Total knee replacement is one of the most successful procedures in all of medicine. In the vast majority of cases, it enables people to live richer, more active lives free of chronic knee pain. Over time, however, a knee replacement may fail for a variety of reasons. When this occurs, your knee can become painful and swollen. It may also feel stiff or unstable, making it difficult to perform your everyday activities.

If your knee replacement fails, your doctor may recommend that you have a second surgery—revision total knee replacement. In this procedure, your doctor removes some or all of the parts of the original prosthesis and replaces them with new ones.

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

When Revision Total Knee Replacement Is Recommended

Implant Loosening and Wear

In order for a total knee replacement to function properly, an implant must remain firmly attached to the bone. During the initial surgery, the implant was either cemented into the bone or press-fit to allow bone to grow onto the surface of the implant. In either case, the implant was firmly fixed. Over time, however, an implant may loosen from the underlying bone, causing the knee to become painful.

The cause of loosening is not always clear, but high-impact activities, excessive body weight, and wear of the plastic spacer between the two metal components of the implant are all factors that may contribute. Also, patients who are younger when they undergo the initial knee replacement may "outlive" the life expectancy of their artificial knee. For these patients, there is a higher long-term risk that revision surgery will be needed due to loosening or wear.

In some cases, tiny particles that wear off the plastic spacer accumulate around the joint and are attacked by the body's immune system. This immune response also attacks the healthy bone around the implant, leading to a condition called osteolysis. In osteolysis, the bone around the implant deteriorates, making the implant loose or unstable. Advances in material science and plastic quality have made osteolysis less common today than in past decades.