The calcium phosphate cement flows into the spongy inside portion of the bone , filling in microfractures and other damaged areas, and it hardens in about 10 minutes' time. The cement braces the bruised or injured joint bone from the inside, and eventually is replaced by new bone as part of the body's natural healing process.

The procedure involves a smaller incision than joint replacement surgery , there is less risk of infection, and a quicker recovery time that means fewer of the side effects associated with being bedridden, Vasileff said. However, subchondroplasty is only feasible in a narrow range of patients. Those with full-blown bone-on-bone arthritis or joint pain caused by damage to the cartilage and ligaments will get little to no relief from the procedure.

"People who have significant arthritis where the cartilage itself is damaged and thinned, this is not going to fix the arthritis," "But there are some people who have some issues with the bone and mild arthritis. needed a knee or hip replacement to deal with that, this could be an alternative. "

Software engineer Ben Wallace underwent subchondroplasty in November to help shore up a damaged hip. "The end of September I noticed I was really struggling to move around my left leg very well," said Wallace, who lives in Columbus, Ohio. Imaging scans revealed a hip in very bad shape, with a misshapen femur.

Subchondroplasty has shown solid potential, but orthopedic surgeon Dr. Matthew Hepinstall is concerned that it might be "oversold" to desperate patients who want to avoid joint replacement surgery. The best candidates for the procedure are those who still have some cartilage protecting their joint, but have somehow "overloaded" and injured the bone, causing swelling and pain.

"We do not want to send the message to people who have bone-on-bone, with big bone spurs and limited range of motion that they're all of a sudden going to get relief from injecting a little bit of cement into their  bone , "Hepinstall said. "This is for people who have a normal joint that has a normal range of motion and normal stability, just a little thinning of the cartilage."