Partial Knee Replacement

What is a partial knee replacement?

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

A surgeon will remove damaged sections of your knee joint and replace them with an artificial joint (a prosthesis) made of metal and plastic.

There are three compartments in your knee joint:

• The medial compartment (the inside section).
• The lateral compartment (the outside section).
• The patellofemoral compartment (the area under your kneecap — your patella).

Surgeons perform partial knee replacements on the medial and lateral compartments.

What conditions are treated with a partial knee replacement?

Arthritis is the most common condition that causes people to need partial knee replacement surgery. Most people who choose to have a partial knee replacement have osteoarthritis.

A healthcare provider might recommend a partial knee replacement if you have severe symptoms that don’t get better after trying nonsurgical treatments, including:

• Joint pain.
• Stiffness.
• Limited mobility (trouble moving your knee).
• Swelling.

How common is partial knee replacement surgery?

Knee replacements as a whole are one of the most common types of arthroplasties. Surgeons in the U.S. perform more than 850,000 knee replacements each year.

Total knee replacements are more common than partial knee replacements because most people with knee arthritis have it in all three knee compartments at once.

How should I prepare for a partial knee replacement?

Your healthcare provider and surgeon will tell you what you need to do to get ready for surgery. In general, you’ll need:

• A physical exam to make sure you’re healthy enough for surgery.
• Blood tests.
• An electrocardiogram to check your heart health.
• A dental cleaning and exam to reduce your risk of developing an infection after surgery.
• Imaging tests, including a knee X-ray. It’s rare, but you might also need magnetic resonance imaging (MRI) or a computed tomography (CT) scan.

Tell your provider and surgeon about any medications and over-the-counter (OTC) or herbal 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 the day before your surgery. Most people need to avoid eating and drinking for 12 hours before their surgery.

What happens during a partial knee replacement?

The day of your surgery, you’ll receive anesthesia to numb your body and make sure you don’t feel any pain. An anesthesiologist will give you either general anesthesia to put you to sleep or regional anesthesia to numb you from the waist down.

During a partial knee replacement, your surgeon will:

• Remove the damaged cartilage and bone in the compartments they’re replacing.
• Insert the prosthetic pieces.
• Insert a plastic spacer that recreates the smooth cushion of your cartilage that was damaged or removed.

How long does a partial knee replacement surgery take?

Partial knee replacements usually take around an hour.

What happens after surgery?

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.

Most people can go home the same day as a partial knee replacement. Your care team will let you know if you need to stay in the hospital overnight.

What are the benefits of a partial knee replacement?

Partial knee replacement is a safe, effective way to relieve long-term symptoms like pain and stiffness. People who have partial knee replacements usually regain mobility and have an increased quality of life.

Partial knee replacements also usually have a much faster recovery time than total knee replacements.

How long does a partial knee replacement last?

Many people who have a partial knee replacement live with their prosthetic pieces for a long time (usually 10 years or longer).

Some people who have a partial knee replacement may need a total knee replacement in the future if arthritis starts affecting their other knee compartments.

What are potential complications?

Some people who have partial knee replacement surgery still experience pain and other symptoms in their knees. Rare complications include:

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

Certain health conditions can make recovering from a partial knee replacement more difficult. Talk to your surgeon about your health history. Tell them if you have:

• Hemophilia.
• Diabetes.
• Other autoimmune diseases (like lupus).

Your surgeon will tell you what you can expect after your surgery and how you can reduce your chances of experiencing complications.

How long does it take to recover from a partial knee replacement?

It may take a few months to completely recover after a partial knee replacement. You should be able to resume most of your usual activities in around six weeks.

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

• Activity level before surgery.
• Age.
• Other health conditions.

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

• Ice your knee: Icing your knee a few times a day for 20 minutes at a time will help relieve pain and swelling.
• Elevate your knee: Keep your knee above the level of your heart as often as possible. You can prop it up on cushions or pillows while lying down or rest it on a footstool if you’re sitting in a chair.
• 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.
• Do home exercises: Your surgeon will give you exercises to do as soon as possible after your surgery. They’ll show you how to perform movements and exercises to strengthen the muscles around your knee and prevent stiffness. Do your exercises as often as your surgeon instructs. They’ll help your recovery and make sure your joint regains its function.
• Go to physical therapy: You’ll work with a physical therapist for several weeks after your surgery. They’ll help you start moving safely, including bending your knee and putting weight on it.

Pain management after a partial 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 nonsteroidal anti-inflammatory drugs (NSAIDs) (if it’s safe for you to take them) and acetaminophen to relieve your pain. Your surgeon will tell you how much of each kind of medication you can take and when you can take it.

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.

When can I go back to work or school after a partial knee replacement?

How long you’ll need to miss work or school depends on how much stress your job or other activities put on your knee. Most people need to rest at home for a week or two after a partial knee replacement. Your surgeon will tell you when it’s safe to return to work or school.

What can I do to help my recovery after a knee replacement?

You’ll be able to walk with a walker right after your surgery. But you’ll probably need help with some everyday activities at home, including:

• Bathing.
• Cleaning.
• Doing laundry.
• Cooking.
• Shopping.

Plan ahead to have a loved one help you after surgery. Your surgeon or healthcare provider can suggest resources if you need help while you’re recovering.

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.

When should I call my healthcare provider?

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

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

Which is better, partial or full knee replacement?

A partial knee replacement is one type of knee replacement. The other type is a total knee replacement.

Total knee replacements are more common. Your surgeon will replace all three compartments with a prosthetic joint.

If you need a partial knee replacement, your surgeon will only replace the compartments that are damaged and leave other, healthy sections intact.

Partial knee replacements usually have a more natural feeling, are easier to recover from and put less stress on your body. That’s why most people who are eligible for partial knee replacements choose them rather than total knee replacements.

One type of knee replacement isn’t better than the other. It’s more about your unique needs, which parts of your knee joint are damaged and why your surgeon thinks one type is the best fit for you.