Physical Therapy After Partial Knee Replacement Surgery

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If you have knee pain due to osteoarthritis (OA), you may benefit from physical therapy to decrease your pain, improve your knee ​range of motion and strength, and improve your overall function. But what if conservative measures like PT and exercise aren't enough to help you return to your full function?

If you continue with knee pain and decreased function, a total knee replacement operation may be necessary to help restore your knee function. Sometimes only one part of your knee is damaged by osteoarthritis, and replacing the entire joint is not necessary. If that is the case, your surgeon may elect to have you undergo a partial knee replacement surgery.

Partial knee replacement surgery, also known as semi-knee replacement or unicompartmental knee replacement, is usually performed when only one side of your knee joint is damaged by OA.

Woman on stationary bike with physical therapist giving advice
Trevor Adeline / Caiaimage / Getty Images

Anatomy of the Knee Joint

Your knee joint is a hinge joint that is comprised of your thigh bone articulating with your shin bone. Your kneecap, or patella, is a small bone that also glides and slides within your knee joint. If you have OA, sometimes the inside and outside part, along with the underside of your patella, is damaged.

Occasionally, only one part of your knee is damaged by the OA.Usually, the medial, or inner, part of your knee exhibits the wear and tear along the cartilage that lines the joint. When this is the case, only the damaged part of the joint needs to be replaced, and a partial knee replacement may be performed instead of a total knee replacement.

Types of Physical Therapy

In the Hospital: On the first day after your surgery, an acute care physical therapist will visit you in the hospital to perform an initial assessment. He or she will measure your knee range of motion and strength and assess your overall functional mobility. Your PT may also measure the amount of swelling around your knee and assess your surgical incision to look for signs of infection.

After surgery, your healthcare provider may have you use a continuous passive motion (CPM) machine to help improve your knee range of motion. Your PT can teach you how to use the CPM machine.

Your physical therapist will teach you basic knee exercises to perform while in the hospital. These exercises are designed to help improve your knee range of motion and improve the strength of your quadriceps, hamstrings, and hip muscles. Be sure to perform your exercises as instructed and ask questions if you have any.

Immediately after your partial knee replacement, you can expect to be using a standard walker or a rolling walker for ambulation. Your physical therapist will make sure it is sized correctly and teach you how to use your walker properly.

You should expect to spend about 2 to 3 days in the hospital, although your surgeon may discharge you to home a day early if you are doing well. If you are having difficulty with basic functional mobility like walking, moving in bed, or climbing stairs, your healthcare provider may have you stay a few extra days to maximize your mobility and safety before you go home.

At Home: Once you are discharged from the hospital, you may benefit from physical therapy at home to help you continue your rehabilitation. Home physical therapy is usually reserved for people whose circumstances do not allow them to leave their home to attend outpatient PT. If you live alone and are unable to drive, for instance, you may benefit from home rehabilitation for a week or two until you are able to safely leave your home to attend outpatient physical therapy.

At home, you can expect your physical therapist to continue working on range of motion and strengthening exercises to help improve your functional mobility. If you have stairs in your home, he or she may have you practice stair climbing to maximize your safety on the stairs.

When you first arrive home from the hospital, you may still be using a walker to get around your house. Your physical therapist can help you with gait training, and he or she can assess when it is time to progress to using crutches or a standard cane for walking.

If your surgical incision has healed, your home PT may assess the scar tissue that has formed as the result of surgery. He or she may perform scar tissue massage and mobilization. Your PT can also teach you how to perform scar massage on yourself to ensure that the skin and underlying tissue are moving properly. You can expect your partial knee replacement incision to be smaller than a total knee replacement incision.

Once you are walking independently and are able to safely leave your home, your home care physical therapist will discontinue rehab at home, and you can attend therapy at an outpatient clinic.

In the Outpatient Clinic: You can expect your first visit to the outpatient physical therapy clinic to be an initial evaluation. Your physical therapist will interview you to gain information about your current status as well as learn about your prior level of function and your goals for physical therapy.

Your physical therapist will measure your knee range of motion and strength, assess the swelling around your knee joint, and assess your overall mobility. A gait analysis may be performed to evaluate the way you are walking.

Your physical therapist may also assess the strength of your hips because hip muscle strength is important for proper walking and for maintaining healthy knees. Specific hip exercises may be prescribed to help keep your hips strong.

A well-equipped outpatient clinic may have specific machines to help improve the strength in your legs and around your knees. Stationary biking may be a part of your partial knee replacement rehab program as this can help maximize your knee range of motion and muscular endurance.

Sometimes specific therapeutic modalities like heat or ice may be used to help control your pain and decrease swelling. A type of electrical stimulation called neuromuscular electrical stimulation (NMES) may be used to help improve the contraction of your quadriceps muscle.

Gait training should continue to be a focus of your rehab after partial knee replacement surgery. Your physical therapist can help you progress to walking with a cane to being able to walk with no assistive device.

Overall, the main focus of physical therapy after partial knee replacement surgery is to decrease your knee pain, restore normal knee range of motion and strength, and help you return to your previous level of function.

Length of Treatment After Partial Knee Replacement

You can expect the rehabilitation after your partial knee replacement surgery to last for 2 to 3 months. Everyone heals at different rates, and everyone's specific condition is different, so your rehabilitation may be shorter or longer depending on your specific circumstances. Be sure to work closely with your healthcare provider and physical therapist to understand your progress after surgery.

A partial knee replacement may be necessary if you have OA in one specific part of your knee joint. After your surgery, you may encounter a physical therapist in the hospital, at home, and in the outpatient clinic. Physical therapy after partial knee replacement may help you quickly and safely return to your previous level of function.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Campi S, Tibrewal S, Cuthbert R, Tibrewal SB. Unicompartmental knee replacement - Current perspectives. J Clin Orthop Trauma. 2018;9(1):17-23. doi:10.1016/j.jcot.2017.11.013

  2. Lespasio MJ, Piuzzi NS, Husni ME, Muschler GF, Guarino A, Mont MA. Knee Osteoarthritis: A Primer. Perm J. 2017;21:16-183. doi:10.7812/TPP/16-183

By Brett Sears, PT
Brett Sears, PT, MDT, is a physical therapist with over 20 years of experience in orthopedic and hospital-based therapy.