Is The Patella Replaced In A Total Knee Replacement

You have likely prepared for months and months to get ready for your knee replacement.  Good chance you have have done ‘prehab’ exercises to strengthen and best prepare your new knee for after surgery.

From the bloodwork to the scans and prep testing, you would assume all questions have been answered before the surgery date.  Heck, some of my patients even know the exact manufacturer and model of knee they will be receiving (a good idea in my mind).

However, a very common question I receive from my patients a week or two after surgery is ‘Did they replace my kneecap or keep the original one?’  Funny how most people just never think to ask the surgeon about this beforehand.  But its not surprising considering all of the other questions you have and the stress leading up to the date of surgery.

So what’s the answer?  Yes, you guessed it:  It Depends.  But we can make a few general guesses as to your situation and give you some information on the subject.

Did They Replace My Kneecap During Knee Replacement?

The only way to truly know if you still have your original kneecap is to ask the surgeon.  What this means is that your surgeon could have left the original or if needed replace your original kneecap with a prosthetic patella.

In a vast majority of total knee replacements, your original patella is kept.  The reason for this is that even after many years of research and development, prosthetic kneecaps simply do not provide the same support as your original kneecap.

The best explanation as to why this is the case is that the kneecap is extremely important in the muscle control in your thigh (quadriceps) muscle group.  Even the slightest change in the muscle pulling mechanism force or direction greatly impacts your knee movement and control.

By keeping your original patella, you’re maintaining the same biomechanics which is key to your maximizing your new knee.  Most surgeons have a good idea going into surgery whether or not they plan to keep the original patella in place.

Reasons to Replace The Patella After TKR

In a small percentage of TKR cases, usually those of older or frail boned individuals, the original patella can be too worn down to continue using.  In these cases, the surgeon will remove the original patella and insert a new prosthetic kneecap in place. 

In these cases, the expected final outcome of that new knee will be less than if the original was kept intact.  The knee strength and range of motion will likely never come close to 100% and your surgeon and physical therapist should relay this to you in depth.

If this is the case for you, don’t be disappointed or fearful of your new knee as it will be structurally fine.  In addition, the new kneecap will never get in the way of significant improvement in pain and movement as compared to your original worn down arthritic knee.  Just understand you may never fully get to 100% of your goals.

Wouldn’t Keeping My Old Kneecap Be a Problem With My New Knee?

Again, it depends.  Your patella might be in very good condition even if your knee joint surfaces are damaged.  In this case, your patella would be left intact as there is not issue.

In most cases, the back of your patella will have some wear and tear and thus will be resurfaced with a polymer button.  This button polymer will provide smooth gliding on the new knee joint surfaces and better outcome in the end.

Again, your surgeon will try at all costs to keep your original kneecap to give you the best possible outcome.  Don’t forget, this is a plastic polymer and you are not getting a brand new kneecap.

Final Thoughts on Is The Patella Replaced In A Total Knee Replacement 

• A Majority of Total Knee Replacements Keep Your Original Kneecap
• A Plastic Polymer Button is Used On the Back of the Patella For Smoothness
• Prosthetic Patellas Do Not Give The Same Outcome vs. Keeping The Original Kneecap