Crossed polydactyly.HS Hosalkar, H Shah, P Gujar, AD Kulkarni
Bai Jerbai Wadia Hospital For Children, Parel, Mumbai, India. , India
A common and conspicuous congenital hand anomaly, polydactyly commonly involves only the hand or the foot. Polydactyly involving both hands and feet is rare. We herewith report two cases of Crossed Polydactyly (Type I) and review the literature.
Keywords: Case Report, Child, Female, Fingers, abnormalities,Human, Infant, Newborn, Male, Polydactyly, Toes, abnormalities,
Historically, crossed polydactyly was recorded in biblical literature as long as 3000 years ago.
Temtamy and McKusick in their classification of polydactyly used as the major criterion whether the polydactyly was isolated or part of a syndrome. Within the broad groups, each case of polydactyly was defined as preaxial or postaxial. Preaxial in the upper extremity means the radial side of a line bisecting the long finger and in lower extremity, on the tibial side of a line bisecting the second toe. Postaxial refers to the ulnar or fibular side, of these lines respectively. Different mechanisms of heredity seem to be involved in each of these types of polydactyly,.
There have been sporadic report of individuals with both preaxial and postaxial polydactyly and in extreme rare cases of crossed polydactyly.
27-day-old neonate, an Indian male child presented with extra digit in both the hands and feet. He was the second child of consanguineous marriage with maternal grandfather giving history of polydactyly. The perinatal history was normal.
On examination, there were six digits in each hand. Both feet had duplication of great toes with preaxial digits articulating with a common metatarsal. The postaxial digits in the hands were floating, with no palpable bones or active movements. The other toes in the feet were essentially normal. Radiological examination revealed preaxial polydactyly with extra toe at 30( angulation to the first metatarsal. Hands revealed floating postaxial polydactyly without any bony element.
A seven-year-old Indian girl, born out of non-consanguineous marriage as a second child. The earlier sibling had died as a stillbirth. This girl was born at full term, uneventful pregnancy with no perinatal and prenatal complications and weighed 4400 gm.
On examination she had crossed polydactyly of both hands and feet, feet being preaxial and hands postaxial. Further clinco-radiological examination revealed no other congenital anomaly.
The term Crossed polydactyly refers to postaxial polydactyly of the hands combined with preaxial polydactyly of the feet (Type I) or preaxial polydactyly and the hands combined with postaxial polydactyly of the feet (Type II). As with polydactylism in general, crossed polydactyly must be expected to occur either as an isolated phenomenon or as a part of syndrome and are rare.
Crossed polydactyly is usually associated with some other anomaly such as syndactyly. Type I is two times more common than Type II. Polysyndactylism is inherited as an autosomal dominant trait, as are almost all isolated malformation of the limbs. However when crossed polydactyly is associated with malformation syndrome, the pattern of inheritance is often autosomal recessive.
An epidemiological analysis in a birth sample of over 4 million aggregates from two comparable birth series, was carried at by Castilla et al, in accordance with a joint Latin American and Spanish study. Crossed polydactyly was present only in 45 cases and most common among them was Type I. family history was positive in 12 cases, one patient had consanguineous parents. This highlights the rarity of this presentation.
In a study carried out by Handforth and published in 1950, he found that polydactyly was most common in the southern Chinese. In a study sponsored by WHO; preaxial polydactyly was the most common digital malformation found among the Chinese of Hong Kong, Malaysia and Singapore. The relative incidence of postaxial polydactyly is apparently higher among the Oriental race than among any other race. No case of crossed polydactyly is reported in either the Handforth or the World Health Organization articles.
Surgical correction of the bifid digit (especially thumb) is almost always indicated, not only for cosmetic improvement but also for better function. Surgical reconstruction generally is performed when the child is about 18 months of age but no later than five years of age. Later revisions (if required), and fusions needed for late angular deformities and instability may be performed at around 8 to 10 years of age.
In case of duplication of soft parts only (type 1) the use of ligatures (commonly used) around the base of the duplication is not recommended because of reports of fatal haemorrhage. In case of partial duplication of digit, including the osseous structures (type 2), and complete duplication of the ray, including the metacarpal (type 3), the extra digit should be excised through an elliptical incision.
The procedure should be done usually when the child is about one year old.
Type - I crossed polydactyly perhaps reflects a single gene or a set of genes which affect the little finger and the big toe similarly. It is worth emphasizing the extreme variability of penetrance and expressivity of the genes responsive for this congenital malformation.
Dr. M G Yagnik - Consultant Hon. and H.O.D. Paediatric Orthopaedics, Dr. A R Bacha. Consultant Paediatric Orthopaedics, Dr. A N Johari Consultant Paediatric Orthopaedics and Dean. Dr. R H Merchant for having permitted to carry out this analysis and presentation.
[Figure - 1], [Figure - 2]