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Second or
third toe transplantation has unique
aspects differentiating the procedure
from great toe transplantation. In Asia,
the second toe is more commonly used to
reconstruct the thumb since the large
toe is needed to wear 'Zori' slippers.
Second toe transplants are usually used
in the United States to reconstruct the
index through small fingers. Using
a second toe in thumb and finger
reconstruction differs considerably from
great toe transplantation and requires
attention to several unique aspects of
this procedure.
Surgical
Technique
Both dorsal
and volar incisions are made in a v-y
fasion to allow primary closure of the
donor site with shortening of the second
metatarsal. The extent of the
incision can be carried proximally to
gain vascular length is necessary, and
can go as high up as the anterior tibial
vessels. In most cases, a great
deal of length is not necessary.
The toe is
isolated with both long flexor and
extensor. The arterial pedicle is
the same as in the great toe harvest,
with the venous system used varying from
patient to patient. It the
metacarpal is needed, it must be
remembered that the metatarsophalangeal
joint is primarily an extension joint,
unlike the mecarpophalangea joint in the
hand, which is a flexion joint. In
some people, especially children, there
is reasonable metatarsophalangeal
flexion.
The toe is
anastomosed in the hand with the volar
or dorsal radial system, depending on
the dominance of the toe arterial
supply. The flexor and extensor
are repaired as are the digital
nerves. The bone repair varies,
depending on the remaining phalanx or
metacarpal in the hand.
With
respect to appearance the second toe is
less aethetically pleasing. It does not
resemble the thumb to the extent that a
great toe does: the nail is smaller, the
distal phalanx is not as prominent with
less volar pulp volume, and the second
toe has two interphalangeal joints
rather than one. The toe also has a
tendency to develop a flexion
contracture. The appearance of this can
be quite bizarre and limits thumb
function to a greater degree than a
single interphalangeal flexion
contracture. To avoid an early
post-operative flexed position and later
contracture, care must be taken not to
repair the extensor tendon with too much
laxity. Rather, tension by the EPL
tendon needs to be maintained on the
reconstructed thumb. The toe is also
k-wired with a single wire keeping the
pip and dip joints in full extension.
This can cause some joint stiffness
which is better than flexion
contractures.
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