Polydactyly, triphalangism of the thumb, and carpal abnormalities in a family

Triphalangeal Thumb Reduction Osteotomy Through a Versatile Spiral Approach

Triphalangeal thumb (TPT) is a congenital condition characterized by the presence of an additional phalanx. Variable degrees of thumb deformity, malalignment, and excessive length are common features. Impairment of hand function has been reported with TPT probably secondary to anomalistic long thumb incompatible with fine hand skills. Abnormal thumb appearance moreover represents a major psychological concern from patient's perspective. Both removal of the extra phalanx and phalangeal reduction osteotomy with resection of the unhealthy extra interphalangeal joint are established methods for correction of the associated excessive thumb length. In our experience, however, previous surgical approaches have not been able to sufficiently reduce the skin and soft tissue surplus, which exists after reduction osteotomy through classic circular incisions. We thus feel that conduction of TPT reconstruction through a spiral incision provides a safe and generous anatomic exposure required for simultaneous reduction of skeletal and soft tissue components.

[Does the thumb have two phalanges or three? Development of ideas since Aristotle]

Many controversies mark the long road of the history of anatomy. The hand is not exempt of them. Even Galen's clear thinking, founded on the strict determinism between the structure of an organ and its function, and based on animal dissection, was criticized. In view of the structural complexity of the hand, we will limit our study to one of the most symptomatic conceptual disagreements: whether the human thumb has two or three phalanges, according to whether we include the first metacarpus, or if the thumb's first phalanx is considered as the initial element. According to the latter theory, there is a missing element in the first digital row, and this missing element is the metacarpus. This theory is ancient and its evolution throughout history is discussed in our study. Finally, we explain the origin and bases of the reasoning that led us to suggest the word 'metaphalanx' to designate the first metacarpus.