joint but merely floats. To illustrate this point we present two cases of unusual patterns of polydactyly that required surgical removal of at least some of the medial element of the duplication to maintain the contour of the foot. The purpose of this paper therefore is to review the pattern of polydactyly of the foot and its surgical treatment, and to look specifically at the treatment of complex fifth-ray polydactyly. Patients and methods The subjects of the study were consecutive patients presenting to the Plastic Surgery Unit at Great Ormond Street Hospital who have undergone surgery for polydactyly of the foot over the last 10 years. We analysed 34 feet of 25 patients and they were grouped according to 34

2 Polydactyly of the feet in children: suggestions for surgical management 35 Table 1 Patterns of polydactyly Transverse axis Total Distal phalanx Middle phalanx Proximal phalanx 2 0 l Metatarsal Tarsal Total 5 2 l Table 2 Associated features Association Number Classification Family history Figure 1--Unilateral third-ray middle-phalanx duplication. Polydactyly hands 3 Proximal phalanx No Polydactyly hand/ l Proximal phalanx Yes infantile scoliosis Polysyndactyly 1 Proximal Yes hands phalanx 5 Polydactyly hand/ 1 Proximal phalanx Yes sublingual ranula Cleft palate/cataracts/ 1 Proximal phalanx Yes micropthalmia left proximal phalanx 2 right Syndactyly l Proximal phalanx 2 No Clinodactyly finger 1 Metatarsal 1 No Maeckel-Gruber 1 Proximal phalanx No syndrome/syndactyly toes 2 bilateral Patent ductus l Proximal Yes arteriosus phalanx 1 7th cranial nerve palsy 1 Metatarsal 5 No Figure 2--Bilateral fifth-ray metatarsal duplication. Blauth and Olason's classification. 4 Medical records, operation notes and radiographs were studied to gain information as to the children's age, sex, family history and any associated abnormalities. Results Of the 25 patients, 13 were female and 12 male, with 16 having unilateral polydactyly and nine bilateral, Six of the children with bilateral polydactyly were female and three male, and of these five had symmetrical abnormalities. Eight of the patients showed a family history of polydactyly of hands or feet, i.e. one or more first-degree relatives affected, seven of these being children with bilateral polydactyly. The average age of the patients at initial operation was 29 months. The results of classification of the polydactyly are shown in Table 1. The commonest ray involvement was the fifth with the first and fourth rays jointly next in frequency. The commonest level of duplication was the proximal phalanx with metatarsal duplication the second most common. Of the cases of polydactyly involving the fifth ray most were treated with simple excision of the lateral duplicated element of the ray. The other cases of uncomplicated phalangeal duplication not involving the hallux were treated with excision of the most lateral digit. Of the cases involving the hallux one patient had excision of a rudimentary metatarsal duplication without the use of any more fixation than a firm compression dressing. All other cases involving the first ray required further measures to stabilise the metatarsophalangeal joint with two patients having K-wire fixation and two requiring osteotomies and K-wires to provide stabilisation. Complications were rare in this series with one documented pin-tract infection and one patient requiring further surgery to excise a bony spur following an excision of a fifth-ray phalangeal polydactyly. All patients had a good cosmetic result with no difficulties in walking or shoe fitting.

3 36 Figure 3--Case 1. Unilateralfifth-ray metatarsal duplicationwith syndactyly, which required transpositionof the fifth toe to sit on the sixth metatarsal base. British Journal of Plastic Surgery Figure 4--Case 1. Intraoperativeview showing excisionof the lateral (sixth) toe and medial (fifth) metatarsal duplication. Case 1 A 2-year-old child presented with synpolydactyly classified as fifth-ray metatarsal polydactyly with associated syndactyly to the level of the distal phalanx (Fig. 3). At operation a skin incision was made to permit excision of the most lateral toe whilst allowing for release of the syndactyly. The accessory fifth metatarsal and sixth toe were removed (Fig. 4) and the fifth toe was transferred to the sixth metatarsal base with K-wire fixation (Fig. 5). This was required to give a normal contour to the foot as had the lateral-most elements simply been excised this would have led to the very hypoplastic medial metatarsal remaining as the outermost element. At 1 year's follow-up the child had no problems with walking or shoe fitting and a good cosmetic result. Case 2 Figure 5--Case 1. Intraoperative view demonstrating lateral (sixth) metatarsal transposedto articulatewith medial(fifth) toe. Many of the children had associated abnormalities, as reported in other series, with polydactyly of the hand being the most common and occurring in six patients (24%) (Table 2), compared to similar figures of 13-34% reported in recent series. 3'7 Other associated conditions included digital anomalies, such as syndactyly and clinodactyly, and a spectrum of other disorders. Two more complicated cases required more involved surgery and are described below. A 1-year-old child presented with unilateral fifth-ray metatarsal synpolydactyly consisting of a hypoplastic extra metatarsal lying medially and a lateral extra digit (Fig. 6). The lateral toe was removed along with the medial rudimentary metatarsal and the lateral-most metatarsal was fixed to the more medial duplicated digit and the lateral collateral ligament was reconstructed. This case again demonstrated the occasional requirement to resect a medial hypoplastic element to give improved cosmesis and function. At follow-up 18 months postoperatively the child had a good cosmetic result with no problems with shoe fitting or walking. Discussion This series demonstrates that management of polydactyly of the foot requires careful preoperative assessment, including radiographs, and the classification devised by Blauth and Olason 4 can be used to define accurately the defects present. Most cases of fifth-ray polydactyly had simple

4 Polydactyly of the feet in children: suggestions for surgical management 37 Figure ~-Case 2. Unilateral fifth-ray polydactyly with syndactyly. (A) Radiograph and (B) clinical photograph. excision of the lateral-most digit and it has been suggested previously that this digit should invariably be excised even if the more medial is hypoplastic. 5'6 In the two cases described resection of a medial metatarsal was required as these were so hypoplastic it would not have been possible to maintain satisfactory foot contour with these as the most lateral metatarsals. These cases show the advantage of adequate preoperative imaging to plan surgery. Our series showed that the commonest defects in polydactyly of the foot involve the fifth, or lateral, ray (60% of cases) with the first and fourth next most commonly involved (15% of cases each), which is in keeping with other studies. 3's It has been suggested previously that medial or first-ray polydactyly is relatively common in the West as compared to Japan, where polydactyly occurs more frequently. Our series shows 15% of such cases, similar to figures reported recently from Japan of 8-16%, which did not bear out this difference. 7 In our study, 32% of patients had a family history of polydactyly of hands or feet, nearly all of whom had bilateral defects. This compares to a figure of 10% from a recent Japanese study. 7 The pattern of inheritance of simple polydactyly is autosomal dominant with incomplete penetrance. The genetic defect underlying the synpolydactyly syndrome of syndactyly between fingers three and four and post-axial polydactyly of the foot is known to be associated with the HOX13 gene. 9 Polydactyly is known to be commoner in certain racial groups, for example Negroes have a birth incidence of polydactyly of per 1000 compared to Caucasians who have an incidence of per l~ Five of our patients had first-ray or pre-axial duplication and these required more complex surgical correction than duplications not involving the hallux. A recent paper from Japan describes the treatment of 14 such patients who had a spectrum of defects ranging from complete metatarsal duplication to incompletely duplicated phalanges and who had excision of the most medial digit in all but two cases. 8 The children in our series all had excision of the medial digit, usually with K-wire stabilisation of the joint. This gave solid fixation with no serious complications and good final results with no functional problems seen at follow-up. Many of the children had associated abnormalities, as reported in other series, with polydactyly of the hands being the commonest; this was marked in cases with a family history of the disorder as has been noted previously. 3 Other associated features included digital anomalies such as syndactyly and clinodactyly and a spectrum of other disorders (see Table 2). Polydactyly of the foot is relatively common and encompasses a wide spectrum of abnormalities, which can be multiple and present along with other, more serious defects. We would emphasise that treatment for each patient must be individualised with a treatment plan incorporating functional and aesthetic considerations. In fifth-ray polydactyly it is not always necessary to excise the most lateral elements, even if this is the simplest course, as where the medial element is very hypoplastic this should be excised instead. This can entail more com= plicated reconstruction of the remaining toes, for example switching phalanxes from the medial to lateral metatarsal once the medial metatarsal has been excised. This series demonstrates that adequately planned surgical management of polydactyly of the foot gives good results with few complications, References 1. Fortems Y, De Smet L, Fabry G. Extra digit at the dorsum of the foot: hypoplastic central ray metatarsal duplication. J Pediatr Orthop 1996; 5B: Coppolelli BG, Ready JE, Awbrey B J, Smith LS. Polydactyly of the foot in adults: literature review and unusual case presentation with diagnostic and treatment recommendations. J Foot Surg 1991; 30: Miura T, Nakamura R, Imamura T. Polydactyly of the hands and feet. J Hand Surg 1987; 12A:

5 38 British Journal of Plastic Surgery 4. Blauth W, Olason AT. Classification of polydactyly of the hands and feet. Arch Orthop Trauma Surg 1988; 107: Huurman WW. Congenital foot deformities. In Mann RA, ed. DeVries Surgery of the Foot. St Louis: CV Mosby Co, 1978: Christensen JC, Left FB, Lepow GM, et al. Congenital polydactyly and polymetatarsalia: classification, genetics and surgical correction. J Foot Surg 1981; 20: Watanabe H, Fujita S, Oka I. Polydactyly of the foot: an analysis of 265 cases and a morphological classification. Hast Reconstr Surg 1992; 89: Masada K, Tsuyuguchi Y, Kawabata H, Ono K. Treatment of preaxial polydactyly of the foot. Hast Reconstr Surg 1987; 79: Goodman FR, Mundlos S, Muragaki Y, et al. Synpolydactyly phenotypes correlate with size of expansions in HOXD13 polyalanine tract. Proc Nail Acad Sci USA 1997; 94: Phelps DA, Grogan DE Polydactyly of the foot. J Pediatr Orthop 1985; 5: The Authors Stephen E. Morley MB ChB, BSc(Hons), FRCS, Research Fellow in Plastic Surgery Department of Medical Oncology, Beatson Laboratories, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK. Paul Smith MB ChB, FRCS, Consultant Plastic Surgeon Department of Plastic Surgery, Great Ormond Street Hospital, Great Ormond Street, London WC1N 3JH, UK. Correspondence to Mr Stephen E. Morley. Paper received 28 January Accepted 22 August 2000, after revision. Published online 9 November 2000.