June literature review - frozen shoulder; how do we treat it?

Frozen shoulder - Instalment 3

How do we treat it?

Ok, so we now know how to identify (here) and diagnose (here) a frozen shoulder (FS), right? Once detected, it seems prudent to know how to help the person who is anxiously waiting for a strategy/plan from you to restore some quality to their life, yes? Good.

What interventions are available to treat frozen shoulder?

Physical therapy

• Exercise therapy, manual therapy, education, etc. etc.
• I’m not including modalities, Neil Asher Technique, acupuncture (soz).

Injection therapy

• Hydrodilatation
• Low volume intra-articular steroid injection
• Subacromial steroid injection

Surgery

• Capsular release
• Manipulation under anaesthetic

As you know, I’m a physio/physical therapist (you know what I mean), therefore my bias leans heavily towards the non-surgical management of any condition, and FS is no exception. In fact, surgery in this group should be considered mostly contra-indicated, save for rare cases where all other management has failed and the person in pain is searching for an escalation of care. Consequently, given I am the author, this review will look at the evidence behind physical therapy (in some of its forms) and injection therapy.

What's the evidence for Physical Therapy

This is a tricky question (that I’ve asked myself, strangely) because physical therapy includes almost everything under the sun. Frustratingly, this affects the available evidence. Physical therapy in the literature can include; massage, mobilisations, manipulation, exercise therapy, education, laser therapy, passive ROM, acupuncture, dry needling (trust me, the list goes on). Physical therapy seems to be quite a heterogeneous intervention and therefore it becomes almost impossible to measure its effectiveness when systematically analysed. To allay this methodological problem, I will break it down into:

• Exercise therapy
• Manual therapy
• I wish I could include education here – but not enough evidence in frozen shoulder

In order to keep this review somewhat brief (hopefully no more than a 10-minute read), I will focus on what I think are the big-ticket bits of evidence that could influence your Rx of FS.

If you talk to any orthopaedic surgeon (well most anyway) they will often say physical therapy is largely ineffective for FS. Physical therapy got a bad name in the Mx of FS due to THIS study published in 2004, which categorically states intensive physical therapy was WORSE for FS Mx compared to “supervised neglect” (patient doing exercises unsupervised at home with an occasional check-in from physio) (Image 1). Looking back at this study, it is actually quite fascinating. The 2 groups were:

1. Intensive physical therapy (heavy GHJ mobilisations and stretching for 2 years)
2. Independent completion of AROM exercises within pain limits and education of the pathology and encouragement to remain active and participate in sport/leisure as able.

In analysing this methodology, it is no surprise to me that group 2 (supervised neglect) performed better. This is how we should manage most people with a chronic illness or pain presentation. Basically, this group received:

• Reassurance and education that often the pain and pathology of FS will improve over time (may not fully resolve, though)
• Encouragement to remain active and participate in social or leisure-based activities (i.e. don’t catastrophise and continue living)
• Enhancement of self-efficacy through a judicious independent performance of HEP
• Reduced hyper-vigilance risk due to not talking about their pain or limitations several times a week for 2 years!

The intensive physical therapy group may have become reliant on passive care (reduced self-efficacy), hyper-vigilant about pain and dysfunction, and had their pain/symptom complex provoked and irritated by frequent painful exercise or treatment. 15 years later, I think we have learnt our lesson from this. I HOPE physiotherapy has progressed and we can recognise that over-treating can take away a person's internal locus of control.

I will qualify this statement; don’t forget the individual in these studies. You need to treat the individual in front of you while doing your best to apply the available evidence. A specific person may require a tailored regime based on their unique personality profile, beliefs, cognitions, compliance likelihood, tissue irritability etc. In many cases, people may derive great benefit in visiting a physio/osteo/chiro weekly for support and guidance (just don’t build up a dependency).

Another thing about this famous paper – it was very poorly executed with a high risk of bias:

• No allocation concealment was described
• No description of the randomisation process
• No blinding of assessors
• Unequal distribution of men and women

Remember this when interpreting this study.

What's the evidence for physical therapy?

Ok, now that study is out of the way, let’s move on to exercise therapy. This is my intervention of choice for FS (who would have thought). Y tho? What's the evidence? Admittedly, it’s shaky, as with everything else for the Mx of FS. A Cochrane review (here) suggests that exercise in combination with manual therapy is likely no better than an intra-articular corticosteroid injection. However, exercise therapy may provide improvements in ROM and patient-reported success compared to an injection.

Specific strengthening for frozen shoulder has recently been shown to be effective compared to a control group (here). In this randomised controlled trial, a pretty basic rotator cuff strength regime involving both isotonic and isometric exercise was performed in addition to some manual therapy and TENS. This was compared to just a manual therapy and TENS group. No surprise to me that the results significantly favoured the active strengthening group for: pain, ROM and function. Was it the improvements in strength that helped or the ACT OF STRENGTHENING? Probably a combo of both, but there are many non-specific positive effects of strengthening, loading, and moving generally. I will blog about this at some point.

My favourite study looking at exercise in the frozen shoulder is this study by Russell et al 2014 (read this here). Essentially, it compared supervised exercise in a group VS independent home exercise VS individual physiotherapy. The group who performed the best was comprehensively those who performed supervised exercise in a group setting (Image 2). The intriguing part of this study was the improvements on anxiety and depression scores in the supervised exercise group. This correlated nicely with reductions in pain and improvements in function. What does this mean? My hypothesis is that exercise in a group setting promotes social belonging and inclusion, reduction of fear-avoidance due to peer support (and maybe competition!), more accountability and compliance due to not wanting to let down others (?), and all the positive non-specific effects of exercise, such as the release of endorphins etc. All of these factors can attenuate feelings of depression and anxiety and we know these psychological conditions are associated with persistent pain.

This is a nice study by Lamplot et al 2018 (here) showing significant improvements in outcomes for FS with an initial intra-articular corticosteroid injection followed by supervised PT (ROM, strength, and education). The supervised PT element of the regime was able to radically reduce the need for a 2nd injection compared to those who did not attend PT. Important note: there was no control group for this study, so interpret with caution.

Manual therapy...

Manual therapy, the indomitable and always controversial, manual therapy. Tribalism has a firm grasp on this vague term and it seems you are either avidly for or against it. My political answer lies somewhere in the murkiness between the black and white or good and bad. I think “touch” has real value in treating people who present to you in pain. It can offer support or comfort BUT it does not correct or relocate tissue/joints. It is well beyond the scope of this lit review to go down the rabbit hole of manual therapy and it’s possible mechanism of action, but here is an article you can read if wanting to know more (Bialosky et al 2009).

What about in FS? The jury is out. Manual therapy could be mobilisations, soft tissue techniques (pick your poison here), dry needling etc. Much of the evidence pertains to GHJ mobilisations.

Mobilisations are shown to be effective in the Mx of FS. BUT probably no more than any other intervention (exercise therapy or injection) (here). Studies have shown improvement in high and low-grade mobilizations of the GHJ with a trend favouring the high-grade mobilisations (here). Note, again there was no control group, so impossible to say improvement wasn’t just natural history.

Common sense interpretation: manual therapy may be effective in reducing the sensitivity of the painful area, may help therapeutic alliance, and may reduce threat etc. It should not be used as a stand-alone treatment and should be performed only in the context of exercise and education being the main pillars of management. Whether you choose high or low-grade mobilisations or massage or whatever, please consider the individual person’s expectations, beliefs and tissue irritability in your selection process.

Injection therapy

I will refer to 3 types of injections:

1. Hydrodilatation (cocktail of cortisone, saline and anaesthetic) (up to 40mL) delivered intra-articularly using CT scan guidance
2. Low volume intra-articular corticosteroid injection (typically 10mL)
3. Subacromial injection (the ol’ classic)

Is there a magic injection? Is there a timeframe when one is more appropriate than the other? For example, when pain is greater than stiffness is a low volume injection better, and if stiffness is greater than pain is a hydrodilatation indicated?

This review will focus on 5 high quality papers (briefly).

Paper 1 is by Sun et al 2016. This systematic review and meta-analysis concluded an intra-articular steroid injection is effective in relieving pain, increasing ROM and improving function. A negative component of this study there wasn’t any delineation between type of injection (dose) or investigation into what stage of FS a particular injection should be used over another (low volume Vs high volume).

Next, is an RCT by Yoon et al 2016. This study compared 3 groups; group 1 was an intra-articular injection (low volume), group 2 was a subacromial injection, and group 3 was a hydrodilatation injection. All 3 injection groups improved similarly at 6 months follow-up, but the hydrodilatation injection method resulted in quicker improvements in all measures at 1- and 3-month follow-ups. This is interesting, I strongly think a patient will be in favour of the quicker improvement, even though it may normalise at 6 months? Certainly, in my experience (anecdotal, I know), this is the case.

Paper 3 is an RCT by Sharma et al 2016. This study had 3 groups again; group 1 was intra-articular steroid injection, group 2 was hydrodilatation, and group 3 was treatment as usual (physio etc.). Both the injection groups improved similarly, with significant improvements occurring in the first 8-12 weeks. The positive effects plateaued thereafter. Both injection groups significantly out-performed physio in the short term, but this effect was lost after a few months, with no differences found between all 3 groups after 1 year (Image 3). Take home summary, injections helped in short term (both high volume and low volume) but were no better than usual care at 12 months follow up. This means we don't have to harass people to pursue an injection if they are reluctant, which seems fair. ;)

Next, Robinson et al 2017 has published a controversial paper (for us anyway) looking at the management after a hydrodilatation injection, comparing supervised physiotherapy Vs an independent home exercise program. The supervised physiotherapy group received manual therapy, mobilisations, exercise therapy etc. At all points in follow-up there were no differences between the groups after injection, meaning independent completion of a HEP was equal to physiotherapy after a hydrodilatation injection (Image 4). Interesting finding. My interpretation is that most people can independently complete a HEP and do quite well after a hydrodilatation, but there will be some (typically with influential psychosocial factors) that may require continued support after an injection. Again, treat the individual, not the group.

Despite some good evidence emerging for hydrodilatation, it's far from a panacea! This systematic review and meta-analysis (here) suggests it has a small, clinically insignificant effect when treating frozen shoulder when results are compiled collectively. Of note, the NNT (number needed to treat) is 12 (!) for a single person to have a beneficial result greater than a control! There also appears to be a weak association between the amount of fluid injected and correlate functional improvement.

However, given frozen shoulder is a persistent and disabling condition that greatly affects quality of life, and does not consistently spontaneously resolve by itself in a certain time period, we must do something. At this stage, it appears an injection followed by some form of exercise therapy has the best evidence.

Conclusion

There we have it, the 3-part FS series is complete. The evidence behind treatment is somewhat conflicting, but at the same time fairly logical. It appears that an injection helps significantly in the short term, less so in the long term. A hydrodilatation injection may provide quicker relief in the short term compared to other injection types. Although, hydrodilatation does have it's limitations. In the future, studies should look at what stage the person with FS is in, for example, is pain greater than stiffness, or is stiffness greater than pain? This may shed light on what injection type is appropriate. Exercise therapy in a group looks promising, mainly because it helps anxiety and depression scores which can negatively impact pain. Manual therapy is murky (surprise), it may help and it may not, although it definitely should never be a stand-alone treatment! As always, education, reassurance, and encouragement to continue engagement in social and values-based activity, as well as exercise, are the main pillars of Mx of any persistent pain presentation, and FS is certainly no different.