He reported in Feb 2011 that he has had pain on & off throughout the years on his left knee. At this time, it was a Report only... there was no time missed. There was no incident or accident to this. This was faxed to MSHA Denver on 5/27/11 -- 888-231-5515 On May 23, 11 -- he did have surgery on his left knee. 5/26/11 was his first shift missed