If a surgeon has told you it is time for a knee replacement, there is a second question worth asking before you book anything. Not whether to have it. Which one.
Most people know total knee replacement exists. Far fewer know that a partial is a separate operation with a different risk profile, and that plenty of candidates never get told about it.
By The First Rehabilitation Team · Reviewed by Dr. Dave Kashuba, Ph.D.
The numbers a surgeon gave us on air
Orthopedic surgeon Dr. Richard Weiner, who has been in practice since before our clinic opened in 1991, laid this out on the Pain 2 Power podcast. Statistics show that over 40% of everyone receiving a total knee could have had a partial instead, he said, while in the United States only about 10% actually get one.
His explanation for the gap is not clinical. "Most of the surgeons who do total knees are not trained to do partials," he said, "so they don't even offer it as an option." Fewer than half of orthopedic surgeons do knee replacements at all. Of those, fewer than half do partials. Of those, fewer than half will do the lateral compartment.
All of which means the operation you are offered can depend on who you happen to be sitting across from.
What makes them different operations
The knee has separate compartments, and arthritis does not always take all of them. A partial replaces only the worn one and leaves the rest of your knee alone.
The structural difference Dr. Weiner emphasises is the ligaments. A total knee "requires dislocation of the joint," a much larger procedure, and the anterior cruciate ligament comes out. About half the time the posterior cruciate goes too. A partial preserves all of them, and that is the reason for the thing patients notice most: "a partial knee can feel like a normal knee, because all the ligaments are preserved." A total knee, in his words, never quite does. It is a tremendously successful operation and it still feels a little different.
His shorthand for the rest was a repeated phrase. Pain, less than half. Risk of infection, less than half. Time to get back to sport, less than half. Blood loss and clot risk, lower again, though the risks with a modern total knee are low to begin with.
Which compartment wears matters too. The inside of the knee goes about eight to ten times more often than the outside, which is the reason worn knees tend to look bow legged. The smaller group who wear the outside look knock kneed, and that lateral partial takes training that fewer surgeons have.
How the decision actually gets made
Not from a scan alone. "You don't treat an X-ray, you treat the patient," Dr. Weiner said, and his sequence starts with your symptoms and your history, then a clinical exam, then imaging, including stress X-rays that show whether the other compartments are holding up.
The question he weighs is durability. A small share of partials, well under one in ten, eventually need converting to a total. Over 90% do not. When the odds of it lasting look good, that is what he recommends.
Age is less of a barrier than people assume. He described doing a partial knee for a 95 year old patient of twenty years, who had done therapy and injections for as long as they worked and then decided she wanted the knee.
Surgery is still the last resort
Worth saying plainly, because a post about replacements can read as an argument for having one. It is not. "Surgery is the last resort," Dr. Weiner said. "The first thing is conservative treatment."
That means avoiding what aggravates the joint, then therapy, then medication or a targeted injection, and only then bracing or an operation. On therapy he was direct about why it comes first: "physical therapy is key because you need to have strong muscles to stabilize the knee to have fewer symptoms." He also prefers injections to pills for a single joint, on the logic that you put the oil where it squeaks rather than exposing the whole body.
Dave's aside during that conversation is the most honest endorsement a partial is going to get from a therapist. He told Dr. Weiner he loses money on them, because those patients need far less rehab than a total knee does.
What rehab looks like either way
Both operations need therapy, and the partial needs less of it. The work is the same in kind: restoring range, then rebuilding the muscles that support the joint, quadriceps first and glutes and calves alongside them, because the knee is carried from above and below.
The strongest thing you can do is start before the operation. Building strength ahead of surgery, sometimes called prehab, means recovering from a stronger baseline, and it changes outcomes. You can begin with the home exercises Dave walks through on the show and bring the rest to an evaluation.
So take one question to your appointment. Ask whether you are a candidate for a partial, and ask whether the surgeon performs both. Dave's advice about choosing anyone who treats you applies here more than usual: do your homework, and do not take the recommendation from the person next to you in the Publix line.
If you are weighing a knee replacement, or recovering from one, we can help with the part that decides how well it goes. We see patients from North Palm Beach and across the county, including Palm Beach Gardens. Call 561-624-4263 or request an evaluation. Read more about how we treat knee pain and post-surgical rehabilitation, browse the physical therapy questions in our FAQ, or hear the full conversation on the Pain 2 Power podcast.
This article is general information, not medical advice. Every situation is different, so please consult a qualified professional about yours.