STANFORD (KPIX 5) — A groundbreaking clinical trial is now underway at Stanford Medical Center targeting people with injured knees, using the patients’ own stem cells to regenerate cartilage.

KPIX 5 spoke to two of the patients participating in the trial. Al Perez is a private investigator who operates out of Martinez. He depends on his knees.

“You want to be able to do the things you like to do,” he explained.

Erik Eastman is a math teacher at San Jose High School. He too depends on his knees. He played football, soccer, and hockey.

“Sports is one of the biggest things in my whole life,” said Eastman.

As the two men go about their day, it’s hard to believe they had bad knees.

“I started having problems with my left knee, which I came to find out that I had moderate arthritis.” said Perez.

“I had surgery five years ago and I’ve had surgery 11 years ago,” recounted Eastman.

The culprit: cartilage. The knee’s shock absorber was damaged in both men.

Whether you’re a pro athlete or a weekend warrior, a nick, tear or breakdown in cartilage can be debilitating and painful – and knee problems are common.

That’s why both Perez and Eastman underwent an experimental procedure at Stanford Medical Center.

“The procedure takes about an hour, it’s outpatient surgery,” explained Stanford orthopedic surgeon Dr. Jason Dragoo, who runs the clinical trial.

Dragoo and his team are testing the what could be the future of knee repair, using adult stem cells harvested from the patient’s own body.

“This is tapping into the regenerative potential that everyone has.” said Dragoo.

Under the right conditions, adult stem cells can transform into cartilage. The hope is that new cartilage will grow and fix the problem.

“I wanted to avoid another knee replacement,” said Perez.

The cells are found in a fat pad, located in the knee.

“It’s a nice way to take advantage of what our bodies have to offer,” said Eastman.

“Regardless of how thin or not we are, we always have a fat pad which is this resource of cells within everyone’s knees,” explained Dragoo.

Using small incisions and minimally invasive tools, the surgeons harvest the fat. Then, using a special technique the fat is broken up and the stem cells are released.

The mix then goes into a special device and when it comes out, the stem cells are concentrated at the top and bottom of the tube. The cells are immediately injected back into the patients knee.

“They never leave the operating room and that breaks down a lot of other barriers.” said Dragoo. “Less chance of infection.”

Lab research shows it works. The cells can turn into initial stem cells beginning in about six weeks. “This is not a science experiment,” said Dragoo. “This is actual medicine.”

Everyone in the trial undergoes traditional knee repair, while two-thirds get the stem cells. Doctors will track cartilage growth using an MRI.

Perez and Eastman won’t find out if they got stem cells until after the trial. But they feel good. In fact, Perez sent KPIX 5 a video of him waterskiing during his Florida vacati0n.

“So far I’ve been able to water ski a little bit, I’ve been able to play golf, walk 18 holes without any residual effects,” said Perez. “So far so good!”

“By the time I’m 65 I want it to be my choice whether I play hockey, not my body’s choice,” surmised Eastman.

The trial is still recruiting patients for two different conditions: osteoarthritis and articular cartilage defects.