This summary of a Cochrane review presents what we know from research on whether using images (e.g. ultrasound) to guide injections into specific sites in the shoulder improves outcomes (e.g., pain, function) compared to no images in patients with shoulder pain.
This review shows that in people with shoulder pain who are treated with a glucocorticoid injection:
- Placing an injection into the shoulder guided by ultrasound imaging may not improve pain or function any more than placing the injection into the shoulder without ultrasound ('blind' injection) or placing the injection into the buttock muscles.
- Success, as assessed by the participant was not reported.
- Ultrasound-guided injection into the sore shoulder may not result in any more adverse events (such as facial redness, warmth, post-injection pain) compared with blind injection into the sore shoulder or injection into the buttocks.
What are the common causes of shoulder pain and what are glucocorticoid injections?
Shoulder pain is most commonly caused by rotator cuff disease. The rotator cuff is a group of tendons that contribute to hold the shoulder joint in place. The rotator cuff helps people lift their arm and reach overhead. In a lot of people, wear and tear of the rotator cuff tendons is a normal part of ageing and they may not have symptoms. However many people will develop pain in their shoulder at some time as the tendons degenerate further and tears in the rotator cuff tendons develop. There may also be inflammation of the shoulder tendons or bursa (another part of the shoulder that helps it move). Often the pain is made worse by sleeping on the affected shoulder and moving the shoulder in certain directions. Often there will be pressure on the tendons by the overlying bone when lifting the arm up. This is called impingement. It may become difficult to use the shoulder in every day activities, sports or work.
Adhesive capsulitis (also called frozen shoulder, stiff painful shoulder or periarthritis) is also a common cause of shoulder pain and stiffness. It is believed to be due to inflammation in the lining of the joint of unknown cause. As well as being painful, adhesive capsulitis also tends to cause stiffness in the shoulder resulting in pain and difficulties moving the arm in all directions. The pain and stiffness in the shoulder can last up to 2 to 3 years before going away but in the early stages it can be very painful.
Glucocorticoids injections are known to relieve shoulder pain but their effect usually wears off after six to eight weeks. Traditionally, a doctor uses anatomic landmarks around the shoulder to guide the injection into the desired location around the shoulder depending upon the cause. The injection can be placed in the shoulder joint or in locations around the shoulder such as the space under the acromion above the top of the humerus and the doctor can approach the patient from the front, side or back.
Sometimes imaging techniques, such as ultrasound are used to more accurately guide the injections into the specific sore part of the shoulder, but it is not known if image-guided injection relieves the symptoms of shoulder pain more effectively than if the injection was delivered 'blind', i.e., without imaging, either into the same location in the shoulder, or even injected into muscle away from the shoulder (e.g., into the buttocks muscle).
Best estimate of what happens to people who have image-guided injection compared with those who have an injection without imaging:
Pain (higher scores mean worse pain):
People who had image-guided injection rated their pain 0.2 points better on a 1 to 9 point scale (ranging from 0.1 points better to 0.07 points worse) 2 weeks after treatment (2% absolute improvement, ranging from 11% improvement to 7% worsening); and 0.6 points better (ranging from 1 point better to 0.24 points worse) 6 weeks after treatment (7% improvement (ranging from 16% improvement to 3% worsening).
Function (lower scores mean better function or less disability):
People who had image-guided injection rated their function 4 points worse on a 0 to 100 point scale (ranging from 13 points worse to 5 points better) at 2 weeks after treatment (4% worsening, ranging from 13% worsening to 5% improvement); and 3 points better (ranging from 11 points better to 5 points worse) 6 weeks after treatment (3% improvement, ranging from 11% improvement to 5% worsening).
- 6 fewer people out of 100 had minor side effects such as transient pain at the site of the injection or facial flushing with image-guided injection (6% absolute improvement, ranging from 16% improvement to 2% worsening).
- 9 people out of 100 had minor side effects with image-guided injection.
- 15 people out of 100 had minor side effects with injection without imaging.
Based upon moderate evidence from five trials, our review was unable to establish any advantage in terms of pain, function, shoulder range of motion or safety, of ultrasound-guided glucocorticoid injection for shoulder disorders over either landmark-guided or intramuscular injection. The lack of any added benefit of ultrasound guided subacromial bursal injection over glucocorticoid injection administered into the upper gluteal muscles of the buttock suggests that the benefits of glucocorticoid may arise through systemic rather than local effects. Therefore, although ultrasound guidance may improve the accuracy of injection to the putative site of pathology in the shoulder, it is not clear that this improves its efficacy to justify the significant added cost.
Traditionally, glucocorticoid injection for the treatment of shoulder pain has been performed guided by anatomical landmarks alone. With the advent of readily available imaging tools such as ultrasound, image-guided injections have increasingly become accepted into routine care. While there is some evidence that the use of imaging improves accuracy, it is unclear from current evidence whether or not it improves patient-relevant outcomes.
The aim of this review was to assess whether image-guided glucocorticoid injections improve patient-relevant outcomes compared to landmark-guided or systemic intramuscular injections in patients with shoulder pain.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL, via The Cochrane Library), MEDLINE (Ovid), and EMBASE (Ovid) to June 2011. We also searched the World Health Organisation International Clinical Trials Registry Platform (http://www.who.int/trialsearch/Default.aspx) to identify ongoing trials and screened reference lists of retrieved review articles and trials to identify potentially relevant studies.
We included randomised controlled trials (RCTs) and quasi-randomised controlled clinical trials that compared image-guided glucocorticoid injection to landmark-guided or systemic intramuscular injection. Outcomes of interest included pain, function, range of motion, proportion of participants with overall improvement and adverse events. There were no restrictions on language or date of publication.
Two review authors independently selected the studies for inclusion, extracted the data and performed a risk of bias assessment. Disagreement about inclusion or exclusion of individual studies and risk of bias was resolved by a third review author.
Five studies (290 participants) were included in the review. The image-guided groups in all trials used ultrasound to guide injection. Four studies included participants with rotator cuff disease; in three the comparator was local landmarks to direct injection into the subacromial bursa and in the fourth the comparator was systemic intramuscular injection into the upper gluteal muscles in the buttock region. One study included participants with adhesive capsulitis and injection was directed into the glenohumeral joint by either ultrasound or anatomical landmark guidance.
No significant differences between groups were observed with respect to reduction in pain at one to two weeks (two trials, 146 participants, standardized mean difference (SMD) -1.44, 95% CI -4.14 to 1.26), or function at one to two weeks (two trials, 146 participants, SMD 0.95, 95% confidence interval (CI) -1.29 to 3.20; back-translated to mean difference (MD) 4 points, 95% CI -5 to 13, on a 0 to 100 point scale, higher score means better function) or six weeks (three trials, 207 participants, SMD 0.63, 95% CI -0.06 to 1.33; back-translated to MD -3 points, 95% CI -11 to 5, on a 0 to 100 point scale) and the sensitivity analyses did not alter these results. While there was a significant difference between groups with respect to reduction in pain at six weeks favouring image guidance (three trials, 207 participants, SMD -0.80, 95% CI -1.46 to -0.14), there was considerable statistical heterogeneity and after removing trials with inadequate allocation concealment and inadequate blinding in a sensitivity analysis, the difference was no longer significant (one trial, 106 participants, MD -0.60 points, 95% CI -1.44 to 0.24 points on a 9-point scale).
No statistical difference in adverse events between groups was identified (10/104 image-guided group versus 16/103 comparator; risk ratio (RR) 0.55, 95% CI 0.17 to 1.85). Minor adverse events reported included transient post-injection pain, facial redness and warmth.