Total Knee Replacement

After the first total knee replacement surgery was performed in 1968, knee replacement surgery has continually evolved in its usefulness, effectiveness, and overall success. Developments in surgical practices, coupled with the use of innovative technologies, make the replacement of your total knee one of the most successful surgeries. Knee replacement procedures continue to grow, year over year, with almost a million successful replacements every year in the United States alone. Total knee replacement surgery is a procedure that replaces the infected, and increasingly painful, joint in your knee with space-age materials designed especially for your knee.

If you’re searching for medical information about, as well as expert care for, a knee replacement, look no further. Florida Orthopaedic Institute’s fellowship-trained surgeons are renowned specialists in this field. We hope you find this information helpful in further understanding what a total knee replacement involves.

OVERVIEW

Sometimes total knee replacement procedures can lose their effectiveness over time, either by the components loosening, becoming unstable or stiff, or becoming infected. If this happens, you will most likely need revision knee surgery. This procedure is very similar to a total knee replacement as it involves the removal and replacement of some or all of your current knee components. The procedure itself varies depending on what caused your total knee replacement to fail. The vast majority of patients who have revision surgery experience favorable long-term outcomes, including relief from pain and increased stability and function.

ANATOMY

The knee is a hinge joint, meaning it can only bend in one direction. It is where the tibia, the femur, and the patella meet. Like most joints in the body, the knee has a dense, fibrous, connective tissue, known as articular cartilage, that seals the joint space between the femur and tibia and prevents the bones from rubbing against each other. The articular cartilage acts as a shock absorber and allows for smooth and stable movement. It has three major compartments:

• Medial compartment (the inside part of the knee-toward the other knee).
• Lateral compartment (the outside part-away from your body).
• Patellofemoral compartment (the front of the knee between the kneecap and thighbone).

DESCRIPTION

A revision knee surgery is a follow-up procedure for a total knee replacement. While total knee replacement is an extremely successful surgery, as time passes the knee replacement components can loosen, become unstable or stiff, cause an infection, or the bones around the implant may break. When this happens, your knee can become painful and swollen as well as feeling stiff or unstable, making it difficult to carry on with your daily activities. When this happens, you may need revision knee surgery.

There are different types of revision surgery. In some cases, only one implant or component of the prosthesis has to be revised. In other situations, all three parts of the implant (femoral, tibial, and patellar), need to be removed and replaced, and the bone around the knee will need to be rebuilt with either metal pieces or bone graft.

Although both procedures have the same goal—to relieve pain and improve function—revision surgery is different than a total knee replacement. It is a longer, more complex procedure that requires extensive planning, and specialized implants and tools to achieve a good result.

DIAGNOSIS

Your Florida Orthopaedic Institute physician will check your medical history and overall health, as well as perform a physical examination to determine if you are healthy enough to go through a revision knee surgery. They may also decide to order some tests to determine if this procedure is right for you. These tests can include:

• X-rays. These tests create images of the dense structures inside the body, such as bone. Your physician may order x-rays taken around the area of the joint replacement to check for loosening or a change in the position of the components.
• Magnetic Resonance Imaging (MRI) or Computed Tomography (CT scans). These tests may be used to determine why your knee replacement failed and the condition of the bone.
• Nuclear Medicine Bone Scan. This test can help determine if the prosthesis has loosened from the bone.
• Blood test. If your total knee replacement has become infected, a blood test will show it.

SURGICAL PROCEDURE

During the surgical procedure, you will first be sedated under general anesthesia. Your surgeon will then cut your knee open in the same spot it was opened during your original total knee replacement procedure. Once the incision is made, the kneecap and tendons will be moved to the side to reveal your knee joint.

Your surgeon will examine the soft tissues in your knee to confirm that they are not infected. After, they will assess all the metal and plastic pieces of the prosthesis to determine which parts have become worn, loose, or shifted out of position.

The original implant will then carefully be removed. If cement was used in the original procedure, it will be removed as well. Once everything is removed, your surgeon will prepare the bone surfaces for the revision implant. In some cases, there may be significant bone loss around the knee. If this occurs, metal augments and platform blocks can be added to the main components to make up for any bone deficits.

Lastly, your surgeon will insert the revision implant, repair any surrounding soft tissues that may have been damaged, and carefully test the motion of the joint. A drain may be placed in your knee to collect any fluid or blood that may remain after surgery.

POST-SURGERY

Together with your surgeon, a physical therapist will give you specific exercises to strengthen your leg and restore range of motion so that you may begin walking and resume other daily activities as soon as possible after surgery.

To restore movement in your knee and leg, your recovery team may recommend the use of a continuous passive motion machine (CPM). This device is a knee support that slowly moves your knee while you are in bed. Some doctors believe that the use of a CPM helps restore early range of motion.

Additionally, your physician may prescribe one or more measures to prevent blood clots and decrease leg swelling. These may include special graded compression stockings, inflatable leg coverings (compression boots), and blood thinners.

One of the most serious complications of revision knee surgery is infection. Although infection occurs in only a small percentage of patients, it can prolong or limit full recovery. To prevent infection, you will be prescribed antibiotics both before and after surgery. The risk of infection is slightly higher after revision surgery than after primary total knee replacement.

NEXT STEPS

Contact your Florida Orthopaedic Institute physician to learn more about revision knee surgery.