Revision Total Knee Replacement

What is Revision Total Knee Replacement?

Revision Total Knee Replacement is the replacement of the previous failed total knee implant with a new one. It is a difficult and complex surgical procedure requiring a detailed preoperative planning, extended operating times, special surgical techniques and different types of implants to achieve a satisfactory result.

Why do implants fail?

Wear and Loosening:
Implants are firmly fixed at the initial knee replacement surgery with the use of bone cement, they may become loose over time. Friction between the metal and the plastic component of the prosthetic implant creates tiny particles that accumulate around the joint. In this process, the bond of the implant to the bone is destroyed by the body's attempt to digest the wear particles due to loss of strong bone. The patient may experience pain, change in alignment, or instability after the strong bond in bone and implant is lost. Aseptic loosening is the most common mode of failure of knee implants.

In total knee replacement, the large foreign metal and plastic implants are used to serve as the new joint. This foreign material is inaccessible to antibiotic. With advances in the technique of surgery, better operating rooms and availability of antibiotics, the risk of infection from total knee replacement is less than 1%.

Treatment of infection varies according to the severity of infection. Majority of the patients are better with just a washout and exchange of plastic part of the implants. But in sever infections two separate operations are required. In the first stage removal of the old prosthesis and insert a block of cement with antibiotics and in

second stage surgery is to insert a new prosthesis after the infection is cleared. Intravenous antibiotics are given during this period to eradicate the infection.

If the patients starts getting the feel of giving way while using of the knee or if the patient has frequent fall it could be attributed to instability. Instability can occurs when the soft-tissue structures around the knee are unable to provide the stability necessary for adequate function during standing or walking. Instability may be the result of increased soft-tissue laxity (looseness), inadequate flexion of the implants, or improper positioning or alignment of the prosthesis.

Patient-Related Factors:
Age, activity level and weight can contribute to implant failure. Younger, more active patients have a higher rate of revision than older, less active patients. Obese patients have a higher incidence of wear and loosening.

Periprosthetic fractures (fractures around the knee implants) that disrupt the fixation or the stability of the implant may require revision surgery.

When do you need revision knee surgery and what are the signs?

Failure of the replacement is indicated by an increase in pain or a decrease in knee function. Persistent pain and swelling can indicate problem in the and the possibility of a revision. The decline in knee function may result in a limp, stiffness, or instability. Patients who demonstrate these symptoms and signs may require revision joint surgery.

Getting ready for a revision surgery?

When the decision for revision knee replacement is made, standard assessments are performed, including X-Rays, laboratory tests. X-rays alone at times may not give the exact diagnosis and further imaging investigations like MRI or bone scan can be required. Joint fluid removal with a needle may be required if infection is suspected to identify the organism.

Post Operative period

Post-operative care after knee revision surgery is very similar to the care of a primary knee replacement. Antibiotics for prevention of infection will be continued a little longer in the postoperative period.

Recovery after the revision surgery is usually a little longer as compared to primary knee surgery.

What happens during surgery?

Most revision total knee replacements take longer to perform than primary procedures. The first step is removal of the implant. In some cases, metal wedges, wires or screws may be used to strengthen the bone. Finally, specialized revision knee implants are inserted.

Risks and complications?

increases the chance of surgical complications. Possible complications include:

  • Infection
  • Bleeding
  • Damage to nerves or blood vessels
  • Intra-operative fractures
  • Blood clots
  • PE (Pulmonary Embolism)

Infection, bleeding, damage to nerves or blood vessels, and intra-operative fractures

What should you expect after surgery?

Greater than 90% of patients who undergo revision procedures can expect to have good to excellent results. Although expected outcomes include pain relief with increased stability and function, complete pain relief and restoration of function is not always possible. Up to 20% of patients may still experience some pain following revision knee surgery. This can persist for several years after the procedure.