During a knee replacement procedure, the damaged portions of the knee joint are removed and the joint is resurfaced with prosthetic components.
Traditionally, the metal prosthetics were held in place with bone cement. However, advances in implant technology have led to knee implants that do not need to be cemented into place. Instead, the textured surface of the implant encourages bone growth, so the implant is rigidly fixed to the bone. Both cemented and cementless knee implants are currently used for knee replacements, depending on the needs of the patient.
Cementless knee implants have a rough, porous surface that encourages new bone growth. The new bone grows into the spaces in the implant, holding it in place without the need for cement. The bones within the knee are shaped with special tools so that they fit snugly with the implant. In some cases, screws or pegs may be used to hold the prosthetics in place while the bone grows. Cementless technology is what we have been using in hip replacements for many years. Because of the complex anatomy and joint mechanics of the knee, older cementless implants did not work as well. Current designs, however, have an outstanding clinical track record now with almost 10 years of follow-up.
The advantage of cementless implants is that patients don’t have to worry about potential complications from cement breakdown in the long term. This was traditionally an area that broke down after 20 or 25 years from the time of surgery. Given that we are performing many knee replacements on patients in their 50’s and 60’s, we believe that using cementless technology on these select patients will increase the longevity of their joints in the long term.