Research: cortisone injection for shoulder complaints

Geschatte leestijd: 6 minuten A corticosteroid injection (such as cortisone) is a popular treatment for some shoulder complaints. But does such an injection actually make sense or do you just cause more harm?

A cortisone injection for shoulder complaints

I have briefly mentioned this topic in a general article about tendon inflammations. In that, I mentioned a study that compared the effects of a cortisone injection and manual therapy in the short and long term. I described (part of) the conclusion as follows:

It has been shown that although recovery is faster in the short term with an injection, a year later, people who received an injection were much more likely to experience complaints again than those who received physiotherapy or even did nothing!

However, that article is almost 5 years old now and apparently, I did not provide a reference for the study (shame on me!!). Given the high frequency of shoulder complaints and the questions about it, I found it important to look up that study again to check my conclusion. In addition, I wanted to know if I had missed earlier studies and if there have been new studies conducted on this topic. Finally, I now especially want to look at the studies on injections for shoulder complaints and not tendons in general.

Corticosteroid injection vs manual therapy and physiotherapy

The oldest study I found is from Dutch soil in 1997. Researchers from the University of Groningen compared the effects of a cortisone injection, manual therapy, or physiotherapy in people with shoulder complaints [1]. The participants were people who had reported to 7 different Dutch clinics with complaints. Initial treatments were with normal painkillers and non-steroidal anti-inflammatory drugs (NSAIDs). Think of diclofenac or ibuprofen for the latter. Only when this did not lead to relief, the participants were divided into three groups with different treatment methods. These were:

• One to three corticosteroid injections (1 ml or 40 mg/ml triamcinolone acetonide in combination with 9 ml or 10 mg/ml lignocaine). The second and third injections followed optionally after 2 and 3 weeks if there was still no decrease in complaints.
• Physiotherapy. Given twice a week by local physiotherapists. They were instructed to perform ‘classical physiotherapy’. Think of rehabilitative exercises and massage.
• Manual therapy/manipulation: Mobilizing and manipulating (middle and top of the) spine, upper ribs, AC joint (connection between shoulder blade and collarbone), and the shoulder joint itself. This happened once a week, for a maximum of six sessions.

“Corticosteroid injection in shoulder fastest in the short term”

Participants filled out a questionnaire every week regarding their pain complaints. After two, six, and eleven weeks, a physiotherapist visited for an evaluation. If clients indicated they were ‘cured’, further treatment was stopped. In the image next to it, you can see the effects over a period of 11 weeks. In it, we confirm what was mentioned in the earlier article about tendon inflammations: Corticosteroids provide the fastest relief of pain complaints. Incidentally, the researchers refer to earlier studies that did not see an effect of the corticosteroid injection. They think this is because they followed a previously tested protocol of injections (injecting in three vulnerable areas in the shoulder).

“Difference between Corticosteroid Injection or Physiotherapy for shoulder in the long term is small”

A year later, a comparison was made again between different treatment methods for shoulder complaints. Again from Dutch soil. This time, however, from the VU University Amsterdam [2]. A more important difference: Now they looked longer at the effect, namely after 3, 7, 13, 26, and 52 weeks. Now only a comparison was made between the injection (40 mg triamcinolone acetonide) and physiotherapy. After 7 weeks, the injection was successful in 77% of the patients. In physiotherapy, this was only 46%. Seven weeks was also the moment when these differences were greatest. After 26 and 52 weeks, these were a lot smaller as seen in the table (‘table 3’). They concluded that a corticosteroid injection is more effective than physiotherapy because it leads to faster relief of pain complaints. British researchers shared the conclusion that the differences were small in the long term, but also saw a slightly larger effect in the group that had received an injection after a year [4].

“No difference in long-term corticosteroid injection or physiotherapy for shoulder”

Fast forward to 2016 when researchers from Stellenbosch University in South Africa conducted a systemic review. They compared the outcomes of the various studies that had looked at the different effects of a corticosteroid injection and physiotherapy until then [3]. In addition to the just discussed study from 1998, they also looked at the outcomes of two studies from 2003 and 2014 [4,5]. Both came to a similar conclusion: Both the injection and physiotherapy are effective in the long term (respectively 6 months and a year), but people who received the injection reported complaints more often during that time.

“Corticosteroid injection only effective in the short term, not in the long term”

But maybe we shouldn’t compare the injection with physiotherapy (or manual therapy) at all. Firstly because then you don’t have a control group that received no treatment at all. The decrease in complaints after a year may simply have been a result of time and not of the treatment. In 2016, another systemic review was conducted, but this time comparing a corticosteroid injection, an injection with an anesthetic, and an injection with a saline solution (placebo). Unfortunately, this only looked at the effect up to three months. Still, that provided a remarkable insight. After two months, a clear advantage for the corticosteroids was still seen. After three months, however, there was no significant difference with the control groups.

Corticosteroids catabolic

But all these studies mainly looked at pain complaints and mobility, not at the specific state of the muscle attachments. Cortisone works catabolically and can convert muscle proteins into glucose for energy [7]. In 2014, a systemic review compared studies on the effect of glucocorticoids, corticosteroids with an effect on glucose metabolism. Cortisone belongs to this class. Their conclusion was clear. It reduces the amount of collagen in tendons by reducing production and increasing breakdown.

Overall it is clear that the local administration of glucocorticoid has significant negative effects on tendon cells in vitro, including reduced cell viability, cell proliferation and collagen synthesis. There is increased collagen disorganization and necrosis as shown by in vivo studies. The mechanical properties of tendon are also significantly reduced. This review supports the emerging clinical evidence that shows significant long-term harms to tendon tissue and cells associated with glucocorticoid injections.

The statement in the introduction that corticosteroids can lead to a worse result in the long term is based on a review of 41 studies from 2010 [9]. However, some nuance must be brought to this. That research not only looked at shoulder complaints, but also other well-known complaints due to tendons: A painful Achilles tendon and tennis elbow. In the shoulders and Achilles tendon, they concluded, the evidence for long-term effects was “small and conflicting”. Regarding the elbow, it worked the other way around and after a year, there were more complaints than when nothing had been done or physiotherapy had been applied.

Conclusion

When it comes specifically to the shoulder, it is unclear what the added value is in the long term of a corticosteroid injection. In the short term, it seems convincing that it can relieve pain complaints faster. For the serious athlete who wants to continue enjoying his sport for a long time, caution might be the wisest choice. ‘If it doesn’t help, it won’t hurt’ is not something I would dare say here. Personally, if I have shoulder complaints, I would rather seek my salvation in physiotherapy or manual therapy, possibly supplemented with non-(cortico)steroidal painkillers.

Sources

1. Winters JC, Sobel JS, Groenier KH, Arendzen HJ, Meyboom-de Jong B. Comparison of physiotherapy, manipulation, and corticosteroid injection for treating shoulder complaints in general practice: randomised, single blind study. BMJ. 1997 May 3;314(7090):1320-5. PubMed PMID: 9158469; PubMed Central PMCID: PMC2126546.
2. Effectiveness of corticosteroid injections versus physiotherapy for treatment of painful stiff shoulder in primary care: randomised trial. BMJ. 1998 Nov 7;317(7168):1292-6. PubMed PMID: 9804720; PubMed Central PMCID: PMC28713.
3. Burger M, Africa C, Droomer K, et al. Effect of corticosteroid injections versus physiotherapy on pain, shoulder range of motion and shoulder function in patients with subacromial impingement syndrome: A systematic review and meta-analysis. S Afr J Physiother. 2016;72(1):318. Published 2016 Sep 27. doi:10.4102/sajp.v72i1.318
4. Hay EM, Thomas E, Paterson SM, Dziedzic K, Croft PR. A pragmatic randomised controlled trial of local corticosteroid injection and physiotherapy for the treatment of new episodes of unilateral shoulder pain in primary care. Ann Rheum Dis. 2003 May;62(5):394-9. PubMed PMID: 12695148; PubMed Central PMCID: PMC1754522.
5. One-year outcome of subacromial corticosteroid injection compared with manual physical therapy for the management of the unilateral shoulder impingement syndrome: a pragmatic randomized trial. Rhon DI, Boyles RB, Cleland JA Ann Intern Med. 2014 Aug 5; 161(3):161-9.
6. Mohamadi A, Chan JJ, Claessen FM, et al. Corticosteroid injections give small and transient pain relief in rotator cuff tendinosis: a meta-analysis. Clin Orthop Relat Res. 2016. [Epub ahead of print, 28 July 2016].
7. Goldberg AL, Goodman HM. Relationship between cortisone and muscle work in determining muscle size. J Physiol. 1969;200(3):667-75.
8. The risks and benefits of glucocorticoid treatment for tendinopathy: A systematic review of the effects of local glucocorticoid on tendon Author links open overlay panelBenjamin John FloydDean, EmilieLostis, ThomasOakley, InesRombach, Mark E.Morrey, Andrew J.CarrFRCS
9. Efficacy and safety of corticosteroid injections and other injections for management of tendinopathy: a systematic review of randomised controlled trials. Brooke K Coombes, MPhty, Leanne Bisset, PhD, Prof Bill Vicenzino, PhD Published:October 22, 2010
10. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)61160-9/fulltext