PITTSBURGH (KDKA) – Cindy McCoy’s knees were worn out: “I was falling constantly. I probably fell four or five times at work.”

She tried various injections, but the damage was too severe.

“It looked like shredded lobster,” she recalls her doctor saying to her. “You are really a serious candidate for a full knee. You are bone on bone.”

But she hesitated, because she was afraid. “The pain. Big baby I am, so that was the thing.”

Her surgeon was doing something new to minimize the pain after surgery — but two weeks before the operation.

It’s a shot — but not steroids or a gel or chicken goo, and not into the joint space.

Dr. Brian Moore. an orthopedic surgeon at Allgheny Health Network’s Forbes Hospital, describes the procedure: “We do a series of injections above and below their knee. It takes about 20 minutes, where we inject the nitrous oxide in the area around where the nerves run.”

“It freezes the outside of those nerves. It causes them to have to regenerate, which can take two to three months. And while they’re regenerating, theoretically they shouldn’t be able to transmit as much nerve pain.”

The injections are called Iovera. Cindy liked what the doctor said it would do for her. “It would cut down on the pain, cut down on how long you would do the pain medication, and recovery time.”

Tiny, compressed cartridges of nitrous oxide — or laughing gas, like at the dentist office — cools the nerves to minus 80 degrees.

“It just kinda sits there in the tissue to freeze em,” Dr. Moore describes.

“They start out watching something on the ultrasound, and finding your nerves,” Cindy says, describing what it was like. “They do a series at the top of your knee, and a series down the side.”

No numbness. No weakness. No stay in the hospital. Patients can walk afterwards.

“When I saw the three prongs coming up, I’m like, oooh, that’s gonna hurt going in there,” Cindy continues, “All you really felt was pressure. You don’t feel any pain and all that.”

Cindy wasn’t sure the injections would do anything, but when she woke up… “I knew that I had surgery, but it wasn’t anything that I needed to say, ‘I need a pain pill right now.'”

“I thought it would hurt really bad, because they have you walk on it right away. It hurt, but not enough to stop me.”

She was so impressed, she asked for it for the other knee. “I says, of course we’re doing the Iovera, right?”

This time, she wasn’t scared to proceed. “If I had not have had it for my first one, I probably wouldn’t have done the second one.”

“The biggest downside is it may not work,” says Dr. Moore. “I would rate our effectiveness over 90 percent.”

It is FDA approved and covered by insurance. “The patients are usually pretty happy,” he adds.

“The hardest thing is to get up, because both your knees are taking all that weight,” Cindy says. “The steps were easy. Now I can run around out back with my grand kids instead of worrying about falling.”

She feels lucky. “I’m not sure there’s a lot of doctors around that do the Iovera. I’m so glad that I did it.”

She’s had both knees replaced, and she has exceeded expectations with her rehab.

To find doctors who use Iovera, click here.