Secondary complications in Wassel II & IV thumb duplication: a comprehensive review of preventive measures.

OBJECTIVES: Thumb duplication is one of the most challenging pediatric reconstructive hand surgeries. Wassel types II and IV are the most frequent, but also the most complex reconstructions as the duplication arises at the joint level. Ablation and reconstruction, the most widely used technique, aims at achieving a stable, well-aligned, mobile and esthetically acceptable thumb. The paucity of reliable surgical guidelines leads to high rates of suboptimal surgical outcomes. This review evaluated the various reconstruction techniques detailed in the literature and highlighted useful methods to prevent common secondary complications. METHODS: A comprehensive PubMed and Embase literature search was made. Inclusion criteria were Wassel type II and/or IV, pediatric patients, and primary or secondary surgeries. Exclusion criteria were Bilhaut-Cloquet reconstruction and its modifications. Techniques were screened, collected and analyzed for the following secondary complications: instability, axial deformity, and contour deformity. RESULTS: Thirty-two articles met the inclusion criteria and were reviewed. Postoperative instability was prevented by tightening the joint capsule by plication, advancement of the volar plate, or reconstruction of the collateral ligaments using a periosteal flap or the double-breasting technique. Axial deformity was prevented by arthroplasty, shaving a triangular portion of the metacarpal head, centralization of eccentric tendons, pulley reconstruction using flexor pollicis longus, or corrective osteotomies of the phalangeal or metacarpal bones using the wedge or oblique techniques. Limited range of motion was prevented by first webspace Z-plasty, and soft-tissue contouring was addressed by planned skin incisions and soft-tissue augmentation. Preoperative, perioperative and postoperative considerations, including splinting, imaging and immobilization, were also described. CONCLUSION: Despite the ongoing advances and abundant knowledge in reconstructive strategies for thumb duplication, there are few studies that reviewed and analyzed the various reported options. This review provides physicians and trainees with guidance in surgical planning to prevent common secondary complications. Further research should focus on the development of standardized assessment tools, enabling reliable prospective comparative studies on thumb duplication reconstruction. LEVEL OF EVIDENCE: IV.

Modified Bilhaut-Cloquet procedure for Wassel type III-IV polydactyly.

BACKGROUND: To investigate the functional and aesthetic results of a new modified Bilhaut-Cloquet procedure for the treatment of Wassel type III-IV thumb polydactyly. METHODS: Thirteen patients with Wassel type III-IV thumb polydactyly who visited the Department of Orthopedics of Hebei Provincial Children's Hospital from 2019 to 2022 were selected. The surgical procedure involved a modified Bilhaut-Cloquet surgery, where two-thirds of the distal part of the dominant finger was retained as the p body of the reconstructed thumb. The triangular bone block of the ablated distal thumb that did not contain the epiphysis and articular cartilage was sutured and fixed, and the neurovascular flap of the ablated distal thumb was used as an augmenting segment of the reconstructed thumb, with the nail bed and nail matrix exquisitely sutured. The evaluation performed according to the Japanese Society for Surgery of the Hand (JSSH) system. RESULTS: All 13 children showed bone healing, no wound infection, nonunion, or deformity healing. None of the children showed a significant reduction in the active and passive mobility of the thumb postoperatively compared with preoperatively. Postoperative evaluation was performed based on the JSSH score, with a mean of 17.15 points (14-19 points), with 11 children rated as excellent and two as good. No severe nail ridges, nail gaps, or nail split deformities of the thumb were observed postoperatively. Postoperative metacarpophalangeal and interphalangeal joint movements were not reduced compared with preoperative movements. All parents were satisfied with the appearance and function of the reconstructed thumb. CONCLUSION: The modified Bilhaut-Cloquet procedure designed in this study was satisfactory for Wassel type III-IV thumb polydactyly without affecting the stability of the interphalangeal joints and preserving joint mobility. The postoperative thumb has a comparable circumference and nail width and was cosmetically and functionally satisfactory, especially for the asymmetric two thumbs, which achieved favorable results.

Lower Extremity Polydactyly Does Not Disturb Finding One's Feet.

Little is known about functional outcomes in children with treated lower extremity polydactyly (LEP). No classification system has been shown to be prognostically useful for functional outcomes. This study investigates whether children with treated LEP learn to walk at an age comparable to the population and whether the SAM (severity of syndactyly, axis deviation and metatarsal involvement) classification system is prognostically useful. In a retrospective cohort of 18 patients, we tested for associations between patient characteristics and SAM scores, age at learning to walk, and ability to fit off-the-shelf shoes. The proportion of children with treated LEP able to walk at 18 months of age was compared with the general population. We found no association between the age at which the 17 participants learned to walk and the severity of syndactyly (p = .214), axis deviation (p = .723) and metatarsal involvement (p = .781), nor between the proportion of patients able to wear off-the-shelf shoes compared to those requiring extra wide off-the-shelf shoes and the severity of syndactyly (p = 1.000), axis deviation (p = 1.000) and metatarsal involvement (p = 1.000). We found a trend between older age at surgery and the need for extra wide off-the-shelf shoes (OR = 1.008, p = .080). We found no significant difference in the proportion of children able to walk at 18 months between our patients (proportion = 1.00) and the general population (proportion = 0.95) (p = 1.000). We found no significant association between different SAM scores and functional outcomes, and none in the proportion of children able to walk at 18 months between treated LEP patients and the general population.

Morphologic Changes in Postaxial Polydactyly of the Foot: A Standardized Quantitative Analysis Using the Watanabe-Fujita Classification.

BACKGROUND: Postaxial polydactyly of the foot is one of the most common congenital abnormalities. A wide forefoot, short toe, and lateral joint deviation are associated with aesthetic and functional outcomes. This study used the Watanabe-Fujita classification to characterize the preoperative and postoperative skeletal morphology of postaxial polydactyly of the foot. METHODS: This retrospective study included 42 patients (51 feet) with postaxial polydactyly treated at age 1 year. Radiographs taken at ages 0 and 3 to 4 years were used for morphologic analysis. The length of the reconstructed toe, the distance between the fourth and fifth metatarsals, and joint deviation angles were measured. The length measures were standardized using the length of the third metatarsal. Morphologic characteristics were compared based on the Watanabe-Fujita classification at ages 0 and 3 to 4 years. Long-term outcomes were also evaluated in patients followed up for longer than 6 years. RESULTS: The fifth-ray proximal phalangeal subtype had the shortest toe length both at ages 0 and 3 to 4 years. Proximal phalangeal joint lateral deviation improved postoperatively in 78% of patients with the fifth-ray middle phalangeal subtype, regardless of reconstruction type. There was no significant change in proximal phalangeal joint deviation between ages 3 to 4 years and 7 years or older. A residual metatarsal was associated with lateral metatarsophalangeal joint deviation and a wide intermetatarsal distance, and required revision surgery. CONCLUSIONS: Morphologic changes of postaxial polydactyly of the foot were successfully characterized using the Watanabe-Fujita classification. This classification could be useful for planning surgical strategies and anticipating morphologic outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Classification of radial polydactyly based on physical characteristics.

BACKGROUND: Previous classifications in polydactyly of the thumb were by the level of duplication on radiography. This study aimed to develop a practical algorithm based on physical characteristics for treatment guidelines. METHODS: The polydactylies were stratified using four physical characteristics: floating, symmetry, dominant side, and joint angulation/nail size. The algorithm identified the hypoplastic type and then stratified the polydactylies as symmetric and asymmetric. The asymmetric type was divided into ulnar dominant and radial dominant. The symmetric type was divided into adequate type and inadequate type. The prediction of treatments was studied retrospectively by the distribution of surgical procedures in 500 patients with 545 affected thumbs, by the new classification and the Wassel-Flatt classification. RESULTS: Of the 545 polydactylies, 78 (14.5%) were categorized as the hypoplastic type, 369 (67.5%) as the ulnar-dominant type, 8 (1.5%) as the radial-dominant type, 70 (12.8%) as the symmetric adequate nail type, and 20 (3.7%) as the symmetric inadequate type. Treatments were excision and reconstruction in 403 polydactylies (73.9%), simple excision in 135 polydactylies (24.8%), and the Bilhaut-Cloquet procedure, ray amputation, and on-top plasty procedures were only performed in 7 polydactylies (1.3%). The distribution of surgical procedures was distinct among the new classification types and was similar among the Wassel-Flatt types. CONCLUSIONS: The new classification stratified polydactylies by physical findings in a stepwise manner. Though surgical technical details are not included, this simple classification is useful for paediatricians and parents to understand how a surgical decision is made. LEVEL OF EVIDENCE: Diagnostic Level IV.

Postoperative deviation in Wassel types II and III radial polydactyly: a retrospective analysis of 73 thumbs.

This study examined the relationship between osteochondral stability and postoperative deviation at the interphalangeal (IP) joint in Wassel types II and III radial polydactyly. Cases with cartilaginous fusion between the radial distal phalanx and the proximal phalanx were classified as type IIB, while the remaining cases were categorized as type IIA. In conventional surgery, the cartilage was routinely resected on the radial aspect of the proximal phalangeal head, while in the modified procedure, this was preserved to avoid postoperative radial deviation. Postoperatively, there was no significant difference between both procedures in type IIA thumbs regarding IP joint deviation, whereas in type IIB/III thumbs, IP joint deviation was significantly higher in the conventional group (mean 19° [SD 16°]) compared to the modified group (mean 0.8° [SD 4.9°]). Surgeons should exercise caution against excessive cartilage excision to preserve osteochondral stability during procedures, especially for type IIB and III radial polydactylies.Level of evidence: IV.

Complications after radial polydactyly surgery: analysis, prevention and management.

Long-term follow-up after surgical correction of patients with radial polydactyly might reveal unexpected or undesired outcomes that are accentuated by growth. It should be stressed that assessment of outcomes differs considerably by the system used. Preoperative examination can elucidate the underlying pathological anatomy of these anomalies and consequently, these anatomical differences should be corrected as much as possible during the first operation to prevent worse outcomes at long-term follow-up. In various long-term studies, the reoperation rate was in the range of 7%-28%, with the most common reasons being deviation, instability, nail deformity and suboptimal appearance. Most unfavourable results occur during growth and are frequently revealed only at longer-term follow-up. Concentration of care to a few centres is advised since these malformations occur in small numbers and experienced surgeons tend to have better results. Consensus on the used assessment system and multicentred studies are essential in future to better understand how we can prevent reoperations.

Prenatal Torsion of Radial Polydactyly: A Gangrenous Mass at the Base of the Thumb.

A patient was born with a mass at the base of the thumb approximately 1.5 cm in diameter on the radial side of the fingers. The mass had globular swelling filled with hemorrhagic fluid and was dark red. X-rays and histology of the excised specimen suggested the diagnosis of gangrene and torsion of polydactyly. Prenatal torsion of polydactyly is not a common occurrence; moreover, prenatal torsion of polydactyly has only been found in ulnar polydactyly. Our case is a novel case of radial polydactyly that was gangrenous at birth owing to prenatal torsion. Diagnosing such a mass at the base of the thumb is important.

On-top plasty combined with modified Bilhaut-Cloquet procedure for reconstructing complicated radial polydactyly.

PURPOSE: To present a surgical technique of combining the on-top plasty with modified Bilhaut-Cloquet procedure for reconstructing a rare type of complicated radial polydactyly and evaluate the outcomes. METHODS: Fourteen complicated radial polydactyly in 13 patients were corrected by combining the on-top plasty with modified Bilhaut-Cloquet procedure. Osteotomies were performed as required, and the acral part of the ulnar thumb was transposed onto the proximal part of the radial thumb. The distal parts of the two thumbs were isolated as neurovascular pedicled composite tissue flaps, including part of the distal phalanx and nail bed, and were attached together in an extra-articular way. The tendons were rebalanced, and the nail bed was reconstructed. Objective and subjective outcomes were assessed. RESULTS: The average follow-up time was 32.4 months (6-60 months). All reconstructed thumbs were rated as good in appearance and function. The mean Vancouver Scar Scale score was 1.3 (range 1-2) and the mean Wang-Gao score of the reconstructed thumbnail was 9.4 (range 8-11). The Tada score for the function of the reconstructed thumb was 5.5 (range 5-6). The main active range of motion (ROM) of the interphalangeal joint (IPJ) was 2.1-38.9°. All parents were satisfied with the outcomes. CONCLUSIONS: Because of the diverse manifestations of thumb polydactyly, individualized surgical treatment is recommended, and careful preoperative planning should be made with the principle of combining the best parts of the two thumbs. By combining an on-top plasty with modified Bilhaut-Cloquet procedure, a satisfactory result can be achieved for treating complicated radial polydactyly.

Tourniquet-Related Nerve Injury Following Reconstructive Surgery for Wassel Type IV Preaxial Polydactyly of 13-Year-Old Boy: A Case Report.

BACKGROUND Congenital thumb duplication comes under the Wassel type IV classification is the hypoplastic variety, with the extra digit growing from the dominant thumb's soft tissue alone. Excising the hypoplastic finger while reconstructing for the retained one has been the most adopted approach. Tourniquets are commonly utilized tools in orthopedic surgeries to reduce the amount of blood, thus enhancing the visibility. Unfortunately, tourniquet-related nerve injury (TNRI) is gaining more attention as a serious complication of tourniquet use in surgery. CASE REPORT A 13-year-old Asian boy with preaxial polydactyly Wassel type IV of the right hand underwent reconstruction surgery. A pneumatic tourniquet was applied at 200 mmHg on the right mid-upper arm and maintained for 90 min. After the surgery, the patient had total weakness with numbness, tingling, and burning sensation from his right upper arm to his fingertips. The neurological examination and nerve conduction studies (NCS) results were consistent with axonotmesis lesions. Pharmacological and physical rehabilitation therapy had successfully restored full motoric and sensory function after 6 months. CONCLUSIONS Nerve injury should be acknowledged as a possible complication from routinely-utilized tourniquets in orthopedic surgeries. Our cases may expand the need for further studies to establish a guideline for tourniquet use and TRNI management.

Ulnar dimelia - a review of 24 cases.

Ulnar dimelia is a very rare unilateral congenital upper limb anomaly (CULA) affecting the whole extremity. Treatment remains difficult because of the complexity and multi-level involvement. Twenty-four cases with duplicated ulna, absent radius and polydactyly from seven European centres were reviewed according to a structured list of parameters. At first consultation, median age 8 months (1-178), the shoulder movement was good in 17 patients or poor in six, and the median passive elbow range of motion was 20° (0°-90°). The resting wrist position was flexed in 22/24 patients. Following stretching and splinting, elbow surgery included resection of the lateral proximal ulna in 11 patients and muscle transfers in six to improve passive movement and increase active elbow motion, respectively. Tendon transfers were performed in eight wrists and a pollicization or pseudo-pollicization in 23 patients. Overall, patients demonstrate acceptable function postoperatively. Guidelines for treatment of this severe CULA are presented.Level of evidence: IV.

A minimally invasive technique for residual zigzag deformities of the thumb.

OBJECTIVE: This study aimed to introduce a minimally invasive technique in correcting residual zigzag deformities after early treatment of thumb duplication followed by fixation with a cemented frame. METHODS: Nineteen patients (14 males, 5 females; mean age, 12 years; age range, 8-14 years) with residual zigzag thumb deformities were treated with the minimally invasive technique from 2017 to 2019. The function and cosmesis of the thumbs were assessed using the Japanese Society for Surgery of the Hand. RESULTS: The mean period between the first and the second operations was 35 months (range, 12-84 months). There were Wassel types III (n=4), IV (n=13), and V (n=2) residual zigzag thumb deformities. Preoperatively, the mean alignment deformities of the interphalangeal and metacarpophalangeal joints were 23° (12-42°) and 18° (11-33°), respectively. The mean function and cosmesis of the thumbs were 12 points (range, 8-14 points). There were 1 fair and 18 poor scores. At the final follow-up (mean, 28 months; range, 24-33 months), the mean alignment deformities of the interphalangeal and metacarpophalangeal joints were 1° (0-4°) and 18° (0-4°), respectively. The mean function and cosmesis of the thumbs were 18 points (range, 16-20 points). There were 5 excellent results, 13 good results, and 1 fair result. CONCLUSION: Residual zigzag thumb deformities can be successfully corrected with the minimally invasive technique, resulting in good functional and cosmetic outcomes. The technique can be used as an alternative in selected cases. LEVEL OF EVIDENCE: Level IV, Therapeutic Study.

Triplication and tetraplication of the thumb: a modification of the Rotterdam classification.

We proposed a modification of the Rotterdam classification for thumb triplication and tetraplication. Twenty-one patients were included (24 cases of thumb triplication and four cases of tetraplication). These were analysed and classified according to a modification of the Rotterdam classification involving three steps; from the radial to ulnar side, we first identified each thumb on radiographs and gross appearance to divide into triplication or tetraplication. Second, we define the levels of duplication and established the nomenclature. Third, the aberrant features and their location were assigned for each thumb, again from radial to ulnar side. A surgical algorithm was also proposed. This modified classification may be helpful for characterizing the rare conditions of thumb triplication and tetraplication for use in patient and management and communication between surgeons.Level of evidence: III.

Midterm Surgical Outcomes of Duplicated Thumbs According to New Classification.

BACKGROUND: Surgical outcomes of duplicated thumbs differ depending on the branching type. The authors developed a new classification system and report surgical outcomes with an average 10.2-year follow-up. METHODS: A total of 529 patients with 562 duplicated thumbs were reviewed. Surgical anatomies were compared with radiographs, and then a new classification system was developed based on branching level and bone shape observed on the radiograph: distal type (D-type), including Wassel types I and II; proximal type (P-type), including Wassel types Ⅲ and Ⅳ, and four subdivisions (Po, Pa, Pb, and Pc) according to bone structure; and metacarpal type (MC-type), including Wassel types V and VI. All hands were assessed using the Japanese Society for Surgery of the Hand evaluation form, and factors causing poor outcomes were analyzed. RESULTS: There were 25% D-type, 59% P-type, and 14% MC-type hands; 2% of hands were not classified. Overall, 351 hands (63%) were directly assessed when patients reached 5 years of age. Seventeen percent of hands had fair results. Good results were achieved in 90% of D- and Po-type hands. Pa-, Pb-, Pc-, and MC-type hands had lower Japanese Society for Surgery of the Hand scores than did D- or Po-type hands. Pa- and Pb-type hands tended to develop interphalangeal joint malalignment and instability, whereas Pc- and MC-type hands developed disorders in the metacarpophalangeal joint with growth. CONCLUSIONS: The authors' new classification system clarifies the potential pitfalls for each type of duplicated thumb. More than 90% of D- and Po-type hands obtained good results. Care should be taken with interphalangeal joint reconstruction for Pa- and Pb-type hands. Meticulous reconstruction of the metacarpophalangeal joint is essential for Pc- and MC-type hands. This analysis provides important information for surgeons and patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, IV.

Prediction of Surgical Outcomes of Radial Polydactyly From the Wassel-Flatt Type and Symmetry of Duplication.

BACKGROUND: The Wassel classification is commonly used for cases of radial polydactyly but has not been used to predict surgical outcomes. This study aimed to investigate the predictive factors of surgical outcomes using the Wassel type and symmetry of duplication. METHODS: Forty-five patients with 47 radial polydactylies were reviewed using the Japanese Society for Surgery of the Hand (JSSH) scores 4.6 years after minor thumb excision and reconstructive surgery. The symmetry index was defined as the metaphyseal width ratio of the minor thumb to the dominant thumb. The relationships between the JSSH scores and operation age, sex, side, follow-up duration, Wassel type, symmetric index, divergent angle, and joint angulation were analyzed by linear regression. RESULTS: The mean JSSH score of the 47 thumbs was 18.3 points (range, 15-20). Five thumbs had fair or poor outcomes (scores <17), all of which were Wassel type IV. The hypoplastic type had a better JSSH score (19.4) than other Wassel types. The symmetric index had a negative relationship with JSSH scores, especially for Wassel type IV (r=-0.68, P =0.001). Linear regression revealed that the symmetric index was the only independent factor significantly associated with JSSH scores among Wassel type IV polydactylies ( P <0.05). The receiver operating characteristic curve suggested a symmetric index <0.74 could predict good or excellent outcomes. CONCLUSION: The symmetry of the 2 duplicated thumbs is an important factor for surgical outcomes. The Wassel type IV polydactylies with a symmetric index >0.74 are at greater risk of fair or poor outcomes after excision and reconstruction, and further studies are warranted to confirm whether the Bilhaut-Cloquet procedure is a good choice. LEVEL OF EVIDENCE: Level IV-Case-control study.

Surgical Excision of Postaxial Polydactyly Type B in the Office Setting.

BACKGROUND: Simple postaxial polydactyly (type B) is a common congenital hand malformation often treated by suture or clip ligation. METHODS: We present a case series of patients with simple postaxial polydactyly treated by surgical excision using local anesthesia in an office setting. RESULTS: The procedure was performed on 78 digits in 48 children with a mean age of 10.2 weeks. There were no intraoperative or early postoperative complications. A follow-up by phone interview was performed at an average of 3.2 years postoperatively. All patients were reported to be pain-free and have normal function without a perceived range of motion deficits. All parents selected the highest level of satisfaction regarding cosmetic outcomes and overall experience with the procedure. CONCLUSIONS: These results demonstrate that an office-based surgical excision is a safe, effective, and economical treatment option and has developed into our standard of care for this common condition.

Usefulness of Intraoperative Arthrography for Postaxial Polysyndactyly of the Foot.

BACKGROUND: Surgery for polydactyly of the foot aims to achieve good cosmesis and improve shoe fitting. An accurate understanding of toe morphology will help to minimize the skin incision or optimize the surgical plan before incision. However, it is difficult to determine the shape of the articular surface using radiographs of children with immature bone. We performed arthrography during surgery for postaxial polydactyly of the foot to assess the cartilaginous structures. The purpose of this study was to investigate the usefulness of arthrography in postaxial polydactyly of the foot. METHODS: We included 36 digits of 31 patients (16 males and 15 females), including 5 bilateral cases. The age at surgery ranged from 9 to 75 months (mean, 20 mo). Intraoperative arthrography was performed and all radiographs and arthrograms were reviewed and classified by 3 observers using the Watanabe classification. The absolute percentage agreement between the observers was calculated. The senior author assigned the arthrograms as the reference. The types determined by the other 2 observers using radiographs and arthrograms were compared with the reference. RESULTS: Full agreement occurred in 66.7% of the radiographs and in 75% of arthrograms. The mean kappa coefficient was 0.58, indicating fair agreement, between the reference and the radiologic assessment, while it was 0.81, indicating excellent or almost perfect agreement, in the evaluation using arthrograms. CONCLUSIONS: Intraoperative arthrography is an easy and reliable diagnostic method that can be used to determine the detailed articular shape. LEVEL OF EVIDENCE: Level III.

Update of surgical treatment of polydactyly.

PURPOSE OF REVIEW: Polydactyly presents with variable extent of duplication and may involve preaxial/radial (hand)/medial (foot), postaxial/ulnar (hand)/lateral (foot) or central duplication. This review will summarize recent advancements in the surgical management of this common entity. RECENT FINDINGS: Modifications to classification systems aim to help guide surgical management of polydactyly. Attempts have been made at quantifying preoperative angulation of the duplicated digits to minimize the chance of residual or recurrent deformity after surgical reconstruction. As a result, consideration should be given to the need for soft tissue correction vs. osteotomy to optimize the clinical outcome. On-top plasty is an option that may be beneficial in 'unequal' preaxial polydactyly, where neither duplicate is preferred on its own. SUMMARY: Polydactyly is one of the most common congenital anomalies in the hands and feet. Determination of surgical intervention often begins with classification systems that exist, which primarily separate these into preaxial, postaxial, and central. Referral for surgical consideration is indicated, given the management is often surgical.

Central polydactyly of the foot: An experience of a treatment of 22 patients.

BACKGROUND: The central polydactyly of the foot is a rare congenital disorder, and its characteristics are not well known. This study aims to investigate its disease concept. METHODS: We obtained the medical records of patients who were treated surgically for central polydactyly of the foot at our hospital during a 32-year period from 1990 to 2021 retrospectively. We compared our clinical data with other case series reports to investigate the characteristics of this disorder further. RESULTS: There were 22 patients (13 males and 9 females) included in our case series. Unilateral and bilateral involvements were observed in 19 (right side: 6 patients; left side: 13 patients) and 3 patients, respectively. The second toe is the commonest duplicated toe (observed in 19 toes). 19 patients had distally duplicated toes (with normal metatarsal bone). Proximally duplicated toes were observed in only two patients. CONCLUSIONS: The incidence of central polydactyly of the foot is almost equal among male and female, and bilateral involvements are few. As this abnormality is rarely reported, further investigations are needed to clarify the clinical presentation of central polydactyly of the foot.