Scary diagnoses, such as spondylolisthesis and Degenerative Disc Disease are often deconstructed during Explain Pain classes. Invariably, the metaphorical diagnosis ‘frozen shoulder’ gets a mention. We offer different names like “stiff shoulder” (quite literal) and inject some humour – “at least there is one benefit of global warming”. The name of this condition used in the literature, ‘adhesive capsulitis (AC)’ is equally fear inducing. It sounds horribly sticky, has hints of Araldite, and suggests that we really don’t know much about this condition.
The metabolic shoulder?
We have just read a great review on AC by Max Pietrzak (2016).
Here is some key thinking from the paper:
-AC is quite common, especially in the over 40s.
-It often resolves within 1-2 years, though there are many reports of longer term symptoms and disability.
-The most common risk factors for AC are age, diabetes and cardiovascular disease
-Diabetes and cardiovascular disease are commonly associated with obesity, with the underlying link being metabolic syndrome
-Metabolic syndrome is a cluster of biological changes including lipid abnormalities, elevated blood insulin levels and an immune response (increased pro-inflammatory cytokines) leading to a chronic low grade inflammatory state
-The strong associations between AC, age, diabetes and cardiovascular disease therefore suggests a common underlying aetiology of metabolic syndrome and chronic low grade inflammation
-Additionally, a dysregulated autonomic nervous system, shifted more to the sympathetic system through the effects of adrenaline, further induces and perpetuates low grade inflammatory states
When did you last throw a spear?
Pietrzak states that “the human shoulder evolved for high speed projectile throwing.” But, given our increasingly sedentary lifestyle (including lack of spear throwing, unless you’re into javelins) it is possible that parts of the shoulder-complex soft tissues are not exercised and stretched commensurate with their evolutionary function. Some of these shoulder tissues may now be subject to the buildup of metabolic by-products, increased pro-inflammatory cytokine production and detrimental effects on the cellular structure.
Within this context, Pietrzak suggests, an injury proximal or distal to the shoulder may trigger off a local and/or systemic pro-inflammatory cytokine, sympathetic and neuroimmune cascade resulting in AC.
Hang on, what is ‘chronic low grade inflammation’?
Chronic low grade inflammation differs from acute inflammation in that it is not localised to a particular part of the body, is of a lower ‘intensity’ and continues for an extended period. It is characterised by the systemic presence of increased numbers of inflammatory and immune cells and their products such as pro-inflammatory cytokines.
Chronic low grade inflammation is increasingly seen as a part of other orthopaedic conditions such as osteoarthritis – once considered a ‘cold’ wear and tear problem (as opposed to the far more overt and ‘hot’ inflammation of rheumatoid arthritis).
In the presence of chronic low grade inflammation, fibrosis of soft tissue can provide a ‘storage depot’ for immune cells and products. This is in keeping with the commonly observed connective tissue infiltration of cytokines, mast cells, macrophages, lymphocytes, T and B Cells in AC.
The psychosocial shoulder
Chronic low grade inflammation can be enhanced by psychosocial stress with complex interactions between pro-inflammatory cytokines, immune cells and compounds, and the extracellular matrix (ECM) – the main building material of dense and loose connective tissues. This process is associated with the formation of extracellular adhesions and cable-like structures – a common feature of AC.
The big picture
The overall picture of adhesive capsulitis that emerges is one of cascading chronic low grade inflammation, perpetuated by dysregulated autonomic function favouring a sympathetic dominance, with an immune balance tipped towards pro-inflammatory cytokines, showing up in a joint in a potential state of increased oxidative stress and acting as a storage depot for immune cells all on the background of a modern, unhealthy lifestyle that promotes psychosocial stress, a pro-inflammatory profile and that fails to fully express the joints evolutionary function, with lots of feedback and feedforward communication loops thrown in!
Back to the clinic
Here’s a few thoughts:
- Explaining ‘frozen shoulder’ as a “self–limiting, treatable, low grade inflamed, and stiff shoulder” might reduce some threat and stress with anti-inflammatory neuroimmune benefits
- Vigorous manual therapy probably leads to more pain, more stress and potentially more inflammation
- A biopsychosocial approach, addressing unhealthy lifestyles (all therapists and medical practitioners have a role here) would seem to have a place, both in treatment and prevention
- Regular, overhead, full range, context-rich, novel, meaningful movement is vital for the over 40s (and the rest)! If you can’t move it, at least imagine moving it.
- Appropriate exercise has a role and is also likely to assist with addressing diabetes and cardiovascular disease if associated
- What about other upper limb pain states, e.g. rotator cuff tears and ‘tennis elbow’?
- Immune buffering behaviours would seem to have an important stress reducing, anti-inflammatory enhancing, lubricin generating role
We’ve heard a bit of a shift from therapists recently in relation to low grade inflamed stiff shoulders – a bit of a lament that there is nothing we can do other than let natural history take its course. But here’s another hypothesis – by understanding the underlying neuroimmune/neuroendocrine biology, and adapting an emergent, biopsychosocial approach, we can help prevent the incidence and reduce the pain associated with this condition.
Please share your thought and comments, and any experiences with low grade inflamed shoulders below.
-David Butler and Tim Cocks
We’re hitting the road and taking our NOI courses right across this great southern land:
Townsville 29 April – 1 May Explain Pain and Graded Motor Imagery
Canberra 3 – 4 May Mobilisation of the Neuroimmune System (only Australian MONIS course for 2016)
Canberra 6 – 8 May Explain Pain and Graded Motor Imagery
Adelaide 14-15 May Pain, Plasticity and Rehabilitation (only Australian PPR course for 2016)
Noosa 17 – 19 June Explain Pain and Graded Motor Imagery
Perth 15 – 17 October Explain Pain and Graded Motor Imagery
EP3 events have sold out three years running in Australia, and we are super excited to be bringing this unique format to the United States in late 2016 with Lorimer Moseley, Mark Jensen, David Butler, and few NOI surprises.
EP3 EAST Philadelphia, December 2, 3, 4 2016
EP3 WEST Seattle, December 9, 10, 11 2016
To register your interest, contact NOI USA:
p (610) 664-4465