Knee Replacement

A knee replacement is surgery to replace all or some of your knee joint. It’s a type of procedure called an arthroplasty (joint replacement).

An orthopedic surgeon will remove damaged parts of your natural knee joint and replace them with an artificial joint (a prosthesis) made of metal and plastic.

Signs you may need a knee replacement

A healthcare provider might recommend knee replacement if you have severe symptoms that make it hard to move or use your knee. Knee pain, stiffness and swelling that don’t get better after trying other treatments can all be signs a knee replacement may be right for you.

Knee arthritis is the most common condition that causes people to need knee replacement surgery. It's rare, but your provider might suggest a knee replacement if you develop post-traumatic arthritis after breaking a bone in your knee joint.

Types of knee replacement surgery

Your surgeon will recommend either a total or partial knee replacement:

• Total knee replacement (TKR): This is the most common type of knee replacement. Your surgeon will replace all three areas of your knee joint — the inside (medial), outside (lateral) and under your kneecap (patellofemoral). It’s also called a total knee arthroplasty (TKA).
• Partial knee replacement (PKR): A partial knee replacement is just what it sounds like. Your surgeon will only replace some areas of your knee joint. They usually do this if only one or two areas are damaged. Partial knee replacements are more common in younger adults who’ve experienced an injury or trauma.

How should I prepare for a knee replacement?

Your surgeon will tell you what you’ll need to do before surgery. In general, you’ll need:

• A dental exam to reduce the risk of germs in your mouth spreading to your knee after surgery
• A physical exam to make sure you’re healthy enough for surgery
• An electrocardiogram to check your heart health
• Blood tests, including a basic metabolic panel (BMP)
• Imaging tests, including a knee X-ray (you might also need an MRI or CT scan)

Tell your provider and surgeon which medications and over-the-counter supplements you take. You may have to stop taking some medications or supplements before your surgery.

Your surgeon will tell you when you should stop eating and drinking (fast) the day before your surgery. You’ll probably need to fast for 12 hours before the surgery.

What happens during a knee replacement?

No matter which type of knee arthroplasty you need, the surgery will follow these steps:

1. An anesthesiologist will give you anesthesia to numb your body and make sure you don’t feel any pain. They’ll use either general anesthesia to put you to sleep during the surgery or a regional anesthesia to numb you from the waist down.
2. Your surgeon will remove damaged cartilage and bone.
3. They’ll insert the prosthetic implants.
4. Your surgeon will insert a plastic spacer that recreates the smooth cushion of your cartilage that was damaged or removed.
5. They’ll reshape your kneecap (patella) to fit your new prosthetic knee joint if they need to.

How long does a knee replacement take?

Knee replacements usually take an hour or two. It depends on the type of arthroplasty you need and how damaged your natural knee joint is.

Your surgeon can give you an estimate of how long the surgery will take while you’re doing your surgery prep.

What are the potential benefits and risks of knee replacement surgery?

Knee arthroplasty is a safe, effective procedure that can relieve long-term pain and help you regain your mobility. Most people who have a knee replacement have reduced pain, increased ability to move and use their knee, and an improved quality of life. If you’ve been avoiding certain activities you used to love, you may be able to get back to them once your knee heals.

Like all surgeries, there’s a small risk of complications after a knee replacement. Complications are rare, but can include:

• Blood clots
• Blood vessel issues
• Infection inside your knee or at your surgery site
• Nerve issues
• Problems with the prosthetic implant, including the device wearing down too soon or loosening
• Reduced range of motion (how far you can move your knee) and stiffness
• Scar tissue inside your knee

What happens after a knee replacement?

After surgery, you’ll be moved to a recovery room. Your surgery team will keep an eye on you for a few hours to make sure you wake up from the anesthesia without complications. They’ll also monitor your vital signs and pain level.

Some people who have knee replacement surgery go home the same day. You might need to stay in the hospital overnight. Your surgeon will tell you when it’s safe for you to go home.

What is the recovery time after a knee replacement?

It usually takes around a year to recover fully after a knee replacement. But you should be able to resume most of your usual activities in six weeks.

Your recovery time will depend on several factors, including your:

• Activity level before surgery
• Age
• Other health conditions

Knee replacement recovery plan

Your surgeon will give you a customized recovery plan, but in general, you should:

• Do home exercises: Your surgeon will give you exercises to start as soon as possible after your surgery. They’ll show you how to perform these movements safely.
• Elevate your knee: Keep your knee above the level of your heart as often as possible. You can prop it up on cushions, pillows or a footstool.
• Ice your knee: Icing your knee a few times a day for 20 minutes at a time will help relieve pain and swelling.
• Keep your incision clean and covered: Follow your surgeon’s incision care instructions carefully. Ask your surgeon when you should change the dressing on your incision site and when it’s safe to take a shower or bathe.
• Start physical therapy: You’ll work with a physical therapist for up to a few months after surgery. They’ll help you start moving safely, including bending your knee and walking.

Your recovery will be easier and safer if you prepare your home ahead of time, including:

• Getting a bench or chair for your shower
• Installing grab bars or getting a commode chair to help you get on and off the toilet
• Removing all tripping hazards, like power cords, rugs and loose carpets
• Securing handrails along any stairs

Pain management after knee replacement

After surgery, you’ll feel pain, especially in the first few weeks of your recovery. You’ll feel pain from the surgery itself and as your body begins to heal.

Your surgeon will suggest a combination of prescription pain medication, over-the-counter NSAIDs (if it’s safe for you to take them) and acetaminophen. They’ll tell you how much of each medication you can take every day or in a certain amount of time.

Talk to your surgeon if you feel like you’re experiencing too much pain or if you’re worried about any complications from taking pain medication.

How long does a knee replacement last?

A knee replacement usually lasts a long time. In fact, almost everyone who has a knee replacement has improved knee function for at least 10 to 15 years. You may live with the prosthetic implants for the rest of your life.

When should I call my healthcare provider?

Call your surgeon or healthcare provider right away if you experience any of the following symptoms:

• Bleeding
• Chest pain
• Fever higher than 101 degrees Fahrenheit (39 degrees Celsius)
• New or worsening pain in your calf, ankle or foot
• Severe pain that doesn’t get better after you take pain medication
• Shortness of breath
• Signs of an infection at your surgery site, including leaking, swelling, discoloration, odor or a feeling of warmth