History-Evolution-of-Foot-and-Lower-Extremity-Biomechanics-and-Foot-Orthoses_Kevin-Kirby

3/26/2015
History and Evolution of Foot and
Lower Extremity Biomechanics
and Foot Orthoses
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine
Oakland, California
Private Practice, Sacramento, California
2015 PAC Symposium: “Biomechanics and the Future of Footcare”
Vancouver, BC
April 17-18, 2015
What is the History of Foot
Biomechanics and Foot Orthoses?
Biomechanics and foot orthoses have
evolved over the centuries
Many talented individuals have increased
our knowledge in foot and lower extremity
biomechanics and about foot orthoses
What people and events have shaped
history and evolution of podiatric
biomechanics and orthoses?
Aristotle
Archimedes
Aristotle (384-322 BC), Greek
scientist and philosopher, was one
of earliest biomechanics authors
His treatise, About the Movement of
Animals (350 BC) provided first
scientific analysis of gait and first
geometric analysis of muscular
actions on bones
First accurately described GRF as :
“…for just as the pusher pushes, so
the pusher is pushed”
Aristotle
(384 BC – 322 BC)
Archimedes (287-212 BC)
was Greek scientist who is
considered one of greatest
mathematicians of antiquity
Discovered principles of
hydrostatics, statics and
physics of levers, working to
solve the problem of moving a
given weight by a given force
“Give me a place to stand on,
and I will move the Earth”
Archimedes
(287-212 BC)
Galen
Leonardo DaVinci
Galen (129-201 AD) was Roman
physician and surgeon
Considered first “sports physician”
Was “team doctor” to Roman
gladiators by age 28
In his work De Motu Musculorum
(On the Motion of Muscles), he
first explained difference between
motor and sensory nerves and
agonist and antagonist muscles
Sought to raise medicine to level
of exact science
Galen
(129-201 AD)
Leonardo DaVinci (1452-1519),
Italian painter, sculptor and
inventor, had keen interest in form
& function of human body
Inspired by desire to accurately
represent human movement in his
paintings and sculptures
In regard to running form on
varied surfaces, DaVinci wrote:
“He who runs down a slope has his axis on his
Leonardo DaVinci
(1452-1519)
heels; and he who runs uphill has it on the toes of
his feet; and a man running on level ground has it
first on his heels and then on the toes of his feet.”
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Giovanni Borelli
Isaac Newton
Giovanni Borelli (1608-1679),
Italian physicist, physiologist and
mathematician, wrote first book on
biomechanics, De Motu
Animalium, in 1685
First to fully describe geometrical
principles of levers of musculoskeletal
system and that muscles
produce much larger forces than
resisting external forces
Borelli found forces required for
equilibrium in various joints of
human body before Newton
Borelli is often called:
“Father of Biomechanics”
Giovanni Borelli
(1608-1679)
Isaac Newton (1642-1727),
British mathematician and
physicist, is considered by many
to be greatest scientist of all time
Invented calculus at age 24
Published Philosophiae Naturalis
Principia Mathematica in 1686
which contained his now famous
Three Laws of Motion
Credited with creating the laws of
inertia, acceleration, action and
reaction forces and of gravity
Isaac Newton
(1642-1727)
Nicolas Andry
Petrus Camper
Nicolas Andry (1658-1742), a French
physician, first coined the term
“orthopedics” meaning “straight
child”
Published book, Orthopaedia: The
Art of Correcting and Preventing
Deformities in Children in1740
“If the feet incline too much to one
side, you must give the child shoes
that are higher on that side, both in
the sole and heel, which will make
him incline to the opposite side.“
Nicolas Andry
(1658-1742)
Petrus Camper (1722-1789) was
a Dutch physician and pioneer in
pediatrics
Published one of first books on
foot deformities, “On the Best
Form of Shoe” in 1781, which
was reprinted into 14 editions
Camper’s book stimulated
interest in placing archsupporting
orthoses into shoes
for children’s flatfoot
Petrus Camper
(1722-1789)
“It is surprising that while mankind in all
ages have bestowed the greatest attention
upon the feet of horses, mules, oxen, and
other animals of burthen of draught, they
have entirely neglected those of their own
species, abandoning them to the ignorance
of workmen, who, in general, can only
make a shoe upon routine principles, and
according to the absurdities of fashion, or
the depraved taste of the day. Thus, from
our earliest infancy, shoes, as at present
worn, serve but to deform the toes and
cover the feet with corns, which not only
render walking painful, but, in some cases,
absolutely impossible.” P. Camper, 1781
Petrus Camper
Shoe Fashions
from 1760
Lewis Durlacher
Lewis Durlacher (1792-1864), a
British chiropodist, was royal
chiropodist appointed to Queen
Victoria
In 1845, he developed leather
foot orthosis to correct for
“plantar pressure lesions” and
“foot imbalances”
Durlacher first described
intermetatarsal neuroma, over
30 years before T.G. Morton
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Hugh Owen Thomas
Newton Melman Shaffer
Hugh Owen Thomas (1834-1891)
was a British orthopedic surgeon
with interest in treating feet
In 1874, Thomas suggested using
a “few pennies worth of leather”
for lifts, bars, and wedges on
shoes to treat foot problems
Invented, in 1876, “crooking” of
shoe heel, to extend the heel
under the antero-medial aspect of
shoe sole for treating pronated
feet (now called “Thomas heel”)
Hugh Owen Thomas
(1834-1891)
Newton M. Shaffer (1846-
1928), a New York City
orthopedist, first described
high arched foot with
multiple clawtoes
Became widely known as
“Shaffer’s Foot”
Also designed a highmedial
arched orthosis
with a heel cup which
became known as a
“Shaffer Plate”
Newton M. Shaffer
(1846-1928)
Royal Whitman
Whitman’s “Weak Foot”
Royal Whitman (1857-
1946) was a 1882
Harvard Medical School
graduate and New York
City orthopedic surgeon
that had special interest
in foot function
Wrote numerous
textbooks on orthopedic
surgery and taught
orthopedics for 40 years
Royal Whitman
(1857-1946)
Whitman’s description of
“weak foot” very closely
matches our current
description of the pronated,
flat-arched foot with an
internally rotated tibia
Whitman’s Three Grades of “Weak Foot”
1 st Degree: The normal foot improperly used, as
shown by the method of standing and walking
2 nd Degree: The foot in which the range of voluntary
motion is restricted, showing disuse of function, and
in which the elements of deformity are apparent
when weight is borne
3 rd Degree: That in which the passive range of
motion is restricted, or in which there are evident
weakness and deformity. This limitation of motion
depends, as a rule, on accommodative changes in
structure to the habitual postures or to the deformity
Whitman R: A study of the weak foot, with reference to its causes, its diagnosis, and its cure; with an
analysis of a thousand cases of so-called flat-foot. JBJS, 8:42-77, 1896.
Whitman’s Foot Brace
Developed in 1885
Made from plaster cast
taken with foot in
supinated position
18-20 gauge sheet
steel was formed into a
high medial arch brace
Goal was to raise
medial arch so foot
would be less pronated
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Percy Willard Roberts
1895 - Beginning of Chiropody
Percy W. Roberts (1867-1937), American orthopedic
surgeon, developed metal foot orthosis in 1912
Roberts foot orthosis had deep inverted heel cup that
attempted to tilt rearfoot into inverted position
Had medial and lateral clips and narrow heel cup
Roberts brace applied too much force over too little
area and tended to cause irritation to plantar foot
During most of 19 th century, medical doctors
showed little interest in treating foot problems
Barbers, families and practically anyone that
showed an interest in treating feet adopted the
“craft” of foot care to fill the void in healthcare of
the foot that was left by medical doctors
In 1895, group of dedicated practitioners in New
York successfully appealed to NY State
Legislature to first establish chiropody (now
podiatry) as a licensed profession
First Podiatry Society
& School Formed
In 1895, Pedic Society of New
York became first official society
for chiropody/podiatry
First school of chiropody
established in New York in 1911
In 1912, first national podiatry
association, and precursor to
current APMA, American National
Chiropody Association, was
formed and is now 100 years old
First Issue of Pedic Society
Items – First “Podiatry Journal”
Alfred Joseph, First
President of National
Association of
Chiropodists”
Podiatric Approach to Foot
Biomechanics in Early 20 th Century
Approach to foot mechanics in
early 20 th century was based
largely on shape of medial
longitudinal arch with “normal foot”
being viewed as having “normally
arched architecture” with
treatments geared toward
restoring a “normal arch”
Many podiatrists relied on
orthopedic shoe makers to make
custom leather foot or steel
appliances to treat “weak feet”
Early 20 th Century
Treatment of “Weak
Feet” Used Whitman’s
Concepts
Otto Frederick Schuster
Otto F. Schuster (1881-
1936) arrived in US in 1906
from Hamburg, Germany
where he had trained as a
brace maker
Schuster started making
Whitman braces for Royal
Whitman and other
orthopedists in NY in 1909
Became a podiatrist in 1911
Otto F. Schuster
(1881-1936)
First Podiatric
Orthopedics Text
Otto F. Schuster became
professor of orthopedics at
NY Podiatry School
In 1927, published first
podiatric orthopedics text,
Foot Orthopedics, later
rewritten by his podiatristson,
Otto N. Schuster
Foot Orthopedics remained
in use as a valuable
textbook until 1950s
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Roberts-Whitman Brace
Dudley J. Morton
In the 1920s, Otto F. Schuster
combined ideas of Roberts
brace with Whitman brace to
make Roberts-Whitman brace
Roberts-Whitman brace had
deep inverted heel cup, high
medial arch and wider profile
that provided better pronation
control and allowed for more
comfortable medial arch
Otto Schuster created
Roberts-Whitman Brace
Dudley Joy Morton (1884-1960)
was physician, anatomist and
anthropologist
Work focused on shortened 1st
metatarsal, “hypermobility” of 1st
metatarsal segment and
correlation of 1 st ray mechanics to
excessive foot pronation
Published book, The Human
Foot, It’s Evolution, Physiology
and Functional Disorders, in 1935
Dudley J. Morton
(1884-1960)
Morton Was First to Describe Load-
Deformation of 1 st Ray in 1935
“If the plantar ligaments of
any segment are slack
when the head of its
metatarsal bone lies on
the same plane as the
others whose ligaments
are taut, that segment will
fail to share in the carriage
of body weight….”
Morton DJ: The Human Foot: Its Evolution, Physiology
and Functional Disorders. Columbia University Press.
Morningside Heights, New York, 1935.
“…the plantar ligaments of the first metatarsal
segment in these feet were lax when the other
ligaments had become tense under body weight;
hence the first metatarsal still retained a margin of
dorsal extension and therefore was ineffective as a
weightbearing structure.”
Morton DJ: The Human Foot: Its Evolution, Physiology and Functional Disorders. Columbia
University Press. Morningside Heights, New York, 1935.
Morton DJ: Physiological
considerations in the
treatment of foot
deformities. JBJS,
19:1052-1056, 1937.
Morton believed “hypermobility of first
metatarsal” affects foot in three ways:
1. Second metatarsal has “increased burden”
since first metatarsal “fails to assume” its
normal share of weight
2. Foot pronates because “medial buttress” is
ineffective until “slack in its ligaments is taken
up” as pronation increases
3. As pronation advances, “functional stresses are
thrown increasingly on muscles on inner side of
ankle, imposing them undue strain”
Morton’s Compensating Insole
In 1932, Morton designed a
“compensating insole” that
focused on elevating first
metatarsal head and
preventing pronation
compensation for short,
“hypermobile” first ray
Morton also designed inshoe
support with high
medial arch-flange to resist
pronation
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First Plaster Splint Impression
Casting of Foot
Edward Reed, MD, an
orthopedic surgeon from
Santa Monica, California,
was first to describe
plaster splint impression
casting for foot orthoses
in 1933
Reed EN: A simple method for making plaster casts of
feet. JBJS, 17:1007, 1933.
Alan Murray & Benjamin Levy
In 1930s, Alan Murray, ice
skater, developed shoe molded
directly onto cast of foot called
the Murray Space Shoe
NY podiatrist, Benjamin Levy,
developed idea of using inner
sole from Murray Space Shoe as
a removable cork and leather
insole with a toe crest, became
known as Levy mold.
Levy B: An appliance to induce toe flexion on weight bearing. J
Natl Assoc of Chiropodists, 40(6):24-33, 1950.
John Tinkham Manter
John T. Manter (1910-1968), was
professor of zoology at Columbia
University and professor of anatomy
at University of South Dakota
Wrote numerous articles on zoology,
animal locomotion and
biomechanics
In 1941, Manter wrote first English
language scientific paper on subtalar
joint and midtarsal joint axes
Manter JT: Movements of the subtalar and transverse tarsal joints. Anat
Rec, 80:397-410, 1941.
John T. Manter
(1910-1968)
Manter’s Mean STJ Axis Location
in 16 Cadaver Feet
Manter JT: Movements of the subtalar and transverse tarsal joints. Anat Rec, 80:397-
410, 1941.
Manter’s Study Determined STJ Axis
to Transverse and Sagittal Planes
Manter’s 1941 study found that mean position
of STJ axis in 16 cadaver feet was angulated
16 0 from sagittal plane and 42 0 from
transverse plane
Manter’s study only determined angular
deviation of STJ axis from cardinal planes,
but did not determine spatial location of STJ
axis in relation to plantar foot (i.e. whether
STJ axis was medially or laterally positioned)
Manter JT: Movements of the subtalar and transverse tarsal joints. Anat Rec, 80:397-410,
1941.
Manter was also one of first researchers to study
axes of rotation of MTJ
Calcaneus clamped in apparatus to stabilize
rearfoot and rods and pointers driven into unknown
bones in forefoot
Pointers aligned against glass plates to determine
axes of rotation
Forefoot moved with unknown magnitude and
direction of input force to determine axes of rotation
Manter JT: Movements of the subtalar and transverse tarsal joints. Anat Rec, 80:397-410, 1941.
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Oblique axis
John H. Hicks
Longitudinal
axis
Manter’s Midtarsal Joint Axes
Longitudinal transverse tarsal joint axis
–9 0 from transverse plane
–15 0 from sagittal plane
Oblique transverse tarsal joint axis
–52 0 from transverse plane
–57 0 from sagittal plane
John H. Hicks
(1915-1992)
John H. Hicks (1915-1992), orthopedic surgeon from
Birmingham, UK, had great interest in foot
biomechanics and performed pioneering research
Wrote series of classic scientific papers from 1953-
1961 on biomechanics of foot, plantar fascial function
and biomechanics of balance relative to GRF
Also determined axes of motion of ankle joint, STJ,
MTJ, first ray and fifth ray
Hicks’ Midtarsal Joint Axes
In 1953, Hicks found two distinct MTJ axes
– Oblique midtarsal joint (OMTJ) axis
– Antero-posterior midtarsal joint (APMTJ) axis
However, Hicks’ MTJ axes were in different
locations to Manter’s MTJ axes
Hicks JH: The mechanics of the foot. I. The joints. Journal of Anatomy. 87:25-31, 1953.
Hicks was first to describe the “Windlass Effect”
of hallux dorsiflexion in 1954
Hicks, JH: The mechanics of the foot. II. The plantar aponeurosis and the arch. Journal of Anatomy.
88:24-31, 1954.
Hallux dorsiflexion in cadavers and live subjects
produced following simultaneous responses:
Increase in medial longitudinal arch height
Inversion of rearfoot
External rotation of leg
Appearance of tight band in region of plantar
aponeurosis
Windlass and Reverse Windlass Effect
Herbert Oliver Elftman
Windlass Effect
Reverse Windlass Effect
Hicks also noted that body weight flattened arch and
plantarflexed hallux more forcefully into ground
Effect of hallux forcefully pressing into ground was
noted to nearly disappear with transection of plantar
fascia in cadaver foot
Hicks JH: The mechanics of the foot. II. The plantar aponeurosis and the arch. Journal of Anatomy.
88:24-31, 1954.
Herbert O. Elftman, PhD,
professor of anatomy at
Columbia University, wrote
many papers on foot and
lower extremity biomechanics
from 1934 to 1970
Elftman proposed that MTJ
has joint axes and motion
that may be affected by
subtalar joint pronation and
supination
Elftman H: The transverse tarsal joint and its control. Clin.
Orthop., 16:41-44, 1960.
Herbert O. Elftman
(1902-1988)
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Elftman thought that in the pronated foot major
axis of TNJ (TN-1) was directly in line with CC-1:
“allows the forepart of the foot to move freely
with respect to hindpart without movement of the
talus with respect to the calcaneus”
Thought that MTJ axis changes in location as
STJ rotates from pronated to supinated position:
“In passing from pronated to supinated position
there is a continuous change in positions of
significant joint elements and, consequently, of
instantaneous transverse tarsal axis.”
Verne Thompson Inman
Verne T. Inman, MD, PhD
(1905-1980) began to
research lower extremity
biomechanics in 1957 at UC
Berkeley due to need for
better prostheses in post-
WW II amputees
His two books: The Joints of
the Ankle and Human
Walking are classics in foot
and lower extremity
biomechanics
Verne T. Inman
(1905-1980)
Howard Davis Eberhart
UC Biomechanics Lab
Howard D. Eberhart was professor in
civil engineering at UC Berkeley, when
accident required BK amputation
Verne Inman, professor of orthopedic
surgery at UC Berkeley, was surgeon
that amputated Eberhart’s leg in 1944
In order to research lower limb
biomechanics and develop better
prosthesis designs, Eberhart teamed
with Inman and became director of
Prosthetics Devices Research Project
at UC Berkeley Dept. of Engineering
Howard D. Eberhart
(1906-1993)
UCBL was center of
research in foot and lower
extremity biomechanics
and prosthetics research
from 1957 to 1974 at
UCSF and UC Berkeley
During its time, UCBL
produced more research
and notable researchers
in foot and lower
extremity biomechanics
than any other in world
Dr. Verne Inman (center), Professor
Howard Eberhart (right), and W.H.
Henderson (in wheelchair) in
Biomechanics Laboratory at U.C.
Berkeley.
D. Gilbert Wright
John B. Saunders
Researcher at UC Biomechanics
Lab who, in 1964, performed
classic studies of range of motion
of STJ during walking and on
elastic properties of plantar fascia
Wright DG, Desai SM, Henderson WH: Action of the subtalar and
ankle-joint complex during the stance phase of walking.
JBJS, 46 (A): 361, 1964.
Wright DG, Rennels DC:
A study of the elastic
properties of plantar
fascia. JBJS, 46
(A):482-492, 1964.
Chairman of Dept of Anatomy at UC
Berkeley from 1938-1956
Coauthored classic article on
determinants of gait, described how
locomotion mechanisms minimize
excursion of CoM during gait
John B. Saunders
(1903-1991)
Saunders JB, Inman
VT, Eberhart HD: The
major determinants in
normal and
pathological gait. JBJS,
35A:543-558, 1953.
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Henderson & Campbell: UCBL
In 1969, dental student, R.E. Isman, did study
with Verne Inman at UC Biomechanics Lab that
measured STJ axis in 46 cadaver feet
STJ was 42 0 inclinated from transverse plane
and 23 0 adducted from sagittal plane
Isman RE, Inman VT: Anthropometric studies of the human foot and ankle. Bull Pros Research,
10:97-129, 1969.
Henderson and Campbell
developed high heel-cupped
polypropylene orthosis with
high medial and lateral flanges
at UC Biomechanics Lab in
1967
Henderson WH, Campbell JW: U.C.B.L. shoe insert casting and
fabrication. Technical Report 53. Biomechanics Laboratory,
University of California at San Francisco and Berkeley, 1967.
UCBL orthosis primarily used
by orthopedic community for
treatment of pediatric flexible
flatfoot deformity
Merton Louis Root
Merton L. Root (1922-2002)
became interested in research as a
WW II army paratrooper
After war decided to pursue career
in podiatry in 1948 after seeing
need for better research in podiatry
Graduated from California College
of Chiropody in 1952
Started world’s first Department of
Podiatric Biomechanics in 1966 at
CCPM in San Francisco
Merton L. Root
1922-2002
San Francisco Bay Area became hub for foot
and lower extremity biomechanics research and
development in late 1950s and 1960s
Root’s Eight Biophysical
Criteria for “Normalcy”
Eight biophysical criteria for
“normalcy” proposed by Root, et
al in 1971
Root ML, Orien WP, Weed JH, Hughes RJ: Biomechanical
Examination of the Foot, Volume 1. Clinical Biomechanics
Corporation, Los Angeles, 1971.
Root, et al proposed that all feet
and lower extremities which did
not meet criteria for “normal”
had structural defects and were,
therefore, “abnormal”
Root’s “Deformities”
Based on STJ Neutral
Root developed biomechanical
classification system based on
concept that STJ neutral was
ideal foot position during gait
Root classified “foot types” with
frontal plane positions of
rearfoot to tibia, forefoot to
rearfoot, and first ray position
relative to 1 st -5 th metatarsal
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Root Developed “Neutral
Suspension Casting Method”
In 1971, Root, Weed and Orien
described “neutral suspension casting
technique” with plaster splints to
accomplish the following objectives:
Capture STJ in neutral position
Dorsiflex the 4 th and 5 th metatarsals
Pronate midtarsal joint to maximum to
“lock” forefoot against rearfoot
Preserve NWB plantar contour of foot
Root ML, Weed JH, Orien WP: Neutral Position Casting Techniques,
Clinical Biomechanics Corp., Los Angeles, 1971.
Root Functional
Orthosis
Root was one of first to experiment with new
materials called thermoplastics and began to
develop his Root Functional Orthosis in 1958
RFO had lower MLA than previous orthoses since
Root didn’t believe that high MLA or arch pain was
necessary to control abnormal pronation
Root designed his RFO to allow the STJ to function
in neutral position by preventing “compensation” for
rearfoot and forefoot “deformities”
Root’s Lectures Notes
Published by Sgarlato
Thomas E. Sgarlato, DPM,
took over as chairman of
world’s first Department of
Podiatric Biomechanics from
Root (due to illness) in 1969
Sgarlato worked with podiatry
students and biomechanics
faculty to publish Root’s
lecture notes as “A
Compendium of Podiatric
Biomechanics” in March 1971
Thomas E. Sgarlato
Normal and Abnormal Function of
the Foot, by Root, Orien and Weed
in 1977, was foot and lower
extremity biomechanics textbook
Text described normal and
abnormal mechanics of foot and
lower extremity, biomechanics of
foot pathologies and how foot
structure may predict foot function
John Herbert Weed
(1938-1992)
William Phillip Orien
E.J. Van Langelaan
E.J. Van Langelaan, orthopedic
surgeon in Netherlands, did first
modern study on motions of STJ
and MTJ in 1983 in his landmark
PhD thesis using 3D xray
photogrammetry
Performed under guidance of
Antony Huson, PhD at University
of Leiden, Netherlands
Van Langelaan EJ: A kinematical analysis of the tarsal joints. Acta
Orthop Scand, 54:Suppl. 204, 135-229, 1983.
E.J. Van Langelaan
Apparatus Used in Van
Langelaan Study
(Videos courtesy of A. Huson, MD, PhD)
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Thoughts from Van Langelaan
“ ...intertarsal joints are not ‘complicatedly structured but
functionally simple hinge joints’. Movements are found to
take place around an axis which moves continuously,
and the position of which could be approximated with the
aid of a bundle of discrete helical axes.”
“The relative axes within a bundle proved to approach
each other more closely at characteristic sites in the
tarsus.” TNJ: central portion of talar head, CCJ: dorsalmedial-superior
corner of CCJ
Benno M. Nigg
Benno Nigg, trained as nuclear
physicist, became interested in
biomechanics in 1971
Founded and developed
world’s largest biomechanics
research facility at University of
Calgary in 1981
Has authored/edited 10 books
and has authored over 290
scientific papers on sports
shoes and foot and lower
extremity biomechanics
Benno M. Nigg
Howard J. Dananberg
Howard Dananberg
popularized concept that
functional hallux limitus was
key to abnormal foot function
FnHL thought to produce
“sagittal plane blockade“
during walking that caused
pronation of foot as result
Patented “kinetic wedge” to
address his theory of “sagittal
plane blockade”
Dananberg, HJ: Gait style as an etiology to chronic postural pain.
Part I. Functional hallux limitus. JAPMA, 83:433-441, 1993.
Howard J. Dananberg
Richard L. Blake
Richard Blake, a 1981 CCPM
Biomechanics Fellowship
graduate, developed the
Blake Inverted Orthosis from
1981-1982
Blake RL, Denton J: Functional foot orthoses for athletic injuries.
JAPMA, 75:359-362,1985.
Blake RL, Ferguson H: Foot orthosis for the severe flatfoot in sports.
JAPMA, 81:549, 1991.
Blake RL: Inverted functional orthoses. JAPMA, 76:275-276, 1986.
Blake RL, Ferguson H: "The inverted orthotic technique:”, in Valmassy,
R.L.(editor), Clinical Biomechanics of the Lower Extremities, Mosby-
Year Book, St. Louis, 1996.
Richard Blake
Blake Inverted Orthosis
As Dr. Blake developed his BIO, he discovered
that increasing levels of cast inversion increased
pronation control from his inverted orthosis due
to increased MLA height and inverted heel cup
However, as cast inversion approached 10 0 , Dr.
Blake noted new orthosis problems:
– Plantar fascial irritation
– Foot slid laterally off of orthosis plate
– Excessive orthosis arch height caused late
midstance pronation, instead of late midstance
supination, during walking
Blake Inverted
Orthosis
Positive cast of BIO inverted
15, 25 or 35 0 which causes
varus heel cup and higher
medial arch to orthosis
Modified medial arch fill and
plantar fascial accommodation
are added to prevent plantar
fascial irritation
Heel cups of 20 mm and flat
rearfoot posts are standard
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New Research on STJ Axis
Location Emphasized STJ Kinetics
In 1987, concept that STJ axis location may be
determined clinically and that GRF medial to STJ axis
causes supination moments and GRF lateral to axis
causes STJ pronation moments was first introduced
Kirby KA: Methods for determination of positional variations in the subtalar joint axis. JAPMA, 77: 228-
234, 1987.
In 1989, concept of rotational equilibrium used to
explain how balance of STJ moments may
explain abnormal internal forces within foot and
different types of foot pathology
Kirby KA: Rotational equilibrium across the subtalar joint axis. JAPMA, 79: 1-14, 1989.
In 1992, medial heel skive technique, was first
described as method to increase varus shape of
heel cup in functional foot orthosis
Designed to increase STJ supination moment from
orthosis and more effectively treat symptoms
caused by excessive pronation moments such as
PTTD and children’s flatfoot deformity
Kirby KA: The medial heel skive technique: improving pronation control in foot orthoses. JAPMA, 82:
177-188, 1992.
In 2001, new theory of foot
function, Subtalar Joint Axis
Location and Rotational
Equilibrium (SALRE) Theory was
first introduced
Described how concepts of STJ
axis spatial location and rotational
equilibrium may be combined to
explain many observations
relating to biomechanical function
Also offered explanation for
biomechanical effect of certain
foot surgeries
Kirby KA: Subtalar joint axis location and rotational equilibrium
theory of foot function. JAPMA, 91:465-488, 2001.
SALRE Theory Explains How
Orthoses Alter STJ Moments
If orthosis is designed to
“control pronation”, ORF
will be shifted medially so
STJ supination moment
is increased
If orthosis is designed to
“control STJ supination”,
then ORF will be shifted
laterally so STJ pronation
moment is increased
Kirby KA: Subtalar joint axis location and rotational
equilibrium theory of foot function. JAPMA,
91:465-488, 2001.
ORF
ORF
ORF
ORF
Supination Area
of Foot Orthosis
Normal STJ Axis Location
As STJ axis becomes
medially deviated, orthosis
has decreased area medial
to STJ axis to cause STJ
supination moments
Medial deviation of STJ
decreases orthosis ability
to supinate STJ
Supination Area
of Foot Orthosis
Child with Flatfoot Deformity
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Tissue Stress Model
Tissue stress model first proposed as
a model for mechanical foot therapy
in 1995 by McPoil and Hunt
McPoil TG, Hunt GC: Evaluation and management of foot and ankle disorders:
Present problems and future directions. JOSPT, 21:381-388, 1995.
Tissue stress model is not a novel
idea since it is based on same ideas
are already in current use in
treatment of parts of body other than
foot and lower extremity
Tissue stress model doesn’t rely on
“unreliable measurement techniques”
Thomas G. McPoil
Gary C. Hunt
Tissue Stress Model
Tissue stress model and its clinical
applications have been discussed by
other authors as a clinical method by
which to more effectively prescribe
custom foot orthoses
Fuller EA: Center of pressure and its theoretical relationship to foot pathology. JAPMA, 89
(6):278-291, 1999.
Fuller EA: Reinventing biomechanics. Podiatry Today, 13:(3), December 2000.
Kirby KA: Tissue stress approach to mechanical foot therapy. Precision Intricast Newsletter,
February 2002.
Kirby KA: The biomechanics of tissue stress. Precision Intricast Newsletter, Payson, Arizona,
March 2002.
Kirby KA: Using the tissue stress approach in clinical practice. Precision Intricast Newsletter,
April 2002.
Tissue Stress Allows Efficient
Determination of Orthosis Goals
Orthosis goals are best achieved by
specifically designing CFO to :
– reduce stress on injured structural components
within foot and lower extremity
– optimize function of foot and lower extremity for
specific weightbearing activities
– prevent other injuries or pathologies from
occurring due to foot orthosis therapy
Steps to Using Tissue Stress
1. Specifically identify anatomical
structures which are source of
patient’s complaints
2. Determine structural and/or
functional variables which may be
source of pathological forces on
injured structures
3. Design orthosis/shoe treatment plan
which will most effectively reduce
pathological forces on injured
structural components, will optimize
gait function and will not cause other
pathology or symptoms
Paul Robert Scherer
Paul Scherer, DPM, is former professor
of biomechanics at CCPM and current
professor of biomechanics at CSPM
Scientific chair for first ten PFOLA
Conferences which were world-class
international events that presented
latest knowledge in biomechanics and
foot orthosis therapy
His book “Recent Advances in Orthotic
Therapy” is premier educational
resource detailing scientific research
evidence for orthosis therapy
Benno Nigg’s
Preferred Movement
Pathway Model
In 2001, Benno Nigg proposed “preferred
movement pathway model” of orthosis function
Nigg proposes that orthoses do not function by
realigning skeleton but rather alter input signals into
plantar foot that change “muscle tuning
Nigg proposed that if foot orthosis counteracts
preferred movement path, then muscle activity will
increase and that optimal shoe or foot orthosis
design will reduce or minimize muscle activity
Nigg BM: The role of impact forces and foot pronation: a new paradigm. Clin J Sport Med, 11:2-9,
2001.
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Chris Nester
Chris Nester, first a podiatrist
then a PhD in biomechanics,
became foot biomechanics
researcher at University of
Salford, UK
Along with coworkers, Nester
has performed important
pioneering bone pin research
in kinematics of foot joints in
both cadaver and live feet
Chris Nester
Nester and coworkers were first to suggest that
previous model of simultaneously occurring oblique
and longitudinal MTJ axes can not occur and should
be replaced by a single moving MTJ axis
Simple concept described by Nester et al is very
important for understanding MTJ biomechanics:
“axes of rotation do not determine the motion at a
joint; rather, the motion determines the axis”
Nester CJ, Findlow A, Bowker P: Scientific approach to the axis of rotation of the midtarsal joint.
JAPMA, 91(2):68-73, 2001.
Important Coworkers Have
Further Developed STJ Theory
Also proposed three “reference axes” for MTJ:
– Medial-lateral MTJ axis (z-axis)
– Anterior-posterior MTJ axis (x-axis)
– Vertical MTJ axis (y-axis)
Nester CJ, Findlow AH: Clinical and experimental models of the midtarsal joint. Proposed terms of
reference and associated terminology. JAPMA, 96:24-31, 2006.
Eric Fuller, introduced concept that
CoP position relative to STJ axis
can be used to predict how
different tissues will be stressed
Fuller EA: Center of pressure and its theoretical relationship to foot
pathology. JAPMA, 89 (6):278-291, 1999.
Co-developed concept of STJ
axis/tissue stress approach to
biomechanical therapy
Fuller EA, Kirby KA: Subtalar joint equilibrium and tissue stress
approach to biomechanical therapy of the foot and lower
extremity. In Albert SF, Curran SA (eds): Biomechanics of the
Lower Extremity: Theory and Practice, Volume 1. Bipedmed,
LLC, Denver, 2013, pp. 205-264.
Eric Fuller
Simon Spooner, PhD, developed STJ
axis locator and promoted analyzing
orthosis function with FEA
Spooner SK, Kirby KA: The subtalar joint axis locator: A preliminary
report. JAPMA, 96:212-219, 2006.
Craig Payne and coworkers showed
correlation of STJ axis location to
supination resistance
Payne C, Munteaunu S, Miller K: Position of the subtalar joint axis and
resistance of the rearfoot to supination. JAPMA, 93(2):131-135, 2003.
Javier Pascual Huerta, PhD and
coworkers demonstrated how max
pronated STJ position affects foot
resistance to supination with orthoses
Pascual Huerta J, Ropa Moreno JM, Kirby KA: Static response of
maximally pronated and nonmaximally pronated feet to frontal plane
wedging of foot orthoses. JAPMA, 99:13-19, 2009.
Simon Spooner
Craig Payne
Javier Pascual Huerta
Future for Foot and Lower Extremity
Biomechanics and Orthoses?
Key to developing better understanding of gait
function and pathologies will be dependent on
research that determines forces and moments
acting on foot and lower extremity
Research into new orthosis designs to reduce
abnormal forces and moments causing certain
pathologies will be important for further progress
Better understanding of biological and mechanical
nature of human tissues will also be critical to
developing better treatment methods
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Biomechanics and Historical
Sources
W. Eric Lee: Podiatric Historian from UK
Lee W E: Merton L. Root: An appreciation. The Podiatric Biomechanics Group
Focus. 2(2): 32-68, 2003.
Richard O. Schuster: Podiatrist from US
(nephew of Otto N. Schuster)
Schuster RO: A history of orthopedics in podiatry. JAPA, 64(5):332-345, 1974.
Benno Nigg: Biomechanics Researcher
Nigg BM: “Selected historical highlights”, in Biomechanics of the Musculo-skeletal
System, 2nd Edition, (B.M. Nigg and W. Herzog, eds), John Wiley and Sons,
New York, 1999, pp. 3-35.
William Eric Lee
Richard Schuster
Benno Nigg
Conclusion
History demonstrates that foot and lower extremity
biomechanics theory and foot orthosis treatments
have all evolved over time
Many individuals have made contributions towards
better understanding of lower extremity function and
treating foot and lower extremity mechanical
pathologies with orthoses
Examples of those that changed history in foot-health
professions show that advances in knowledge require
sacrifice, determination and hard work
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