Key takeaways
- Osteoarthritis (OA) is the most common cause of knee arthritis. Knee replacement may help when other treatments are not sufficient.
- Surgeons may perform a total, partial, or bilateral knee replacement. These procedures involve removing damaged bone and cartilage and then placing metal and plastic parts to restore smoother movement.
- Recovery usually includes a 1-night hospital stay, postsurgery physical therapy, and at-home exercises. Many people can resume driving within about 4 weeks of surgery.
Osteoarthritis (OA) is the most common form of knee arthritis and can result in significant pain and disability. Symptoms are often worse with weight-bearing, and in advanced cases, even daily activities can become a challenge.
When movement difficulties and pain levels become too severe, knee replacement surgery may be an option.
There are multiple types of knee replacement surgery:
- Total knee replacement (TKR): replacement of your whole knee
- Partial knee replacement: replacement of only the affected part of your knee
- Bilateral knee replacement: replacement of both knees at the same time
In most cases, people undergo knee replacement surgery because they have OA. TKR is very common — surgeons in the United States perform more than 700,000 TKR procedures each year.
In a 2025 study involving 1,702 people who had undergone replacement of one or both knees,
In most cases, knee replacement surgery is performed under a combination of general anesthesia, peripheral nerve blocks, and spinal anesthesia. You’ll also receive at least one dose of antibiotics to reduce the risk of infection.
During the procedure, the surgeon will remove bone and diseased cartilage from the area where your thigh bone (femur) and shinbone (tibia) meet at your knee joint. They will then replace those surfaces with a metal implant.
The surgeon might also use a piece of special plastic to replace the back side of your kneecap and place the same plastic material between the two metal parts. The plastic provides smooth surfaces on both bones of your knee joint so that it can flex and bend more freely and painlessly.
After surgery
Most people spend 1 night in the hospital after a TKR surgery, but it’s possible that you’ll need to stay longer or that you’ll be able to go home the same day.
Your doctor will prescribe pain medication and monitor you for complications.
Shortly after your operation, a physical therapist will start helping you with the following:
- weight-bearing therapy, including standing and walking
- a combination of physical and occupational therapy to help you adapt to your new knee
You’ll need to continue these exercises at home.
Once you can perform certain tasks, such as getting out of bed alone and using the bathroom, you will be able to go home.
You may need to use a cane or walker for a short time after your operation.
Most of your recovery and rehabilitation will take place at home after you leave the hospital. Some people need home healthcare or assistance.
Your doctor will most likely prescribe physical therapy at a local clinic for continued rehabilitation. The physical therapist at this clinic will suggest exercises you can do at home.
Recovery varies for each person, but most people are allowed to return to driving within 4 weeks of the procedure.
Before your surgery, it may be a good idea to prepare your home for your return.
A few weeks before the procedure, your surgeon will take you through a preoperative evaluation, or pre-op.
They will ask you questions about:
- your overall health
- your medical history
- any medications and supplements you take
- any specific concerns you may have
They will also do the following:
- Carry out tests, such as kidney and lung tests and an electrocardiogram (EKG), to check that you’re ready for the procedure and assess for possible complications.
- Ask you to sign a consent form and provide details of emergency contacts.
- Let you know about any preparations you should make before the day of the procedure. For example, you may need to stop taking certain medications temporarily.
The cost of TKR surgery can vary, depending on where you have the procedure and your overall health at that time.
Other health conditions unrelated to your knees may affect the procedure and cost as well.
When considering the cost of TKR surgery, you should factor in additional costs for:
- your hospital stay
- therapy during your recovery at home
- follow-up appointments and care
- any help you need at home
- transportation costs
You’ll also need to know how much your insurance will cover and how much you’ll need to pay out of pocket.
Exercise plays a key role in preventing knee damage and supporting your knee during treatment and recovery.
Exercise can help prevent joint damage by strengthening the muscles around your knee and helping you avoid unwanted weight gain.
This is true both before and after surgery, whether for a natural or an artificial knee.
Chronic pain and mobility issues can increase the risk of social isolation. Joining an exercise class may be a good way to connect with other people, some of whom may have similar health issues.
Physical activity can also help you feel good and
Which exercises?
Activities that may be helpful include:
- walking
- cycling
- strengthening exercises
- water exercise
- tai chi
- yoga
In addition to exercise, doctors may recommend weight loss to help manage OA in certain people.
After surgery
After a knee replacement, your physical therapist will most likely give you an exercise protocol to follow. It will involve getting back on your feet as soon as possible after surgery and walking a little farther every day.
These exercises will help strengthen your knee and speed up your healing.
It’s important to follow your care team’s instructions carefully so that your recovery stays on track. Doing so can allow you to return to your usual daily activities as quickly as possible and help you create a routine to support your health on an ongoing basis.
You will have pain for a while after your knee replacement, but your doctor will prescribe medication to help you manage it.
It’s important to let your doctor know how well your medication is working and whether you experience any side effects.
Any surgical procedure can involve complications. After knee replacement surgery, there may be a risk of:
- infection
- blood clots
- continuing pain, even when the surgery is successful
- stiffness
Most people do not experience severe complications and are very happy that they had their knee replaced. Your care team will work with you to ensure that the risks are as low as possible.
Replacement knees can wear out, at which point a second knee replacement may be needed. However, a 2019 research review found that
OA is a very common reason that people have knee surgery, but surgery may also be necessary for people with:
- a knee injury such as a ligament tear or meniscus tear
- a structural knee issue that they were born with
- rheumatoid arthritis
Most people who experience knee pain can manage it without ever needing surgery. Your doctor may suggest:
- losing weight
- getting more exercise or following a specific exercise plan
- using over-the-counter or prescription medications
- getting injections
Making the decision
A doctor may perform some tests to find out whether you need surgery, and you’ll have a chance to ask questions.
In most cases, a TKR reduces pain and improves mobility. However, the procedure can be costly, recovery can take several weeks or months, and there is a small risk of complications.
For these reasons, you should learn as much as you can about the pros and cons of knee replacement surgery before moving forward with it.
In a partial knee replacement, the surgeon replaces only the damaged part of your knee.
Compared with a TKR, this procedure has the following advantages:
- It involves a smaller incision.
- You’ll lose less bone and less blood.
- Recovery is usually faster and less painful.
However, if you have a partial knee replacement and later develop arthritis in the parts of your knee that were not replaced, you may need additional surgery in the future.
In bilateral (double) knee replacement surgery, the surgeon replaces both knees at the same time.
If you have OA in both knees, bilateral replacement may be a good option, as it means you’ll have to go through the procedure and the recovery process only once.
However, bilateral knee replacement is a much more intensive surgery than a unilateral replacement, and not every person is a candidate for it. If you do have a bilateral procedure, your rehabilitation will probably take longer, and you’ll likely need much more help during recovery.
Knee replacement surgery is a very common surgical procedure that can improve daily functioning and quality of life.
After surgery and recovery, many people can return to activities they used to do, such as walking, bicycling, golf, tennis, and swimming (although swimming is an option only once the incisions are fully healed).
While any surgery will have some risks, this procedure is considered safe, and most people experience less pain and greater mobility afterward.
Before deciding to go ahead with knee replacement, talk with your doctor about the benefits and risks, including the cost and the amount of time you may need to take off from work.