Elizabeth Hofheinz, M.P.H., M.Ed. • Mon, August 4th, 2014
Wayne G. Paprosky, M.D. is a hip and knee surgeon at Midwest Orthopaedics at Rush who is on the hunt for a ‘more perfect’ way to do knee revision surgery…and he may have found it. He told OTW, “My colleagues and I noticed that the results of cemented revision knee surgery leave a lot to be desired. We developed the idea of using cones to enable us to avoid the use of bone cement for long term fixation and Zimmer crafted the implant.”
“When you remove the cement from the top of the tibia it usually leaves hole. If you fill it with cement it loosens up and results in shin pain. You can avoid this if you put a cone in the upper part of the tibia or the lower part of the femur, put the implant inside of that, and then attach it to metal. The cones, made of trabecular metal, are very porous (like pumice). You hammer it into the top of the bone and it sticks to the inside of the bone and bone grows into that. You then cement the metal shank of the prosthetic to the inside of the metal.
“We were surprised to find that patients feel better so much faster than with cement. It was also surprising that they did not have as much shin pain. Additionally, after two years there were no lines around the cement that suggested preliminary loosening. Thus far, we have done about 60 of these surgeries and there are no downsides thus far. In my opinion using these cones in revision knee surgery is the wave of future. We will soon be submitting these results for publication.”