Scoping the shoulder (arthroscopy) for an impingement syndrome is responsible for up to 70% of all shoulder problems.
A study in the past showed that the scientific clinical evidence in favor of this type of shoulder surgery is scarce.
This study compared performing the real surgery against a fake/placebo surgery. They found that the differences were small and not clinically important.
The authors stated that the findings send a strong message that the burden of proof now rests on those who wish to defend the standpoint that shoulder arthroscopy is more effective than non-surgical interventions.