Your New Knee: Rehab and Physical Therapy

Medically Reviewed by David Zelman, MD on June 30, 2023
4 min read

You’ve just had knee replacement surgery. Your doctor fixed what was wrong, but initially you’ll still feel a bit of pain and stiffness. Now that the surgical procedure is done, it’s your turn to make sure the surgery is a complete success. That means working to restore strength and mobility to your knee.

The process of rehabbing begins the day after surgery. You’ll be up on your feet, probably with the help of a cane, crutches, parallel bars, or a walker. You will meet with a physical therapist who will walk you through a series of exercises to improve movement and increase the blood flow to your legs and feet. That’s important because it prevents blood from clotting.

Your physical therapist will also show you how to get in and out of bed, and how to use the crutches or the walker. A nurse or occupational therapist will show you the best way to dress, bathe, and use the toilet.

Your knee will get stronger as you keep moving. Your therapist may ask you to walk up and down the hospital corridor or outside. They may assist you in climbing stairs. By the time you’re ready to go home, you should be able to bend your knee at a 90-degree angle, bathe and dress on your own, and only use walking aids sparingly.

Your doctor and physical therapist will lay out a series of exercises you should do when you are about to be discharged. Here are some exercise goals they likely will set for you:

  • Walk for short periods -- first inside your house, then outside -- to increase mobility.
  • Slowly climb stairs, do chores, and work on other everyday activities.
  • Continue to do the knee-strengthening exercises that you learned from the hospital’s physical therapist.

Once you leave the hospital, you might move into a rehab facility. At rehab, a team of nurses, physical therapists, and occupational therapists, among others, will put together a program based on your condition and health. In addition to making you stronger, the staff will help you manage any pain you might have. They’ll also show you how to care for yourself when you go home.

Some patients decide to rehab at home. For many, that might not be a bad idea. Studies show that patients who receive physical therapy at home do as well as those who go to an in-patient facility.

What exercises you do and how long you do them depends on your age and your overall health. The length of time you spend rehabbing your knee -- as an inpatient or outpatient -- will vary. Expect to work with a physical therapist for at least a few weeks after your surgery. Most patients can take care of themselves within 3 to 6 weeks.

What can you expect from exercising? For one thing, walking is important. Doctors recommend walking 20 to 30 minutes two or three times a day. The goal is not only to strengthen the knee, but to slow the development of scar tissue that can reduce your range of motion. Other exercises include:

  • Leg lifts: These involve straightening your knee on a bed and tightening your thigh muscles. You then lift your legs off the bed several inches and hold them in that position from 5 to 10 seconds and then lower them slowly.
  • Ankle pumps: Lie on your bed with your ankles hanging off the end. Next, move your foot back and forth. This will strengthen calf muscles and improve circulation in your legs.
  • Short-arc quads: Your quadriceps are a group of muscles that control your knee joint. You can exercise them by lying on your back with your legs extended. Put a pillow under your operated leg. Lift the heel of your operated leg off the bed. Hold for five seconds. Try to do one set of 10 repetitions three times a day.
  • Straight leg raises: Just lie on your back and raise one leg at a time, holding it in the air for 5 seconds. Do one set of 10 reps three times a day.

There are many other exercises that will build up strength in your leg. Your physical therapist can help you with them. In the end, the pain you once experienced will be greatly reduced. You’ll be able to do most things that you’ve done in the past before your knee became damaged.