Orthopedics - Oleksa A.P. 2006

Congenital malformations of the upper extremity
Congenital hand malformations
Polydactyly and polyphalangism

Polydactyly is a condition characterized by an extra number of fingers on the hand or toes on the FOOT. Polyphalangism is an increased number of Phalanges, such as when the thumb, or sometimes both thumbs, has three phalanges, or when a duplicated distal phalanx is present on any digit.

The number and degree of development of supernumerary digits and phalanges can vary. Hexadactyly is the most common presentation, though cases with two, three, or even five extra fingers have been documented (Fig. 126).

Polydactyly can be either unilateral or bilateral.

Supernumerary digits may possess a complete Anatomical Structure, developing normally and remaining fully functional; alternatively, they can be anatomically defective (such as a rudimentary phalanx of the thumb suspended by a slender soft-tissue pedicle).

Polyphalangism may affect one or more fingers or toes. The most common presentation is unilateral distal biphalangism of the terminal phalanx of the thumb or great toe, though a thumb may also feature three normally developed phalanges.

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Fig. 126. Bilateral polydactyly of the hands.

In some cases, only a partial cleft of the distal phalanx occurs. In all such cases, the nail on the accessory phalanx is normally developed, whereas splitting of the distal portion of the bone phalanx results in a wide, undivided nail. Polydactyly may be combined with Syndactyly and other hand malformations.

M. V. Volkov suggests dividing polydactyly into three types: bifurcation of the border digit (the first or fifth); replacement of the border digits with multiple extra digits; and the presence of accessory rudimentary digits.

While numerous variants of polydactyly and polyphalangism exist, Diagnosis is typically straightforward. Upon discovering extra digits in a newborn, parents immediately seek medical assistance.

It is worth noting that a rudimentary digit or phalanx attached by a slender soft-tissue pedicle is not always removed surgically, as traditional practices often involve tying off the pedicle with a thread so that the ischemic digit eventually withers and drops off.

In cases of polydactyly and polyphalangism, preoperative radiography of the hands is essential to determine the condition of the digit, its relationship to adjacent fingers, its functional capacity, and its cosmetic appearance.

There are instances where a supernumerary digit proves superior both cosmetically and functionally because it articulates with an accessory metacarpal bone and exhibits a normal anatomical structure. In such cases, the surgeon, in consultation with the patient, must determine the optimal surgical strategy—preserving the best-functioning digit while excising the redundant digit and its corresponding metacarpal bone, if present.

During surgery, the Base of the proximal phalanx must not be left behind; retaining the epiphyseal Cartilage will allow continued longitudinal bone growth, which often necessitates revision surgery.

Surgeries are performed under general anesthesia. Tissue incisions are made at the base of the supernumerary digit or phalanx, ensuring an adequate Skin margin to allow tension-free closure of the wound for optimal cosmetic results.