The Finnish Shoulder Impingement Arthroscopy Controlled Trial (FIMPACT) compared surgical treatment of shoulder impingement syndrome to placebo surgery. Two years after the procedure the study participants, both those in the group who underwent surgery and the ones in the placebo group, had equally little shoulder pain and were equally satisfied with the overall situation of their shoulder.
The most common diagnosis for shoulder pain that requires treatment is shoulder impingement, and the most common surgical treatment is decompression through keyhole surgery. nearly 21,000 decompression surgeries done in UK every year, and ten times that many in the United States.
— source helsinki.fi