DorsiflexionAssisting Ankle Brace

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Dorsiflexion-Assisting Ankle Brace

• Andrea Albergo
• Thomas Burney
• Lauren Gallagher
• Alice Hammer
• Sheila Powenski
• Ben Yaffe

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Problem Statement

• What
• The design of a ankle brace that assists in
  dorsiflexion, designed specifically for an
  athlete whose desired range of ankle motion is
  greater then a patient with a goal of only
  walking.
• When
• Two week turn-around from fabricated parts to
  completed brace construction
• Who
• Design is specifically for Jason Williams, and
  will be individually tailored for his use.

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QFD
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Product Design Specification

• Results from QFD Indicated
• Mission Statement
• An ankle brace will be designed to assist
  dorsiflexion and cushion heel strike for users
  with pereneol nerve damage.
• Customer Needs
• Lightweight brace (1-2lbs maximum)
• Unobtrusive size
• Design Requirements
• Attachment to leg must be secure and comfortable
• Ability to vary amount of damping
• Variability of dorsiflexion time

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Product Design Specification (cont.)

• Competition
• According to nationally renowned orthotist no
  products currently exist that enable athletic
  performance in this type of brace.
• Intended Market
• Product designed specifically for Jason Williams,
  if successful the brace could possibly be a model
  for more versatile braces for non-athletic
  patients.
• Cost Prediction
• 150 - 250, plus occasional part replacement
  costs

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Updated Gantt Chart
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Information Gathered

• The Gait Cycle
• Eight stages progressing through a single stride
• Stance Phase 60 gait
• Initial Contact to Pre-Swing
• Hamstrings and dorsiflexors in ankle remain
  active
• Quadriceps and gluteal muscles work to maintain
  stability
• Swing Phase 40 gait
• Initial swing to terminal swing
• Ankle dorsiflexion occurs with the contraction of
  anterior tibialis muscle
• Running Progression of Gait Cycle
• Two periods of double float are substituted for
  the two periods of double support
• Stance time becomes less then swing time

http//www.orthoteers.co.uk/Nrujpij33lm/Orthgait.
htmPHASES
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Information Gathered

• Specific Injury of Patient
• Peroneal Mononeuropathy local damage to a
  single nerve, commonly the peroneal nerve (not
  disease or systemic condition)
• Steppage Gait walking with a foot drop where
  toes hang down and foot slaps on heel strike
• Can be caused by peroneal nerve trauma
• Causes injured person to lift foot excessively
  high to avoid dragging toes
• Causes of Peroneal Neuropathy
• Knee injury or trauma
• Injury during knee surgery

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Concept Generation Idea 1

• Pros
• Less bulky
• Less likely to hinder plantar flexion
• May provide more power for jump
• Cons
• Not best damping solution
• Springs may fatigue
• May not work well for low or changing speeds

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Concept Generation Idea 2
Brace connecting to leg

• Pros
• Most likely to accomplish damping effectively
• Fewer moving parts for wear and tear
• Cons
• More bulk then other two
• Needs lubrication
• May hinder plantar flexion

Weak Spring to lift foot
Plastic Crown attached to shoe
One Way Damper
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Concept Generation Idea 3
Spring loaded pivot point (to return cam to
original location). Electronic Locking mechanism
prohibits the cam from rotating engaging the
spring

• Pros
• No unnecessary force to overcome
• Fewer moving parts
• Cons
• Very intricate design
• Need Electrical Engineering help
• Need data on pressure, etc.

Plastic Crown attached to shoe
Pressure Sensor
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Concept Evaluation
Pugh Decision Matrix
Reference Concept Idea 2 Score BBetter,
WWorse, SSame
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Concept Evaluation

• Pugh Concept Evaluation led to the decision
  of..
• CONCEPT IDEA 2.

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Product ArchitectureSchematic Diagram

• The Leg Attachment will have fundamental
  interactions with the damper and the spring.
• The damper and spring will have interactions with
  the shoe, which will produce desired effects on
  patients foot

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Product ArchitectureClustering
Energy storage and dissipation system
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Product ArchitectureGeometric Layout
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Design Considerations

• Impact standard use hit from side
• High forces jumping, landing, planting
• Varying contacts jogging or walking (heel)
  sprinting (forefoot)
• Sudden forces direction changes
• Hysteresis need instant response
• Sweat
• Temperature

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Design Analysis

• Kinematics Analysis
• 7 DOF
• Angular rotation of upper leg
• Angular rotation of lower leg
• Ability to predict the position and rotation of
  foot during any period of time
• Dynamics Analysis
• Impact force of foot hitting the ground
• Solve for the vertical displacement of the torso
  during any period of time in the gait cycle.

KEY M mass of upper body MH, LH mass and
length of upper leg, respectively MK, LK mass
and length of lower leg, respectively ?H, ?K
rotational displacement of hip and knee,
respectively
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Design Analysis Contacts

• Harvey Johnson
• professional orthotist with more then 30 years
  experience in brace construction
• Mike Huff KLab
• Providing experimental results of the rotation of
  the hip and knee in the gait cycle as a function
  of time
• Providing assistance with the use of filming and
  force plate equipment
• Dr. Kielb
• Assistance in the modeling of the lower body
  during gait cycle

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References

• Gait Cycle - http//www.orthoteers.co.uk/Nrujpij3
  3lm/Orthgait.htmPHASES
• Walking/Gait Abnormalities http//health/allrefe
  r.com/health/walking-gait-abnormalities-info.html
• Ankle Foot Biomechanics http//www.orthoteer
  s.co.uk/Nrujpij33lm/Orthfootmech.htm