12/23/2016    Don Peacock, DPM

The MIS Akin Osteotomy (Keith Gurnick, DPM)

I agree with Dr. Gurnick's conclusion with
regard to the necessity of weight-bearing
lateral x-rays for appropriate assessment. In
my original post, I included both AP and
lateral x-rays pre and post. Only the AP x-rays
were published.

This patient had a relatively small IM angle
and our differing measurements may reflect some
differences in how we are viewing the IM angle.
Our measurements are not drastically different,
and as Dr. Gurnick states good correction is
noted. Also both of us are getting improved
changes in the HA angle and IM post-operatively
to within the normal range.

I have plenty of other cases showing stronger
corrections in the IM for moderate to severe
bunions using MIS protocols. For these
patients, I use a procedure that I have
published called the PRIBB procedure and I
employ percutaneous fixation with this
procedure. You can look up that publication and
see more drastic IM angle corrections using
this MIS surgical technique. I would be happy
to post some of these as well.

There is some shortening and Dr Gurnick
measures 4-5 mm shortening. That's actually
good. The average shortening in a traditional
Austin is 4-6 mm in studies published (Klosick,
et al. ref in McGlamry). In this study an
average of 6 mm shortening was seen after the
Austin and only 5 patients out of the 85
complained of transfer metatarsalgia and the
shortening did not correlate with symptoms. X-
ray evaluation alone cannot predict transfer
metatarsalgia except in excessive shortening
cases. To combat the shortening seen using a
burr I describe how to do this in the PRIBB
technique.

Remember that studies show improvement of 1st
ray stability after bunion correction even in
the inevitable shortening we get with 1st ray
head osteotomies. Dr Gurnick's post is a nice
academic post and his points are all valid.
Lateral x-rays are mandatory for true bunion
surgery evaluation as he states and showing the
whole foot x ray is important. All posts would
be better evaluated if we show the laterals and
APs of the entire foot.

Don Peacock, DPM, Whiteville, NC

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12/26/2016    Dieter J Fellner, DPM

The MIS Akin Osteotomy (Keith Gurnick, DPM)

On the question of the shortening of the first
metatarsal S/P osteotomy: this is really not an
issue, and might often be a desirable effect.
With an osteotomy to decompress and reduce the
mechanical forces on the joint, this results in
the 'buckling' and displacement of the 1st
MTPJ.

There are two important caveats:

First, the sesamoid apparatus must be
positioned in the correct anatomical alignment,
in relation to the first metatarsal head. There
is very little tolerance to this rule, if a
surgeon wants to optimize on outcome, a
flexible 1st MTPJ and provide for a lasting
correction. Secondly, the sagittal alignment of
the first metatarsal must be balanced correctly
with the lesser metatarsals. This requires of a
surgeon a need to exercise due diligence,
intra-operatively to evaluate and adjust, as
required. This second requirement will take
into account the position and flexibility of
the segment and loading response - this is an
acquired skill, one that requires good
judgment.

If I have an issue with some of the minimally
invasive bunion surgery techniques, it is the
fact that a surgeon cannot always easily
evaluate effectively, to make such an
adjustment intra-operatively, when this is
required. The SERI procedure is a notable
exception.

When both criteria are satisfactorily met, the
1st metatarsal will correctly engage the
Windlass mechanism to allow for correct
function and weight distribution, in gait. In
such a circumstance, the absolute length of the
first metatarsal is almost irrelevant - or at
least a secondary concern. A short metatarsal
will not, then, automatically expose a patient
to the risk of transfer metatarsalgia, or
related issues.

Dieter J Fellner, DPM, NY, NY