Cortisone injections are very popular in musculoskeletal medicine for all types of conditions. Specifically at the shoulder, sub-acromial bursa injections are frequent for the management of rotator cuff related shoulder pain/sub-acromial pain syndrome, but what is their effect?
This meta-analysis suggests the results are hit and miss. After 3 months there is no difference between a corticosteroid injection (CSI) and a placebo injection. 1 out of every 5 people who receive a CSI will experience a slight and transient relief of pain that will not be apparent at the 3 month mark.
DISCLAIMER! Anecdotally (in my experience) I have seen CSI offer significant relief of pain and as a result greater shoulder function. However, I have also seen them do nothing and occasionally worsen people due to the pain and irritation associated with having the intervention. So what do we do?
A logical and reasoned approach would be to commence a conservative exercise regime and if after at least 6 weeks there are no signs of improvement (despite dilligently performing an exercise program - the right exercises too!) then a conversation could be had about the efficacy of a CSI. In this case we also have to consider the biological implications of corticosteroid on human tissue - can actually inhibit healing due to disruption of collagen deposition. The injection is in no way fixing any pathology, it is merely a potent directed anti-inflammatory intervention. Does it improve strength or tissue tolerance? Does it provide education on appropriate tissue loading? Does it result in better outcomes long term? NO NO NO.
In summary, CSI are still in widespread use for the treatment of rotator cuff related shoulder pain (sub-acromial pain syndrome/sub-acromial impingement). Their effectiveness appears to be short term and sporadic. Should be used after failure of a proper conservative strengthening/loading regime of at least 6 weeks. Education must then be given that rehabilitation is still required after injection.