Circumduction is a “walking problem” that is characterized by the leg swinging out to the side.
This is typically a compensatory strategy to prevent someone from catching the foot on the ground.
Before we dive into what might be causing you to swing the leg around the side, it is important to explain the swing phase of “normal walking”
The swing phase of walking
Under normal conditions during the swinging phase of the walking cycle, the knee bends and the foot bends upward (dorsiflexion). This is, in essence, to “shorten the leg” so that it will clear the ground
What causes circumduction?
Circumduction is the result of a movement problems that prevents the leg from being able to “shorten” to clear the ground during the swinging phase. Stated another way, if the “swinging leg” is longer than the other leg, it can’t clear the ground. This might include the inability to lift the foot and/or the inability to bend the knee. There are several reasons why this might happen.
Problem #1: A “stiff leg” and/or Spasticity in the knee muscles
Spasticity (involuntary muscle contraction) in the quadriceps can make it hard to bend the knee. In this case the leg will remain “long” through the swinging phase and might cause you to compensate by swinging the leg around the side.
Problem #2: Drop foot
A true drop foot will cause the foot to point downward during the swinging phase of the walking cycle and might cause someone to swing the leg around the side to clear the ground.
Problem #3: Spasticity in the lower leg muscles
The inability to lift the foot can be due to spasticity (involuntary movement) in the muscles that make the foot point downward.
Problem #4: Plantar flexion contracture
A plantar flexion contracture is when the muscles that point the foot downward shorten and prevent the foot from being able to bend up to a minimum of a 90 degree angle causing the foot to remain slightly pointed through the swinging phase. This can be the result of a prolonged hospitalization and/or bedstay. A plantar flexion contracture can also happen if:
- Someone is not diligent with a stretching routine
- Does not wear their prescribed ankle foot orthosis (AFO) during the day.
- Does not wear their night splint consistently at night.
Problem #5: An AFO that is not designed appropriately
Circumduction can also be the result of a poorly fitting ankle foot orthosis (AFO). There are 2 “big picture” categories of AFOs. There are AFOs that are meant to lift the foot (in the case of foot drop). These braces do not necessarily prevent the foot from pointing. For instance if someone has spasticity in the muscles that point the foot downward. Without digressing to far from the topic of this post, it is important to note the difference. If someone has spasticity in the muscles that point the foot downward and yet are in a brace that does not have a feature called a “plantarflexion stop” (found only in braces designed for a spastic foot), the foot will point through the swinging phase of the walking cycle and may result in someone compensating by swinging the leg around the side.
The other all to common problem is when a brace is designed in a slightly pointed position. Most of the time this is due to someone having a plantar flexion contracture (muscles that point the foot have shortened and the foot is not able to flex up to a 90 degree angle). If this is the case and the foot is not able to achieve at least a 90 degree angle, it is important to build up the opposite shoe in an effort to accommodate for the pointed foot and prevent other movement problems from developing.