In this weeks Neuromechanics weekly, Dr Waerlop takes us from the cortex to the muscle spindle. The journey through the neuraxis continues….
So, the question you need to ask is why they cut the leg off and transplanted the foot/ankle 180 at the lower femur.
If you think about it, it is because he needed a joint to flex like his old knee. If they put the foot on forward there would be no knee bend (ie. his knee would have only bent as much as you can point your foot…….the motion of ankle plantarflexion. This would have been extremely insufficient in range to move as well as this fella is moving. )
By doing a rotation transplasty and putting the foot on backwards he could take advantage of the large range of ankle dorsiflexion. They talk about the toes alot in this video but this really has nothing to do with the success of this surgery, functionally anyways. The genius of this surgery was using the ankle as a knee hinge.
Pretty amazing stuff. Enjoy the brain-twister in understanding how he is using ankle dorsiflexion to replicate knee flexion. !!!!
taking Gait to another dimension……… Shawn and Ivo
Here Dr. Allen of The Gait Guys introduces some of the initial information necessary to understand proper shoe fit. Topics include body anatomy, shoe anatomy, physiology, biomechanics and compensation patterns. This was part of a private industry lecture where The Gait Guys were asked to help improve the understanding of the concepts critical to better shoe industry choices.
Ivo and Shawn …. what we do while you are sleeping.
our version of crop circles !
watch for signs of our presence at your local beach or wheat field near you !
you are not alone…….
photo from . http://nakedonsharppointystuff.blogspot.com/
So. How did you do?
As you can see, this individual lists to the R upon weight bearing on that side (midstance); did you pick up the increased progression angle of the foot on that side? How about the mild genu valgus?
Why would someone walk like this? There are a few plausible explanations.
1. he has a weak gluteus medius on the R side.
2. he has a R short leg and needs to lean to that side to get the long leg side (L) to clear.
3. impaired left ankle rocker (causing premature heel rise and left side early departure) could also cause him to accelerate onto the right as well.
His options to compensate are to either lean to the weak side (R) or to shift his pelvis to the weak side (R). He could also circumduct the leg or flex the thigh to get that side to clear the ground. He has a mild BL circumdcution, probably to clear the knee from the opposite one.
His increased arm swing on the L is to help propel him forward, most likely due to weakness of the external obliques to assist in initiation of flexion of the thigh, and weakness of the gluteus medius, which also helps to propel the leg forward. He also does not push off adequately with the R leg; This is probably due to loss of hip extension and inadequate ankle rocker on that side.
The increased progression angle on the R helps to stabilize his body weight because he is leaning the torso to the R and his center of gravity moves right as well (he makes a wider base for himself)
Yup, you’re a geek! We remain The Geeks of Gait…Ivo and Shawn
oh look, it appears (but a little hard to tell) ……but it appears we have a casualty !
here is what her ankle is saying …..
“oh no, we do not have enough ankle dorsiflexion to be on this bad boy…….so, who wants to take it guys…….. how about you hyperpronate Mr. Arch, and to help we will drive Mr. Knee medially.” ?
better have enough ankle dorsiflexion if you are gonna play with this monster !