There is very little clarity on what frozen shoulder actually is among research literature. Because of the vague diagnostic criteria and poor understanding of the condition, chiropractors and physical therapists sometimes mis-diagnose shoulder pain.
What is frozen shoulder or adhesive capsulitis?
The first description of what might have been a frozen shoulder was published in a report by Duplay in 1875. The term “frozen shoulder” was coined much later by Codman in 1934. He defined it as a shoulder condition that is painful, with limitations in elevation and external rotation. According to him the pain is usually felt near the deltoid muscle insertion on the upper arm bone (humerus).
Today, frozen shoulder goes by different names – adhesive capsulitis or even arthrofibrosis. The term “adhesive capsulitis” was introduced in the United States when Neviaser in 1945 argued that the term “frozen shoulder” was a misnomer. His reason was that frozen shoulder was not cold but, in fact, hot. He was referring to the warmth that is associated with the inflammation process associated with the condition.
Interesting enough, it was Neviaser himself who later found NO adhesions in the shoulder capsules he operated on.
Today, there are multiple definitions to what is a frozen shoulder.
From a clinical perspective, it refers to a painful shoulder condition that is characterised by stiffness and a significant loss of range of motion – typically in external rotation. One of the classic complaint with when it comes to adhesive capsulitis is shoulder pain when lifting arm.
From a pathophysiological perspective, it is sometimes referred to a condition where there is excessive scar tissue (or adhesion) formation. (Research doesn’t seem to support this.)
Fun fact 1: The third most common cause of musculoskeletal disability is shoulder pain – after low back pain and neck pain.
How is adhesive capsulitis diagnosed?
This is why there is all the confusion. There is no diagnostic criteria for frozen shoulder!
Most papers agree the most obvious sign is a reduction in both passive and active range of motion.
Passive range of motion refers to the movement of your shoulder as facilitated by another person i.e. a chiropractor moving your arm while your arm is relaxed. Active range of motion refers to the shoulder movement that is the result of you moving your arm by yourself without assistance.
There is no agreement on how much range of motion loss is required to meet a frozen shoulder diagnosis. British Medical Journal Best Practice Guidelines defined frozen shoulder as a condition with “progressive severe restriction” in range of motion. Severe is pretty vague but I am guessing a mild stiffness would not cut it.
A clinical commentary published in 2013 suggested an “almost complete loss of external rotation” as defining clinical feature of a frozen shoulder.
A clinical review published in Bone and Joint Journal, in the same year, suggested external range of motion of 45 degrees or MORE to be classified as mild frozen shoulder. They study didn’t put a upper limit to it – i.e. 89 degrees, which is a one-degree loss of full external rotation, would still meet their diagnostic algorithm for a frozen shoulder.
N.B. Full external rotation of a healthy shoulder is considered 90 degrees.
It is also generally agreed that diagnosis of frozen shoulder is one that is by exclusion. This means ruling out all other possible causes of the presenting shoulder complaint.
Reference: Diagnosis and management of adhesive capsulitis (2008)
Frozen shoulder causes
In biopsies of people with frozen shoulder, chronic inflammatory responses were evident in the tissue sampled. The hypothesis is that these processes lead to a decrease in joint volume and, as a result, restricts shoulder (glenohumeral) movements to give a reduction in your range of motion.
Studies have gone on to suggest that tissues affected in the anterosuperior (front-top) region of the shoulder joint results in a limitation of external rotation (cranking your arm up and back) while tissues affected in the posterior (back) region results in a internal rotation (cranking your arm down and back) limitation.
This sounds reasonable until a study published in 2015 showed that patients with frozen shoulder experience an increase in range of motion in the affected arm when they were under general anesthesia. The increase is dramatic – at 44 degrees at the minimum and as high as 110 degrees in another patient.
If frozen shoulder is indeed cause by the a reduction in the joint capsule volume (as a result of chronic inflammation) , why would range of motion increase by virtue of general anesthesia alone?
Most of us still subscribe to the biomedical model when it comes to pain and healthcare. However, we already know the biomedical model is flawed and does not fit into the current understanding of pain or musculoskeletal disorders. You can read more about pain in our blog post on lower back pain.
Bottom line: Ascribing your shoulder pain to frozen shoulder and your frozen shoulder to a capsular contracture is a reductionist and over-simplified approach to your shoulder pain. It is unlikely for anti-inflammatory to help with frozen shoulder pain.
Frozen shoulder therapy following a biomedical or biomechanical model
Manipulation under anaesthesia
The treatment is kinda as the name suggest, shoulder manipulations is performed while you are under general anesthesia. I’ve included a YouTube video for your reference because that will give you a full idea of what actually happens.
Not surprisingly, there are risks to the procedure. They include possible fracture of the humerus (arm), shoulder dislocation, rotator cuff tears, glenoid fractures, brachial plexus (nerve) injuries, labral tears.
I don’t actually think there is any studies that compared manipulation under anaesthesia vs. placebo. However, there are other studies looking into manipulation under anesthesia.
Study 1: Manipulation under anesthesia for primary frozen shoulder
37 patients were treated with manipulation under anesthesia for frozen shoulder. 35 were satisfied with the procedure with 16 shoulders experiencing moderate to severe disability at three months follow up.
Unfortunately the study didn’t compare it to placebo or other treatment.
Study 2: Manipulation under anesthesia with home exercises versus home exercises alone in the treatment of frozen shoulder
125 patients with randomly allocated to either receive manipulation under anaesthesia with home exercises or home exercises alone.
There was no difference in shoulder pain or working ability outcomes between both groups. There are – not surprisingly – small improvements in range of motion for the manipulation group.
The perceived shoulder pain intensity were also comparable between groups.
The authors concluded that manipulation under anesthesia did not add an advantage to an exercise program alone.
Hydrodilation or arthrographic distension
This treatment might take a bit of effort to understand. It works by injecting local anesthetic into the joint at a high pressure with the intent of distending the shoulder joint (make the joint bigger).
Study 3: Arthrographic joint distension with saline and steroid improves function and reduces pain in patients with painful stiff shoulder
When compared to placebo, active shoulder abduction (arm movement away from midline of body), and hand behind back movements are better in the hydrodilation group at three weeks. At 6th and 12th weeks, there was no difference in these outcomes between hydrodilation and placebo. Problem Elicitation Technique scores. however, were higher in the hydrodilation group at 3, 6, and 12 weeks.
Between patients who received hydrodilation with corticosteroids vs. corticosteroids alone (no dilation), there was no difference in outcomes.
Study 5: Thawing the frozen shoulder
This study compared hydrodilation to manipulation under anesthesia. The hydrodilation group performed significantly better than in the frozen shoulder patients in the manipulated group through the the six-month follow-up period. While most patients’ treatments were successful, those who received hydrodilation fared better than those who received manipulation.
Bottom line: There are multiple treatment options available for frozen shoulder. However, it is unclear which treatment delivers the best outcomes.
Physiotherapy treatment for frozen shoulder
77 patients with frozen shoulder participated in a study that compared intensive physical therapy vs supportive therapy with exercises for two years.
I haven’t had a chance to look up the full text of the paper yet but based on the abstract in the group that didn’t receive intense physiotherapy 89% had normal or near-normal painless shoulder at the end of two years. In the intense-physiotherapy group, only 63% achieved the same outcome at the end of two years.
I will need to come back to look at more details of what was done for the treatment between groups.
Study 7: Intraarticular corticosteroids, supervised physiotherapy, or a combination of the two in the treatment of adhesive capsulitis of the shoulder
This is a strange study design, we will come to that later. In this one-year follow up study, all groups responded the same at 12 months. At three months, the corticosteroids plus physiotherapy (group one) and corticosteroids alone (group two) responded better than sham corticosteroid (group three) plus physiotherapy group and the sham corticosteroid (group four) alone group.
- Group one = corticosteroids plus physiotherapy
- Group two = corticosteroids alone
- Group three = sham corticosteroid (i.e. saline) plus physiotherapy
- Group four = sham corticosteroid (i.e. saline) alone
The authors conclusions were that adding supervised physiotherapy accelerated range of motion improvements. However, physiotherapy alone had limited efficacy. The thing is there wasn’t a physiotherapy alone group. Not sure if that’s a fair clinical trial design.
For the study to be able to make that conclusion, there should be a sham physiotherapy group vs. actual physiotherapy group. Alternatively, a physiotherapy alone group. (They did have a corticosteroid alone group.)
Again, I’ll need to look into the study to see what exactly was done to the patients for the physiotherapy group.
Study 8: Frozen shoulder: prospective clinical study with an evaluation of three treatment regimens
The study compared steroids vs. mobilisations vs. ice therapy vs. no treatment and reported no significant no long-term advantage between any of the treatments. In the early stages of frozen shoulder, steroid injections may be useful for pain and how much you can move your shoulder.
That kinda makes sense I guess. A little disappointed the study didn’t compare active care or exercises.
Study 9: Comparison of High-Grade and Low-Grade Mobilization Techniques in the Management of Adhesive Capsulitis of the Shoulder
Another study that compared passive therapies. In essence, high grade mobilisation works better than low grade ones. I would have much preferred to see a placebo or a sham control group. Oh well.
Bottom line: It is not clear if physiotherapy works. It is quite disappointing because we would like to see more research on exercises for a frozen shoulder. We’ll update this section over the next couple of weeks.
Frozen shoulder is rarely a stand-alone condition
This is another can of worms.
Despite frozen shoulder being a diagnosis of exclusion, many people who are diagnosed with frozen shoulder actually presents with other underlying shoulder disorders.
A 1991 study looked at 150 patients who were referred to a shoulder clinic for a diagnosis of “frozen shoulder”.
Out of the 150 patients, only 37 qualified for the “frozen shoulder” diagnosis. The other 113 patients had frozen shoulder from other painful causes such as rotator cuff impingement or tear.
The 37 who were determined to have a “frozen shoulder” undergone arthroscopy. It findings show a patchy vascular reaction around the biceps, with a reduction in the capacity of the joint. No adhesions were seen.
People with diabetes also seem to be at a higher risk for the condition.
Bottom line: There are many people who are diagnosed with frozen shoulder but often such diagnosis comes with other shoulder pathology. It is possible the “frozen shoulder” symptoms are due to the other shoulder disorders present.
Perhaps a diagnosis is not important
A clinical commentary published a couple of months ago suggested that perhaps we should ditch specific shoulder pain diagnoses. A generic diagnostic term rotator cuff-related shoulder pain (RCRSP) was suggested to encompass a number of conditions from subacromial impingement or pain syndrome to rotator cuff tendinopathy.
While frozen shoulder was not specifically mentioned, perhaps it should be included?
British Medical Journal published in 2005 that there is a tenancy for clinicians to label any patient with a stiff, painful shoulder as a case of frozen shoulder. The paper strongly recommend against it.
Tim Bunker – an Orthopaedic Senior Registrar – in 1985 published a clinical commentary to suggest a new name for frozen shoulder: HGAC.
To the patients, it can be humeroglenoid acromioclavicular syndrome. To clinicians? Haven’t Got A Clue.
Does frozen shoulder exist?
I am not the only one who feels that way. When I was discussing the a potential frozen shoulder case with a Singpapore physio, his reply was: “Ah ?.. frozen shoulder.just gets tossed around like it means nothing.”
I am thankful I am not the only one who feels that way.
In my opinion, the current research climate really doesn’t support frozen shoulder as a clinical condition.
Five takeaway lessons on adhesive capsulitis
First, there is no real clarity to the diagnostic parameters that make a frozen shoulder a frozen shoulder.
Second, there is a tenancy for doctors to wrongly diagnose any stiff and painful shoulder as a frozen shoulder.
Third, most frozen shoulder diagnosis comes with other underlying shoulder disorders, which would by default make that a misdiagnosis. (Because frozen shoulder is a diagnosis of exclusion – i.e. no other shoulder disorder.)
Fourth, it’s somewhat a fair statement to say all frozen shoulder treatments work equally bad.
Fifth, we have been talking about chucking the diagnostic label out so why attempt to label it in the first place?
Let’s call a spade a spade. A stiff shoulder is a stiff shoulder. A painful shoulder is a painful shoulder. A stiff and painful shoulder is a stiff and painful shoulder.
Treat the shoulder pain and the shoulder stiffness, not the label. No?