Frozen Shoulder Symptoms
Evidence based frozen shoulder information...
Frozen Shoulder Symptom Questions Answered On This Page...
What are the symptoms of a Frozen Shoulder?
The onset of frozen shoulder symptoms are gradual. In most cases of frozen shoulder there will be significant pain levels including nocturnal pain early in the condition. Over the initial few weeks and months there will be a typical pattern of shoulder stiffness/ reduction to shoulder range of motion. Symptoms of frozen shoulder generally follow 3 symptomatic stages...
What is a Frozen Shoulder?
Frozen shoulder is a medical condition that leads to a progressive onset of pain and stiffness developing at the shoulder. Rather than typical causes of joint pain such as degenerative/ age related changes or an injury, the cause of a frozen shoulder is thought to be an immune triggered response but the exact causes are unknown. A Frozen shoulder may also be described as an Adhesive capsulitis by some clinicians due to the condition primarily inflaming and fibrosing the shoulder joint (glenohumeral joint) soft tissue capsule.
Who gets a Frozen Shoulder?
Although the exact cause is unknown, Frozen Shoulder is common in certain groups including:
People between the ages of 45-60
Women are affected more than men
People with diabetes (high blood sugar readings)
People with thyroid problems
People with high blood cholesterol
It is thought to be common in these groups as they all are a cause of low grade inflammation in the bodily tissues. It is postulated that this low grade inflammation over time may trigger an immune system inflammatory response in the shoulder capsule to trigger a frozen shoulder.
What are the stages of a frozen shoulder?
Without treatment, most, but not all cases of a frozen shoulder will follow a typical pattern of symptoms which have traditionally been described as “freezing”, “frozen” and “thawing". The freezing stage is characterised by high levels of pain and gradual reduction in range of motion (stiffness). The frozen stage characterised with persistent loss of range of motion but improved pain levels and the thawing stage a gradual return of the shoulder range of motion. To find out more about typical timeframes please scroll down this page to How long does a frozen shoulder last?
The more recent advents of the terms "pain dominant" and "stiffness dominant" frozen shoulders have been used in an attempt to standardise the way clinicians treat a frozen shoulder. The standard this has aimed for is to offer an early form of steroid injection for painful frozen shoulders to reduce inflammation and to offer gentle rehab exercises for stiff (but less painful) frozen shoulders. For more information about the best treatment for frozen shoulder symptoms please go to frozen shoulder treatment.
Many articles have described a distinct pattern of symptoms which develop in a frozen shoulder. The first reports on this condition were based on descriptions from surgeons based on what they observed while operating on cases of frozen shoulder. In later years, histology samples (looking at the shoulder tissues and cells of these tissues under a microscope) were described as well. Findings from these research papers and other studies observing patients symptoms have concluded that typical frozen shoulders undergo distinct symptom stages as we describe here:
Frozen Shoulder Stage 1: Freezing (pain dominant):
The "freezing" - or "pain dominant" stage of a frozen shoulder is characterized by high levels of inflammation within the soft tissue capsule and ligaments of the shoulder joint. Many histological studies (studies which look at the cells and tissue under a microscope) have found high levels of blood vessel (vascular) infiltration to the shoulder capsule as well as a high number of mononuclear cells (cells involved in an immune system response). Due to the inflammation patients often suffer with high degree of pain, especially night pain. The movements of the shoulder at this stage will begin to gradually stiffen due to fibrosis of the shoulder joint capsule.
Frozen Shoulder Stage 2: Frozen (stiffness dominant):
The "stiffness dominant" stage of a frozen shoulder signifies the reduction of the active inflammation of the shoulder joint capsule and ligaments. However, the prolonged inflammation of the shoulder capsule and ligaments during the freezing/ pain dominant stage results in a tough, inflexible soft tissue capsule - essentially it leaves the shoulder capsule and ligaments with scar tissue. Thus, in this stage frozen shoulder pain improves but the shoulder movements remain very stiff.
In this stage of a frozen shoulder, high numbers of cells known as fibroblasts which are involved in tissue repair during and following inflammation have been demonstrated in the shoulder capsule. Furthermore, the type of soft tissue being made appears to be a tougher and stiffer type than normally found in the shoulder capsule and ligaments (collagen type 2). This stage can be likened to the tough, raised scar that you feel on your skin several weeks and months after you have cut yourself.
Frozen Shoulder Stage 3: Thawing (resolution):
As it's name implies the "resolution" stage of a frozen shoulder signifies the process in which the tougher form of soft tissue collagen in the shoulder is slowly remodelled to form a more normal, flexible joint capsule. As with other injuries such as a deep cut to the skin or a badly sprained ankle this stiffness will resolve over several months so patients will notice a gradual increase in their range of motion again over this period of time. In most cases of frozen shoulder, the range of motion will not get back to completely normal but will not disable activities of daily living.
Cho, C.H., Song, K.S., Kim, B.S., Kim, D.H. and Lho, Y.M., 2018. Biological aspect of pathophysiology for frozen shoulder. BioMed Research International, 2018. Link to article
Hand, G.C.R., Athanasou, N.A., Matthews, T. and Carr, A.J., 2007. The pathology of frozen shoulder. The Journal of bone and joint surgery. British volume, 89(7), pp.928-932. Link to article
Neviaser, J.S., 1945. Adhesive capsulitis of the shoulder: a study of the pathological findings in periarthritis of the shoulder. JBJS, 27(2), pp.211-222. Link to article
Neviaser, R.J. and Neviaser, T.J., 1987. The Frozen Shoulder Diagnosis and Management. Clinical Orthopaedics and Related Research (1976-2007), 223, pp.59-64. Link to article
Reeves, B., 1975. The natural history of the frozen shoulder syndrome. Scandinavian journal of rheumatology, 4(4), pp.193-196. Link to article
Where is the pain in a frozen shoulder?
Frozen Shoulder pain is normally felt in the front and outer aspect of the shoulder deltoid muscle region as well as the upper arm. In some cases, frozen shoulder pain may even be felt in the forearm, hand and fingers.
The location that we feel pain in, is often not over the anatomical structure which is causing the pain. We call this the somatic pain pattern or somatic referral pattern and every anatomical structure in the body which feels pain has one. Typical examples which are well known to the public are heart pain referring down the left arm and kidney stones giving rise to acute lower back pain. Our musculoskeletal tissues also have a somatic referral pattern.
In many causes of shoulder pain, doctors and physiotherapists are asked by patients to "examine my arm" as this is where our patients are feeling their most intense pain. In fact, sometimes I will ultrasound scan my patient's upper arm to show them that it is normal during a shoulder scan.
So, where is the somatic pain pattern for a frozen shoulder? Studies have investigated this previously in several differing ways. Gerber, et al (1998) investigated this question by injecting a painful substance (salt water) around each shoulder structure and then asking participants where they felt their pain. Using this method, they found the AC joint referred pain to the lateral neck and trapezius muscle. However, irritation of the sub-acromial space referred pain to the deltoid muscle, upper arm and sometimes in to the forearm and fingers.
Bayam et al (2011), asked 94 patients where their pain was located and matched the pain patterns against a diagnosis based on imaging and clinical assessment from 2 experts. The results can be seen in the diagram below. These results confirm that apart from AC joint pain, patients will feel shoulder pain in the deltoid and upper arm region in the majority of cases (taken from the article Bayam, L., Ahmad, M.A., Naqui, S.Z., Chouhan, A. and Funk, L., 2011. Pain mapping for common shoulder disorders. pathology, 14(5), p.9.).
Singh et al (2015) looked at a far greater number of patients (783) and also specifically published figure for 56 patients diagnosed with a frozen shoulder. Again, they concluded that frozen shoulder pain is felt in the outer aspect of the deltoid region and upper arm.
These studies of differing methods all confirm that the most likely site of pain in a frozen shoulder is the deltoid region and upper arm. However, this referred somatic pain pattern may be similar in many other common shoulder conditions including shoulder impingement, shoulder bursitis and rotator cuff pain and tears so it should not be used for diagnosis. To find out more about how a frozen shoulder can be diagnosed follow this link - How is a frozen shoulder diagnosed?
Bayam, L., Ahmad, M.A., Naqui, S.Z., Chouhan, A. and Funk, L., 2011. Pain mapping for common shoulder disorders. pathology, 14(5), p.9. Link to article
Gerber, C., Galantay, R.V. and Hersche, O., 1998. The pattern of pain produced by irritation of the acromioclavicular joint and the subacromial space. Journal of shoulder and elbow surgery, 7(4), pp.352-355. Link to article
Singh, S., Mohammad, F., Gill, S., Kumar, D. and Kumar, S., 2015. Role of pain mapping in shoulder disorders. International Journal of Orthopaedics, 2(3), pp.323-327. Link to article
How long does a frozen shoulder last?
Published studies indicate that the majority of frozen shoulder cases will significantly improve with regards to pain levels, function and range of shoulder range of motion without active treatment. However, several caveats to this exist:
The timeframe to maximal improvement from a frozen shoulder may be as long as 2-3 years in most cases.
A significant percentage of frozen shoulders (studies range from approximately 20% - 50%) may cause mild pain or functional deficit long term.
A small percentage of frozen shoulders may cause significant long term pain or disability (<10%).
Given the long time frame to recovery and significant nocturnal pain and disability during the early stages it is generally accepted that a steroid injection or hydro-dilatation procedure should be offered to patients. For more information about these treatments please scroll to the dedicated frozen shoulder treatment section.
The general consensus among doctors and physiotherapists (which arises from their teaching as an undergraduate) is that a frozen shoulder will improve without treatment. Most clinicians will give a rough estimation of 18 months from initial onset of symptoms to full resolution with this timeframe broken down in to 6 month blocks for each of the 3 stages which we discuss in the section above on this page.
However, the available studies indicate that this traditionally recognised view regarding timeframe to recovery may be too short and that significant numbers of frozen shoulders will develop some mild long term symptoms. 4 such studies are discussed here...
Reeves, et al was the first study to look at this question in 1975. They performed a prospective study which managed to follow up 41 frozen shoulders and concluded that the mean average duration to full recovery was 30.1 months. They also reported a slight restriction in shoulder range of motion persisted long term in more that 50% of the frozen shoulders evaluated and 3/41 frozen shoulders reported significant deficit in shoulder function.
Similarly, Shaffer et al (1992) found that when a long term follow up on 62 cases of frozen shoulder was conducted (over 2-11 years from initial onset) 50% had mild stiffness or pain in the shoulder ongoing. Clinically assessed shoulder range of motion was also restricted at the long term follow up (compared with the other shoulder) in 30% of the frozen shoulders.
Using the Oxford Shoulder Score as a measure of shoulder symptoms, Hand et al (2008) published a study with a greater sample size (269 frozen shoulders). There was a mean average of 4.4 years after initial onset of symptoms to follow up. Their data reported only 59% of patients had "normal" or "near normal" shoulders at follow up. However, only 6% of patients reported severe long term symptoms. Timeline to peak of symptoms from initial onset was documented at 1-3 years.
Lastly, in 2020 and titled "Is frozen shoulder completely resolved at 2 years after the onset of disease?", Kim et al investigated this question with a sample size of 234 frozen shoulders. As a mean average, pain scores (VAS) reduced from 6.7 to 1.5. A satisfaction grading system known as the subjective shoulder value used more widely in the USA reported the following:
very satisfied 43.2%
very unsatisfied 3.4%
Hand, C., Clipsham, K., Rees, J.L. and Carr, A.J., 2008. Long-term outcome of frozen shoulder. Journal of shoulder and elbow surgery, 17(2), pp.231-236. Link to article
Kim, D.H., Kim, Y.S., Kim, B.S., Sung, D.H., Song, K.S. and Cho, C.H., 2020. Is frozen shoulder completely resolved at 2 years after the onset of disease?. Journal of Orthopaedic Science, 25(2), pp.224-228. Link to article
Reeves, B., 1975. The natural history of the frozen shoulder syndrome. Scandinavian journal of rheumatology, 4(4), pp.193-196. Link to article
Shaffer, B., Tibone, J.E. and Kerlan, R.K., 1992. Frozen shoulder. A long-term follow-up. JBJS, 74(5), pp.738-746. Link to article
Can a frozen shoulder cause neck pain?
A frozen shoulder causes inflammation, pain and stiffness in the soft tissue capsule of the shoulder joint (glenohumeral joint) as well as changes to the sub acromial area (bursa and rotator cuff tendons above this joint). These structures do not cause neck pain themselves.
However, neck pain is a common clinical complaint from patients with a frozen shoulder. Therefore, it is probable that the compensatory movements adopted due to the shoulder stiffness places extra stress on the joints and soft tissue of the neck and causes pain in these cases.
For a full explanation of where frozen shoulder pain is felt please scroll up this page to the section - Where is the pain in a frozen shoulder?
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