Medical Musings, Health Hypotheses & Therapeutic Thoughts
What is Frozen Shoulder Syndrome (FSS)
Almost everyone has heard of ‘frozen shoulder’, but very few have a good idea of what it entails. To be honest, even the medical profession understands what happens quite well, but not so much the why, even though it was first described in the eighteen hundreds [i], and affects about three to five percent of the population [ii] .
Frozen shoulder is a bit of a catch-all term, and when coined in the 1930’s, described a condition with slow-onset shoulder pain, inability to lie on the affected side, restricted movement of the arm (particularly lifting it or turning it outwards), and a normal radiologic appearance (that is, nothing discoverable on x-ray) [iii]. It has also been known as adhesive capsulitis, referring to the fibrous joint capsule surrounding the shoulder joint.
You may remember that to allow the shoulder to do everything it needs to, you need the bony joint surfaces and soft tissue structures to permit a lot of movement. This means that the capsule that surrounds the shoulder, or glenohumeral joint, is baggy, with lots of folds. The idea is (or was) that adhesions, or sticky bits, between the folds stopped the arm from moving as far as it could/should. However, the evidence for these capsular adhesions is a bit controversial, which is why we now ‘stick’ (Sorry! Couldn’t resist!) to the term “frozen shoulder.”
The current thinking is that is not an ‘adhered’ joint capsule, but rather a contractured one (‘contracture’ is the [?permanent] shortening or hardening of a muscle or joint). So rather than that nice baggy capsule with lots of loose folds that have stuck to each other, you have a sort of tightening, like shrink-wrap. We still don’t know why that might happen, though!
Anyway, the long and short of it is that we do not really know what causes frozen shoulder syndrome (FSS). As with many conditions, FSS can occur on its own, or as a result of other issues. The first is called primary or idiopathic frozen shoulder, whereas if it is associated with other diseases and conditions, it is called secondary frozen shoulder.
Causes of FSS
Despite the lack of any particularly compelling evidence to link frozen shoulder with any one particular factor, several issues are thought to trigger FSS:
Trauma such as a rotator cuff tear (see previous blog!), broken arm or even surgery – it should be noted that is [obviously] more common after shoulder surgery, but not limited to such.
Metabolic/endocrine/hormonal such as thyroid disease, diabetes mellitus and other auto-immune disorders, where the body’s own immune system naively but enthusiastically attacks things wrongly identified as intruders [iv],[v],[vi],[vii],[viii]. With female sufferers (whom are affected more than men), onset is often around the same time as the menopause, implying a hormonal link [ix].
Neurological issues such as stroke and Parkinson’s disease can also trigger FSS.
Heart problems such as ischaemic heart disease (not getting enough blood to the heart) and hypertension (high blood pressure) have also been implicated.
Drugs, for instance some antibiotics and antiretrovirals (and other drugs, such as the grandiosely-named protease inhibitors, used to treat HIV). Some people also report developing FSS after immunisations, such as influenza or pneuomococcus.
Probably the biggest factor that we know about is inactivity. Most patients with FSS have undergone some period of shoulder immobilization, for one reason or another. This may be one of the ways that surgery has an impact (you are normally asked to not move around too much immediately after an operation). One study looked at patients undergoing neurosurgery who had immobilized shoulders for various periods, and found that the incidence of FSS was 5-9 times greater than in the general population[x].
So, the typical presentation for frozen shoulder would be someone in their fifties or sixties (peak age of onset being mid-fifties), more likely to be a woman than a man, and with a history of one or more of the above-listed factors, likely involving not moving one or both arms for a prolonged period. Interestingly, the non-dominant shoulder is slightly more likely to be affected.
Symptoms of FSS
The symptoms of frozen shoulder have traditionally been divided into three phases, and given the catchy monikers of freezing, frozen, and thawing.
Freezing (Stage 1) is characterised by gradual onset of diffuse (widespread, difficult-to-localise) shoulder pain. This stage can last from weeks up to nine months or so, but a year is not unheard-of.
Frozen (Stage 2) constitutes a gradual, progressive loss of shoulder range of movement. You may find that it is not actually that painful in this stage, and the frustration comes more from not being able to bloody lift your arm than unremitting agony. Unfortunately, guys, this stage can last anywhere from a few months to nearly two years (four to twenty months would be a quoted figure).
Thawing (Stage 3) consists of a phase of gradually (but not necessarily constantly) increasing range of movement. This can also be a protracted stage, ranging from another few months (ok, around 4-5) to another couple of years (well, 26-odd months).
It is extremely rare to get frozen shoulder bilaterally (on both sides) at the same time (Thank goodness!), but around 6-17% of poor, limp-armed patients who have recently recovered from a bout of FSS will find an ominously-familiar ache in the other shoulder within five years, although recurrence in the same shoulder is unlikely[xi],[xii].
Next up I will discuss is the treatment options for Frozen Shoulder Syndrome (FSS)...
[i] Duplay S. De la periarthrite scapulo-humerale [On scapulo-humeral periarthritis]. Rev Pract D Trav De Med. 1896;53:226. French
[ii] Manske, R. & D. Prohaska, “Diagnosis and Management of of adhesive capsulitis” Curr Rev Musculoskelet Med. 2008 December; 1(3-4): 180–189
[iii] Codman, E.A. (1934) The Shoulder Thomas Todd: Boston, MA
[iv] Bulgen, D.Y., Binder, A., Hazleman B.L. et al (1982) “Immunological studies in frozen shoulder” Journal of Rheumatology 9(6):893-8
[v] Bulgen, D.Y., Hazleman B.L., & Voak, D. (1976) “HLA-B27 and frozen shoulder” Lancet 1(7968):1042-4
[vi] Morén-Hybbinette I, Moritz U, Scherstén B (1987) “the clinical picture of the painful diabetic shoulder--natural history, social consequences and analysis of concomitant hand syndrome” Acta Med Scand. 1987;221(1):73.
[vii] Lequesne M, Dang N, Bensasson M, Mery C (1977) “Increased association of diabetes mellitus with capsulitis of the shoulder and shoulder-hand syndrome” Scand J Rheumatol. 1977;6(1):53
[viii] Huang YP, Fann CY, Chiu YH, Yen MF, Chen LS, Chen HH, Pan SL (2013) “Association of diabetes mellitus with the risk of developing adhesive capsulitis of the shoulder: a longitudinal population-based followup study” Arthritis Care Res (Hoboken). 2013 Jul;65(7):1197-202.
[ix] Ewald, A. (2011) "Adhesive capsulitis: A review" American family physician 83(4):417–422
[x] Bruckner FE; Nye CJ (1981) “A prospective study of adhesive capsulitis of the shoulder ("frozen shoulder') in a high risk population” Q J Med. 1981; 50(198):191-204
[xi] Rizk TE, Pinals RS. “Frozen shoulder” Semin Arthritis Rheum. 1982;11:440–452.
[xii] Guyver PM, Bruce DJ, Rees JL “Frozen shoulder - A stiff problem that requires a flexible approach” Maturitas. 2014 May; 78(1):11-6.
Picking up where we left off last time.....
We were discussing the intricacies of the shoulder complex, and its relationship with surround body structures and areas. We noted that the shoulder is extremely mobile, with very little in the way of bony congruency (stability from the shape of the joint(s), and hence relying on the supporting musculature.
A particularly important group of these is known as the rotator cuff, so called because they form a cuff around the top of the arm bone and are (surprise surprise!) responsible for arm rotation. 54% of asymptomatic (i.e. not having pain or problems) patients aged 60 years or over were found to have partial or complete tears of the rotator cuff on MRI (a type of imaging), which should give you some idea of how hard those poor little fellows work over the course of our lives.
So why does the rotator cuff have to work so hard?
As previously mentioned, the shoulder is an incredibly mobile [series of] joint[s], and allows incredible mobility, but at the expense of stability.
There is a fibrous capsule surrounding the shoulder joint proper (the glenohumeral joint), as there is around many/most of the joints in the body. In the shoulder, this fibrous layer is both thin and loose, allowing a wide range of movement. The tendons of the rotator cuff blend with and reinforce this fibrous layer of the joint capsule, helping to protect and stabilize the joint.
Although they all have separate functions (some turn the arm out and the shoulder, others inwards etc.), the rotator cuff muscles work as a group to hold the head of the humerus (top of the arm bone) in the glenoid fossa (remember I described the shoulder as not so much of a ball-and-socket, but as a ball-and-tiny-saucer?). The glenoid fossa is the technical term for that little saucer-shaped depression) during arm movements. They also passively support the dependent (hanging) humerus while sitting or standing, especially supraspinatus. The arm would dislocate downwards out of this socket were it not for the rotator cuff (and the angle of the fossa). They also work with the bigger deltoid muscle to lift the arms out to the side.
In short, the rotator cuff helps us to support the shoulder and control fine movements that then enable us to use the wonder of evolution, the hand, and lets your move your arms around over your head without everything smashing together.
Common injuries of the rotator cuff
Rotator cuff overuse issues start early in life, with oedema (swelling) and haemorrhage (bleeding) of the tendon and bursa. This can start before the age of twenty five.
Stage II involves fibrosis and tendinitis, that is, the thickening and scarring of connective tissue (a general term that includes tendons, ligaments, cartilage, bone, and even fatty tissue and blood, but for these purposes refers to the tendons of the muscles) and inflammation/irritation and degeneration of the tendons. This broadly speaking takes place from the ages of around 25-40 years of age.
Stage III involves tearing of the rotator cuff, which can be either partial or full-thickness tears, and typically takes place over the age of 40.
Additionally, rotator cuff pathology is often bilateral (both sides), even when one side only is symptomatic (painful), and those with one painful side have been shown to be at risk of developing pain and tear progression on the other side (see refs at bottom of page). This is possibly related to compensatory overuse of the non-painful side.
It is also possible to have an acute or sudden-onset tear, often caused by a fall onto an outstretched arm, or trying to lift/catch something unexpectedly heavy. These may occur with or without the above-mentioned changes over time.
Bursitis is when a small fluid-filled sac that is designed to cushion from shock/friction itself gets irritated or infected. The most common bursitis in the shoulder of the subacromial bursa.
Impingement syndrome happens when outer end of the shoulderblade, called the acromion, contacts or impinges on the tendon, bursa, or both.
Primary impingement is due to structural issues (i.e. how we are built). Some of us have smaller sub-acromial spaces than others. Osteoarthritis (wear and tear) can make this worse due to little bony spurs called osteophytes that further reduce this space.
Secondary impingement is normally a result of dynamic instability (i.e. how we use our shoulders). If the rotator cuff muscles are weak, they do not do their job well; so are unable to prevent the head of the humerus from riding up into the sub-acromial space as we lift our arm. This also leads to pinching of the tendon and/or bursa.
Of course, inflamed/swollen tendons and bursae also take up more room, further decreasing the potential sub-acromial space, so these problems can co-exist and reinforce each other.
An Honourable Mention… goes to bicipital tendinopathy, which is inflammation/irritation of the long head of biceps tendon or its sheath.
It is rarely seen in isolation, and normally co-exists with rotator cuff pathology/impingment or other shoulder issues. Like the above, it is normally caused by overuse/degenration, shoulder instability, tendon impingment or trauma.
Stay tuned to our next blog installment on the shoulder, treatment..
[i] Mall NA, Kim HM, Keener JD, et al. Symptomatic progression of asymptomatic rotator cuff tears: a prospective study of clinical and sonographic variables. The Journal of bone and joint surgery American volume. 2010;92(16):2623–33
[ii] Moosmayer S, Tariq R, Stiris M, Smith HJ. The natural history of asymptomatic rotator cuff tears: a three-year follow-up of fifty cases. The Journal of bone and joint surgery American volume. 2013;95(14):1249–55
Shoulder pain is pretty common, with only the back and the knee giving more of us grief (1,2). It can also be stubborn. According to the British Medical Journal and the British Journal of General Practice, only about 50% of new episodes of shoulder pain presenting to medical doctors show a complete recovery after six months (3,4), After a year, that figure has only risen to 60% (5)!
So why is it that the shoulder causes so many - and seemingly such persistent - issues?
Largely, it is because the shoulder itself is a very complex bit of kit, with a lot of interactions with the structures around it.
The "shoulder joint" is actually a constellation of several joints (see figure below):
(1) the scapulothoracic joint , which is not a true joint at all, but rather the interface, or articulation, between the shoulder blade and the rest of the thoracic cage (mid back and ribs).
(2) the glenohumeral joint , which is the shoulder joint proper (the ball-and-socket, although it's more like a ball-and-tiny-saucer).
(3) the acromioclavicular joint between the bony bit at the end of your shoulder and your collarbone,
(4) the sternoclavicular joint, between the collarbone and breastbone. This is the only bony connection point between the arm and the rest of the skeleton - everything else is controlled by muscles!
In order for your shoulder to do its job, all of these must be working well - and together. The shoulder is incredibly mobile, but to get as much movement as it has, there has to be a trade-off - stability. Because it is unstable, the shoulder relies on a complex balance of muscles around it to function (in an upcoming blog I will talking about a particularly important group of these, the rotator cuff).
The diagram below is culled from some of my old student notes, and should give some idea of the complexity of the muscles that act on and around the shoulder, as well as further down the arm.
On that note, it is also important to remember that the shoulder does not exist in isolation, but is the attachment point to the rest of the body for your arm, elbow, forearm, wrist and hand.
As an (ex-)anthropologist, I could wax lyrical on the majesty and intricacy of all the thingummybobs and anatomical wonders that make your arms - and most importantly, hands - the marvels of nature that they are. Opposable thumbs, baby, they're what make us unique. But I digress...*
So the presence of the rest of the upper limb complicates things a bit. The body is a master at compensation, and, if things are going wrong down at the coalface (for example, the hand and wrist), it will quite happily sacrifice anything up the chain to maintain that wonderful hand and wrist mobility.
So, hand, wrist and elbow problems can also cause shoulder issues.
Likewise, as we touched on briefly in the last shoulder blog) other common contributors to shoulder pain include the neck, thoracic spine (mid-back) and ribs.
The viscera (internal organs; heart, lungs, liver, stomach etc.) or neurological issues (such as stroke etc.) can also give rise to pain in the shoulder. This is why it is important to have your shoulder pain checked out by a trained professional.
So, in short, there is a lot going on. All the different forces from the arm, your trunk and ribs (including breathing) as well as head and neck are meeting in this area and interacting, so it is no surprise that so many shoulder issues remain unresolved.
If you just look at the shoulder in isolation, instead of also looking at these related areas in the rest of the body, you can often miss these crucial predisposing and maintaining factors (vulnerabilities that helped your problem develop, and issues that are preventing your recovery).
Your osteopath is trained to examine and assess each of these components and how they relate to each other, and will treat as many of them as possible. In this way, even if some underlying damage is present, the body’s ability to compensate and cope will allow normal function.
Specific shoulder issues are presented in our next blog on the rotator cuff. Also stay tuned for further upcoming blogs on other shoulder issues e.g., bursitis, frozen shoulder.
*if you are interested in this sort of thing, start with Evolution of the human hand: the role of throwing and clubbing, and follow the references from there....!
4, Picavet HS, Schouten JS. Musculoskeletal pain in the Netherlands: prevalences, consequences and risk groups, the DMC(3)-study. Pain 2003;102:167–78
5. Urwin M, Symmons D, Allison T, Brammah T, Busby H, Roxby M, Simmons A, Williams G. Estimating the burden of musculoskeletal disorders in the community: the comparative prevalence of symptoms at different anatomical sites, and the relation to social deprivation. Ann Rheum Dis 1998;57:649–55.
1. P. Croft, D. Pope, A. Silman, The clinical course of shoulder pain: prospective cohort study in primary carePrimary Care Rheumatology Society Shoulder Study Group. Br Med J 19963136012
2. D. A. Van der Windt, B. W. Koes, A. J. Boeke, W. Deville, BA Bouter. L. M. De Jong, Shoulder disorders in general practice: prognostic indicators of outcome. Br J Gen Pract 19964651923
3. D. A. Van der Windt, B. W. Koes, A. J. Boeke, W. Deville, BA Bouter. L. M. De Jong, Shoulder disorders in general practice: prognostic indicators of outcome. Br J Gen Pract 19964651923
Some potential causes
Shoulder pain can be debilitating - you don't realise how much you use your arms until you can't any more!
What's more, shoulder pain can be due to any one of a number of structures within the shoulder itself (it's a complicated area!), or it can come from the neck, thorax (upper and mid-back), or ribs - commonly, several of these at once. It is also possible for various problems with the internal organs (or 'viscera') to refer pain to the shoulder, such as the heart, lungs, liver or gallbladder, or stomach (among others).
For this reason, your osteopath will ask you lots of questions that might not seem relevant to the pain you are feeling, but please bear with us - there is method in our madness! They will also perform a number of examinations and assessments of these different areas before coming up with a treatment plan.
This will often involve a stretching and strengthening regime for the affected areas. While this is important for many areas of the body, it can be even more crucial for shoulder issues. Not many people realise that your arm is only connected to the rest of the skeleton through your collarbone (or 'clavicle'). This is not a very strong bony connection, obviously, so the body relies on heaps of different muscles to help control and stabilise the area. Many of these are shared, and help with movement and control of the neck, or breathing, or the torso, or all of the above! If some of these are too tight, or too weak, this leads to problems. Elbow and wrist function is also very important - any issues in these areas will track 'further up the chain', so this will also need to be checked.
In the next few weeks, we will consider some of the more common reasons for shoulder pain, and suggest a few things you can do to help them.
Obviously, a blog post is no substitute for professional assessment and treatment of an area, so be careful when and if you follow any advice contained in one, and contact your health professional if you have any questions or concerns.