Shoulder Special Test: Infraspinatus and Internal Rotation Resistance Strength Test (IRRST) Tests

The Infraspinatus and Internal Rotation Resistance Strength Test (IRRST) Tests are a series of tests used to evaluate the strength of the shoulder abductors and internal rotators, specifically the infraspinatus and other rotator cuff muscles.The tests involve the patient actively performing shoulder abduction against resistance from the clinician or an external force. The ability of the patient to resist external rotation of the shoulder is also assessed in different variations of the test.

Transcript

00:00:0400:00:06
This is Brent of the Brookbush Institute, and in
00:00:0400:00:06
...blank
00:00:0600:00:08
this video we're going to go over two special,
00:00:0800:00:10
or orthopedic tests for the shoulder
00:00:1000:00:12
that are indicative of either
00:00:1200:00:14
impingement or rotator cuff damage. I'm
00:00:1400:00:16
going to have my friend, Melissa, come out.
00:00:1600:00:18
She's going to help me demonstrate these
00:00:1800:00:19
tests. The reason we've paired these
00:00:1900:00:21
tests is I think you're going to find
00:00:2100:00:24
they look very similar to the Kendall
00:00:2400:00:26
manual muscle tests we've gone over in
00:00:2600:00:28
previous videos. The first one is
00:00:2800:00:31
actually called the Internal Rotation
00:00:3100:00:33
Resisted Strength Test. I'm going to have
00:00:3300:00:36
Melissa go ahead and bring her shoulder
00:00:3600:00:38
into 90 degrees, her elbow in 90
00:00:3800:00:39
degrees of flexion, and her wrist is
00:00:3900:00:41
going to be in neutral. I'm going to
00:00:4100:00:43
brace her elbow a little bit here. I'm
00:00:4300:00:45
going to go ahead and put my hand behind
00:00:4500:00:49
her hand and have her press back into my
00:00:4900:00:51
hand to externally rotate the shoulder.
00:00:5100:00:53
I'm not going to try to overpower her. I'm
00:00:5300:00:54
just going to match her strength. Press
00:00:5400:00:57
as hard as you can, Come on, come on.
00:00:5700:00:58
Alight, you don't have to actually egg
00:00:5800:01:00
people on, but you do want to take mental
00:01:0000:01:03
note of how strong she is in external
00:01:0300:01:06
rotation. Now, I'm going to do the same in
00:01:0600:01:08
internal rotation. Alright, go ahead and
00:01:0800:01:12
press into my hand. Good. Good. And what I
00:01:1200:01:16
want to note is: Are they about equal? If
00:01:1600:01:20
internal rotation is weaker than
00:01:2000:01:23
external rotation, that is indicative of
00:01:2300:01:26
either a rotator cuff problem or
00:01:2600:01:29
impingement. Of course, the other sign
00:01:2900:01:31
that we always go back to is- go ahead
00:01:3100:01:34
and press in- "Does this replicate the
00:01:3400:01:36
symptoms you were talking about?" Always
00:01:3600:01:38
remember to ask that question. So,
00:01:3800:01:43
pain and/or weakness in internal
00:01:4300:01:45
rotation when compared to external
00:01:4500:01:48
rotation is a positive result for that
00:01:4800:01:50
test. Now, the other test we're going to
00:01:5000:01:53
do looks exactly like the manual muscle
00:01:5300:01:56
test for external rotation. I'm going to go ahead and
00:01:5600:01:58
brace her elbow hit a little bit here. I
00:01:5800:01:59
want to make sure I show her what I'm
00:01:5900:02:01
doing, what we want her to do. So, "Go ahead
00:02:0100:02:04
and turn your hand out this way." Because
00:02:0400:02:06
what you'll find is if you guys go, "Just
00:02:0600:02:08
press out," people tend to do that old
00:02:0800:02:13
school like deltoid machine thing. We
00:02:1300:02:14
want to test external
00:02:1400:02:17
rotation here. So, "Go ahead and externally
00:02:1700:02:21
rotate. Does that hurt? Does that provoke
00:02:2100:02:23
the symptoms you're talking about?"
00:02:2300:02:26
So, if it's pain or if I know some
00:02:2600:02:29
real significant weakness she may be- "Go
00:02:2900:02:32
ahead press out"- if she just gives way under
00:02:3200:02:34
a little bit of pressure, that's a
00:02:3400:02:37
positive sign for this test. Alright,
00:02:3700:02:39
guys, so, we have two tests here. We have
00:02:3900:02:42
the Internal Rotation Resisted Strength
00:02:4200:02:45
Test, and then we have the Infraspinatus,
00:02:4500:02:49
or External Rotation Resistance Test.
00:02:4900:02:52
Both of these tests can be used for
00:02:5200:02:56
either rotator cuffs or impingement. We
00:02:5600:02:58
do have to keep in mind that these
00:02:5800:03:00
probably should be used within testing
00:03:0000:03:02
clusters, because what I'm about to tell
00:03:0200:03:04
you is going to be a little confusing.
00:03:0400:03:06
These tests actually have higher
00:03:0600:03:09
specificity than some of the other tests
00:03:0900:03:11
we've already talked about, like the Neer,
00:03:1100:03:13
or the Hawkins Kennedy, or the Yocum, or
00:03:1300:03:16
even the Supine Impingement Test.
00:03:1600:03:19
These tests tend to be more specific
00:03:1900:03:23
than sensitive, which makes absolutely no
00:03:2300:03:26
sense to me. We have tests that-
00:03:2600:03:29
obviously, if they're testing for
00:03:2900:03:32
impingement, why are we rotating and
00:03:3200:03:34
testing the strength of our rotator cuff?
00:03:3400:03:36
So, this is already bringing in more
00:03:3600:03:39
diagnosis, making it a more specific test.
00:03:3900:03:42
Ah, fun with research. Guys, if you weren't
00:03:4200:03:44
confused about specificity and
00:03:4400:03:48
sensitivity before, you probably are now.
00:03:4800:03:50
That's okay, because sometimes it
00:03:5000:03:53
doesn't work out mathematically as it
00:03:5300:03:56
should. Let's start thinking through this
00:03:5600:04:01
logically though. Obviously, moving,
00:04:0100:04:05
resisting, resistance- using our strength
00:04:0500:04:06
in this position- for somebody with
00:04:0600:04:08
shoulder impingement is not going to
00:04:0800:04:11
feel very good. We already have
00:04:1100:04:13
some external rotation and some
00:04:1300:04:15
abduction that's probably already
00:04:1500:04:16
starting to compress on some of those
00:04:1600:04:20
subacromial tissues. In this position,
00:04:2000:04:24
external rotation, if somebody has pain
00:04:2400:04:29
in this position, they're probably pretty
00:04:2900:04:30
far along
00:04:3000:04:33
in that impingement syndrome. They're
00:04:3300:04:37
probably really, really inflamed. Also,
00:04:3700:04:39
keep in mind that if we have a rotator
00:04:3900:04:41
cuff tear- let's say we have a
00:04:4100:04:44
subscapularis tear- is this going
00:04:4400:04:46
to hurt? Yeah, yeah that's going to hurt a
00:04:4600:04:50
lot. If we have a supraspinatus or an
00:04:5000:04:52
infraspinatus tear, is this going to
00:04:5200:04:56
hurt? Sure. So, how do we differentiate
00:04:5600:04:58
between impingement and rotator cuff tear?
00:04:5800:05:00
Well, we're going to have to think about
00:05:0000:05:03
our subjective examination, realizing
00:05:0300:05:06
that ruptures and tears are usually
00:05:0600:05:08
acute. They usually happen with some sort
00:05:0800:05:11
of incident that happened rapidly.
00:05:1100:05:13
They're usually not chronic- not that
00:05:1300:05:15
they can't be. If this was a
00:05:1500:05:18
gradual onset, I might be thinking more
00:05:1800:05:20
towards impingement, whereas if this was a
00:05:2000:05:22
sudden onset, I might be thinking more
00:05:2200:05:24
towards rotator cuff, or maybe if they
00:05:2400:05:26
had a history of rotator cuffs. And then,
00:05:2600:05:28
of course, we have to start adding all of
00:05:2800:05:32
our other test results to this. So, if
00:05:3200:05:35
let's say I do some other rotator cuff
00:05:3500:05:39
tests and they come back negative, but I
00:05:3900:05:42
do a bunch of impingement tests and they
00:05:4200:05:45
all come back positive, then these two
00:05:4500:05:50
tests probably help us solidify our
00:05:5000:05:54
impingement hypothesis, as opposed to
00:05:5400:05:59
solidify a rotator cuff hypothesis. Now,
00:05:5900:06:02
how would I use this? Of course, I would
00:06:0200:06:04
use this within a testing cluster, and I
00:06:0400:06:07
would be looking for the concordant
00:06:0700:06:08
sign, which I keep talking to you guys
00:06:0800:06:11
about. You want to find your quick tests.
00:06:1100:06:14
We're all short on time. So, as you're
00:06:1400:06:16
going through your tests and find the one that
00:06:1600:06:18
immediately provokes their symptoms, man,
00:06:1800:06:19
you want to make note of that, because
00:06:1900:06:21
when they come to the next time, that's
00:06:2100:06:22
the one you're going to go back to. You're
00:06:2200:06:23
not going to go through your whole
00:06:2300:06:25
battery of tests again. You're going to
00:06:2500:06:28
go back to that one provocative test, and
00:06:2800:06:30
then that's the one you're going to keep
00:06:3000:06:32
going back to as you test different
00:06:3200:06:35
interventions. So, maybe I want to release
00:06:3500:06:37
a few things and then see how that works,
00:06:3700:06:40
test my hypothesis. Maybe I then want
00:06:4000:06:42
to activate a few things, test my
00:06:4200:06:45
hypothesis. Maybe I want to try something a
00:06:4500:06:47
little bit more outside of the box,
00:06:4700:06:49
although I know us movement
00:06:4900:06:51
professionals think in this way. Maybe I
00:06:5100:06:53
want to try some thoracic spine
00:06:5300:06:56
mobilization or manipulation, thinking
00:06:5600:06:58
that maybe scapular dyskinesis is
00:06:5800:07:00
contributing to shoulder instability and
00:07:0000:07:04
see if that improves. Well, I now have-
00:07:0400:07:06
let's say this is her concordant sign-
00:07:0600:07:08
I now have a quick test that I can
00:07:0800:07:11
keep coming back to after each
00:07:1100:07:13
intervention. We are going to be talking
00:07:1300:07:15
about those testing clusters in
00:07:1500:07:18
future videos. Please stay tuned. Let me
00:07:1800:07:20
give you guys a quick review here of
00:07:2000:07:23
these two tests. I hope you guys will
00:07:2300:07:26
keep watching. So, starting with the
00:07:2600:07:30
Internal Rotation Resistance Test: I'm
00:07:3000:07:32
going to go ahead and bring her arm up
00:07:3200:07:35
to 90 degrees of abduction, elbow 90
00:07:3500:07:38
degrees of flexion, and wrist neutral. The big
00:07:3800:07:41
sign on this test is internal rotation
00:07:4100:07:43
weaker than external rotation. That
00:07:4300:07:45
should make sense to you guys from a
00:07:4500:07:47
kinesiology standpoint. Your internal
00:07:4700:07:50
rotators are much bigger and stronger. So,
00:07:5000:07:52
if your internal rotation rotators are
00:07:5200:07:53
testing weaker than your external
00:07:5300:07:55
rotators, that's an issue. We go ahead and
00:07:5500:07:58
test external rotation first. Alright,
00:07:5800:08:01
that feels pretty strong. We test internal
00:08:0100:08:05
rotation. That's also pretty strong, so that's a
00:08:0500:08:07
negative test, unless it happened to- "Did
00:08:0700:08:09
that provoke your symptoms?" Oh, it did
00:08:0900:08:11
provoke her symptoms. Well, then that's a
00:08:1100:08:12
positive, actually. That's still a
00:08:1200:08:13
positive test. I want to remember
00:08:1300:08:17
that for my future quick tests. Again, the
00:08:1700:08:19
External Rotation Test looks exactly
00:08:1900:08:21
like that Kendall MMT. I'm going to go
00:08:2100:08:23
ahead and brace her elbow here a
00:08:2300:08:25
little bit, hold her elbow and make sure she's
00:08:2500:08:27
not doing the old-school deltoid
00:08:2700:08:30
exercise here. Go ahead and press out
00:08:3000:08:33
in external rotation. She's very, very
00:08:3300:08:35
strong, so I'm not getting any indication
00:08:3500:08:37
there. "Does that provoke your symptoms?"
00:08:3700:08:40
Yes, oh, that provokes her symptoms, so we
00:08:4000:08:42
have some some serious issues here
00:08:4200:08:44
having to do with either impingement or
00:08:4400:08:46
rotator cuff, and I need to continue
00:08:4600:08:49
testing. Guys, I hope you will continue to
00:08:4900:08:50
learn your assessments. If you're not
00:08:5000:08:53
assessing, your guessing. Step up your
00:08:5300:08:54
assessment game
00:08:5400:08:57
and continue watching these videos