Corticosteroid Injections Give Small and Transient Pain Relief in Rotator Cuff Tendinosis: A Meta-analysis

updated Jul 6, 2017

Tags: injections, bad news, tendinosis, shoulder, medicine, treatment, pain problems, overuse injury, injury, head/neck

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Do steroid injections reduce the pain of rotator cuff tendinosis? How many people do you have to inject to get a good result? Does more than one injection help? This review sought the answers in eleven mostly small studies of 700 patients (including three studies that included multiple injections). The answers were disappointing, other than confirmation of minor temporary pain relief. There was there was no effect for most patients at three months, multiple injections made no difference, and five patients need to be treated to get good results for one. The conclusion of the study is an articulate indictment:

Corticosteroid injections provide—at best—minimal transient pain relief in a small number of patients with rotator cuff tendinosis and cannot modify the natural course of the disease. Given the discomfort, cost, and potential to accelerate tendon degeneration associated with corticosteroids, they have limited appeal. Their wide use may be attributable to habit, underappreciation of the placebo effect, incentive to satisfy rather than discuss a patient's drive toward physical intervention, or for remuneration, rather than their utility.

original abstract†Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

BACKGROUND: The ability of injection of corticosteroids into the subacromial space to relieve pain ascribed to rotator cuff tendinosis is debated. The number of patients who have an injection before one gets relief beyond what a placebo provides is uncertain.

QUESTIONS/PURPOSES: We asked: (1) Do corticosteroid injections reduce pain in patients with rotator cuff tendinosis 3 months after injection, and if so, what is the number needed to treat (NNT)? (2) Are multiple injections better than one single injection with respect to pain reduction at 3 months?

METHODS: We systematically searched seven electronic databases for randomized controlled trials of corticosteroid injection for rotator cuff tendinosis compared with a placebo injection. Eligible studies had at least 10 adults and used pain intensity as an outcome measure. The Hedges's g as adjusted pooled standardized mean difference (SMD) (which expresses the size of the intervention effect in each study relative to the total variability observed among pooled studies) and NNT were calculated at assessment points less than 1 month, 1-2 months, and 2-3 months. The protocol of this study was registered at the international prospective register of systematic reviews. Eleven studies of 726 patients satisfied our criteria for data pooling. Three studies containing 292 patients used repeat injections. A random effects model was used owing to substantial heterogeneity among studies. The funnel plot indicated the possibility of some missing studies, but Orwin's fail-safe N and Duval and Tweedie's trim and fill suggested that missing studies would not significantly affect the results.

RESULTS: Corticosteroid injection did not reduce pain intensity in adult patients with rotator cuff tendinosis more than a placebo injection at the 3-month assessment. A small transient pain relief occurred at the assessment between 4 and 8 weeks with a SMD of 0.52 (range, 0.27-0.78) (p < 0.001). At least five patients must be treated for one patient's pain to be transiently reduced to no more than mild. Multiple injections were not found to be more effective than a single injection at any time.

CONCLUSIONS: Corticosteroid injections provide-at best-minimal transient pain relief in a small number of patients with rotator cuff tendinosis and cannot modify the natural course of the disease. Given the discomfort, cost, and potential to accelerate tendon degeneration associated with corticosteroids, they have limited appeal. Their wide use may be attributable to habit, underappreciation of the placebo effect, incentive to satisfy rather than discuss a patient's drive toward physical intervention, or for remuneration, rather than their utility.

LEVEL OF EVIDENCE: Level I, therapeutic study.

original abstract†Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

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