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1890 Silver Cross Blvd. #255 New Lenox IL 60451

27 W 130 Roosevelt Rd.
#2E, Winfield, IL 60190


8:30 am - 5:00 pm Monday- Friday

After hours Always Available by appointment

After Hours Available By Appointment

24/7/365 on call 1-866-746-3552

Patient Care. Dedication. Quality.

Home / Blog / Basic Biomechanics of an Ankle Foot Orthosis – AFO – In Plain English

Basic Biomechanics of an Ankle Foot Orthosis – AFO – In Plain English

The Basic Biomechanics of an Ankle Foot Orthosis

You have come to the right webpage for a basic biomechanics breakdown of AFOs.

(*If you want to watch these biomechanics at work, click on the following link : https://rinella-op.com/foot-drop-brace-afo-kafo/ )

A. ) Sagittal Plane Biomechanics Basics (In plain English!)

If we are talking about the sagittal plan, this means the movements of picking your toes up or pushing them down.  Or, we are talking about the knee buckling (as if to fall forward) or it can hyperextend backwards.

When someone has a drop foot the angle of the ankle can fall to a degree that is greater than 90 degrees.  This means that they are dragging their toe when they try to clear their limb (swinging the leg through) and their foot might slap the floor when they take each step.

An AFO can help maintain the proper ankle angle to avoid this foot drop.  The angle is often times set to 90 degrees which prevents the limb from going into a “foot drop” and thus in a sense, becoming longer on one side than the other. – When you support and hold that ankle angle at neutral, then you are helping to support the knee also in the sagittal plane.  For example, if you look down as you bend your knee the ankle angle will reduce.  If however, we are holding the ankle angle at 90 degrees then your knee is less likely to buckle or hyperextend.  – The videos presented to you above will help to illustrate the point we are making.

B.) Coronal Plane Biomechanics Basics (In plain English!)

This is the other major plane of movement that an AFO is involved with.  The coronal plane would mean that we are looking at the ankle from the side and we are talking more about side to side movements.  Like for example, if someone rolls their ankle, it would be a side to side instability issue.

An AFO can (depending on the style you get) help to stop coronal plane instability.  This means that you will need support on the sides of your ankles and it will either be an articulated AFO style or a “Solid” ankle style most likely.  – If the ankle rolls to one side, or the other the plastic at this point can stop the instability from becoming an injury.

C.) Transverse Plan Biomechanics Basics (In plain English!)

This plan is obviously important, but there is far less twisting going on when someone walks, versus having a drop foot or knee buckling.  Sometimes people will swing their foot inward and their might be a rotary component there, which might call for something that is commonly referred to as a “sabolich” trim line.

If you would like to watch some videos on the use of an AFO and how it can help walking Biomechanics, click on this link : https://rinella-op.com/foot-drop-brace-afo-kafo/

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