Remember the popliteus? To recap, it contracts at the initial contact phase of the walking gait cycle, to act as an accessory PCL (look HERE
to read about that), then contracts eccentrically to slow the rate of internal rotation of the femur on the tibia until midstance, so as not to macerate the meniscus; It then contracts concentrically to accelerate the external rotation of the femur on the tibial plateau so it rotates faster then the tibia, to protect the meniscus as well. So, internal rotation of the femorotibial complex from initial contact to midstance and external rotation of the complex from midstance to preswing. Got it?
Now look at the video of this gal with L sided medial knee pain and past history of a left tibial plateau fracture in her youth. Do you see it? Hmmmm; doesn’t look like internal rotation does it? Don’t see it? Remember that the whole complex SHOULD be internally rotating until the swing phase leg passes the stance pase leg. See it now? Considering that the popliteus tested weak on the clinical exam, does this surprise you?
Agreed that there are many factors initiating internal rotation (and thus pronation) of the stance phase leg from initial contact to midstance, like plantar flexion, adduction and eversion of the talus, contraction of the lower leg anterior compartment muscles, eccentric contraction of the quads and hamstrings, just to name a few, can you see how (a least theoretically) one bad player can ruin the team?
Yes, popliteus rehab, along with abdominal core and foot core endurance exercises are in her future.
Dr Ivo Waerlop, one of The Gait Guys
#popliteus #kneepain #kneeproblem #thegaitguys #gaitanalysis