A 2017 meta-analysis confirmed that there is only a very small and usually unimportant reduction in pain and improvement in function at 3 months (e.g. an average pain reduction of approximately 5 on a scale from 0 to 100). A separate review found that most people would consider a reduction in pain of approximately 12 on the same 0 to 100 scale important—suggesting that for most people, the pain reduction at 3 months is not important. Arthroscopy did not reduce pain or improve function or quality of life at one year. There are important adverse effects.