What can you expect before and after surgery?

photo of a couple walking along a beach (PantherMedia / Jasper Grahl) After getting a knee implant, you stay in the hospital for about 7 to 10 days. Afterwards, you will usually have three weeks of rehabilitation. 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.

A knee implant (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 for some time. It takes several months to get used to the knee implant 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 implant too.

Knee implants 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 joints.

How can you prepare for surgery and the time afterward?

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 antibiotics. 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.

It’s also a good idea to prepare for the time after your hospital stay – especially if you don’t go directly from the hospital to rehabilitation treatment, but first spend a few days at home. If family or friends aren't available to help you, you can apply to your health insurance 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.

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
  • Flat, well-fitting, non-slip shoes without laces
  • Sneakers
  • A long shoehorn to put on shoes
  • 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 anxiety. Pain after surgery can also be relieved in many ways. Our list of questions for the doctor can help you get answers to your questions. 

What can you expect after surgery?

Rehabilitation starts in the hospital on the day of surgery or the next day. Your 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 weakened. To prevent movements that may loosen or overload the knee implant, 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 implant 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 closed 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 infection. This rare complication has to be treated quickly: If the infection doesn’t go away, the implant 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 implant.

For people who have had a partial (unicompartmental) knee replacement, outpatient physical therapy is often enough. Those who have had a total knee replacement usually have inpatient rehabilitation – typically immediately after leaving the hospital, but no later than two weeks afterwards. The rehabilitation treatment usually takes three weeks. The application for rehabilitation treatment is typically submitted during the hospital stay with the help of hospital social services.

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, flat shoes with anti-slip soles. But many people have a lower risk of falls after getting a knee implant 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 your knee before surgery. The range of motion is measured in degrees: 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 are suitable 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 a knee implant. 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 knee implant:

  • 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 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 knee implant and how fast you are recovering. People can usually return to work after 2 to 3 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 a knee implant – and neither are activities where you have to stand on ladders, scaffolds, 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.