Surgery for shoulder impingement: a systematic review and meta-analysis of controlled clinical trials

Background: Shoulder impingement is one of the most common nontraumatic upper limb causes of disability in adults. Our aim was to evaluate the efficacy of surgical intervention in comparison with nonoperative or sham treatments in patients with shoulder impingement in terms of both pain and functional outcomes.

Methods: We conducted a systematic review and meta-analysis of randomized controlled trials. Two reviewers independently screened MEDLINE, Embase, PubMed and Cochrane databases for randomized controlled trials published from 1946 to July 19, 2018. A risk-of-bias assessment was conducted for all included studies, and outcomes were pooled using a random effects model. The primary outcome was improvement in pain up to 2 years. Secondary outcomes were functional outcome scores reported in the short term (≤ 1 yr) and long term (≥ 2 yr). Heterogeneity was assessed using the I² statistic. Functional outcome scores were presented along with minimal clinically important differences to provide clinical context for findings.

Results: Thirteen randomized controlled trials (n = 1062 patients) were included in this review. Eligible patients had a mean age of 48 (standard deviation ± 4) years and 45% were men. The pooled treatment effect of surgical intervention for shoulder impingement did not demonstrate any benefit to surgery with respect to pain relief (mean difference −0.07, 95% CI −0.40 to 0.26) or short-term functional outcomes (standardized mean difference −0.09, 95% confidence interval [CI] −0.27 to 0.08). Surgical intervention did result in a small statistically significant but clinically unimportant improvement in long-term functional outcomes (standardized mean difference 0.23, 95% CI 0.06 to 0.41).

Interpretation: Evidence suggests surgical intervention has little, if any, benefit for impingement pathology in the middle-aged patient. Further research is required to identify those patients who will reliably benefit from surgical intervention as well as optimal conservative treatment strategies.