While a Total Knee Replacement can lead to a more active life without chronic knee pain for most people, the replacement may, over time, begin to fail and your surgeon may recommend a second, or revision, surgery. Although most total knee replacements are very successful, the primary implant could fail from a number of factors. These can include an implant loosening from the underlying bone due to wear and tear, infection, or instability of the ligaments around the knee.
Revision surgery is different from the initial primary total knee replacement and is generally a longer, more complex procedure. The primary replacement procedure replaces the joint of the knee with a metal implant involving three components. The revision surgery however, may involve replacing a single component or all three components. The revision involves removing the affected component(s) and rebuilding the bone around the knee with components with longer stems to provide more stability and fit more securely.
For more information and illustrations, check out the American Academy of Orthopaedic Surgeons website at: http://orthoinfo.aaos.org/topic.cfm?topic=A00712