Rotator-cuff surgery seemed like Waddell’s last option. It would mean losing the use of his arms, and his ability to move on his own, for several months. And he worried that, if surgery failed, he would have to give up any strenuous physical activity. “Being able to ask a lot of my body makes me feel good,” he said. “It’s a lot of who I am.”

As Waddell considered his options, a friend suggested looking into a treatment known as platelet-rich plasma, in which doctors inject a modified version of the patient’s own blood into injured tissue. Eager to avoid surgery, Waddell flew to Washington, D.C., to see Victor Ibrahim, a sports-medicine doctor who specializes in P.R.P. Ibrahim found that Waddell had a torn rotator cuff in one shoulder and a torn biceps tendon in the other. Using ultrasound to locate the precise locations of the injuries, Ibrahim injected the tendon and rotator cuff with P.R.P. Over the course of a month, he repeated the procedure twice more.

In the weeks afterward, Waddell saw his strength improve and his pain decrease; he says he is now “close to one hundred per cent,” and is no longer thinking about surgery. “I was shocked that I kept getting better,” he said. “It had been so bad for so long.”

The outcome didn’t surprise Ibrahim, who estimates that he has treated around five thousand people with P.R.P. over the past five years. He says that the treatment can repair tendons, ligaments, cartilage, and nerves, and can even regrow tissue that has been frayed or damaged. This, he suspects, is what happened with Waddell’s rotator cuff. “For a lot of conditions, it’s almost a wonder drug,” Ibrahim told me. “We’ve figured out a way to help the body regenerate itself.” click here for full story