What is knee replacement surgery?
Knee replacement surgery, or arthroplasty, is a procedure where damaged bone and cartilage in the knee are replaced with metal and plastic parts, which helps reduce discomfort and improve movement for people with severe knee problems.
The most common reasons people need knee replacement surgery are:
- Osteoarthritis
- Rheumatoid arthritis
- Injuries to the knee
While most knee replacements are done for people between 50 and 80, younger people with knee joint issues may also be candidates for the surgery.
Types of knee replacement
Knee replacement surgery can be done in two ways: total knee replacement or partial knee replacement.
- Total knee replacement: This surgery involves replacing the entire joint line — the inside, outside and sometimes under your kneecap — to help improve pain and movement.
- Partial knee replacement: In this surgery, only the damaged areas of your knee are replaced. It's often recommended for people with damage to just one or two parts of the knee, especially if caused by prior injury.
Depending on your situation and preference, your surgeon may use robotic technology that can offer personalized fit and placement of your artificial joint.
Why might I need knee replacement?
Your doctor may recommend knee replacement surgery if you're dealing with severe symptoms that don’t improve with other treatments, such as:
- Pain in your knee
- Stiffness
- Trouble moving your knee
- Swelling
- Knee deformity
Arthritis is the most common reason people need knee replacement surgery. While many people who get a knee replacement have osteoarthritis, some with rheumatoid or other inflammatory arthritis may also need the procedure.
In rare cases, knee replacement may be recommended if you've had a bone fracture in your knee that leads to post-traumatic arthritis. This type of arthritis can develop after an injury, such as a car accident, a fall or a sports-related incident.
How to prepare for knee replacement surgery
Your surgeon may require you to have a physical exam from your primary care provider to make sure you are healthy enough for surgery. You may also need certain tests, such as an electrocardiogram to check heart function and blood and urine tests to check for infection and other conditions.
Your provider may recommend working with your primary care provider or specialist to manage chronic conditions, such as diabetes or heart disease, to help ensure you’re healthy enough for surgery.
You will also need to plan for your recovery. You might have difficulty getting around as you heal, and making modifications to your home in advance can help. This might include:
- Arranging help with cooking, cleaning, grocery shopping and other chores
- Creating a temporary living space on one floor of your home if you have multiple floors
- Getting a stable armchair with a firm back and cushion and a footstool to elevate your leg
- Installing safety bars in your shower, purchasing a shower chair and installing a toilet riser with arms
- Removing tripping hazards, such as cords or loose rugs
If necessary, a social worker can talk to you about whether you need inpatient rehab after surgery. Inpatient rehab may offer extra assistance if you live alone.
What to expect with knee replacement surgery
A knee replacement involves replacing natural bone and tissue with metal and plastic parts. Surgeons may use 3D imaging and advanced technology to select an implant that fits your anatomy, so the implant fits as well as possible and lasts a long time. On average, knee replacements last 15 to 20 years, however, with recent advances in technology, current implants may last for much longer.
Before surgery
Follow your doctor’s instructions for eating, drinking and taking medication on the days leading up to and the day of your surgery.
You will be given general or regional anesthesia (a spinal) for the procedure. If you have a spinal, you will be numb from the waist down during the surgery. Just before the procedure, you will meet with an anesthesiologist. They will talk to you about how the anesthesia will be administered during the procedure and ask if you have any allergies.
During surgery
Total knee replacement is the most common type of knee replacement surgery, where the damaged ends of the thigh bone and shin bone are replaced with metal and plastic components.
The main steps of a total knee replacement include:
- The surgeon makes an incision at the front of your knee and moves your kneecap to the side to access the joint behind it.
- The damaged ends of the shin bone and thigh bone are removed.
- New metal and plastic parts are fitted over the ends of both bones to create a new joint. In some cases, the back of the kneecap may also be replaced with a new component.
- The kneecap is repositioned, and the incision is closed with stitches or staples, and then covered with a dressing and bandage.
- After the surgery, you'll be moved to a recovery room, where you'll be monitored until you're fully awake. Pain management medications may be provided.
A partial knee replacement is an option when arthritis affects only one part of the knee. In this procedure, only the damaged bones on the affected side are replaced with metal and plastic components. This surgery is like a total knee replacement but involves a smaller incision, generally leading to faster recovery.
After surgery
You may need to stay in the hospital for one or two days after surgery, but some knee replacement surgeries are done as outpatient procedures, which means you can go home the same day.
There is an increased risk of blood clots after knee replacement surgery. To help prevent this, you may be asked to:
- Move early: You'll be encouraged to sit up and start walking with crutches or a walker shortly after surgery.
- Apply pressure: You might wear elastic compression stockings or inflatable air sleeves on your lower legs. These sleeves help squeeze and release your legs to increase blood flow, which can lower the risk of blood clots.
- Take blood thinners: Your doctor may prescribe blood thinners, either through an injection or oral medication, to reduce the risk of clots. Depending on your mobility, activity level and overall risk, you may need to take these for several weeks after surgery.
You'll also be asked to do breathing exercises regularly and gradually increase your activity level. A physical therapist will guide you through exercises to help you strengthen your new knee. After leaving the hospital, you'll likely continue physical therapy either at home or at a center.
Knee replacement recovery
Recovery from knee replacement usually takes about a year, but most people can get back to everyday activities within six weeks. How long it takes to recover depends on your activity level, age and overall health.
Here are some general tips to help with your recovery:
- Ice your knee: Apply ice for 20 minutes several times a day to help with pain and swelling.
- Elevate your knee: Keep your knee raised above your heart as much as possible, using pillows or a footstool.
- Care for your incision: Follow your surgeon’s instructions on how to keep your incision clean and covered. Ask when it’s okay to shower.
- Physical therapy: You’ll work with a therapist for a few months to help you move safely and regain strength.
- Do your exercises: Regular exercises will help strengthen your muscles and prevent stiffness. Follow your surgeon and physical therapist’s advice on how often to do them.
Most people can drive again around four to six weeks after surgery, once your knee can bend enough to get in and out of the car comfortably and your muscles are strong enough to brake safely and accelerate.
Knee replacement surgery usually brings pain relief, better movement and an improved quality of life. After fully recovering, you can enjoy walking, swimming, golfing and biking. However, you may want to avoid high-impact activities like jogging or contact sports. Be sure to talk with your healthcare team about safe ways to stay active after surgery.
Care Companion
If you have surgery at Baylor Scott & White, the Total Knee and Hip Care Companion is a digital resource within the MyBSWHealth app that connects you to your surgeon and care team. If preferred, a loved one can serve as your proxy through Family Account Management. The Total Knee and Hip Care Companion provides pre and postsurgical tasks, records your recovery progress and keeps your healthcare team informed of your success, so you can feel confident healing at home.
Care Companion is available through most orthopedic surgeons on the medical staff. Check with your doctor’s office about service availability.
Knee replacement risks
Like any surgery, knee replacement surgery comes with some risks. Possible complications include:
- Bleeding
- Infection
- Blood clots in the legs or lungs
- The new knee joint becoming loose or wearing out
- Fractures
- Ongoing pain or stiffness
In some cases, the knee joint may not work as expected, or it may need to be replaced again in the future. There’s also a chance that nerves or blood vessels near the surgery site could be injured, leading to weakness or numbness. In rare cases, the surgery may not fully relieve the joint pain.
Other risks may depend on your health condition. Be sure to talk to your doctor about any concerns you have before the procedure.
Frequently asked questions
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How long does knee replacement surgery take?
Knee replacement surgery usually takes between one to three hours. The time can vary based on whether it's a total or partial replacement and the complexity of your surgery. Your surgeon will give you a specific estimate based on your needs.
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How long does it take to recover from knee replacement?
Recovery from knee replacement usually takes about six weeks to get back to everyday activities, but full recovery can take up to a year. Following your doctor’s advice, attending physical therapy, and avoiding heavy activity will help you heal more smoothly. Everyone’s recovery time is different.
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How long does a knee replacement last?
A knee replacement usually lasts 15 to 20 years for most people, however recent advances in technology may allow the knee replacement to last longer. How long it lasts can vary based on your health and activity.
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Can you kneel after knee replacement?
Yes, most people can kneel after knee replacement, but it’s important to take it slow and follow your doctor’s advice. You might feel some discomfort at first, and your knee may not move as easily right away. With time, strength and proper technique, kneeling should get easier.
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Can you run after knee replacement?
Running after knee replacement is usually not recommended because it can stress the joint and cause discomfort or damage. Instead, low-impact activities like walking, swimming or biking are better options. Always check with your doctor before attempting running, and if approved, start slowly and gradually increase intensity.
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How painful is knee replacement surgery?
Knee replacement surgery can be painful, especially in the first few days, but the discomfort is usually manageable with medication. It gets better over time, and physical therapy helps you regain strength and mobility, which helps with the pain. Most people find the pain after surgery much less than what they experienced before.
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What are knee replacements made of?
Knee replacements have three parts: a metal femoral component (top), a metal tibial component (bottom) and a piece of plastic in between the two metal pieces. If your surgeon resurfaces your kneecap joint, the patellar component (kneecap) is made of metal or plastic. Your surgeon may choose materials like cobalt-chrome alloy, titanium or other metal or plastic based on what's best for your health, needs and activity level.