Revision surgery on a previously repaired knee is a complex procedure that requires thorough planning, specialized implants and tools, and sophisticated surgical techniques.

Today’s knee implants can be expected to last 10 to 30 years in most cases. This is a timespan that for many patients represents the remainder of their lives. The increasing longevity of knee implants is due to several factors:

• More surgeries are being performed on older patients, who tend to put lower demands on their implants.
• New materials and techniques have improved the implant’s fixation to bone, which historically has been the weakest link in any surgically repaired joint.
• Innovations in implant technology have significantly decreased the amount of wear particles created by friction on joint surfaces.

However, with increasing numbers of younger patients undergoing total knee replacement, and with seniors continuing to live longer, it becomes a foregone conclusion that many patients will outlast their implants. Our surgeons are currently revising many knees that were first replaced in the 1980s and early 1990s.

Another indication for revision knee surgery is infection or early failure of an implant.

Diagnosis

The decision to perform knee revision surgery is based on several factors. The joint may become painful or swollen, due to implant loosening, wear or infection. The function of the implant may decline, resulting in a limp, stiffness, or instability. Finally, comparison of x-rays may reveal a change in the position or condition of the components.

Patients who demonstrate one or more of these symptoms and signs may be candidates for knee revision surgery. To confirm the need for the procedure, a standard assessment is performed by your surgeon. It includes a patient history and physical examination, as well as various laboratory tests, x-rays and other radiographic studies.

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Nonsurgical Options

Pain resulting from a failed joint replacement may initially be treated with an increase in pain medication or other nonoperative options. This approach is subject to a number of limitations and drawbacks, including side-effects ranging from drowsiness to gastrointestinal upset and constipation.

Revision may be postponed through increased reliance on a gait-assistive device such as a cane or walker. Likewise, a brace may help eliminate episodes of joint instability. However, many patients find such measures overly cumbersome.

Simple modification or restriction of activity can itself be a form of symptom management. The less active a patient is, the less likely he or she is to be symptomatic.

Finally, in the case of an infected joint, some symptoms can be controlled through the use of suppressive antibiotics. The success of this approach has been mixed, and in any event is unlikely to eradicate the actual infection without surgery.

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Proceeding With Surgery

All joint revisions involve an assessment of the quality of the existing bone, removal of the previous implant (or parts), reconstruction of the remaining bone and soft tissue, and insertion of a new implant (or components). In knee revision surgery, consideration must be given to the femur (thigh bone), tibia (shin bone), and patella (kneecap) components.

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Before Surgery

Donation of blood may be necessary prior to the operation, due to the extensive dissection that is often required in revision surgery. As with other types of joint surgery at Plaza, administration of antibiotics begins just before the start of a revision procedure, to help prevent infection.

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Special Considerations

Revision surgery is likely to involve a more extensive incision than was needed for the primary procedure. The larger incision facilitates removal of the previous implant and any associated scar tissue, and simplifies insertion of the new implant or implant component.

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Special Techniques

The bones of the knee must undergo reconstruction following removal of the previous implant. In some cases, the amount of bone the surgeon has to work with is almost equal to that which existed at the time of the primary procedure. In other cases, more severe bone loss will have occurred, requiring the surgeon to make use of bone graft and/or metallic plates, blocks, and screws.

Once reconstruction is complete, the process of implantation can begin. Several different approaches are possible. The new implant or implant components

• Can be about the same size as the primary implant components, or they can have extensive stems, wedges, and build-ups if bone quality is poor,
• May substitute for damaged or absent ligaments,
• Often rely on cement for fixation, although occasionally uncemented techniques are used.

Once the new components are in place, closure of the surgical site is performed. Antibiotics and blood-thinning medications are continued in the postoperative and recovery period.

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Recovery and Rehabilitation

In most cases, physical therapy is initiated no more than 24 hours after the conclusion of the procedure. It continues for up to three months.

Gait-assistive devices, such as a walker or crutches, are employed early in the recovery period. Patients will progress as quickly as possible to a cane. Your surgeon will direct the implementation of your specific rehabilitation program.

Some patients will begin the process of rehabilitation in an institutional setting, while others will opt for home and outpatient therapy.

Restrictions on activity remain in place for six to 12 weeks. The return of strength and a normal gait may take up to two years.

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Conclusion

Knee revision surgery becomes necessary when pain, swelling, limp, stiffness, or instability of the primary implant reach an unacceptable level. In the hands of a fellowship-trained Plaza orthopedic surgeon, a knee revision procedure may represent your best chance for a more active and pain-free future. The orthopedic surgeons at Plaza have published articles and taught other doctors the principles of knee revision surgery.

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Frequently Asked Questions

“What are the main things that can go wrong with a primary total knee replacement, creating the need for revision surgery?”

Some or all of the components of a primary knee implant may need to be replaced for any one of a number of reasons. These include wearing out or loosening of the implant components, as well as persistent infection that resists eradication through more conservative measures.

“What are the steps involved in a knee revision procedure?”

Knee revision surgery requires that the previous implant (or components of it) be removed, along with whatever cement, scar tissue and damaged bone may be present. After any needed reconstruction and remodeling of the remaining bone and joint, the new implant components are positioned and fixed in place, and the surgical site is closed.

“What are the risks of knee revision surgery?”

Complications associated with knee revision surgery are similar to those for the primary procedure. However, the success rate is usually lower than that for primary surgery because the bone is weaker and revision procedures are more complex.

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