What is Knee Replacement?

In total knee replacement surgery, the parts of the bones that rub together (joint surfaces) are resurfaced with metal and plastic implants. Using special, precise instruments, your surgeon will typically remove the damaged surfaces of all three bones (femur, tibia and patella). The replacement surfaces will then be fixed into place.

The surface of the femur is resurfaced with a rounded metal component that comes very close to matching the curve of your natural bone. The surface of the tibia is resurfaced with a metallic component, similar to that same flat surface that has been removed.

This flat metal component holds a smooth plastic piece made of ultra-high-molecular-weight polyethylene plastic that serves as the cartilage. The undersurface of the kneecap (patella) may also be resurfaced with an implant made of the same polyethylene plastic.

What bones are involved in total knee replacement?

Your knee is the largest joint in your body. Three bones make up your knee. Your upper leg (femur) has a rounded end that moves by rolling and sliding across your lower leg (tibia). The last bone is your kneecap (patella). Your patella moves by sliding over your femur. Your thigh muscle (quadriceps) is connected to your tibia through the patella allowing you to extend your knee.

How do I prepare for knee replacement surgery?

Once your doctor and you decide that you need to have total knee replacement, a date will be scheduled for your surgery. The following is a list of things that both you and your surgeon may have you do:

General physical examination;
Donate one to two units of your blood in the event that a transfusion is required (autologous blood transfusion);
Discuss general preparation with your surgeon;
Discontinue use of non-steroidal anti-inflammatory drugs (they may inhibit your blood’s ability to form clots).

What happens during knee replacement surgery?

A small intravenous line will be inserted into your arm on the day of surgery so that antibiotics and other medications can be administered during the surgery. You will be taken to the operating room and given anesthesia. The surgical team will then scrub your knee and sterilize it with a special solution.

Your surgeon will make an incision that will expose your knee joint. Your joint will then be prepared for the implants with special surgical guides and precision instruments to remove the damaged surfaces of the bone and re-align your lower limb. Once the implants are in place, the surgeon will check your knee for proper function and make any necessary adjustments. The incision will then be closed with sutures and surgical staples. The surgeon may then place a tube that will drain fluids out of the surgical site.

A sterile bandage will be placed over the wound and you will be taken to a recovery room.  As the anesthesia wears off and you slowly regain consciousness, a nurse will be there with you. The nurse may encourage you to cough or breathe deeply to help clear your lungs. Once you are fully awake, you will be taken to your hospital room. Your knee will remain swollen and tender for a few days.

What can I expect after surgery?

The surgeon will place you on a rehabilitation program that will help you regain strength, balance, and range of movement in your knee. The program is tailored to each individual patient.

You will typically have a hospital stay of three days. About 24 hours after surgery, you will probably be asked to stand. Within the next 24 hours, you will probably use a device that helps you recover mobility, called CPM machine (continuous passive motion) and you will also probably begin to walk a few steps with the help of a walker. Once your surgeon has determined that you have sufficiently recovered, you will be discharged from the hospital.

Depending on your progress, you may be transferred to a rehabilitation facility for a few more days. Your bandages and sutures will usually be removed before you leave the hospital. Your physical therapist will instruct you in proper home care and may continue to work with you. It is important that you continue your exercises once you are at home.

How soon can I return to normal activities after surgery?

Most patients are able to walk with a cane within six weeks after surgery. Most patients can drive a car within seven to eight weeks after surgery. Your normal daily activities should exclude contact sports or activities that put excessive strain on your joints.

What is unicondylar knee replacement surgery?

Unlike total knee replacement surgery, unicondylar knee replacement surgery is a less invasive procedure that replaces the arthritic parts of the knee where isolated damage is present. Rather than removing the surface of all three bones (femur, tibia and patella) and replace the entire joint, the unicondylar knee replacement allows the surgeon to treat isolated knee damage on the inside or the outside of the knee. However, although unicondylar knee replacement may be an attractive alternative under very specific circumstances, in most cases a total knee replacement is considered to be the preferred procedure. To determine if you are a potential candidate for unicompartmented knee replacement, you should consult your physician.