10/21/2019    Don Peacock DPM, MS

Re-evaluation of Traditional Angular Parameters for Austin Bunionectomies

The surgeon did a great job with this. The
minimally invasive Austin Akin for bunion
correction is not a new technique. The first
article on the subject was published by Gorman and
Plon in 1983. They used non-fixated osteotomies.
The Wright procedure known as the MICA (minimally
invasive Chevron Akin) is the same procedure many
U.S. MIS podiatrist have employed for over 40
years. The only thing new is the use of headless
compression screw fixation instead of K-wire,
regular screws or non-fixation. The combination of
MIS and compressive screw fixation does yield
great results as reported in the literature. The
debate between fixated and non-fixated MIS
techniques has not been put to the test by
comparative research.

The x-ray appears to have a nice correction. The
pre-op angle is > 18 and the post-op angle IM is
around 2. This is good radiographic result. This
example is a well-executed surgery with good bone
to bone contact post-op.

MIS HAV technique parameters are the same as
traditional procedures. If the head is moved over
excessively problems with the technique arise. I
am aware of several MIS cases that have resulted
in significant complications as a result of
overaggressive lateral translation of the head
using screw fixation. The surgeon cannot rely on
the screw fixation to replace the need for
adequate bone to bone contact.

The same rules apply to both minimally invasive
and traditional HAV surgery. The head osteotomy
should be used in cases where the correction can
be safely made by moving the head over and
maintaining adequate bone to bone contact with the
first metatarsal.

High IM angles can be corrected with head
osteotomies using minimally invasive techniques
depending on width of the 1st metatarsal (same as
traditional). I would caution surgeons not to rely
on screw strength to stabilize an unduly laterally
translated head osteotomy. An IM of 18-20 is
maxing out the MIS head osteotomies comfort zone
just like it is for traditional techniques. There
is no difference in the results obtained by MIS
HAV correction and traditional except for lower
MIS VAS scores in the early post-op period. The
results are essentially the same between the 2
disciplines.

Don Peacock DPM, MS, Whiteville, NC

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