Knee Replacement

Overview

What is knee replacement surgery?

Knee replacement surgery removes damaged or diseased parts of the knee joint and replaces them with metal or plastic parts. Also called knee arthroplasty, it’s a safe, effective procedure that can help you feel better and move better.

How does partial knee replacement differ from total knee replacement?

Most arthroplasties target the entire knee joint, an operation called a total knee replacement. But some people choose to have a partial knee replacement.

To understand the difference, it helps to know the knee’s compartments, or sections. It has three:

  • Inside (medial).
  • Outside (lateral).
  • Under the kneecap (patellofemoral/anterior).

The partial approach fixes a single section. So healthcare providers call it unicompartmental replacement. A total knee replacement addresses all three sections. Generally, only younger adults with symptoms in one knee section benefit from partial replacement.

Who gets knee replacement surgery?

You may consider knee replacement surgery if:

  • Arthritis in the knee or a knee injury has severely damaged the mating surfaces of the joint.
  • Pain and stiffness give you trouble doing everyday activities, such as walking up or down stairs or getting in and out of a car.
  • Swelling and inflammation don’t go away with rest and medication.Your knee is deformed, such as looking swollen or not shaped normally.

What the alternatives to knee replacement?

A healthcare provider may recommend knee replacement surgery after other treatments for knee pain don’t help anymore. These earlier options may include:

  • Exercise or physical therapy to strengthen the muscles around the joint which will provide stability.
  • Knee arthroscopy for mechanical issues.
  • Medications such as NSAIDs and cortisone shots.
  • Walking aids or supports (for example, a cane or walker) and bracing.

How common is knee replacement surgery?

The surgery is very common. Surgeons started doing it in the 1960s, with regular updates to techniques and implants along the way.

Almost 800,000 knee replacements currently get performed each year in the United States. The surgery is often done in older adults whose knees have worn down over time. But it’s also become popular in middle age, as people want to stay active.

Procedure Details

How do I determine if I need a knee replacement?

If you’re considering knee replacement surgery, talk to an orthopedic surgeon. Orthopedic surgeons specialize in operations to fix joints and muscles.

Your orthopedic surgeon will:

  • Ask about your symptoms, including how severe they are and how long you’ve had them. The surgeon may also ask whether anything makes symptoms better or worse, or whether symptoms interfere with your daily life.
  • Take your medical history to learn about your overall health.
  • Examine you to check knee motion, strength and stability.
  • Order X-rays of your knee. The images can help the surgeon understand how much damage is in your knee. Advanced imaging (MRI) is rarely helpful in the arthritic knee.

The orthopedic surgeon will then make a recommendation for surgery or another treatment option.

What happens before knee arthroplasty?

If you and your surgeon decide to move forward with knee replacement, you may need:

  • Blood tests.
  • Dental exam to help lessen the risk of infection from surgery.
  • Electrocardiogram to make sure your heart is strong enough for surgery.
  • Physical exam to make sure you’re healthy enough for surgery.

What happens during knee arthroplasty?

The day of surgery, you will receive anesthesia to prevent pain during the operation. You will have either a regional (spinal block) or general anesthetic. Your anesthesia team will decide what type of anesthesia is right for you.

Knee arthroplasty takes about an hour or two. The surgical team will:

  • Make an incision (cut) in the knee area.
  • Remove any damaged cartilage and bone.
  • Place the knee implant and position it properly.
  • Secure the implant into place using cement or without cement.
  • Insert a piece of polyethylene (plastic) that creates a smooth, gliding surface between the metal parts of the implant.
  • Close the incision.

What happens after knee arthroplasty?

After surgery, you will get moved to a recovery room. The healthcare team will watch you for a short time to make sure you wake up from the anesthesia without complications. They’ll also monitor your vital signs and pain level.

Occasionally, people who have knee replacement surgery go home the same day. If you need to stay in the hospital, it will likely be for one day. Additional time spent in the hospital is based on medical necessity.

Will I need any treatments after knee replacement?

Your healthcare team will prescribe medications to help you manage pain after surgery, such as:

  • Acetaminophen.
  • Opioids. (Provided for limited time following surgery.)
  • NSAIDs.

To prevent blood clots and control swelling, your healthcare team might also recommend:

  • Blood thinners, such as aspirin or injectable Enoxaparin based on individual risk of blood clot formation.
  • Compression devices, usually used while hospitalized. These are mechanical devises which provide intermittent compression.
  • Special support hose.

Your team will ask you to move your foot and ankle around frequently to maintain blood flow at home. They’ll also show you special exercises to help strengthen your knee and restore motion. Exercises are very important to the success of your knee replacement. Initially, physical therapy will be in the home. Arrangements for this in home PT are made at the time of discharge from the hospital.

Risks / Benefits

What are the advantages of knee replacement?

Long-term, you may still feel some discomfort and have to limit high-impact activity to protect the replacement joint. But knee replacement can relieve a lot of the pain and help you move much better. More than 90% of people who have a total knee replacement still function well 15 years after surgery.

What are the risks or possible complications with knee replacement surgery?

Although knee arthroplasty is a very safe procedure, rare complications may occur:

  • Blood clots.
  • Infection.
  • Injury to the nerves or blood vessels around the knee.
  • Problems with the implant, such as the device wearing down too soon or loosening.
  • Scar tissue inside the knee.

Recovery and Outlook

When can I get back to my everyday activities after knee arthroplasty?

Your doctor will give you specific instructions. But many people can get back to their everyday activities three to six weeks after surgery.

Your healthcare provider will give you specific instructions about recovery. You will gradually increase activity, starting with a slow walking program. You will be encouraged to stand, climb stairs and perform other normal household activities as soon as possible.

How long does a knee implant last?

Most modern knee implants last 15 years or longer after surgery. Eventually, with normal activity, the plastic implant may begin to wear down or loosen.

Younger people who have knee arthroplasty sometimes need a second knee replacement later in life.

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

Soon after surgery, you will be able to walk with a cane or a walker. But you will need help with everyday activities, such as:

  • Bathing.
  • Cleaning and doing laundry.
  • Cooking.
  • Shopping.

Plan ahead to have a friend or loved one help you after surgery, or tell your healthcare provider if you’ll need help.

Your recovery will also be easier and safer if you adjust your home ahead of time. Things to consider include:

  • Bench or chair in the shower, as well as secure safety bars.
  • No tripping hazards, like cords and loose carpets.
  • Secure handrails along any stairs if you use stairs.
  • Stable chair with a back, two arms and a firm seat cushion, along with a footstool to elevate your leg.
  • AVOID reclining chairs as they DO NOT allow for proper elevation of your post surgical leg.

When to Call the Doctor

When should I seek medical attention after knee replacement?

After you go home, call your healthcare provider right away if you develop any of the following symptoms:

  • Chest pain and/or shortness of breath.
  • Fever higher than 101 degrees Fahrenheit (fluctuations in body temperature are to be expected following surgery).
  • Incision problems, like bleeding, leaking, swelling, redness or odor.
  • Pain in your calf, ankle or foot that is new and gets worse.

A note from Cleveland Clinic

If you have severe knee pain but medications and therapy aren’t helping, knee replacement may provide the answer. This common and effective surgery can reduce pain and get you back to everyday activities. Talk to your healthcare provider or an orthopedic provider about whether knee arthroplasty is a good option for you.

Last reviewed by a Cleveland Clinic medical professional on 02/05/2021.

References

  • American Academy of Orthopaedic Surgeons. Accessed 2/17/2021.Total Knee Replacement. (https://orthoinfo.aaos.org/en/treatment/total-knee-replacement/)
  • American Association of Hip and Knee Surgeons. Accessed 2/17/2021.Full vs. Partial Knee Replacement: What’s the Difference? (https://hipknee.aahks.org/full-vs-partial-knee-replacement-whats-the-difference/)
  • National Institute of Arthritis and Musculoskeletal and Skin Diseases. Accessed 2/17/2021.Knee Problems. (https://www.niams.nih.gov/health-topics/knee-problems/advanced)
  • National Library of Medicine. Accessed 2/17/2021.Beyond Pain Relief: Total Knee Replacement Surgery. (https://magazine.medlineplus.gov/article/beyond-pain-relief-total-knee-replacement-surgery)
  • National Institute of Arthritis and Musculoskeletal and Skin Diseases. Accessed 2/17/2021.Joint Replacement Surgery. (https://www.niams.nih.gov/health-topics/joint-replacement-surgery)

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy