AFOs - Ankle Foot Orthoses

Conventional vs. Total Surface Bearing/Thermoplastic

Total Surface Bearing/Thermoplastic is always preferable due to increased control areas and the reduced pressures on the skin that results.  Therefore, the total surface bearing orthoses provides more comfort and better function than the conventional alternative.  Total Surface Bearing/Thermoplastic designs are also considerably lighter, have a better durability/weight ratio, are easier to clean, and can easily be chance to different shoes. 

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Conventional AFOs can be a valuable tool, however, they are generally a last resort behind Total Surface Bearing/Thermoplastic or hybrid designs.  Conditions that merit their use include conditions with fluctuating edema or fluid retention, or patient preference. 

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Conventional

Indications

Conditions with fluctuating edema or fluid retention
Patient preference
Heat sensitivity - as seen occasionally with Multiple Sclerosis (thermoset or carbon braces are also an option)
Patient's leg can not be casted or scanned - can only be traced or measured (very rare).

Contraindications

Cosmesis
Stirrups make changing shoes difficult

Advantages

Accommodates fluxuating edema better than total contact designs.
Only requires a tracing of the leg and measurements in order to fabricate.

Disadvantages

Higher pressures on the skin due to forces being applied to a relatively small surface area.
Less control is available due to reduced surface area.
Joints and uprights tend to be heavy
Cosmeticaly unappealing
Control of the foot relies on the shoe.

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Total Surface Bearing/Thermoplastic

 

Indications

Any time significant changes in volume are not anticipated

Contraindications

When significant changes in volume are not anticipated
Patient preference

Advantages

Increases control
Reduces pressures on the skin
More comfort
Considerably lighter
High durability/weight ratio
Easy to clean/ hygienic
Can easily be chance to different shoes. 

 

Disadvantages

Does not accommodate for changes in volume as well as conventional systems

 

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Static Type Ankle Foot Orthoses

Solid Ankle Foot Orthosis (SAFO)

Pros and Indications

 

Cons and Contraindications

 

 

 

Floor Reaction [Ankle Foot] Orthosis / Ground Reaction [Ankle Foot] Orthosis  (FRO/GRO)

Function / Indication

 

Same functions as solid AFO in frontal plane.
In the sagittal plane, provides significant knee extension moment during weight bearing/stance phase.
This can be an excellent alterative to a KAFO design for patients with trace or weak quadriceps in that it can achieve knee stability while maintaining efficiency by reducing weight and bulkiness.
Note - Articulated designs may help in allowing for more normal step length/gait by not unnecessarily blocking plantarflexion.

Often used with

Crouch Gait

Cons / Contraindications

 

Recurvatum or unstable knee
Knee extension moment compromised with external foot rotation in excess of 25 degrees.
Presence of knee flexion contractures exceeding 15 degrees
Must be able to get ankle to neutral or slight plantar flexion.
Minimum of fair quadriceps strength needed if applied bilaterally (because the sound side allows the patient to know where they are placing the effected side).
Presence of some trunk balance needed or ability to use walking side.
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http://www.orthomerica.com/custom/cus_images/afo_ptbo.jpg

 

 

 

 

 

 

 

Patella Tendon Bearing Ankle Foot Orthosis (PTB AFO)

Function / Indication

40 - 60 percent of the weight baring responsibilities of the plantar surface of the foot or the ankle jt.

Relieve weight bearing below the knee.

Typically used for:
            Fracture management
            Arthritic joints
            Painful conditions of the heel
Problems with ulceration

Cons / Contraindications

Conditions of skin and peripheral circulation which can not tolerate the pressure of the PTB.

Unstable knee joint

 

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http://www.orthomerica.com/custom/cus_images/afo_ptbo.jpg

 

 

 

 

 

 

 

 

Patent Bottom Ankle Foot Orthosis

 

PTB AFO with an additional stainless steel upright that is attached to the AFO and is deflected anteriorly to attach to a stainless steel plate at the mid-foot.  A rocker-bottom tread (e.g. tire tread)  is added to the patent bottom which is approximately 1/4 the length of the foot.  There is also a build-up added to the plantar surface of the foot for unloading purposes.

 

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Note - Thermoplastic designs are preferred.

 

 

 

 

Dynamic Type Ankle Foot Orthoses                           

Articulated / Hinged Ankle Foot Orthosis (HAFO)

Pros and Indications

 

The most versital AFO that is designed.

Can be made to be a Solid AFO to start and then move into a limited articulation, then change range of motion as rehabilitation dictates

Controls medial/lateral stability at the ankle

Controls the end points of dorsiflexion/plantar flexion range

Does not necessarily interrupt the three rockers in stance phase of gait

Excellent diagnostic orthosis during the post-trauma rehab period due to multiadjustable by therapist without use of any tools*.  *Depending on joint type.

Cons / Contraindications

 

Joint increments may not match anatomical changes.

Difficult to apply with severe spastic varus or valgus deformity at the subtalar joint.

 

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Posterior Leaf Spring Ankle Foot Orthosis (PLS AFO)

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Function / Indication

Primary function is to control plantarflexion at heel strike and maintain dorsiflexion during swing phase.

Flexible to allow for increased motion

 

Cons / Contraindications

Patients with tone

Patients requiring control of dorsiflexion.

 

Design

Narrow trimlines
Footplate with very little medial/lateral support
Remaining components are the same as the solid ankle AFO

The amount of flexability is given by, 1) the contour or radius (the more the radius is softened, the more the brace is able to flex naturally)  2) Thickness, and 3)  AP trimline

Start with 5 degrees of dorsiflexion - standard , may be increased.
May lower contours and reduce foot plate as needed by the pt.

Custom and off-the-shelf options