ORTHOTIC SYSTEMS

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ORTHOTIC SYSTEMS

• Ankle-Foot Orthoses (AFOs)

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ORTHOTIC PRINCIPLES
Description

• An Orthosis is an external device with
  specialized functions that acts upon the
  musculo-skeletal system.
• Orthotics is the field of study concerned with
  the design, fabrication and application of such
  devices

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ORTHOTIC PRINCIPLES
Terminology

• Orthoses are described or referred to by the
  joints or regions they encompass
• The major joints (Hip, Knee, Ankle, etc.) are
  combined in various ways along with the ending
  Orthosis to designate a particular orthosis
• Commonly the first letters of the joint names
  are combined to form acronyms (KAFO, AFO,KO, etc.)

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ORTHOTIC PRINCIPLES
Functions

• Substitution and/or enhancement of motor function
• Control of joint alignment in sagittal and
  frontal planes
• Immobilization and protection of affected areas

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ORTHOTIC PRINCIPLES

• 3-point force systems
• Reduction in unwanted angular rotation
• Stabilization about a joint, bone or skeletal
  segment

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ORTHOTIC PRINCIPLES

• 3-point force systems
• Reduction in unwanted angular rotation
• Stabilization about a joint, bone or skeletal
  segment

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ORTHOTIC PRINCIPLES

• Lever systems and rotation
• Momentum generated by push-off of contralateral
  limb
• Forward motion generated by rotation of lever
  system

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ORTHOTIC PRINCIPLES

• Lever systems and rotation
• Momentum generated by push-off of contralateral
  limb
• Forward motion generated by rotation of lever
  system

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ORTHOTIC PRINCIPLES

• Lever systems and rotation
• Momentum generated by push-off of contralateral
  limb
• Forward motion generated by rotation of lever
  system

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ORTHOTIC PRINCIPLES

• Lever systems and rotation
• Momentum generated by push-off of contralateral
  limb
• Forward motion generated by rotation of lever
  system

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ORTHOTIC PRINCIPLES

• Lever systems and rotation
• Momentum diminished by resistance of ipsilateral
  forefoot
• Backward motion generated by rotation of lever
  system

Axis of rotation
Center of Gravity (Body Weight)
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ORTHOTIC PRINCIPLES

• Lever systems and rotation
• Momentum diminished by resistance of ipsilateral
  forefoot
• Backward motion generated by rotation of lever
  system

Axis of rotation
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ORTHOTIC PRINCIPLES

• Lever systems and rotation
• Momentum diminished by resistance of ipsilateral
  forefoot
• Backward motion generated by rotation of lever
  system

Axis of rotation
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ORTHOTIC SYSTEMS

• Ankle-Foot Orthoses (AFOs)
• Indications
• Substitute for/enhance weak or absent
  dorsi/plantar flexors
• Stabilize foot/ankle in coronal and sagittal
  planes
• Provide some knee stability in sagittal plane

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Ankle-Foot Orthoses (AFOs)
Plastic
Metal
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Metal AFO

• Indications
• Wide fluctuaton in edema
• At-risk foot (absent or diminished sensation
  w/edema, visual inpairment, etc.)

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Metal AFO

• Uprights
• Aluminum - lightweight
• Stainless Steel - strong

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Metal AFO

• Stirrups
• Solid - stability
• Split shoe change

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Metal AFO

• Ankle Joints
• Free Motion

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Metal AFO

• Ankle Joints
• Dorsi-flexion Assist

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Metal AFO

• Ankle Joints
• Double-action

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Metal AFO

• Auxillary Controls
• Varus/Valgus Control Strap
• Controls varus or valgus of rearfoot during
  weight-bearing

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Metal AFO

• Auxillary Controls
• Laminated Footplate

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Metal AFO

• Auxillary Controls
• Pre-tibial Shell

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Fitting Criteria for Metal AFOs

• Height
• Top of calf no less than 1 1/8 below fibular
  head
• Width
• (A) Calf band is of sufficient width to control
  tibia in frontal plane yet not cause undue
  pressure
• (B) Uprights follow contours of ML calf
  outline with gt1/4 clearance from skin
• (C) Ankle joints are spacedgt3/8 1/4 from
  ML malleoli, respectively

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Metal AFO Considerations

• If the orthosis is articulated then insure that
  the orthotic ankle joint axis is aligned with the
  anatomical ankle joints
• Plantar and/or dorsiflexion stops should be
  adjusted equally within medial and lateral ankle
  joints
• Uprights should be situated mid-line on ML sides
  of lower leg calf band should be deep enough to
  allow this
• If patient supplies own shoes insure that they
  fit well before attaching orthosis
• Check skin integrity (esp. at calf band, ankle
  joints and shoe) after 1/2 hr. of use. If there
  are no problems resume use, checking every 4
  hours for the first few days

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• Intentionally Blank

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• Intentionally Blank

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• Intentionally Blank

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• Intentionally Blank

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Plastic AFOs (PAFOs)
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Plastic AFOs (PAFOs)

• Solid
• One-piece with no separate components rigidity
  determined by thickness and shape
• Articulated
• Incorporates ankle joints and other components to
  allow controlled ROM

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Plastic AFOs (PAFOs)

• Solid
• Rigid

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Plastic AFOs (PAFOs)

• Solid
• Posterior Leafspring (PLS)

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Solid PAFOs

• Thickness
• Typically between 1/8 1/4
• Angle
• Û dorsiflexion Û knee flexion
• Û plantarflexion Û knee extension

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Solid PAFOs

• Material
• Polyproplyene for strength
• Co-Polymer for flexibility
• Cross-sectional shape determines rigidity

Flexible
Solid
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Articulated Plastic AFOs

• Ankle Joints

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Articulated Plastic AFOs

• Free or limited motion
• Variable motion

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Articulated Plastic AFOs

• Free or limited motion

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Articulated Plastic AFOs

• Free or limited motion

Oklahoma
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Articulated Plastic AFOs

• Variable Motion

Friddle VM
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Articulated Plastic AFOs

• Variable Motion
• Camber Angle

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Plastic AFOs

• Auxiliary Components

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Plastic AFOs

• Auxiliary components
• Posterior ROM Components

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Plastic AFOs

• Auxiliary components
• Compcore
• Reinforces plastic in stress-sensitive areas

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Plastic AFOs

• Auxiliary components
• Pre-tibial shell
• Enhances knee extension
• PTB modifications can reduce weight bearing below

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Plastic AFOs

• Auxiliary components
• Anterior shell
• Best for immobilization of foot/ankle

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Plastic AFOs

• Varus/valgus modifications
• Creates effective 3-point system to control
  varus/valgus

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Plastic AFOs

• Molded footplate
• Adds foot control
• Facilitates use of metal AFO ankle joints

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Fitting criteria for Plastic AFOs

• Trim Lines
• Around proximal calf area shell is closely
  contoured
• Side trim line placement determined by use
  although a 3/16 gap between the orthosis and
  the skin is desirable to accommodate volume
  fluctuation
• Along the foot the medial and lateral walls are
  high enough to control any pronation/supination
• The medial and lateral distal edges terminate
  just proximal to the 1st and 5th metatarsal
  heads, respectively

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Fitting criteria for Plastic AFOs

• Height - Top of AFO is gt 1 1/8 below fibula head
• Width - Proximal calf area is of sufficient width
  to control tibia in frontal plane yet not cause
  undue pressure
• Since heel height influences function of orthosis
  type of footwear should be determined prior to
  fabrication
• Athletic footwear w/removable insoles and velcro
  straps instead of laces is preferred
• Patients w/vision and/or sensory impairment
  require close monitoring to insure skin integrity