I appreciate Barry Mullen, DPM’s supportive
words about the value of "Rootian" biomechanics.
I don’t necessarily understand Dr. Shavelson’s
explanation of his own theories or some of his
attempts at describing the biomechanical
theories of Merton L. Root, DPM, et al.
In his reply to Dr. Mullen, Dr. Shavelson
stated “Discussing a re-alignment of the
hindfoot in the same breath as hallux valgus and
varus reveals an American podiatry fixation that
is crying for change. Why fix the kitchen when
the problem is in the living room. PostopThotics
for bunions are forefoot-focused. 'Subtalar
joint dominance” doesn’t fly once one
understands the forefoot dominance in a flexible
forefoot functional foot type and bunion
formation.”
Dr. Root attempted to describe individual
functional and structural conditions in the
forefoot, rearfoot and leg and theorized how,
when considered individually, each of these
conditions might influence the function of the
foot and leg. He attempted to explain how
biomechanical conditions and forces in one
segment or area might influence conditions and
forces in another segment or area. Dr. Root was
keenly aware of and went to great lengths to
describe how forefoot conditions and forces can
influence the rearfoot and conversely, how
rearfoot conditions and forces can influence the
forefoot. Evaluating the influence of multiple
conditions makes biomechanics more complex but
not impractical.
As a simple example, Dr. Root theorized that
forefoot varus can be compensated by subtalar
joint pronation in order to bring the medial
aspect of the forefoot in contact with the
supporting surface. When the foot then
compensates by pronation at the subtalar joint,
the foot has more potential mobility than when
it is less pronated or supinated at the subtalar
joint (the mobile adaptor, rigid lever concept).
One cause of hallux abductovalgus and bunions is
hypermobility of the 1st ray during late
midstance and propulsion. Therefore, a forefoot
varus that results in increased subtalar joint
pronation can cause hypermobility of the 1st
ray, thereby contributing to bunion formation.
Dr. Root’s treatment recommendation would have
been to cast the foot in the neutral position at
the subtalar joint while maintaining the
midtarsal joint fully pronated. This casting
technique will produce a negative cast that
captures the inverted plantar plane of the
forefoot. By intrinsically or extrinsically
posting (wedging) the forefoot in a varus
attitude with an orthosis, the forefoot no
longer needs to evert to achieve ground reaction
force and therefore, the demand for pronation
compensation at the subtalar joint might be
reduced or eliminated. Reducing excessive
subtalar joint pronation reduces hypermobility
of the 1st ray, and therefore in theory, can
reduce forces that might otherwise contribute to
HAV and bunion formation.
I chose this example to demonstrate that Dr.
Root’s theories were not simplistic and that
contrary to popular belief, he was not just
focused on the subtalar joint or “subtalar joint
dominance”. In the words of Drs. Root, Weed and
Orien (Normal and Abnormal Function of the Foot
pg. 297):”The subtalar joint, by virtue of its
triplane axis of motion, can move in any of the
three cardinal body planes. Therefore, the
subtalar joint most frequently moves to provide
the position demanded by a one plane deformity.
In other words, the subtalar joint is able to
move in any direction necessary to compensate a
deformity of the lower extremity.”
To some degree, one could argue that Dr. Root
essentially viewed the subtalar joint as a
submissive rather than a dominant joint since it
frequently functioned in a compensated position.
While I agree that there is room for improvement
in lower extremity biomechanical theory, I can’t
help but be frustrated to see Root’s theories
taken out of context or oversimplified by many
in the podiatric community.
One of the primary differentiating
characteristics of a Root-type functional
orthosis is the shape of the anterior aspect of
the orthotic shell, which is designed to support
any inverted or everted osseous condition of the
forefoot, including but not limited to those
produced by a forefoot valgus, a plantarflexed
1st ray, a forefoot varus or a forefoot
supinatus. A properly casted, prescribed and
made Root type functional orthosis is both
forefoot and rearfoot focused and attempts to
influence the function of the foot and lower
extremity within the limits imposed by an in
shoe device.
There are an array of prescription orthotic
modifications that can be utilized by the
practitioner in an attempt to achieve an optimal
functional result. So in response to the
question of “Why fix the kitchen when the
problem is in the living room?”, I would say
because they may be connected by a common
foundation, roof and walls which in some cases,
might be an important fact to consider.
Mr. Jeffrey Root, Root Laboratory, Inc.,
jroot@root-lab.com
Initially, this discussion started with what
appeared to be a case of idiopathic hallux
varus. Now, it has progressed or digressed into
a discussion on the basics of what I like to
call BIOMAJIC. Root vs. Shavelson(FLEB). I do
not claim to be a biomechanics expert or an
innovative thinker. I do claim to have years of
experience in surgery which requires a sound
understanding of the way the foot works. What is
successful in some does not work in others.
Biomechanics principles should be used as a
teaching tool for students and practitioners.
Biomechanical principles are simply theoretical
tools as much as we enjoy arguing about them. My
advice to the younger podiatrists is to learn
ALL the principles-- you will find out that
every patient is different from a surgical
standpoint and through training and experience
you will learn how to apply the principles.
One of the several topics that I feel strongly
in disagreement with is the “postopthotic.” I
can tell you from my experience generally if you
do not fixate an osteotomy of the foot, you will
get more non-unions—the idea of letting the
bones seek their own level has failed in my
hands and many others. The idea of putting a
post-operative patient in some orthotic for 3
weeks as I understand a “postopthotic” is just
does not make common sense from a practical and
medical standpoint.
I get my best results when I perform osteotomies
by doing a complete preop evaluation looking at
both the rear foot and forefoot on each
individual, performing the osteotomy checking
position on the table and fixating the bone in a
position that I determine to be the best. I
don’t think that there will ever be a formula
for that.
Dr. Cohen, one of the original posts on this
case, suggested multiple minimal incision
nonfixated osteotomies for this case which would
be a disaster in my hands. Perhaps Dr. Shavelson
believes that a postopthotic would change that.
If so, I would like to see some studies that
support it.
Tip Sullivan, DPM, Jackson, MS,
tsdefeet@MSfootcenter.net
