NEW YORK (CBSNewYork) — Millions of active baby boomers are developing osteoarthritis.

They’ve worn out the cartilage in joints like the knee and many have been told there aren’t great alternatives or replacements.

As CBS2’s Dr. Max Gomez reported, the cartilage can be replaced.

Osteoarthritis is wear and tear arthritis. The nice smooth cartilage on the ends of all bones has worn away, and the knees are where that often shows up first.

You may have heard of bone on bone arthritis, that’s when there is no more cartilage, and it hurts a lot, but there is a way to replace it.

Cheryl Christie is an active baby boomer. She works out five times a week, plays softball, snowboards, and kayaks, but after a couple of knee injuries and ACL surgery, her right knee was shot.

“Oh I had a lot of pain. Every step, every step. Like an ice pick in my knee. The doctor only told me I had arthritis in my knee,” she said.

Cheryl has essentially worn away large areas of cartilage on the ends of her thigh bone, and growing cartilage back in adults is almost impossible.

“By the time you’re an adult, cartilage doesn’t have a way to get nutrients to support a healing response. So we have to become creative,” Dr. Riley Williams said.

For Dr. Williams, creative means finding a way to use bone and cartilage plugs to replace the missing cartilage.

Dr. Williams just presented a long-term study of cartilage replacement in patients from 40 to 62. These are patients who are normally not thought to be good candidates for cartilage surgery.

The key is getting donor cartilage and bone.

“Our bones are pretty similar. If you take a bone from me and put it into you, you won’t reject it,” Dr. Williams explained.

The plug is mostly bone with a thin layer of cartilage on top. The plug is surgically inserted in the knee. Years after surgery, the cartilage in Cheryl’s knee is surviving quite nicely.

But MRIs don’t tell you how a knee feels.

“I feel awesome. Pain free. I play softball, snowboard, etc,” she said.

The donor plug comes from the same people who donate organs and other tissues. It’s thoroughly tested for infectious diseases for two weeks before it’s implanted in a knee.

Not everyone with knee arthritis is a good candidate for this procedure, it mostly depends on how much damage has been done.