BOSTON -- Tendon and ligament sprains and strains are among those most common and the most difficult-to-treat injuries. But a new treatment may change how fast patients heal by using their own blood, television station WCVB reported.

Elif Sachs suffered an injury in her back.

"There was like a 'crack,' and Monday morning I couldn't walk," she said.

The world-class fencer endured severe lower back pain for more than a year before doctors correctly diagnosed the source.

"I was just depressed, and in pain all the time," said Sachs. "I couldn't compete in Division 1 events anymore."

Sharon Caw is a more typical baby boomer, but like Sachs, she struggled with debilitating knee pain. "I really couldn't walk more than five minutes, and I was using crutches," she said. "They suggested total knee replacement, which shocked me."

Now rehabilitation specialists are discovering that a fix for a laundry list of ailments might be simple, affordable and safe.

In a treatment known as PRP -- or platelet rich plasma therapy -- doctors draw a little of the patient's own blood, then spin it in a centrifuge to separate the platelets. Just a teaspoon of the concentrated, healing cells is then injected into the site of the injury.

"Once those healing cells are in there," said Dr. Joanne Borg-Stein, of Spaulding Rehabilitation Hospital, "they start making whatever the connective tissue is, the tendon, or the ligament, and they start secreting more chemicals that tell the body, 'OK, it's time to start making these tendon and ligament structures again.'"

Patients say the procedure itself can be very uncomfortable. There is often bruising and swelling at the site of the injection, but within days or weeks, chronic painful ligament, tendon and muscle injuries disappear.

"The pain started going away. So where I was at, like 70 or 80 percent of my limit for pain, it went down to 30 percent, and that's huge," said Sachs.

Two members of the Pittsburgh Steelers had platelet rich plasma therapy before the 2009 Super Bowl. Doctors said a single treatment can help professional athletes heal three times faster than normal, returning them to competition sooner.

But PRP's potential for the vast majority of baby boomers and weekend warrior-type athletes may forever change rehabilitation medicine.

"I've been in practice for 20 years and this is definitely the most exciting thing that has happened," said Borg-Stein.

"I'm not using crutches, I'm not using the cane, I'm not using a knee brace, and I'm not taking daily pain meds," said Caw. "I'm just amazed at the result."

Borg-Stein said PRP has been used on only a small number of patients. Doctors are eager for long-term studies, but said that because a patient's own blood is used, it's generally considered safe and there is a low risk of rejection.

The cost or PRP at Spaulding Rehabilitation Hospital is about $500. The therapy is not currently covered by health insurance.