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.
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.
Conditions with fluctuating edema or fluid retention
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).
Stirrups make changing shoes difficult
Accommodates fluxuating edema better than total contact designs.
Only requires a tracing of the leg and measurements in order to fabricate.
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
Control of the foot relies on the shoe.
Any time significant changes in volume are not anticipated
When significant changes in volume are not anticipated
Reduces pressures on the skin
High durability/weight ratio
Easy to clean/ hygienic
Can easily be chance to different shoes.
Does not accommodate for changes in volume as well as conventional systems
Pros and Indications
Cons and Contraindications
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
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.
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:
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
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.
Note - Thermoplastic designs are preferred.
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.
Joint increments may not match anatomical changes.
Difficult to apply with severe spastic varus or valgus deformity at the subtalar joint.
Primary function is to control plantarflexion at heel strike and maintain dorsiflexion during swing phase.
Flexible to allow for increased motion
Patients with tone
Patients requiring control of dorsiflexion.
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