Minimally Invasive Total Knee Replacement

What is total knee replacement?

Total knee replacement is surgery to replace a damaged knee joint. A minimally invasive surgery uses a smaller cut (incision) than a traditional total knee replacement. This type of surgery typically requires special tools so that the surgeon can see and do the procedure through the smaller incision.

The knee has several parts: the lower end of the thighbone (femur), the upper end of the shinbone (tibia), and the kneecap (patella). A smooth substance called cartilage caps the ends of these bones and keeps the bones from grinding together. When there is damage to the knee joint, these bones may scrape together abnormally and cause pain.

During minimally invasive total knee replacement, your surgeon makes an incision to access your shinbone and thighbone. Next, they remove a portion of the bones that make up the knee joint. Your surgeon replaces these bone parts with metal components that recreate the joint surface. A layer of plastic is placed between the metal components for smooth gliding.

Minimally invasive total knee replacement often takes place under general or spinal anesthesia.

Why might I need total knee replacement?

You might need a total knee replacement if you have significant damage to your knee joint. Different types of medical conditions can damage this joint, such as:

• Osteoarthritis (most common)

• Rheumatoid arthritis

• Osteonecrosis

• Injury or fracture of the knee joint

• Bone tumor in the knee joint

This damage might be very painful and limit your normal activities. The procedure may help decrease your pain, improve your joint mobility, and quality of life. Usually, healthcare providers only recommend total knee replacement when you still have significant problems after trying more conservative treatments, like pain medicines and corticosteroid shots (injections).

Talk with your healthcare provider about the benefits and risks of having minimally invasive total knee replacement instead of traditional total knee replacement. Minimally invasive total knee replacement uses a smaller incision than a traditional knee replacement, so it may lead to less pain and decreased recovery time. But it's not yet clear if the procedure leads to increased risk of certain complications.

In some cases, you may have other surgical options, like shortening the bone or a partial knee replacement. Talk with your healthcare provider about the risks and benefits of all your options.

What are the risks of total knee replacement?

Most people do very well with their minimally invasive total knee replacement. But as with any surgery, the procedure does carry some fairly rare risks. Possible complications of the surgery include:

• Infection

• Excess bleeding

• Blood clots

• Injury to nearby nerves

• Loosening of the components of the knee

• Limited knee motion

• Need for a revision knee replacement surgery in the future

• Stiffness of the knee

There is also a very slight risk that the procedure might not relieve your pain. Your own risk of complications may vary according to your age and your other medical conditions. Ask your provider about the risks that most apply to you.

How do I get ready for total knee replacement?

Ask your provider how you should plan to get ready for your surgery.

Tell your provider about all medicines you are taking, including:

• All prescription medicines

• Over-the-counter medicines such as aspirin or ibuprofen

• Illegal drugs

• Herbs, vitamins, and other supplements

Ask if there are any medicines you should stop taking ahead of time, like blood thinners.

If you smoke, try to quit before your surgery.

If you are overweight, your provider may advise you to try to lose weight before your surgery.

Ask your provider about exercises to do before your surgery to increase leg strength and flexibility. This can speed up your recovery.

Follow all directions you're given for not eating or drinking before surgery.

You may want to make some changes to your house to make your recovery smoother. This includes things like adding a handrail in your shower and removing loose rugs in your home.

In some cases, your provider might want additional tests before you have your surgery. These might include:

• X-rays. These give information about your hip.

• MRI. This gives more detailed information about your hip.

• Electrocardiogram (ECG). This is to check that your heart rhythm is normal.

Follow any other instructions from your healthcare provider.

What happens during total knee replacement?

Your provider can help explain the details of your particular surgery. An orthopedic surgeon will perform the surgery aided by a team of specialized healthcare professionals. The whole procedure may take a couple of hours. In general, you can expect the following:

1. Most likely, you will be given spinal or general anesthesia so that you’ll sleep through the surgery and won’t feel any pain or discomfort during the procedure.

2. A healthcare professional will carefully watch your vital signs during the surgery, like your heart rate and blood pressure.

3. You may get antibiotics, during and after the procedure, to help prevent infection.

4. Your surgeon will make an incision over the middle of your knee, cutting through your skin and underlying tissue.

5. Your surgeon will remove the damaged portions of your thighbone and shinbone, removing a little of the bone beneath as well.

6. Next, metal implants are placed into the joint space, usually cementing them into the remaining bone.

7. In most cases, your surgeon will also remove part of the underside of the kneecap.

8. A plastic spacer is inserted into the space between the metal implants, for ease of movement.

9. The layers of your skin and muscle will be surgically closed.

What happens after total knee replacement?

Talk with your surgeon about what you can expect after your surgery. You may have a lot of pain around your incision after your procedure, but pain medicines may help to relieve your pain. You should be able to get back to a normal diet fairly quickly.

You may get imaging, like an X-ray, to see the results of the surgery. You might be able to go home within several days depending how well you progress.

Your surgeon will tell you when you can put weight on your leg. You may have specific instructions about limiting your movements. You might need to use a walker, crutches, or a cane for a few days or weeks. A physical therapist can help you increase your range of motion and strength. You should be able to go back to most light activities within a few weeks. During this time, you may find it helpful to have some extra help at home.

You might have a small amount of fluid draining at the incision site. This is normal. Let your surgeon know right away if you have an increase in redness, swelling, or fluid leaking out at the incision site. You should also let your provider know if you have high fever, chills, or severe pain that does not improve.

Make sure to keep all of your follow-up appointments with your surgeon. You may need to have your stitches or staples removed a week or so after your surgery.

Most people note a significant decrease in their pain after a total knee replacement. You may have some remaining stiffness in the joint, as well as more limited range of motion.

The mechanical parts of your knee may wear out or loosen over time. Because of this, you may need a revision surgery at some point. But most people will still have functioning knee replacements 15 years after their surgery. You may be able to extend the life of your implant through regular low-impact exercise, while not doing any high-impact exercises (like jogging), and taking steps to prevent falling.

Next steps

Before you agree to the test or the procedure make sure you know:

• The name of the test or procedure

• The reason you are having the test or procedure

• What results to expect and what they mean

• The risks and benefits of the test or procedure

• What the possible side effects or complications are

• When and where you are to have the test or procedure

• Who will do the test or procedure and what that person’s qualifications are

• What would happen if you did not have the test or procedure

• Any alternative tests or procedures to think about

• When and how you will get the results

• Who to call after the test or procedure if you have questions or problems

• How much you will have to pay for the test or procedure