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Partial knee replacement patient enjoying the outdoors again after recovering from the surgery

What is partial knee replacement?

Partial knee replacement, also known as partial knee resurfacing, is a type of arthroplasty (joint replacement) surgery. Unlike total knee replacement, which replaces the entire joint, this procedure replaces only the damaged portions of the knee, preserving as much of the healthy joint as possible.

In a partial knee replacement, the surgeon removes the damaged parts of your knee and replaces them with an artificial joint (known as a prosthesis) made of metal and plastic. This surgery focuses on the inside, outside or kneecap joint part of your knee. Depending on your situation and preference, your surgeon may use robotic technology that can offer a personalized fit and placement of your artificial joint.

Since partial knee replacements use a smaller incision, recovery is typically faster. Most people spend less time in the hospital and can return to their regular activities more quickly than with a total knee replacement.

Who is a candidate for partial knee replacement?

If you have osteoarthritis that causes significant knee pain and affects your daily life, your doctor may recommend having knee replacement surgery. Usually, surgery becomes an option if other treatments are no longer effective.

You might benefit from a partial knee replacement if only one area of your knee is damaged—the inside (medial), outside (lateral) or front between your kneecap and thighbone (patellofemoral). That’s why doctors may refer to the procedure as a “unicompartmental” knee replacement.

You may not be eligible for a partial knee replacement if you have:

  • Ligament damage in your knee
  • Inflammatory arthritis, such as rheumatoid arthritis
  • Significant stiffness in your knee
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How to prepare for partial knee replacement

To determine if you’re a good candidate for partial knee replacement, your orthopedic surgeon will carefully assess your knee pain and overall health.

  • Pain location

    If your pain is mostly on the inside or outside of the knee, partial replacement may be an option. If the pain is widespread, a total knee replacement might be more appropriate.

  • Physical exam

    Your doctor will check how well you can move your knee and test the strength of the ligaments. If your knee is too stiff or the ligaments are damaged, partial knee replacement might not be recommended.

  • Imaging

    To understand the damage better, your doctor will order X-rays to check for arthritis and joint wear. Sometimes, an MRI scan may be used to take a closer look at the cartilage and soft tissue.

    This thorough evaluation helps your surgeon decide the best treatment plan for you, based on your specific needs and lifestyle.

The laminectomy surgery

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Surgeons can perform a laminectomy in one of two ways.

During an open laminectomy, they will make a single large incision to access and remove the lamina. During minimally invasive laminectomies, they make a single small incision and use a tool called a tubular retractor that pushes muscle aside, so the surgeon doesn’t have to cut through it. The surgeon uses imaging to know where to place the retractor and inserts small instruments into it to perform the procedure. Your specific spinal condition will determine which techniques are the best for you, and a discussion with your surgeon will help make that decision.

Depending on your diagnosis, you may have a laminectomy with spinal fusion or a discectomy procedure.

Before the procedure

Follow your doctor’s instructions for eating, drinking and taking medication on the day of your surgery.

Just before the procedure, you will meet with an anesthesiologist. They will talk to you about how the anesthesia will be administered during the procedure. Your surgeon will also talk with you beforehand and mark the surgical site on your knee with a marker. You will be given general or regional anesthesia (a spinal) for the procedure. If you have a spinal, you will be numb from the waist down and also take medicine to help you relax or sleep during the procedure.

During the procedure

Partial knee replacement surgery usually takes about one to two hours to complete. Your surgeon will make a small cut at the front of your knee. Next, your surgeon will prepare the bone by using special saws to remove damaged cartilage. Your surgeon may use robotic assistance to make precise measurements and cuts.

They will then recreate the affected surface of the joint using metal coverings. This is called knee resurfacing. In many cases, the surgeon will use bone cement to attach the metal parts to the bone. Sometimes, surgeons press-fit the metal pieces to the bone, allowing the bone to grow onto them.

The final step is placing a plastic spacer between the two metal implants to help the joint move smoothly.

After the procedure

After surgery, you'll be moved to a recovery room, where nurses will monitor you closely as you wake up from anesthesia. They'll check your vital signs, such as your heart rate, blood pressure and oxygen levels, to ensure everything is stable.

Once you're fully awake and your discomfort is under control, your care team will decide the next steps. Many people can go home the same day, but if your doctor feels you need additional monitoring or support, you may stay in the hospital overnight.

Before you're discharged, your care team will review instructions for managing pain, caring for your incision and starting gentle exercises to help your recovery. If you're going home, make sure you have someone to assist you with transportation and basic tasks as you settle in.

Partial knee replacement recovery

Recovering from a partial knee replacement takes a few months, but most people can get back to their usual activities in about three to six weeks. Your recovery time will depend on factors like your age, overall health and activity level before surgery.

Your surgeon will create a recovery plan just for you, but here are some general tips to help you heal:

  • Use ice to reduce pain and swelling: Apply an ice pack to your knee for 20 minutes several times a day.
  • Elevate your leg: Keep your knee above your heart as much as possible. Use pillows to prop it up while lying down or a footstool when sitting.
  • Take care of your incision: Follow your doctor’s instructions for keeping your incision clean and covered. Ask when it’s safe to shower or change your bandage.
  • Do your exercises: Start the exercises your surgeon recommends as soon as possible. They help strengthen your knee and prevent stiffness.
  • Go to physical therapy: A physical therapist will guide you through safe movements and exercises to help you regain strength and mobility.

Pain management 

It’s normal to feel some pain as you recover, especially in the first few weeks. Your doctor may recommend a combination of prescription pain medication and over-the-counter pain relievers such as acetaminophen to keep you comfortable. Let your healthcare provider know if your discomfort feels unmanageable or if you’re worried about side effects.

Returning to work or school 

Most people can return to work or school after two to three weeks, depending on how much stress the activity puts on your knee. Your doctor will let you know when it’s safe to go back.

Tips for an easier recovery

You’ll be able to walk with a walker soon after surgery, but you’ll likely need help with daily tasks like cooking, cleaning and bathing. Arrange for support from family or friends or ask your healthcare team about resources to help you.

Prepare your home before surgery by:

  • Adding a shower chair or bench
  • Installing grab bars in your bathroom
  • Removing tripping hazards like loose rugs or cords
  • Securing handrails on stairs

These steps will help make your recovery smoother, safer and more comfortable.

patient in need of Partial knee replacement sitting down outside with knee pain

What are the risks of partial knee replacement?

Complications are rare with this procedure, but all surgeries come with some risks. While partial knee replacement can relieve pain for many, some people may still experience knee discomfort or other symptoms.

Rare complications include:

  • Blood clots
  • Infection in the knee or at the incision site
  • Nerve or blood vessel damage
  • Issues with prosthetic implants, such as loosening or early wear
  • Scar tissue formation in the knee
  • Stiffness or reduced range of motion

Your surgeon will explain what to expect after surgery and provide guidance to help minimize the risk of complications.

Frequently asked questions

  • How long does a partial knee replacement last?

    Prosthetic pieces from a partial knee replacement should last at least 10 to 15 years. If arthritis develops in other compartments of the knee, a total knee replacement could become necessary in the future.

  • Why do partial knee replacements fail?

    Partial knee replacements may fail if you develop arthritis in other parts of your original knee, the prosthetic parts loosen or the plastic spacer wears down. When any of these things happen, you may need a total knee replacement.

  • Can you run after a partial knee replacement?

    Yes, you can run after a partial knee replacement, but it's best to wait at least six months. During recovery, try low-impact activities like swimming, cycling or yoga. While most people get back to daily activities, running long distances or marathons isn't the usual goal.

  • What is the recovery time for a partial knee replacement?

    Recovery from partial knee replacement usually takes three to six weeks. With proper physical therapy, you might return to activities like golf in six to 10 weeks. Early on, you'll use a walker or crutches, but by weeks three to four, you'll be walking more easily and can start light exercises.

  • Can I kneel after a partial knee replacement?

    Yes, you can kneel after a partial knee replacement, but it might be uncomfortable at first. Start with soft surfaces and use knee pads for protection. Talk to your surgeon or physical therapist to make sure you’re doing it safely and at the right pace for your recovery.