What can you expect before and after surgery?

Photo of a couple taking a stroll along the beach
PantherMedia / Jasper Grahl

After getting an artificial knee joint, you stay in the hospital for about 7 to 10 days. The surgery is followed by rehabilitation treatment. The aim of rehabilitation is to improve recovery, increase the range of motion of the knee, and help you learn to use your new joint.

If you have advanced osteoarthritis of the knee, an artificial knee joint (prosthesis) can relieve pain and improve your quality of life. But it doesn’t work exactly like a normal knee.

After surgery, it’s important to have rehabilitation treatment. It takes several months to get used to the artificial knee and to be able to move it enough. By that time, the swelling and pain have improved. The muscles and ligaments are then strong enough to fully support the artificial joint too.

Artificial joints have a limited lifespan. But you can do a lot to help them work properly and last longer – such as making active use of rehabilitation treatment and moving the knee afterwards too, with exercise that’s easy on the joint.

How can you find a suitable hospital to have the surgery at?

The site www.endocert.de can help you to find a suitable hospital in Germany. It lists certified centers that implant prostheses inside the body ("endoprostheses") and commit themselves to comply with certain quality requirements. You can also look for a hospital in the "White List" ("Weisse Liste" in German). This is a reference guide published by the Bertelsmann Stiftung foundation and various consumer and patient groups.

In Germany, hospitals are only allowed to perform full knee replacements if they can prove that they do at least 50 of these operations per year. There is no such minimum number of procedures for partial knee replacements. So if you decide to have a partial knee replacement, it's a good idea to look for a hospital that has done this procedure often enough.

How can you prepare for surgery and your stay at the hospital?

You will temporarily have to stop taking certain medications before surgery. It's helpful to your doctors if you take a complete list of your medications to the appointment you have before surgery. It’s also important to tell them about any allergies you may have – for example, to metals or medications like . Metal allergies can cause skin redness or itching, for instance when you wear jewelry or glasses with metal frames, or after skin contact with metal buttons or belt buckles.

If you smoke, you can improve your recovery by quitting a few weeks before surgery. Wounds have been proven to heal better after quitting smoking.

It helps to have the following in the hospital:

  • A tracksuit that’s easy to put on, with wide legs
  • Well-fitting, non-slip shoes without laces
  • Sneakers
  • A long shoehorn
  • A backpack or shoulder bag to transport things when using crutches

Last, but not least: Nobody likes to have surgery, and some people worry about the surgery and the pain afterwards. But various strategies can help you deal with the anxiety. Pain after surgery can also be relieved in many ways. It's helpful to talk about your worries with the doctor before the surgery and to have any remaining questions answered. Our list of questions for the doctor can help you to figure out what you still want to know.

How can you prepare for the time after the procedure?

It's a good idea to start preparing for the time after your hospital stay early enough – especially if you aren't going to have inpatient rehabilitation treatment immediately afterwards. If you are dependent on assistance, you can apply to your health insurer for domestic help or home nursing care.

Before going to the hospital, it also helps to get rid of tripping hazards in your home, like loose cables or curled-up rug edges, and to stock up on food. A non-slip shower mat and a toilet seat raiser can make everyday life easier too.

What can you expect after surgery?

Rehabilitation starts in the hospital on the day of surgery or the next day. The knee will be carefully bent and straightened by a physical therapist. Sometimes it’s also moved using a special device known as a continuous passive motion machine. Studies show that starting rehabilitation treatment earlier can speed up recovery.

After surgery, the muscles, ligaments, and tendons that stabilize the joint are weak. To prevent movements that may loosen or overload the artificial knee joint, you learn how to sit up from a lying position, how to stand up, dress and undress, and how to use crutches safely. In the week after surgery, physical therapy is continued with various exercises.

How quickly the leg can bear your full weight again depends on things like the type of prosthesis you have been given. Cemented artificial knee joints, which is the type most commonly used in Germany, can bear your weight faster than cementless ones can.

How long does it take for the surgical wound to heal?

Some fluid may ooze from the surgical wound in the first few days after surgery. The surgical stitches or staples can be removed about 10 to 15 days after surgery.

If the wound hasn't healed properly within a week or if a fluid is still oozing out of it, it’s important to find out why. Redness, fever and pain can be signs of a joint . This rare complication has to be treated quickly: If the doesn’t go away, the prosthesis may need to be exchanged.

What happens during rehabilitation?

Rehabilitation after knee replacement surgery aims to improve the healing process, help you move the joint more easily, and teach you how to move around with the new knee joint and use it in everyday life. It takes some time to get used to the artificial joint.

The following information describes the situation in Germany. Some things may be done differently in other countries: Rehabilitation can be done in an outpatient, inpatient, or a "short-term" inpatient setting. The application for rehabilitation treatment is typically submitted during the hospital stay with the help of hospital social services. The kind of rehabilitation treatment that is selected depends on various factors, including the type of implant, for example. It's best to discuss the options with your doctors and the hospital's social services.

Rehabilitation typically begins immediately after your hospital stay, or at the most two weeks after you leave the hospital. This kind of follow-up treatment is also known as an Anschlussheilbehandlung in Germany. Inpatient rehabilitation usually lasts about three weeks. If you have outpatient or short-term inpatient rehabilitation, you live at home and go into the hospital during the day.

The rehabilitation treatment consists of various elements, like physical therapy, lymphatic drainage, relearning how to walk, and different types of exercise therapy. Last but not least, you learn what you can do with the implant and how to prevent problems.

During rehabilitation, you will also find answers to questions about going back to work, disability law, and possible pension benefits.

How long does recovery take and what do you have to consider?

It typically takes up to six weeks for the muscles to recover enough to support the joint. After about three months, it’s usually possible to return to work and start doing suitable types of sports. But don’t be disappointed if your recovery takes longer. How well it goes depends on things like your age, muscle condition, general health, type of joint replacement, and motivation.

Especially in the first three months after surgery, it’s best to avoid squatting, kneeling and crossing your legs for a long time, as well as lifting and carrying heavy objects and making sudden, forceful movements. It’s also important to prevent falls – for example by getting rid of tripping hazards in your home and wearing well-fitting, non-slip shoes without heels. But many people have a lower risk of falls after getting an artificial knee joint than they did before anyway. So there’s no reason to be overly careful.

How much can you move a knee implant?

The range of motion of the knee after surgery depends on things like the type of implant and how much you could move it before surgery. The range of motion is measured in degrees of flexion: When your leg is straight, it’s at 0 degrees of flexion, and when it’s at a right angle, it's at 90 degrees of flexion. On average, people who have had a total knee replacement reach a range of motion of 100 to 110 degrees or more in the long term. That’s enough for many activities, like cycling. But it’s not always possible to reach this range of motion.

What types of sports work well after a knee replacement?

Exercise is important after getting a joint replacement too – because strong muscles, tendons, and ligaments support the implant. But the lifespan of an implant also depends on how much strain is put on it. That’s why some activities and sports are better than others for people with an artificial knee. The following are recommended:

  • Going for strolls, Nordic walking and easy hikes in areas that aren't too hilly
  • Cycling (but not mountain biking on bumpy terrain)
  • Swimming, especially strokes with a flutter kick
  • Water aerobics
  • Dancing
  • Light exercises

The following activities put a lot of strain on the artificial joint:

  • Jogging
  • Sports like tennis, squash or soccer, where the joints are exposed to high-impact, rotation or jerky movements
  • Sports with body contact and a risk of falls, like martial arts

For many sports, like golf or cross-country skiing, it depends on how well you could do them before having a knee replacement. When you start a new sport, you're more likely to make risky movements or have accidents due to lack of experience. When cycling, it’s also important to correctly adjust the saddle height. If the saddle is too low, you might have to bend your knee more than when the height is right.

It’s best to talk with your doctor about the activities that may be suitable for you.

Can you return to work and, if so, when?

There’s no one answer to this question either since it depends on your job, your implant and how fast you are recovering. People can usually return to work after two to three months. It is sometimes a good idea to start slowly, working a few hours a day at first and then gradually increasing your hours (known as the “Hamburg model” in Germany).

Jobs where you have to kneel or squat a lot or lift heavy things aren't suitable for people who have an artificial knee joint – and neither are activities where you have to stand on ladders, scaffolding, roofs, or uneven surfaces a lot. Doctors and the social services at the rehabilitation facility can help if you have work-related questions.

You can drive a car as soon as you can easily get in and out of it and safely operate the pedals.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Please note that we do not provide individual advice on matters of health. You can read about where to find help and support in Germany in our information “How can I find self-help groups and information centers?

Updated on August 24, 2021
Next planned update: 2024

Authors/Publishers:

Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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