November 25, 2025
By Mark Hammerberg, MD
My name is Mark Hammerberg and I am one of the surgeons in the Orthopedic Center of Excellence here at Denver Health. This article is going to give you everything you need to know about knee replacement surgery. You will learn what knee replacement surgery is, who can benefit from having a knee replacement, and the basics of how a knee replacement gets done here at Denver Health.
What is the knee?
Most of us know what the knee is, but when we talk about the knee, we are talking about three bones:
- The femur, also known as the thigh bone
- The tibia, also known as the shin bone
- The patella, also known as the kneecap bone
Where those three bones come together, is what we call the knee joint, where the thigh bone is connected to the leg bone. Inside of those three bones is a glistening tissue called cartilage. Cartilage is what allows smooth motion of the knee joint.
What is a knee replacement?
When you think of a knee replacement, you can think of it as a cartilage replacement. What we are doing is we're cutting out the cartilage, which lines the joint, and we're replacing the cartilage with artificial parts, made of metal and plastic.
When we do knee replacement surgery, we make an incision through the side of the kneecap, through the skin, fatty tissue and muscular tissue. That allows us to then move the kneecap over and bend the knee to get to the inside of the knee joint. We then cut all the worn-out cartilage out, much like peeling a potato, removing a little bit of the bone with every portion of "peel." With precise saw cuts, the femur will look like a stop sign and the top of the tibia will just have a flat, bony surface. The knee replacement, which remember, is just replacing the cartilage, takes the form of a piece of metal that is now attached to the end of the femur, much like a crown on a tooth, but it's a very big tooth and a very big crown.
The cartilage replacement on the tibia is another piece of metal, along with a piece of plastic. That plastic now forms the new articulation where the joint comes together, allowing for smooth motion of the knee. So instead of worn-out cartilage, which hurts and is painful and doesn't let you get very far, we now have a restored, replaced knee joint with artificial cartilage. The underside of the kneecap also has cartilage, which we removed, and we replace that cartilage with some more artificial plastic coating for the back of the kneecap. And that's a total knee replacement.
Why do a knee replacement surgery?
There's a lot of diagnoses or different words that we use to explain why we do a knee replacement. Ultimately, the reason for a knee replacement is worn-out cartilage. A name for worn-out cartilage is arthritis, means inflammation of the joint. The body's response to the wear and tear and the aging of cartilage is that it cannot heal the cartilage. It tries to heal it, but it just results in inflammation, meaning the inside of your knee joint is inflamed. Inflammation means it is red, swollen, tender and doesn't function well. You can think of arthritis like a sunburn on the inside of your knee. "Arth -" is Greek for joint; "- itis," is Greek for inflammation. So just like a sunburn is red, swollen, painful and tender, the inside of your knee if you have arthritis, is red, swollen, painful and tender. The cure is get rid of the worn-out cartilage because it cannot heal itself and we replace it with artificial metal and plastic. About 80% of the United States population will go on to have some form of knee arthritis.
Who needs a knee replacement?
The people who need a knee replacement are people with knee arthritis who have tried everything else and still their knee arthritis is a major impediment to their daily life. Their knee arthritis gets in the way of their daily function. It prevents them from doing the things that they need to do to make their life complete. We all define that as different. Maybe some people define a complete life as being able to ski a couple of ski runs. Others may define a complete life as being able to walk 18 holes at a golf course or being able to run around after your grandkids and not just sit in one place. For whomever you are, you have an idea of what it means to have a complete life and what you require of your knee to be able to live it.
What to try before getting knee surgery?
There are several things you can try before getting a knee replacement. I always recommend weight loss. Another recommendation is regular low-impact aerobic fitness. Both of those things have been shown to decrease knee arthritis pain for people who have it and they kind of go hand-in-hand. But it turns out that even if you don't lose weight, the simple participation in a regular low-impact aerobic fitness routine has been shown to decrease knee arthritis pain, whether you lose weight or not. And independently, weight loss itself has been shown to decrease knee arthritis pain. So why not work on both of those things simultaneously?
How can over-the-counter medications help knee pain?
When exercise and weight loss is not enough, you can try taking one of the many over-the-counter, non-steroidal anti-inflammatory medications, such as ibuprofen, Advil, naproxen or Aleve. These can also come in prescription strength. They're very safe medications. But if you're taking these medications on a daily basis, you should really do so in consultation with your primary care provider so that you don't run into any problems such as potential side effects or drug interactions. I've known people who've been on the maximum dose of ibuprofen for multiple decades and they've lived to tell the tale. So it is safe, but you must do so cautiously. Another medicine that works is acetaminophen or Tylenol. Again, if you take any medicine regularly, you should do so in consultation with your primary care physician.
When should you see an orthopedic surgeon for knee pain?
If you've tried exercise, weight loss and medications and you want to know if there is anything else you can do to help your knees and get more out of your life, one good suggestion is to come see one of us, here at the Denver Health Orthopedic Center of Excellence. We will examine your knee, evaluate what you have been doing, talk about other things you might do and talk about surgery. We can also talk about ways to avoid surgery.
When should you get a knee injection to help with knee pain?
One thing that is short of surgery that you might like to consider is having a knee injection. You can have multiple different kinds of injections. I often recommend steroid injections, and if these work, they can be repeated. There are other types of injections that can be provided for knee arthritis and it's between each individual patient and his or her physician as to what may or may not be the right injection for them, if any at all. Steroid injections can provide several months of relief, and if they work, they can be repeated. If they don't work, there's no sense repeating them. But many patients go for many, many years on injections. They might ultimately need to have a knee replacement. Steroid injections can help delay the time at which a knee replacement is done, for those who need it.
Why get same-day knee replacement surgery at Denver Health?
Here at the Denver Health Orthopedic Center of Excellence, we have top-notch surgeons, top-notch therapists, top-notch anesthesiologists, and we're all operating at the forefront of our technology. You may have heard of same-day total joint replacement. Well, that's the way we do it here. You may have heard of opioid-sparing total joint replacement. That's the way we do it here. We use multimodal anesthetic protocols involving spinal blocks, peripheral nerve blocks, all in an effort to minimize the effects of anesthesia, get you going faster, and leaving the hospital early. In most cases, people go home on the day of surgery.
So if you're having knee pain, make an appointment with our Orthopedic Center of Excellence today – we'd love to see you and talk to you about the best option to get you back to doing what you love.
