Revision Knee Replacement

The knee is the largest joint in the human body and proper function and health of the knees is required to perform most everyday activities. The knee is made up of the lower end of the femur (thighbone), the patella (kneecap), and the upper end of the tibia (shinbone). Articular cartilage, which is a smooth substance that protects the bones and allows them to move freely, covers the ends of the three bones and acts as the main "shock-absorber". Between the femur and the tibia are two C-shaped cushioning wedges known as the menisci that act as the secondary "shock absorbers". Large ligaments (tough bands of tissues) help hold the femur and the tibia together in order to stabilize the joint by preventing excessive movement. The lining joint is covered by the synovial membrane, which is a thin lining that releases fluid that lubricates the cartilage, reducing the friction within the knee joint and providing nutrition to the cartilage. All of these components work together to facilitate proper function of the knee.

Overview

If the knee experiences severe damage due to arthritis or traumatic injuries, performing simple, day-to-day activities can become very difficult. An individual might even start to feel pain while sitting or lying down. If non-operative treatments such as medication, injections, and the use of assistive walking devices such as walkers or crutches are no longer helpful, a total or partial knee replacement might be a good solution. These implants are made to last upwards of 15 years, but when a knee replacement no longer functions correctly, revision surgery is often required where the old prosthetics are replaced with new ones.

With wear and tear, the original components of a knee replacement break down and possibly loosen from the surface of the bones to which they were previously attached. This loosening can cause significant pain and instability in an individual's day-to-day activities. In such cases, a revision knee replacement surgery might be a viable option. Revision knee replacement involves replacement of some or all of the prosthetic implants from the primary knee replacement. Due to the alterations made to the bone structure during the original knee replacement surgery, a revision is more complex than the original procedure.

Symptoms

Individuals who require a revision knee replacement surgery typically experience these symptoms:

• Diminished stability and/or reduced function of the replaced knee joint
• Pain or infection after the initial knee replacement surgery

Diagnosis

Failure of a total knee replacement can be diagnosed with a patient history, physical examination, as well as imaging studies.The physician will examine the knee for the symptoms mentioned above along with assessing the motion, stability, strength, and overall alignment. The physician will obtain X-rays or blood work to look for infections and to determine the extent of damage and deformity in the knee. The physician will educate you on the benefits from this surgery as well as what to expect post-operatively.

Treatment

A revision knee replacement can take anywhere between two to four hours to complete and occurs in the following order:

• Removal of Old Implants - During this step, the old components that are loose or worn from their original attachment are carefully removed to avoid loss of underlying supportive bone.
• Bone Preparation - If cement was used in the previous knee replacement surgery, it is carefully removed from the bone surfaces. The damaged bone is then removed.
• Replacing Components - The bone surfaced removed from the previous step is then replaced with prosthetic fittings that match with the new components. The new components may have stems to reinforce the components to the bone
• Resurfacing the Patella - Depending on the integrity of the patella and the physician's preference, the undersurface of the patella may be cut and resurfaced with a plastic "button". If the button was removed during the initial step, it is replaced.
• Reinserting a Spacer - In order to create a smooth, gliding surface, a medical-grade plastic spacer is reinserted between the femoral and tibial component.

Recovery

After a revision knee replacement surgery, there will be some pain, but the medical team will provide the proper medication to make the patient as comfortable as possible. Walking and knee movement will being soon after the surgery where a physical therapist will provide instructions on the specific exercises to strengthen the leg and restore knee movement to allow for walking and other activities post operatively. The majority of the recovery process will occur at home where proper care must be taken in terms of wound care, diet, and activity as prescribed by the physician and physical therapist. Patients who have undergone revision total knee replacement surgery generally resume most activities six to eight weeks post operatively. Each patient is unique, so the recovery period will vary depending on the level of activity the individual hopes to resume; this should be discussed with the physician as well as the physical therapist.

Disclaimer

CALL 911 IMMEDIATELY IF YOU ARE HAVING A MEDICAL EMERGENCY!

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