So now we're going to move on to the knee exam.
This is one of my favorite exams actually.
So we're going to start off by
just doing gross inspection.
When I'm looking over here at the knee,
there's a couple of things that I'm looking for.
First of all, in an older patient
and here's my model here.
You'd be looking for just bony enlargement.
And those essentially represent osteophytes
that are progressively enlarging the bone
on either the femur, the end of the
femur or on the tibial plateau there as well.
And so you'd be able to
see that on the patient here
by just seeing some evidence
of enlargement of the bones.
In addition, patients with osteoarthritis
in particular, 80 percent of the time,
they have varus deformity.
And that's because for the most
part, when people get osteoarthritis,
it's more likely to involve
the medial compartment.
So in my model here, again, this is a right leg,
This is the fibula, this is the tibia, this is
your femur, lateral epicondyle, medial epicondyle.
If a person loses cartilage in the medial
side, then what's going to happen over time
is the medial side of the knee will collapse
and the knee will become increasingly deformed,
such that we have, we end
up with a varus deformity.
Normally as we look down again at our
patients, there's this angle called the Q angle,
which goes from up here,
down the leg to the kneecap
and then down here to
the middle of the ankle.
And that line is essentially just slightly
valgused, it's the term that we describe
knees coming closer together,
it's just slightly skewed valgus,
maybe 5 degrees, no more than 10 degrees.
But as this patient gets older,
as you get more arthritis
and you have collapse of the medial
compartment, that angle turns the other way
and you start getting varus.
And so people who have advanced osteoarthritis
tend to look a little bit "bow-legged"
is the phrase that we would use,
bow-legged rather than knock-kneed.
So that's one thing that I can look
for and I can tell right off the bat
that her knees as a young person
appear to have a normal Q angle,
it's the name of that angle
that I was just describing.
The next thing that I'm going to look for on
inspection is I'm always looking for scars
to make sure there wasn't something
missed on the surgical history and
any evidence of bulging of the knee
that might suggest an effusion.
So let's start off by moving on to palpation.
So palpation, I'm going to look
for some specific bony landmarks.
First off, to find the joint line, I sometimes
find that can be tricky to find the joint line
when the patient's knee is fully extended
but if I flex the knee just a bit,
I'm going to find a very easy,
to find little concavity here that represents,
hold your knee there for just a moment,
this space right here between the end
of the femur and the top of the tibia
and so you, I'm basically creating
a hollow when I open up the knee
and that represents the medial joint
line so I can feel that very easily.
You'll note that it's right at the end
of the kneecap, you'll find that space.
I'm going to walk along that space and I'm
looking for any tenderness in that area,
tenderness in the medial or the lateral
joint line, maybe from osteoarthritis,
because there's some synovial cysts and basically
just some disruption of the cartilage in that area,
which could be painful.
It could also be indicative of
medial or lateral meniscal injuries,
which would also be tender in those areas.
So those would be the main things that I'd
be looking for with joint line tenderness.
Just distal to the medial joint line by just
a few centimeters is the pes anserine bursa.
The pes anserine bursa is where three different
musculotendinous structures are going to insert.
And those are the sartorius coming
from up here which will insert here,
the gracilis coming from here and
then the semitendinosus from here
and they're all inserting there.
And the reason that this structure is
called the pes anserine bursa is because
'pes' means foot and
'serine' refers to the goose.
It's called the goose foot area because those three
tendons come together like a little goose foot.
And since those three tendons are coming
there and they're very important in terms of
particularly adduction of the legs,
people can get inflammation there
right at the insertion of the bursa, and so
folks with pes anserine bursitis will have
exquisite tenderness, warmth, possibly
some redness right at that spot.
And showing that again here on my
model, it'll be right around here.
It's something you normally can't palpate.
But a person who has pes anserine
bursitis, that won't be subtle.
The next part of palpation is going to be
looking at the, looking for an effusion.
And there's three things that I'm
going to do to assess for an infusion.
The first thing I'll do is assess for warmth,
putting my hands on the knees like so.
If there's clearly one very hot joint,
like somebody who has acute gout,
then it won't be subtle, it
will be very easy to pick up.
But in some instances, it's a bit more subtle.
A person who has chronic knee disease from a
recent meniscal injury maybe a week or two ago,
it may not be quite as obvious.
So one trick that I do is once my, the
skin of my right and left hands have gotten
acclimated to the temperature of the
skin of each knee, if I then swap hands,
I've now doubled the amplitude of
the temperature difference between my
my left hand and the new
area of skin that I'm going to.
So if this was just a little bit warmer,
my hand had gotten a little bit warmer
and so when I switch it over to the cold knee, I should
be able to more readily appreciate the distinction
between those two areas.
The other thing to note, if somebody
has bilateral knee effusions,
is that the knee, the temperature
of the knee should always be cooler
or certainly no warmer than the tibial area.
Tibia is a very vascular bone.
There's a lot going on there.
And so the tibias are warmer than overlying
the knee under normal circumstances.
Next, I want to assess for the presence of
an effusion not just based on temperature,
but actually trying to assess how
much fluid there might be there.
So we've got two test to do that.
One is called the 'patellar ballottement test'.
What I typically do is I use my right
hand to pull soft tissue out of the way.
This is more important in
folks who have extra adiposity.
So you're pulling the soft
tissue out of the way.
Then I bring my left hand over the top.
I'm pushing down any fluid
in the suprapatellar area
so that any fluid that's in the knee
is now right behind the kneecap.
So now when I push down on the kneecap, if
there's any evidence of fluid behind the kneecap,
the kneecap will now float in the
water like a buoy in the water.
And we use the term ballottement to indicate that.
Shown here on my model, this is my kneecap.
If there's a lot of fluid behind it, it's going to be
floating above the surface of the patellofemoral groove
And when I push down on it, I'll feel
that knock, that knocking sensation
as it knocks against the anterior
surface of the patellofemoral groove.
So that's patellar ballottement.
And the next test is called the 'Bulge sign'.
And again, I'm trying to get all the fluid
from one side over to the other side,
over to at least this section or
on the lateral side of the knee.
And having done that, when I sweep
down the right side of the leg like so,
if there's any fluid inside the knee,
you'd see this sudden pocket of fluid
bulge out on the medial aspect here.
And that's because the fluid
inside a knee, it's not water.
It's much more viscous than that.
So if I move it over to one side, it'll stay there
almost like, not, a little bit thinner than honey.
When I push down on the side suddenly to be pushed
over to the other side and you'll see this very
visible bulge appear if there's a
sufficient amount of fluid in the knee.
So those are our main tests to look for a
patellar effusion, I'm sorry, a knee effusion.
Now let's move on to assess
the ligaments of the knee.
There's four main ligaments.
You've got your medial collateral,
medial collateral, lateral collateral,
and then inside is ACL and the PCL,
your anterior collateral and your
posterior collateral ligaments.
And this one conveniently has a
torn medial collateral ligament.
To highlight that if a patient has a completely
torn or very nearly completely torn ligament,
particularly the MCL, when I stress
it, there's going to be more laxity,
there on one side than the other,
there's just going to be a soft endpoint,
just like when we were talking about the ankle.
Whereas if the ligament is completely
intact, even if it has been strained
and there's a little micro tears in
it, then there should be a hard stop
when I try and bend the
knee in the other direction.
So let's take a look at that now.
So I lift up the knee, I flex it about 30 degrees.
Some people will do it in full extension.
I prefer to do it at this angle.
I'm putting my hand on the medial thigh and
you'll note that I'm not putting my hand
where the pain is because that's going to blur
things because I would be exerting pressure
on the medial joint line.
So I want to move my hand away from
the area that's causing discomfort,
rotate out a bit, push down the
thigh, lift up on the foreleg.
And by doing that, I'm straining
the lateral collateral ligament.
So again, here is the leg.
I'm rotating it out and now I'm lifting
up the femur or lifting up the tibia.
And you can see that by doing so, I'm
stressing the lateral collateral ligament.
and I'm looking for either laxity or
the reproduction of pain when I do that.
If I want to test the medial collateral
ligament, I'm going to try and strain this area.
So I put my hand on the other side of the
thigh, I pull up on the foreleg like this
and I'm straining the medial collateral ligament
to see if that reproduces the patient's pain.
So those are the medial collateral ligaments.
Now, let's take a look at the ACL.
There's two tests that have been used to
investigate the anterior cruciate ligament
and I'll first show the 'drawer sign'.
So putting the knee at 90 degrees,
I'm going to close this, if I may.
And just putting a little bit of weight
here, I'm going to pull forward on her knee
and what I'm doing is looking for a difference between
the excursion of the tibial tuberosity forward.
If it's more on this side than it is on this side,
I'd be concerned that the ACL here has been torn
because that's supposed to prevent
anterior translocation of the tibia.
The other test, which it turns out is actually
been shown to be a bit more sensitive and specific
for an ACL injury is to put the knee at more
like 20 degrees and simply pull up in this way.
It's accomplishing the same thing, but it turns out
that it's just a bit easier to detect an ACL injury
when you perform that test
called the 'Lachman's test'.
Next up, we'll test the posterior cruciate ligament.
That's going to be done by, again,
putting the patient's knee at 90 degrees.
It's a little bit easier because I don't have
to sit on her foot to accomplish this.
I'm simply pushing her tibia backwards.
The posterior cruciate ligament prevents
posterior translocation of the tibia,
and I'm going to compare one side to the other.
So that completes assessment of the various ligaments,
we can now move on to taking a look at the menisci.
Now we're going to assess the menisci.
Just to remind you, we have a
medial and lateral meniscus,
it's essentially a figure eight structure
that has a medial and a lateral side.
And 80 percent of the time when people have
a meniscal tear, it's the posterior meniscus.
So shown on my model again here, I'm
going to push the patella out of the way.
And again, this is a right knee.
So this is the medial meniscus.
This is the lateral meniscus.
If I flip this over, it's really this
area that's most likely to get torn.
And when it's torn, you'll have
what's called a bucket handle lesion
where this torn meniscus flips over on itself
and can cause a lot of pain
when the patient's walking.
If it's an anterior lesion and
it's flipped over on itself,
what will happen is the patient can't fully extend
their knee because of this piece of cartilage
that's stuck in the way.
So that's called blocked extension.
And you may simply get that from the history
when you're talking to the patient that
sometimes they walk and their knee
gets stuck while trying to ambulate.
So we're going to try and do two tests that look
at the structure, the function of the meniscus.
So first off, let's do the McMurray.
And if this is the person, if this is the
knee that the patient is having trouble with,
you're going to be doing
the McMurray on both sides.
One's to test the medial meniscus and
one's to test the lateral meniscus.
I always find that this test is also
useful because I'm simultaneously testing
range of motion of the knee because
I'm going to fully flex her knee.
So I like to be efficient when
I'm doing the physical exam.
And oftentimes my range of motion testing comes
into play while I'm doing other maneuvers.
And this is a good example of that.
So, doing the, I'll start with the
medial meniscus, it involves three steps.
So it really is one of the most complicated
parts of the musculoskeletal exam
and understanding the
anatomy is really important.
But remember that the meniscus is
attached to the tibial plateau.
It's not attached to the femur.
So anything I do to rotate the tibia,
and simply rotating her foot like this
is actually rotating the tibia, even
though the range of motion of the knee
we focus on flexion and extension.
There is pivoting, there is some
pivoting that happens with her tibia.
So when I rotate her tibia, I'm actually
rotating the menisci on top of her tibia.
So the first thing I'm going
to do is flex her knee.
And then because I want to catch the posterior
aspect of that meniscus, I'm going to
externally rotate her tibia because what
I've done now is I've brought that posterior
ring of the medial meniscus forward.
So now when I try and catch it while extending
her knee, I should be able to feel a pop
as I bring her knee back into full extension.
I'm going to do that again.
I'm going to put my finger on the joint
line, which we talked about finding before,
because if there's going to be a pop,
I'm really going to feel it there.
Her ankles rotate it out.
I'm putting a little bit of varus strain on the knee
and out I go like that to see if I can find a pop
or a reproduction of pain would
also be a characteristic feature.
Secondly, I'm going to do the lateral
meniscus, so it starts with flexion.
Then again, there's in this case
internally rotating the tibia.
So I'm bringing the tibia this way, which brings the
posterior aspect of the lateral meniscus forward,
putting my fingers again on the joint line.
And now I'm going to extend while also putting
a little bit of valgus stress to really pinch
that lateral aspectof the knee.
So it looks like this.
To do it very quickly on both sides, it's kind of
a little dance you're doing with the knee,
so that's the McMurray.
And of course, I would, typically I
would do the unaffected knee first
to make sure I've got a baseline
before moving on to the knee where the
patient is complaining of symptoms.
The next test for the meniscus is I'm going to
have the patient roll over onto your stomach,
if you wouldn't mind, Shayla.
And this test is a similar concept, I'm trying
to basically put pressure on the meniscus
and see if I can find a spot where there's
a defect in the meniscus or one piece
that's folded over on another.
So I'm simply taking the knee
and I'm pushing down while moving
the knee in a similar kind of
way that I was doing before.
I'm just doing it from this position.
I find this is useful for patients who have
too much pain to go through the meniscus
or if they have significant range of motion
issues and they can't fully flex their knee.
I only need to get to 90 degrees to be
able to do this, this particular test.