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The hand and foot, although anatomically different, have many common features. The potential dexterity of the foot and toes is illustrated by arboreal monkeys, who have developed grasp and prehension in their feet to a high degree. In these primates, the hallux is larger than the thumb because the foot is used to grip branches for standing, whereas the hand is used in a hook-like fashion to swing from branch to branch; therefore, the thumb is relatively small and vestigial, with minimal ability for opposition.1 This potential dexterity in the foot is also illustrated by patients with total upper extremity amelia, who learn to feed and clothe themselves, manipulate typewriters, and drive cars entirely with their feet and toes.2 In humans, the great toe and the thumb have almost identical bone length, although the bones are heavier in the foot. Unfortunately, the remaining four toes are considerably shorter than fingers, but they do have a tactile pulp pad and dorsal nail, although it is smaller than a fingernail.
Because of these anatomic similarities, the great toe is ideally suited for thumb reconstruction, and the other toes are well suited for partial digital reconstruction. Total finger length cannot be restored with a toe transplant, except occasionally in the index or little-finger position, where shortness will not be obvious. The unique quality of the pulp of the fingers can be restored with neurovascular island flaps from the great toe or other toes, restoring the compartmented resilient pulp tissue with good sensory reinnervation.
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One can expect the restoration of useful sensation in neurovascular island flaps and toe transplants when the digital nerves of the toe are carefully sutured to the proximal nerves in the hand.
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