Jon Roegele has compiled lots of information about pro players having Tommy John surgery. Though the return to play rate is excellent, we really can’t tell how well these players pitched after their return from surgery. ERA/WHIP/innings pitched/FIP/BB, etc would help tell the story of how well these players actually do.
http://www.hardballtimes.com/an-analysis-of-available-tommy-john-surgery-data/