ORTHOTIC SYSTEMS
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Transcript of ORTHOTIC SYSTEMS
ORTHOTIC SYSTEMS
Ankle-Foot Orthoses (AFOs)
ORTHOTIC PRINCIPLES
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
Description
ORTHOTIC PRINCIPLES
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.)
Terminology
ORTHOTIC PRINCIPLES
Substitution and/or enhancement of motor function
Control of joint alignment in sagittal and frontal planes
Immobilization and protection of affected areas
Functions
ORTHOTIC PRINCIPLES
3-point force systems Reduction in
unwanted angular rotation
Stabilization about a joint, bone or skeletal segment
ORTHOTIC PRINCIPLES
3-point force systems Reduction in
unwanted angular rotation
Stabilization about a joint, bone or skeletal segment
ORTHOTIC PRINCIPLES
Lever systems and rotation Momentum
generated by push-off of contralateral limb
Forward motion generated by rotation of lever system
Heel Lever
Toe LeverCenter of Gravity (Body Weight)
CG
Axis of rotation
ORTHOTIC PRINCIPLES
Lever systems and rotation Momentum
generated by push-off of contralateral limb
Forward motion generated by rotation of lever system
CG
ORTHOTIC PRINCIPLES
Lever systems and rotation Momentum
generated by push-off of contralateral limb
Forward motion generated by rotation of lever system
Axis of rotation
ORTHOTIC PRINCIPLES
Lever systems and rotation Momentum
generated by push-off of contralateral limb
Forward motion generated by rotation of lever system
Axis of rotation
ORTHOTIC PRINCIPLES Lever systems and
rotation Momentum
diminished by resistance of ipsilateral forefoot
Backward motion generated by rotation of lever system
Center of Gravity (Body Weight)
CG
Axis of rotation
ORTHOTIC PRINCIPLES Lever systems and
rotation Momentum
diminished by resistance of ipsilateral forefoot
Backward motion generated by rotation of lever system Axis of
rotation
ORTHOTIC PRINCIPLES Lever systems and
rotation Momentum
diminished by resistance of ipsilateral forefoot
Backward motion generated by rotation of lever system Axis of
rotation
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
Ankle-Foot Orthoses (AFOs)
Metal Plastic
Metal AFO
Indications Wide fluctuaton
in edema At-risk foot
(absent or diminished sensation w/edema, visual inpairment, etc.)
Metal AFO
Uprights Aluminum -
lightweight Stainless Steel -
strong
Metal AFO
Stirrups Solid - stability Split – shoe
change
Metal AFO
Ankle Joints Free Motion
Metal AFO
Ankle Joints Dorsi-flexion
Assist
Metal AFO
Ankle Joints Double-action
Metal AFO
Auxillary Controls Varus/Valgus
Control Strap Controls varus
or valgus of rearfoot during weight-bearing
Metal AFO
Auxillary Controls Laminated
Footplate
Metal AFO
Auxillary Controls Pre-tibial Shell
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 M&L calf outline with >1/4” clearance from skin
(C) – Ankle joints are spaced>3/8” & 1/4” from M&L malleoli, respectively
A
B
C
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 M&L 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
Plastic AFOs (PAFOs)
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
Plastic AFOs (PAFOs)
Solid Rigid
Plastic AFOs (PAFOs)
Solid Posterior
Leafspring (PLS)
Solid PAFOs
Thickness Typically
between 1/8” & 1/4”
Angle Û dorsiflexion =
Û knee flexion Û plantarflexion
= Û knee extension
Solid PAFOs Material
Polyproplyene for strength
Co-Polymer for flexibility
Cross-sectional shape determines rigidity
Flexible Solid
Articulated Plastic AFOs
Ankle Joints
Articulated Plastic AFOs
Free or limited motion
Variable motion
Articulated Plastic AFOs
Free or limited motion
DF Assist Neutral
Tamarack
Articulated Plastic AFOs
Free or limited motion
Oklahoma
Articulated Plastic AFOs
Variable Motion
Friddle VM
Articulated Plastic AFOs
Variable Motion Camber Angle
Plastic AFOs
Auxiliary Components
Plastic AFOs
Auxiliary components Posterior ROM
Components
Plantar StopDorsi-Assist
Plastic AFOs
Auxiliary components Compcore
Reinforces plastic in stress-sensitive areas
Plastic AFOs
Auxiliary components Pre-tibial shell
Enhances knee extension
PTB modifications can reduce weight bearing below
Plastic AFOs
Auxiliary components Anterior shell
Best for immobilization of foot/ankle
Plastic AFOs
Varus/valgus modifications Creates effective
3-point system to control varus/valgus
Plastic AFOs
Molded footplate Adds foot control Facilitates use of
metal AFO ankle joints
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
Fitting criteria for Plastic AFOs Height - Top of AFO is > 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