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This is Brent of the Brookbush
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Institute and in this video we're going to go
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over a special test for the knee, specifically for the LCL and MCL. These
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are the valgus and varus stress tests. I'm going to have my friend Melissa come
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out, she's going to help me demonstrate. Now these valgus and varus stress tests
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are supposed to try to side bend the knee, and you can imagine if I try
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to side bend the knee, when I side bend it the side farthest away is going to open
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up and of course that's what these ligaments are supposed to prevent. So if
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we start with the valgus stress test. The valgus stress test is trying to push
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her knee this way which means her medial or inside knee would open up during side
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bending. If I can actually make her knee open up, something's wrong with her MCL,
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that's what her MCL is supposed to be preventing her from doing. So I'm
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going to get a nice lock on her lower leg here to do this test, and the
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reason being is, number one - I want to stabilize the tibia so I'm going to get
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this hand around her tibia close to her knee, but I also want to
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stabilize the foot to try to control for tibial internal and external rotation,
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otherwise when I go to press I end up with all of this stuff, her knee
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just flops around on me. So I want to get a nice lock that way and
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then I'm going to use this hand on her femur and I'm going to push this way while
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bending her tibia towards me to try to open up her medial knee, and I can
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feel that because if you notice, this thumb is right over the joint line.
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So I'm going to go like this, I can't get it to open up but I'm also going to ask -did that
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hurt? That actually hurt her a little bit. So although I can't gape her knee we are
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positive for maybe some MCL strain or at least some MCL pain here. But we're not
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done yet, we also have to do this test at 30-degrees and here's where you better
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make sure you have good lock on her tibia, because when you go to press, this
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is where you get all sorts of like this stuff -which is hip internal rotation.
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I need to make sure I'm locked so that I'm still trying
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side bend her knee, how does that feel? That's still pain too. Okay so we
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have pain both in full extension and pain at 30-degrees. Now why did I do
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it at full extension and 30-degrees, well it ends up that when you're fully
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extended your strap like PCL at the back of the knee is totally taut, which holds
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your tibia plateau against your femoral condyles pretty tightly, and since those
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are two flat-ish surfaces it is possible that without an MCL your PCL by itself
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will keep your knee from gaping because you have two flat surfaces being pressed
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against each other. So if I was to get her medial knee to open up here
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there's actually a good chance that we don't only have MCL injury, we might have
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PCL as well. Whereas if we're here, it's probably not
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here, like let's say we get negative here but positive here then it's probably MCL
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only. Now she has pain in both and no opening that actually doesn't tell us
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much more than it's probably MCL, it could be PCL, it doesn't seem like
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anything's ruptured. That's what we get from that and I hope you follow the
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logic there. So now let's flip this test around for the LCL and do our varus
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stress test. So what I'm actually going to do is I'm going to sit down on the table,
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I'm now going to lock her tibia on my other arm here. I have the same setup as
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I had on this arm, and now I'm going to push the femur this way into a knees
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bow out side bending. I'm going to put this thumb over her joint line and I get no
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opening up, that joint line isn't moving at all. But again if my
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goal was to test the LCL I know in this position that her PCL could be giving us
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a false negative result, right her PCL is holding her knee together even though
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she might not have an LCL, so what am I going to do? 30-degrees, put a little
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slack in that PCL, make sure I have a good lock because I
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don't want rotation to mix up my test, and make sure I'm just doing side
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bending. How did those feel? Alright so those are fine, that's fine. So she's
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definitely negative for any LCL issues.
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She is positive for some MCL issues though, so that gives us a little
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indication of some of the stuff that Melissa might have done. Now since she
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doesn't look like she has a rupture we might start with some physical therapy,
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and see if we can improve her symptoms before I would send her out for any sort
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of imaging or physician's diagnostic assessment. So just to review
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real quick, make sure on both of these you lock, make sure you're doing 0
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and 30 because at 0-degrees our PCL can fool us. This way varus, lock, pushing
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out this way, 0-degrees and 30-degrees because PCL can fool us. So if
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you have any questions whatsoever let me know, just leave a question in the