Within the physiotherapy world the identifying and treatment of a loss of shoulder internal rotation thought to be caused by posterior shoulder stiffness has become more and more popular for those patients suffering with shoulder pain who do a lot of overhead activity, be it swimming, throwing, playing tennis, weight lifting or just generally lifting things up and down daily.
However there has been debate on how best to identify and treat it, and even if we should be worry about it at all, as it maybe just a perfectly normal adaptation to over head movement that may not be contributing to any shoulder problems or pains.
Posterior shoulder tightness in over head movements is thought to be caused via two possible mechanisms, first by a phenomenon where it's thought nocioception and irritation to the antero-superior (upper front) structures of the shoulder, such as the supraspinatus tendon and sub deltoid bursa, creates a reactive stiffening to the postero-inferior (lower back) structures, namely the capsule and its thickened portion catchily called the PB IGHL (posterior band of the inferior glenohumeral ligament) as well as the posterior rotator cuff tendons these being the teres minor and infraspinatus. It is thought these may tighten and contract in an effort to withdraw the humeral head away from the noxious stimuli, think a bit like when you touch a snail head and you see it withdraw! I attempted a little drawing below to try and describe it better.
Diagram of a shoulder demonstrating 'Obligate Translation'
This is thought to work for a while, helping to re center the humeral head and potentially reduce the sub acromial compression and irritation, but then unfortunately the stiffening of the postero-inferior structures begins to cause its own problems and actually starts to cause a loss of humeral head centring via a process called obligate translation and so further compounds the original problem and pain (source) by pushing the humeral head further anterosuperiorly!
The second theory of why posterior shoulder stiffness occurs, is thought to be via microtrauma to the posterior portions of the shoulder in the deceleration phases of fast movements into internal rotation, such as when a thrower releases the ball in the throwing action! Speeds of movement here have a been measured at a staggering 7400° per second (source), producing huge forces and so we can see how this can cause trauma. The anterior shoulder tissues are also thought to get repeatedly lengthened in this scenario due excessive external rotation and hyperangularion movements that throwers can get their shoulders into.
Excessive external rotation from repeated throwing
Identifying posterior shoulder stiffness is done by looking at the amount of internal rotation a shoulder has at it's glenoid humeral joint in an elevated position.
A loss of internal rotation has been given the catchy ancorynm of G.I.R.D, standing for Glenohumeral Internal Rotation Deficit, it can be tested by checking one arm against another for the amount of internal rotation each has in a number of ways, and if the painful affected side has less than 25° internal rotation than the opposite side then a GIRD diagnosis is made.
A common way a GIRD is checked is by what I call the 'scarecrow test' (my own term, but not my test) where you stand or sit upright (usually shoulder blades against a wall to avoid leaning forwards or backwards) elbows out to side, and then let the hands 'dangle' underneath the elbows, like a scarecrow! If the painful shoulders forearm doesn't 'dangle' as much it's classed as a GIRD, see the image below for an example
Another test (and subsequent treatment) used to identify GIRDs is the sleeper test, this where you lie on your side arm out in front as shown below to fix the scapular, then push the hand down to the floor using the other hand, again if the painful forearm has less movement, indicated by a reduced ability to get hand to the floor and again if a deficit of more than 25° is seen then diagnosis of a GIRD is made
Finally anither simple measure of spotting reduced internal rotation is by placing the hand up behind the back and again comparing it to the other side, but as this is a movement that also relies on other shoulder and joint movements and can be effected by other factors.
However, there's always a however, the notion that all shoulders have 180° of rotation is also flawed in my opinion and experience, but regardless of this checking for Total Range of Motion deficits from side to side, I feel is far more useful than doing just the scarecrow or sleeper tests that just look at internal rotation from the same starting point, ie neutral.
Ok, so you think you have seen one shoulder having less total rotation than the other, hopefully its the painful arm! BUT… before you start and jump on the treatment planning, some care needs to be used when interpreting these tests in isolation. There are some other factors that can masquerade as a stiff shoulder.
These are bony abnormalities such as humeral retroversion (basically a twist in the long upper bone in your arm) and glenoid anteversion (a bony deformation of the angle of the socket of the shoulder). These bony deformities mean that the shoulder can look like they have less rotation and obviously these cannot be addressed with physiotherapy or any other therapy as last time I checked we cant stretch or release bones, also don't forget joint surface degenerative changes and although rarer keep in mind AVN (Avascular Necorsis) or rare synovial conditions like PVNS (pigmented vili nodular synovitis) and/or osteo chondromatosis. Finally don't forget plain old simple dominant handedness asymmetry all of which affect range of movement.
So how can we see if there are any of these bony or rare abnormalities contributing to a loss of rotation, well obviously a MRI or even CT scan would be immensely helpful, but these aren't always available or practical to use. Maybe experience of feeling the 'end feel' of the movement can help a bit, but unfortunately the shoulder rotation movements don't have firm 'bony end feels' so I'm afraid that's not reliable, so unfortunately I don't have any helpful real world answers here, except just be aware that bony abnormalities do exist and be aware of them being a potential source of loss of shoulder movement, and if in doubt refer on.
Right, back on track there are many shoulders that lose rotation movement due to soft tissue changes, and these changes could potentially be a source of altered shoulder biomechanics and if there is a loss of rotation in a shoulder that you think is contributing to shoulder pain then it has to be addressed and rectified.
However we cant just assume its just the capsule or its ligament that's stiffened, as I heard and seen some therapists do, we can't ignore the other soft tissues that overlie the capsule namely the posterior rotator cuff these will also have undergone possible shortening structural changes due too the loss of movement over time, so both need to be 'worked on', and both have different methods of doing this.
For the contractile more pliable and superficial cuff, then manual soft tissue methods can be used in and around the shoulder, how and what these techniques do phyiscally or neurologically is highly debatable and are for discussion again in another blog, but in my experience and opinion some poking, prodding, pulling etc needs to be done, see…. I do like some manual therapy!
For the deeper non contractile capsular tissue a different approach has to be used as no amount of rubbing or poking here is going to get to that. Some argue that glenohumeral joint mobilisations, glides and distractions techniques involving moving the joint surfaces into different planes and angles do affect the capsule and the ligament, again very debatable and again maybe discussed in another blog, I do use joint mobilisations as I feel they do something, but my guess is its neurological rather than mechanical.
But regardless we must combine all these techniques with a comprehensive vigorous home stretching and mobilising program that will do most of the work and 'releasing' for the patients stiff posterior shoulder.
I have a saying… rehab is like baking a cake, I'm the chef, the patient the ingredients, I provide the reciepe, the patient has to mix the ingredients together and bake the cake, and occasionally in a therapy session I'll add a cherry and some sprinkles on top ie mobs etc… Cheesy I know!
Now there is debate (isn't there always in this business) as to what are the best techs and stretches to use when dealing with a stiff posterior shoulder, Mike Reinold on his site disputes the use of the Sleeper stretch as a treatment option, here, and I can see why, as it can place the shoulder into a risky 'impingement' position (I hate that term read why here) and so has the potential to create more pain and irritation especially as most of these shoulder have 'impingement' symptoms, argh just used that term again.
However, I find that if you modify the position, by getting the patient to lie more on their back then the arm is in a more frontal plane it reduces the risk of adverse sub acromial compression (somewhat). The only trouble is they now can't do the stretch themselves very well as they cannot reach over with the other hand to apply the stretch. This is where the therapist comes in to great affect, as this position does allow the therapist to apply joint mobilisations at the same time, so getting a double bonus effect, stretch and joint mobilisations so hitting both the contractile tissue and the capsule. The positions and angles of the arm, i.e. height of the elbow and inclination of the forearm can be changed slightly according to patient comfort and amount of stiffness as well as the amplitude of the glides can also be controlled, in all I think this is a great way to help reduce a loss of internal rotation.
McClure 2007 also highlighted that perhaps the Sleeper stretch isn't as good as another stretch called horizontal adduction (reaching across your body, see below) in reducing posterior shoulder stiffness and so should be used as well in my opinion.
Horizontal Adduction Stretch
Finally and ever so importantly what we should NEVER forgot is 'what caused the loss of movement in the first place', no stiffness starts out of nowhere, there is always a trigger. This could be cuff weakness or imbalance, poor scapular positioning, over training or general overload, poor technique, or even a central neurological driven change etc etc, but I will guarantee that if you just treat the stiffness in isolation yes the patients pain can and does reduce and they will go away happy, for a short while, but it wont be long before they start to get the same issue again and the pain returns due to the underlying cause not being identified and so will be back unhappy, or not be back at all, as they go elsewhere even more unhappy.
So in summary make sure you check for a TROMDs not just GIRDs and try and ascertain that it's not a bony structural asymmetry and is a factor that can be rectified. Then more importantly work on finding out why it occurred in the first place and address that with vigour as you work on releasing the stiffness.
As always thanks for ready