Polydactyly of the Foot: A Review

Novel Finding of an Excess Bone in Postaxial Polydactyly of the Foot

Background

Postaxial polydactyly is a common congenital foot anomaly. However, the severity of the anomaly varies from simple cases with only soft tissue duplication to complex cases with bone and joint disorders. In our clinical practice, we found a new morphological anomaly of postaxial polydactyly. We encountered several cases of postaxial polydactyly with bone fragments located between the fourth and fifth toes. The bone fragments were independent of the joint cavity. The mechanisms underlying its development remain unknown because it is a novel disorder. In the present study, we investigated the characteristics of the excess bone to formulate an embryological hypothesis.

Methods

We examined the frequency and trends in the occurrence of excess bone using data from photographs and radiographs of these cases. An example of a disorder similar to excess bone is mosaic-like alignment, as reported by Iba et al. We also compared the characteristics of the mosaic-like alignment with those of the excess bone. Based on these data and existing embryological knowledge, we hypothesized the origin of the excess bone.

Results

Excess bone and mosaic-like alignments showed different characteristics. Therefore, both were considered completely different disorders. We hypothesized that excess bone was caused by damage to the interdigital ectoderm immediately before interdigital programmed cell death.

Conclusions

We encountered a new form of postaxial polydactyly. This can be a factor influencing the treatment strategy because it can affect alignment and stability.

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.

Neonatal Assessment: Put Your Best Foot Forward

BACKGROUND

Assessment of the foot is an essential part of the newborn examination. Foot abnormalities range from an isolated deformity due to intrauterine positioning to a functional impairment due to a structural malformation. The purpose of this article is to review assessment, abnormal findings, and current treatment options of common foot deformities.

EVIDENCE ACQUISITION

A review of literature was conducted using keywords in PubMed, Google Scholar, and CINAHL databases from 2018 to 2023.

RESULTS

Although assessment techniques for the neonatal foot remain the same, recent nonsurgical treatment options are available for a variety of neonatal foot deformities. Early recognition allows for proper evaluation of foot deformities and corrective measures.

IMPLICATIONS FOR PRACTICE AND RESEARCH

Neonatal providers equipped with knowledge of common foot problems can provide support and anticipatory guidance to families.

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.

Preaxial polydactyly of the foot in an adult patient diagnosed by X-ray after a trauma

Polydactyly, or hyperdactyly, is a frequent malformation, with a reported incidence between 0.37 and 1.2 per 1000 live births. Most cases encountered in medical practice are sporadic cases, usually presenting one-sided manifestations. More frequently, polydactyly can be detected prenatally through an ultrasound examination, if not, it is usually diagnosed at birth, during the first physical examination. Although the clinical diagnosis is relatively easy in patients with manifest cases, it can sometimes be present with mild or partial forms that are not clinically evident on physical examination, resulting in later diagnosis and treatment. We reported a particular case of polydactyly of the foot not clinically manifest, diagnosed in a 39-year-old Caucasian Male patient with a history of recurrent localized pain in the big toe often associated with subungual bleeding, since he was a child who came to our emergency room following a car accident. Polydactyly is a frequently reported congenital malformation which may present in many different varieties of deformities. In this case, the X-ray, which was required after a car accident, leads to the incidental diagnosis of polydactyly in an adult patient. As described, because of the functional limitations related to this malformation, as well as to limit recurrent pain, and subungual anomalies, the patient underwent to a surgical correction to improve its quality of life.

A Seven Toes Foot: Case Series as an Isolated Dysplasia With Variety of Appearance

A seven toes foot is an extremely rare foot disorder. It may appear as part of a complex limb dysplasia or as an isolated deformity. We present five children with a seven toes foot. Supernumerary bones of the foot were found either as isolated duplicated great and little toe either affecting proximal bones, including the metatarsals or midtarsal bones, characterized as mirror foot. Radiological examination with X-rays was adequate for the evaluation of the affected foot. All patients had dysplasia isolated to the foot. Spine dysplasia was found in one child, and a hypoplastic unilateral little finger in another. The affected foot had a plantigrade shape without leg length discrepancy (LLD). The aesthetic of the enlarged foot with the problems of shoe wear was the main concern of the dysplasia. Surgical treatment was provided after the walking age. Surgery was demanded to provide a cosmetically acceptable foot. Removal of the supernumerary rays, either the medial or the central rays, was performed after the radiological evaluation. Our results were satisfactory, and none of our patients required additional interventions, although a mild varus position of the great toe was still observed in one patient.

Pediatric Forefoot Deformities

This article explores different pediatric forefoot deformities including syndactyly, polydactyly, macrodactyly, curly toe, and congenital hallux varus. The epidemiology and genetic background are reviewed for each condition. Preferred treatment options and recommended surgical techniques are discussed with review of the current literature.