00:04 - 00:07This is one of the Brooke Bush Institute in this video. We're doing
00:07 - 00:10two tests for the posterior cruciate ligament. That
00:10 - 00:13is the PCL. I'm gonna have my friend Yvette come
00:13 - 00:16out. She's gonna help me demonstrate the posterior drawer test
00:16 - 00:19as well as the quadriceps active test and explain why
00:19 - 00:22I chose those two particular tests. Now first things
00:22 - 00:25first. We do have to think about our predictive values
00:25 - 00:28guys. I don't use these tests on everybody who
00:28 - 00:31walks in the door. If I'm doing a posterior cruciate
00:31 - 00:34ligament test. There is a reason for me to believe
00:35 - 00:38That of that ruptured her posterior cruciate ligament IE. She's had some
00:38 - 00:41sort of trauma to her knee or she has some sort of feeling of
00:41 - 00:44kind of massive instability and this needs
00:44 - 00:47to be checked. Now, these two tests are not hard to do
00:47 - 00:51a couple details. You have to remember the the posterior drawer
00:50 - 00:52we're going to do at 90 degrees.
00:52 - 00:55Just like we did that anterior drawer test. And then
00:55 - 00:58of course the weird cue is we sit on the foot which
00:58 - 01:01is always one of those cues people like do you really have to sit on
01:01 - 01:04the foot? Yes, you have to sit on the foot. That's what you're gonna do to help
01:04 - 01:07stabilize the tibia, so it doesn't rotate on you or move
01:07 - 01:10further into flexion as you go into put
01:10 - 01:13some pressure. Now, the more important cue is
01:13 - 01:16the details around hand placement for this test.
01:17 - 01:20You want to wrap your hands around the quad get your
01:20 - 01:23thinar eminence your your thumb pads
01:23 - 01:23here.
01:24 - 01:27Over the tibia, so you got some good forced to
01:27 - 01:30push with and then the tips of your thumb. This is the
01:30 - 01:33important part are going to go right over that joint line. So you're
01:33 - 01:36not relying only on your eyeballs to
01:36 - 01:39try to see through skin to see if the tibia moves
01:39 - 01:42you're actually relying on the feeling of the tibial Plateau
01:42 - 01:45moving with your thumbs. So what this
01:45 - 01:46test would look like is I would come here like this.
01:47 - 01:51I would get myself set up and then I
01:50 - 01:53would bet you. Okay. All right
01:53 - 01:56good and then I would go ahead and give some some good
01:56 - 01:59little thrusts. Like I was trying to mobilize her knee did that
01:59 - 01:59hurt at all?
02:00 - 02:02No, that didn't replicate your symptoms.
02:03 - 02:06Now so it didn't replicate her symptoms and I didn't feel
02:06 - 02:09huge motion. Now. There are some texts that
02:09 - 02:13suggest that a positive posterior drawer
02:12 - 02:15is grated that is zero to
02:15 - 02:18five millimeters is a grade one five to
02:18 - 02:21ten millimeters is a grade two and then greater than 10 millimeters is
02:21 - 02:24of course a Grade Three, although I
02:24 - 02:27have to imagine that grading like that is not particularly
02:27 - 02:30reliable. It might be something for you to keep in the back
02:30 - 02:33of your mind just as a good scale
02:33 - 02:37for how much motion a positive
02:36 - 02:39test would feel like once again
02:39 - 02:42guys. This posterior cruciate ligaments are not ruptured
02:42 - 02:43often.
02:43 - 02:46So this is not going to get be something that you're gonna feel
02:46 - 02:49a whole lot of times throughout your career. Alright, so
02:49 - 02:52maybe we think about those scales zero all
02:52 - 02:56the way up to 10 millimeters being one full centimeter, as
02:55 - 02:58you know, you start getting up into that
02:58 - 03:01range of a centimeter of motion. This is definitely a positive
03:01 - 03:01test.
03:02 - 03:06now the reason why we're not just going to do the posterior drawer
03:05 - 03:08test is this test in most
03:09 - 03:13Research studies is sensitive but
03:12 - 03:14not particularly specific.
03:15 - 03:18And what that means is if you get a
03:18 - 03:21no right it's sensitive if you get a no
03:21 - 03:24there's a good chance that there isn't a PCL tear.
03:24 - 03:27But if you get a yes, we're still
03:27 - 03:28not sure.
03:29 - 03:32Right. So this isn't a great test for diagnosing with
03:32 - 03:35it's a better test to screen with we do
03:35 - 03:39have to make the one caveat that some of the studies out
03:39 - 03:43there also show. This test does have some problems with sensitivity because
03:42 - 03:43of
03:45 - 03:48False negatives having to do with like the
03:48 - 03:51quadriceps being active and guarding against getting
03:51 - 03:54any posterior motion or somebody getting into this
03:54 - 03:57position their tibia falling all the way back as far
03:57 - 04:00as it can go and then when you push on it, you get no further motion
04:00 - 04:03because essentially the tibia has gone where it
04:03 - 04:06can without the PCO. All right, so to make
04:06 - 04:07up for that.
04:07 - 04:10We're gonna go ahead and add the quadriceps.
04:10 - 04:11negative test
04:12 - 04:15Right. So the quadriceps active test looks like this.
04:16 - 04:17I'm going to
04:18 - 04:19keep her in about the same position.
04:20 - 04:23I'm going to use this hand over her quad to
04:23 - 04:26make sure it's relaxed. All right, so I want to
04:26 - 04:29make sure it's not active. If you don't know what a relaxed quad versus an active
04:29 - 04:32quad feels like have them go ahead and push into
04:32 - 04:35your hand like go ahead and slide your foot down the table
04:35 - 04:38good. All right. So now I know what active feels like good now
04:38 - 04:39totally relax good.
04:40 - 04:43Right, so she's nice and calm here. I'm then
04:43 - 04:46gonna use this hand for the test as a brace on
04:46 - 04:49front of her ankle. I'm gonna get my eye level with where
04:49 - 04:52I just had my thing my thumb tips right
04:52 - 04:53with the joint line.
04:54 - 04:57And then what I'm gonna have her do is go. Okay. Go ahead
04:57 - 05:00and slide your foot down the table. There you
05:00 - 05:02go. Can I relax do that one more time for me?
05:03 - 05:06Good, and if I see all the sudden her tibia Move
05:06 - 05:09anteriorly Like an anterior Glide?
05:09 - 05:11That's a positive test.
05:12 - 05:15Now this test according to research is more specific.
05:16 - 05:17Than sensitive.
05:18 - 05:18so
05:19 - 05:22you got to stay with me here in the
05:22 - 05:22sense that
05:23 - 05:27I don't actually have research to suggest that the two tests combined are
05:26 - 05:29more accurate than one or the other but it would make
05:29 - 05:32sense that if we have a sensitive test and a specific
05:32 - 05:35test and we get the same
05:35 - 05:38answer for both. We're probably in pretty good shape as
05:38 - 05:42far as our accuracy goes this quadriceps
05:41 - 05:44active test also helps get
05:44 - 05:47around one of those false negative
05:47 - 05:50issues with the posterior drawer test,
05:50 - 05:53which is okay the tibia fell all
05:53 - 05:56the way back because I had no PCL and
05:56 - 05:59then when I pushed on it, it didn't go any further back. Well that
05:59 - 06:02person who gave me a false negative on the posterior drawer
06:02 - 06:03because they're tibia fell back.
06:04 - 06:07Should be positive on the quadriceps active test.
06:08 - 06:11Of course if you got positives on these two tests and they
06:11 - 06:12hadn't already seen a physician.
06:13 - 06:17You're probably going to want to refer out for Imaging anyway.
06:18 - 06:21All right guys, so hopefully all of that made sense. You
06:21 - 06:23got the more sensitive we think.
06:24 - 06:28posterior drawer test the more specific quadriceps active
06:28 - 06:30test which also fills in
06:31 - 06:34One of the problems with the false negative on the posterior drawer.
06:34 - 06:37We're going to combine the two of those to try to
06:37 - 06:40get better accuracy for our diagnosis of
06:40 - 06:42PCL tear.
06:43 - 06:46what these two tests look like in success succession is
06:47 - 06:48sit on the foot.
06:49 - 06:52Wrap around the quad find The Joint line. Give it
06:52 - 06:53a couple good presses.
06:54 - 06:57All right, that seems negative. Let's double
06:57 - 06:57check.
06:59 - 07:02Hand placement here my eyes where my
07:02 - 07:03thumbs were just at.
07:03 - 07:06Make sure her quads nice and relaxed good
07:06 - 07:09go ahead and slide your foot down the table. I don't
07:09 - 07:12see any emotion. That's also negative if I
07:12 - 07:15wanted to be doubly. Oh, I guess I'm quadrupley
07:15 - 07:18sure, right because I'm gonna go two times to I could
07:18 - 07:21do these same two tests on her other
07:21 - 07:24side to compare assuming that she has one effective side
07:24 - 07:26and one unaffected side.
07:27 - 07:30Guys, if you have any questions on these tests whatsoever. Please leave
07:30 - 07:33your comments in the comments box below.
07:33 - 07:35I'll get to answering them as soon as possible.