Session: Pathology-Specific Orthoses

Pathology-Specific Orthoses:
Evidence-Based vs. Myths and Misconception
Paul R. Scherer, DPM
Clinical Professor
College of Podiatry Medicine
Western University of Health Sciences
Financial Disclosure:
ProLab Orthotics
What do we really know about foot
pathology?
What do we think we know about foot
pathology?
Pathology-Specific Orthoses
§  Plantar Fasciitis
§  Hallux Valgus / Hallux Rigidus
Plantar Fasciitis
Objective
To match the unique needs of each
pathology with a specific orthotic
prescription, in order to improve
clinical outcomes.
Focus on the Goals
§  Eliminate the imitators
§  Understand the pathology and foot types
§  Capture the foot type
§  Make the right orthotic
Occurrence
§  1,000,000 patient visits per year (1995-2000)
§  Physicians only
§  Age= 83% between 25-64
v Riddle,
2004
National Ambulatory Medical Care Survey
Lamont Factors
1983 (with Shama)
A very small percentage of
the population with heel
spurs experience heel pain.
So, why do we call it heel
spur syndrome?
Lamont Factors
2003
None of the patients who
underwent plantar
fasciotomy for heel pain had
histologic evidence of
inflammation.
Why call it plantar fasciitis?
Goal 1
Eliminate the imitators BEFORE the orthotic fails
§  Tarsal tunnel
§  Rheumatoid arthritis
§  Gout- drug induced
§  Psoriatic arthritis
§  Lupus
§  Reiter’s
§  Ankylosing spondylitis
Goal 1
Eliminate the imitators BEFORE the orthotic fails
§  Peripheral neuropathy
§  Arterial Insufficiency
§  Irritable Bowel
§  Infracalcaneal Neuritis
§  Talar fracture
§  Fracture
§  Cyst
Goal 2
Understand the pathology and foot types
It is not subtalar pronation that stretches the plantar
fascia, it is supination of the midtarsal joint.
(Translation- Inversion of the forefoot on the rearfoot)
Goal 2
Understand the pathology and foot types
The most effective way
to decrease strain on
the plantar fascia is to
evert the forefoot
-Kogler, et al, JBJS, 1999
Goal 2
What foot types supinate the Mid Tarsal Joint?
§  47% forefoot valgus
§  24% everted heel
§  20% plantarflexed first ray
Goal 2
What foot types supinate the Mid Tarsal Joint?
§  47% forefoot valgus
§  24% everted heel
§  20% plantarflexed first
ray
Goal 2
What foot types supinate the MTJ?
§  47% forefoot valgus
§  24% everted heel
§  20% plantarflexed first
ray
Goal 2
It is not the pronation…..
But rather the midtarsal joint
compensating for the foot type!
Your job is to stop the MTJ from compensating.
Goal 3
Capture the foot type
The foot “type” must be captured in the negative
cast if the orthotic is to have the right shape.
Goal 3
Capture the foot type
The compensation is the
supination of the MTJ
(inversion of the forefoot).
The orthotic must pronate the
MTJ (eversion of the forefoot).
Goal 3
Capture the foot type
The orthotic lab must balance
the cast to the forefoot in
order to limit MTJ motion
*Adding a varus post, when there is no
varus, will supinate the MTJ.
Goal 4
Make the Right Orthotic
A soft orthotic holding the foot in the
compensated position guarantees failure.
A rigid poly orthotic, made from minimum fill
cast, without a rearfoot post has a success rate
of 86% !
Scherer, 1988 JAPMA
Orthotic Recommendation:
Everted Forefoot
§ 
§ 
§ 
§ 
§ 
§ 
§ 
Neg Cast – 1st Ray Plantarflexed
Cast Fill - Minimal
Heel Cup - Standard
Width - Standard
Cast Work – No Skive
Post – 0/0
Forefoot Extension- Reverse
Morton’s or Valgus Wedge*
*Kogler Effect
Orthotic Recommendation:
Everted Rearfoot
§  Neg Cast – 1st Ray
Plantarflexed
§  Cast Fill - Minimum
§  Heel Cup - Deep
§  Width - Standard
§  Cast Work – Medial
Skive – 2-4mm
§  Post – 0/0
Orthotic Recommendations
Summary: Don’t
§  Don’t Invert the Forefoot on the Rearfoot
•  Don’t Use Weightbearing Casting
•  Don’t Forget to Plantarflex the First Ray
•  Don’t Prescribe Varus Posts
•  Don’t Prescribe Morton’s Extensions
•  Don’t Dispense Orthoses that Gap from the Arch
of the Foot
Take Home Message
It is the control of the MTJ, not
the STJ that relieves the tension
on the plantar fascia and reduces
patient symptoms.
Summary
§ Determine a differential diagnosis
§ Understand the pathology and foot types
§ Cast out the supinatus
§ Make a rigid orthotic that limits MTJ
motion
Functional Hallux Limitus
Deformity
vs.
Pathology
Hallux Abducto Valgus
(Deformity)
Functional Hallux Limitus*
(Pathology)
* Laird PO, Functional Hallux Limitus, Illinois Podiatrist 1972
Orthopedic Literature
Barker 1884-
Pronation
Root, M., Weed, J. W. Orien, Normal and
Abnormal Function of the Foot, 1977
The Theory of HAV
Pathomechanics
When the first ray goes up…
…the big toe joint won’t
work.
Roukis, T., Scherer, P., JAPMA, 1996
Roukis, T., Scherer, P., JAPMA, 1996
1st MPJ Axis Location
Plantarflexed 1st Ray
Dorsiflexed 1st Ray
Mankey, M, Mann, R., Seminars in Arthroplasty 1992
Foot Types that Drive
the First Ray Up
§  Everted calcaneus
§  Flexible forefoot valgus
§  Congenital plantarflexed
first ray
Not all axes of the big
toe joint tilt the same
…some more …
some less
Kelso SF, Richie DH, Cohen IR, JAPA,
1982
So what’s the story?
The Theory of Proximal
Stability
&
The Range of Motion of
the Midtarsal Joint
Midtarsal Joint Affect
§  A midtarsal joint that has a lot of
dorsiflexion prevents 1st ray dorsiflexion
§  A midtarsal joint that has minimal
dorsiflexion promotes 1st ray dorsiflexion
Essentials for Pathology
§  A deforming force that makes the first
ray go up
§  Limited range of motion of the
midtarsal joint- not enough motion to
compensate for the deforming force
The Theory of HAV
Pathomechanics
§  The first ray dorsiflexes
§  The first ray inverts- inverting the joint axis of the big toe
§  The ROM of big toe dorsiflexion decreases
§  The heel lift creates a dislocation moment because
there is insufficient freedom of motion
§  The greater the 1st ray dorsiflexion, the more profound
the deformity
Roukis, T., Scherer, P., JAPMA, 1996
All Feet
Other Feet
Foot Type A, B or C
Small MTJ ROM
Large MTJ ROM
First Ray Dorsiflexed
Functional Hallux Limitus
Large 1st Ray ROM
Small 1st Ray ROM
Large Tilt of 1st MPJ Axis
Small Tilt of 1st MPJ Axis
Hallux Abducto Valgus
Hallux Rigidus
The Theory of HAV
and Hallux Limitus Development
§ 
§ 
As heel lift occurs, in the
presence of restrictive
dorsiflexion, a dislocation
moment is produced
Since the joint cannot move in
the sagittal plane, the joint
subluxes in the other two planes
leading to HAV or Hallux Limitus
Thought:
If the previous story demonstrated that
increasing GRF under the 1st met head
in a normal foot dorsiflexes the first ray
producing FHL…
Could an orthoses that decreases GRF
under the 1st met head decrease both
FHL and joint destruction?
Two Phase Study on Orthoses
Influence on 1st MTP ROM
§  Phase 1- Stance Study
§  Phase 2- Gait Study
Phase 1
Stance Study Hypothesis
§  A properly casted and produced functional
orthotic can plantarflex the 1st metatarsal in
stance and increase the 1st MTP ROM for
patients with FHL
Previous Investigation
§  “In all cases the range of dorsiflexion of the big
toe increases”
v Whitaker
J, JAPMA 93: (2) 118, 2003
§  Regarding the effects of foot posture and
inverted orthoses on hallux dorsiflexion…
“Difference is not statistically significant”
v Munteanu,
JAPMA 2006
Materials
§  WB goniometer
measurement
§  Casted with ray
plantarflexed
§  Poly functional- min fill
§  2 mm Kirby skive
§  14 mm heel cup
§  Wide width
§  Rear post 4/4
Materials
Stance Experiment
Methods: 27 Subjects
§ 
§ 
§ 
§ 
N= 49 feet
•  11 males
•  16 females
Greater than 50° dorsiflexion
NWB*
Less than 12° dorsiflexion in
stance *
No trauma
§  Weight
•  Max= 280 lbs.
•  Min= 105 lbs.
•  Ave= 166 lbs.
§  Heel Position
* Our definition of Functional Hallux Limitus
•  5 inverted
•  4 perpendicular
•  40 everted
•  Ave. heel eve= 5.6°
Results: Increase in Degrees of
DF
§ 
All 49 feet
increased their DF
ROM
§ 
Largest= 22 °
§ 
Smallest= 2 °
§ 
Mean= 8.48 °
Results: Increase of Dorsiflexion
Without Orthoses (WB DF)
§ 
Mean= 9.71 °
§ 
Least= 4 °
§ 
Most= 12 °
With Orthoses (WB DF)
§ 
Mean= 18.7 °
§ 
Least= 12 °
§ 
Most= 36 °
Average orthotic effect- 93%
increase in ROM
What was the change related to?
§  Gender- No
§  Shoe size- No
§  Right or Left foot- No
§  Weight- No
§  The change in RCSP- No
§  Did it matter how much or how little the RCSP
was everted- No!
Phase 1 Conclusion
§  Regardless of gender, shoe size, or weight,
a functional orthotic, fabricated from a
negative cast with the first ray plantarflexed,
will increase the 1st MTP joint range of
motion in stance for patients with FHL an
average of 93%.
What’s next?
§  Can we prove orthotics increase the range of
motion in gait … by demonstrating a decrease in
sub hallux pressure
Phase 2
Gait Experiment Hypothesis
§  A properly casted and produced functional
orthotic can plantarflex the 1st metatarsal in gait
and increase the 1st MTP ROM for patients with
FHL
Gait Experiment
Methods: 18 Subjects
§ 
§ 
§ 
§ 
N= 36 feet
•  8 males
•  10 females
§  Weight
Greater than 50° dorsiflexion
NWB*
Less than 14° dorsiflexion in
stance *
No trauma/arthritis
* Our definition of Functional Hallux Limitus
•  Max= 280 lbs.
•  Min= 105 lbs.
•  Ave= 160 lbs.
Materials
§ 
§ 
§ 
§ 
§ 
§ 
§ 
§ 
Casted with ray plantarflexed
Poly functional- min fill
2mm Kirby skive
14 mm heel cup
Wide width
Rear post 4/4
Standard shoe
Tekscan/F Scan
• 
• 
7 steps- removed 1st and last
steps
Hallux mask for maximum
pressure from heel left to toe off
Without orthotic
With orthotic
Tekscan
Without orthotic
With orthotic
Tekscan
Assumption
§  Decrease in hallux pressure at heel off =
increase in 1st MTPJ motion
Results: Hallux Peak Pressures
§ 
Mean Change=
2.65 PSI (14.7%)
§ 
§ 
Greatest 10.38 PSI (49%)
Least 0.31 PSI (2%)
§ 
ALL 36 feet had a
decrease in sub hallux
pressure
Results:
Decrease in Hallux Peak Pressure
Without orthoses
§  127.85 KPa
With orthoses
§  108.93 KPa
Pressure under the
hallux at heel lift:
decreased 18.92
KPa (14.7%)
Was the change related to
RCSP at stance?
NO!!!
Conclusion
§  A functional orthotic fabricated from a
negative cast with the first ray plantarflexed,
will increase the ROM of the 1st MTPJ joint
as demonstrated by a decrease in hallux
pressure, at heel lift in gait, an average of
14.7 %.
Summary
§  In the first study, with the use of the orthotic
during stance, hallux dorsiflexion was increased
an average of 92.5%
§  In the second study, with the use of the orthotic
in gait, sub-hallux pressures were reduced an
average of 14.7%.
Observations
§  Virtually all hallux ulcers are related to hallux limitus
•  Barrett & Mooney 1973
•  Daniels 1989
•  Boffeli 2002
§  Could orthoses be effective in improving the prognosis
of subhallux ulcers?
§  Could orthoses demonstrate improved clinical outcomes
in patients with HAV and Hallux Rigidus?
§  If FHL is a precursor to HAV, could orthoses
demonstrate improved clinical outcomes postoperatively in patients having bunion surgery?
Orthotic Recommendations
§  Cast
•  Plantarflexed 1st
§  Heel
•  Normal
§  Width
•  Wide
§  Correction
•  4 mm skive
•  5º inversion
§  Addition
•  Reverse Morton’s
Extension
§  Top Cover
•  To the Toes
Orthotic Recommendations
Acknowledgements
§  Brooks Shoe Company, Seattle, WA
§  Tekscan Inc, Boston, MA
§  Biomechanics Research Fund,
San Francisco, CA
§  ProLab Orthotics, Napa, CA
Thank You