Introduction to Ankle Foot Orthoses
Original Editors - Khloud Shreif
Introduction[edit | edit source]
Ankle foot orthoses AFOs are external biomechanical devices utilized on lower limbs to stabilize the joints, improve the gait and physical functioning of the affected lower limb. AFO is used as supportive devices and aid for ambulation through different gait stages by providing foot clearance, used to limit or assist ankle and foot ROM like; dorsiflexion, plantar flexion, improve balance, decrease the risk of falling, help with weak musculature of lower legs, and to return to previous activity or facilitate patient mobility.
They are found in different types and different materials and can be modified according to the use and the development of the person if it is used for children. They made from thermoformed plastic material that enables to add modification and adjustments. AFOs are used as night splints to prevent contractures in some cases, patients with stroke , and other neurological conditions such as SCI and children with cerebral palsy.
Types of AFOs.[edit | edit source]
Traditional plastic AFO.
- They are used to provide maximum medial/ lateral joint stability and are better for short-term use.
- They are easy to apply, cover a variety of needs, and are an economic choice, they can be customized by heat molding.
- They have difficulty inserting in shoes.
- They have a lower profile than traditional AFO, easy shoe fit, and can also be customized by heat molding.
- Provide moderate lateral stability.
- Assist with static ankle dorsiflexion and are suitable for the moderately active person.
- They have free cub space for the heel and calf muscle so they are comfortable in use.
Carbon Fiber AFOs.
- They are modern dynamic and semi-flexible AFO with lightweight, have 10-15 degree for footplate the tilting start at the metatarsal heads.
- Open heel design and their low profile design help to avoid the pressure and contact with critical pressure points of foot in addition to stability and strength.
- There is lateral support to control the medial instability, ankle pronation and eversion, or medial support for patients with lateral ankle instability.
- They are the best choice for an active person to encourage the normal gait pattern, and control torsion forces.
Assessment[edit | edit source]
It is important to determine what type of AFO will be suitable according to patient conditions and to help with the rehabilitation process with orthoses.
Subjective assessment for the patient prior to application of device including:
- Patient’s medical history, primary pathology, and the diagnosis of his/her condition.
- Patient's occupation, ADL activities, mobility status, and level of independence. In addition, explain to the patient the aim of the orthoses and if there is an expectation for a usage time frame.
Objective assessment including:
- Physical examination for skin condition if there is edema, wound, skin pathology, any adhesions or scars, and bony landmark.
- Strength of the muscles, available joint ROM, joint stability and any signs reflect any neural deficit problems.
- Functional assessment at static and dynamic positions: evaluation of balance, deviation from the normal posture, and joint position from three plans of movement at W.B.
- Dynamic positions include patient’s gait analyses, evaluation for functional strength, and the ability to transfer.
Measurement [edit | edit source]
The following measurements of the lower leg and the foot are taken for optimal AFO from, the position knee flexed and foot rested on the ground following measurements are taken:
- The length of the foot from the longest point is taken.
- The width of metatarsal heads at the widest point of the foot.
- Measurement above the ankle at the level of the two malleoli.
- Three circumference measurements of the lower leg the first one above the ankle joint, another point 3 inches above it, and the last circumference around the head of the fibula.
- The length of the leg from the ground to the head of the fibula level.
Fitting[edit | edit source]
The majority of AFO or any other orthoses will need few adjustments, reshaping, adding straps, or internal pads.
- The patient sitting on chair or edge of the bed, and the foot on the ground
- Need to make sure the skin is dry, then wear long socks to avoid direct contact pressure on the skin.
- First place the heel in the AFO’s heel cup and apply the ankle strap for stability and to make sure the heel is in place.
- For the malleoli landmark, avoid direct pressure and digging into the skin, also too much space around will harm the skin, and affect the efficiency of the AFO.
- The length of the footplate is also important that means the extent of the toes are rested and are in a comfortable position.
Troubleshooting [edit | edit source]
- The skin around the AFO may experience red marks at the site of the pressure of AFO that is normal and will relive in about 30 minutes. If there are any blisters or sores at the site of AFO or redness that doesn’t relieve, the patient will need to consult the physiotherapist
- Common areas of pressure are important to take care of such as pressure point around the fibular head, as it may cause injury to the peroneal nerve.
- Medial malleolus irritation may occur due to medial tibial displacement, or the hinge of the medial side is in the improper place. Using internal shoe modification like the medial flare that will limit and control the tibial displacement and wearing long socks will decrease the pressure on the malleoli
- Talonavicular irritation that patients may experience with functional AFOs
- Wearing unsuitable AFO for long period will negatively affect the muscles of the leg.
- Sometimes will have difficulty to insert into the shoe and not all shoes will be suitable to wear with AFO.
- The patient will need to an extent a good hand strength to help with wearing the AFO.
How to take care of your AFO
By use a wet cloth to wipe AFO, and dry it with a towel or leave it to dry naturally. Don’t soak in water.
Sources[edit | edit source]
References [edit | edit source]
- Daryabor A, Arazpour M, Aminian G. Effect of different designs of ankle-foot orthoses on gait in patients with stroke: A systematic review. Gait & posture. 2018 May 1;62:268-79.
- Totah D, Menon M, Jones-Hershinow C, Barton K, Gates DH. The impact of ankle-foot orthosis stiffness on gait: A systematic literature review. Gait & posture. 2019 Mar 1;69:101-11.
- Foot and Ankle Associates of North Texas. AFO - Measuring Leg Size . Available from: http://www.youtube.com/watch?v=gwVl_LipyGg[last accessed 22/6/2021]
- NHS Greater Glasgow and Clyde. NHSGGC - Orthotics Patient Information: Fitting AFO to self . Available from: http://www.youtube.com/watch?v=Ws88kuZYcyk[last accessed 22/6/2021]