| Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al. | |||
| As in great-toe transplantation, age, hand dominance, occupation, specific requirements for the reconstructed digits, and the general health of the patient are important factors. In thumb reconstruction with the second toe, the presence of at least a small part of the first metacarpal and carpometacarpal joint are of assistance. The longer the metacarpal stump, the greater the mass of thenar musculature remaining, and the better the motion produced by intrinsic muscles. A tendon transfer may be necessary to provide opposition of the second-toe transplant when few or no thenar muscles remain. The short toe extensors can be used as part of these transfers. The short toe extensor muscle mass can also be used to build up thenar and hypothenar mass with a microneurovascular transplant.
Problems with the second-toe transfer include its natural tendency for metacarpophalangeal hyperextension and interphalangeal joint flexion. The range of motion in all joints following toe transplantation is usually not great, particularly if the interphalangeal joints have been pinned in full extension for 4 to 6 weeks to prevent excessive flexion. In children, however, it is possible to get up to 90 degrees of motion at the DIP or PIP of these transplants. When transferred to the thumb position, the second toe does not provide the power of a great toe in grasp and pinch. Also, appearance is less like that of a thumb than in great-toe transfer. |
Another important consideration is the level of the web spaces adjacent to the second toe. The web spaces are located at the midproximal phalangeal level of the toe, and therefore it is often difficult to design flaps on the hand to fill the lateral defects that occur where the web spaces are incised (i.e., there is no lateral skin proximal to the level of the midproximal phalanx, the level of the web space). This anatomy often necessitates that skin grafts be placed on the lateral aspects of the reconstructed digits. The bulky plantar pad over the second metatarsal head must often be thinned to avoid excessive bulkiness in the reconstructed digit. The triangular skin flaps extending from the toe base are usually designed on the plantar and dorsal aspects of the foot, apices facing proximally. Ideally, complete closure of the foot and the reconstructed digit can be accomplished without skin grafts. While planning the flaps, keep in mind that, if skin grafts are necessary, they are better tolerated on the hand than on the foot. Even when the second metatarsal joint and metatarsal shaft are not needed, a more aesthetic closure can be achieved by removing the MT joint and distal metatarsal shaft, decreasing the space between the large toe and third toe. The web space is |
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