The 3 Types of Knee Replacements: What You need to Know

The 3 Main types of total knee replacements are Cemented, Uncemented, and the newly arriving Robotic Assisted.  Robotic assisted can also be cemented or uncemented, but as of the writing of this article most robotic assisted systems appear to be uncemented.

Cemented Knee replacements have a quick drying cement applied to the hardware to allow for fast, solid fixation.  This approach is usually done for those who are older with poor quality bone health due to osteoporosis or other diseases.  It is also believed these implants don’t last quite as long and are good for 15-20 years.  The cement can come loose if a person does lots of high impact activity over many years. In the event of an infection that requires the hardware to be removed, this can be more complicated as the surgeon has to remove all the dried cement from the joint space (also called debridement)

Uncemented TKRs are exactly as they sound. They are secured by the natural growth of bone around the implanted prosthetic. The implant has a special surface to stimulate bone growth and it is secured at the time of surgery with only a couple of screws. More precision by the surgeon is required when cutting out diseased bone to ensure the best fit possible. This approach is better for younger, healthier patients who have good bone health.  It is believed to last longer than cemented TKRs and put up with more wear and tear as there is no cement that can crack or chip off.  In the event of an post surgical infection that requires hardware removal from the patient, this is easier to take this out with no cement to clear from the joint space.

Robot Assisted TKRs are very new.   Pre planning scans are performed and software determines the exact cuts that need to be made.  It is believed that the robot can deliver a more consistent and accurate cut for the placement of prosthetic to maximize the uncemented TKRs placement.  This procedure may also be less physically taxing on the healthcare staff who performs the procedure.  As with any computer system, it is only as good as the humans who are operating it and the possibility for human error during the data entry is possible.  Overall, the research on these newly performed procedures is good and could suggest less post surgical infections. But it still needs to be researched more before that can be said definitively.  

Asking your doctor which type of surgery he plans to perform is good to know as it has implications for rehab.  I sometimes encourage my uncemented total knee replacement clients to use an assistive device a little bit longer, as a fall on the uncemented knee can cause hardware failure in the first couple weeks.  In general I don’t recommend people begin to attempt to kneel for at least 6-8 weeks, especially if it is uncemented.  Grandparents who wants to crawl around with their grandkids and are having a fast recovery sometimes need to be held back a little bit due to the physiological limitations of bone growth.

So which procedure should you get? ……….. The one your surgeon recommends!

Your healthcare providers probably never went over this with you because they are swamped with charting and paperwork.  Consider hiring us for online coaching!  We offer general advice, emotional support, and accountability via an app to make sure you are doing what needs to be done to have your flexibility & strength be the best it can be.