Ask-a-Doc:
What's the Difference Between Partial and Total Knee Replacement?

Hello, I’m Dr. Keith Berend. 

I’m frequently asked, “What is the difference between a partial and a total knee replacement?”

Well, it is exactly that. In a partial knee replacement, the surgeons are just replacing the inside part of the knee where the bone-on-bone knee arthritis is, and leaving behind the normal structures and the normal cartilage on the outside, the kneecap, and the normal ligaments. 

In doing so, it’s a much less invasive or minimally invasive procedure to have a partial knee replacement. It’s important to understand that a partial knee replacement does replace the entirety of the disease. It just doesn’t replace the parts of the knee that are normal. 

So, on the inside part of the knee or the medial compartment is the most common partial knee replacement that we see. It usually takes about an hour to perform surgically. The real big differences between a partial and a total knee replacement are as follows.

First of all, the risk of significant complication after surgery is about a third or 60% less with a partial knee replacement than a total knee replacement. It doesn’t mean that there is no risk of complication. It simply means that the bad things that can happen happen much less frequently with a partial knee replacement, because it’s that much less of a surgery.

So, things like blood clots, infection, transfusion risk, and even things like death and heart attack, substantially less risk with a partial knee than with a total knee. 

Number 2: the recovery is usually much, much faster. It’s a minimally invasive procedure to resurface the bad part of the knee, and therefore, it requires much less rehabilitation. The physical therapy programming is is the same between a partial and a total knee replacement. But the patient routinely will progress through that physical therapy significantly faster with a partial knee replacement, because it is so much less invasive than a total knee replacement. 

And then, finally, an issue of function. By preserving the normal ligaments of the knee, particularly the ACL or the anterior cruciate ligament, is preserved with a partial knee. And if it’s present, it’s taken out with a total knee. And the knee is much more mechanical with the total knee, whereas the partial knee replacement is much more normal. 

So, the function of the knee itself after surgery is much more normal. Patients can move faster, are able to do stairs, and declines much better. They have a better range of motion. They routinely are stronger with a partial knee replacement than they would be with a total knee replacement. 

The 3 very significant benefits are less risk, faster recovery, and substantially better function with a partial knee replacement.

But what is the downside? 

Patients will routinely say, “If I’m having this surgery done, just do the whole thing. I don’t want to have to come back.”

But what they’re really saying is, “What’s the chance of revision? What’s the chance of failure of this device?”

And when we’ve looked at our own series of partial knee replacements, of which we’ve done more Oxford partial knee replacements than any other practice in the world, we looked at our series and compared the Oxford partial knee to a standard total knee replacement, and we found the survivorship to actually be exactly equal. 

The chance of revision, the chance of needing another surgery at some time during your life, is about 1% per year. And that’s a cumulative risk. And so, in the first year, that’s a complication. You’ve had to have another surgery for some reason. But if you extrapolate 20 years post-op in any age group, there’s about an 80% chance that you’re doing fine and the implants functioning great, whether a partial or a total. 

And so, why do the whole knee replacement up front if the risk of revision is the same? Well, you have those three benefits that we talked about earlier.

If you want to know more about partial and total knee replacements, contact us at JIS Orthopedics. Our specialists in New Albany and St. Clairsville, Ohio, can give you the answers you are looking for. Schedule a visit with us today!