Garret Richards and Andrew Heaney of the Angels both tore elbow ligaments last season, and both underwent stem cell treatment to try to repair the injury. It appears to have worked for Richards, but not for Heaney:

Even with less-favorable odds than reconstructive surgery, which has an 80% success rate for returning to action and 67% for pitching 10 games or more, stem cell therapy is gaining acceptance as an option for pitchers with partial UCL tears. The recovery time is shorter – 3-5 months instead of 12-18 – and the treatment less invasive.

There are limitations. Biological approaches based on stem cells or platelet-rich plasma (PRP) won’t repair a complete tear of the ligament. The location of the injury and its extent factor into the chances of success. And players whose ligament doesn’t recover, then have to undergo surgery, extend their window of time for returning to action.

So the expected recovery time is four months versus 15 months. So if all partial tears undergo stem cell treatment, the average man months lost would be 11 versus 15 for every going under the knife. I suspect as time goes on, doctors will better predict which tears respond better to cells, and which need surgery.

I also wonder if pitchers might opt for early stem cell treatment as a preventive measure. Could a stem cell injection every two years keep the ligament healthy, fixing micro tears that eventually become bigger? Maybe that’s the way to greatly eliminate the injury.