AFOFC (ankle foot orthosis and footwear combination) tuning is undoubtedly one of my favourite areas in orthotics. In Australia this concept is fairly recent (around 6 years or so) and it saddens me to say not all referring specialists know about this process. I hope to enlighten the general public and provide some simple yet interesting examples.
Evidence based practice
The evidence for AFOFC tuning is ever increasing with new case studies, recommended practices and journal articles being released. Depending on your background, you may be interested in the very first article that discussed AFOFC tuning that was written by one of the pioneers in this area. The article was published in 2010 in the journal “Prosthetics and Orthotics International” and is titled “The importance of being earnest about shank and thigh kinematics especially when using ankle-foot orthoses” by Elaine Owen. If you are an orthotist, physiotherapist, referring specialist or someone who has an interest in biomechanics, I cannot recommend this article enough!
The foot is pointing down…it’s going the wrong way!!!
If I had a dollar for every time a patient, physiotherapist, or doctor said this to me I would have enough money….well… in honesty to pay for a really expensive meal – like a really really nice one that’s super fancy.
The point is, making an AFO in plantarflexion (pointing down) seems very counterintuitive – I mean, these patients need help clearing their foot (getting the foot up) in swing phase. Well it goes a little deeper than that.
There are two parts to the walking cycle; swing and stance. Imagine taking a step with your right leg. From the moment your heel touches the ground until your toes lift off the ground behind your body, that is stance phase. When your leg is behind you and “swings through” to land in front of your body, that is called swing phase. The human body makes a very good pattern of this and the “normalised” gait (way of walking) requires the least amount of energy which is why humans walk the way they do. There are expected ranges of motion people should achieve when walking – the knee at one point she be completely straight (extended) and the foot must point up at some parts (dorsiflex), and point down (plantarflex) in other parts. If you cannot achieve these movements because your disability or condition affects your muscles or bones, AFOFC tuning makes this possible again – the end result should be the same because we make certain allowances in other areas.
There are expected ranges of motion people should achieve when walking – the knee at one point she be extended, the foot must dorsliflex and plantarflex. If you cannot achieve these movements because your disability or condition affects your muscles or bones, AFOFC tuning makes this possible again – the end result should be the same because we make certain allowances in other areas.
Need an example?
I don’t know about you but my calf muscles have a really crappy length (it something I am working on at the moment). If I squat as low as I can go, I can’t get my heels to touch the ground – I have reached my end range.
Now, if I got some wedges and put them under my heels, I have not changed the angle of my ankle but I have given myself more surface area to work on and now I can shift my weight a little more posteriorly (backwards) and redistribute the pressure. This means when I stand back up it will be so much easier because I can generate more power over more muscle groups because I have more of a platform to work with.
This concept is one of the most important concepts used in AFO tuning – don’t place the leg at it’s end range! Now this squat example is good and if you have a phone book and crappy calf ranges like me, feel free to try it out yourself and feel the difference, but I must reiterate that walking is far more complex than squatting and the importance of not placing the ankle in its end range is even more important for someone who already has weak muscles i.e; a cerebral palsy patient with spasticity in their muscles.
I must reiterate, that walking is far more complex than squatting and the importance of not placing the ankle in its end range is even more important for someone who already has weak muscles i.e; a cerebral palsy patient with spasticity in their muscles.
Another simple example is paying attention to how you walk barefoot, in high heels and in stiff work boots – it is all so different and your walking pattern will be influenced by the flexibility of your footwear and the pitch of your footwear (please see my page on “What makes a good shoe” for more details).
What do these tuned AFOs and shoes look like?
There are so many possibilities because every patient is different. I am starting to build up a collection and so I will keep adding to this page.
- The following AFO and shoe is used by a patient who has cerebral palsy, weak muscles and contractures (muscles that are stuck and can’t stretch through a full normal range) at his ankles, knees and hips. When we started, we measured this patient’s muscles and have measured them after months of physiotherapy and gait retraining in these AFOs and shoes. I am happy to say that we have gained muscle length in both legs and now his left leg can be stretched another 10 degrees then what is used to, and his right leg can be stretched a whole 20 degrees more than what it used to!
2. This next example is for another patient with similar presentation to the previous patient but I wanted to talk more about the shoes. As you can see, there is a lot of material in that shoe and consequently you cannot flex the sole – it is as stiff as concrete and for this patient that is a good thing. When he walks, he almost “sinks” into the ground – imagine bending the hips, knees and ankles. So having a stiff sole manipulates certain vectors (forces with direction and magnitude) and pushes his knees back into extension. Remember my talk on heel and toe levers? If not you should visit the page “What makes a good shoe?”
3. This next example is for a patient who hyperextends her knees when she walks. She also has cerebral palsy and has what we call an “overactive plantarflexion – knee extension couple”. This basically means that her calf muscles (these are used to plantarflex the foot or point the toes down) have so much tone, that when this girl tries to make her knee straight and extended, the muscle pulls her knee backwards.
So for this patient I wanted to promote knee flexion, particularly earlier on in her gait (walking) cycle which is why the heel flares out to the back. To help with the knee flexion I also made the pitch (slope of the shoe) quite dramatic as it will force the patient’s shank forward and flex the knee. Most importantly I made the toe part of the shoe thin and flexible so that her body didn’t have to overcome as much material and stiffness (remember stiffness in the toes makes the knees extend in late stance)