Total knee replacement components are usually attached to the bone using bone cement. There are techniques which do not use cement, rather a coating on the implant to encourage bone to grow onto it. In either case, the attachment of implants to bone can fail. This can happen very early on if there has been a technical problem with implantation surgery, but more usually it happens a number of years after surgery. The bearing surface also contains a section of a very high density plastic: this too wears out with time. Unfortunately, there is usually a degree of damage to the bone at the same time; this can be quite extensive in some cases.
It is important that your surgeon has a range of options available to him to reconstruct the knee after failed knee replacement. This may include advanced surgical approaches, complex implants and even custom made components in some cases. The results of revision knee replacements have historically been quite poor - particularly with problems of ongoing pain and stiffness. They are improving with use of modern techniques and very careful selection of the right operation to deal with each patient's unique situation.
Where bone has been damaged, it can be replaced with bone graft or metal substitution. You may require scans to help in the decision making processes if this is required. Please discuss this with Mr. Miles, who will be happy to explain why he has chosen the implants he recommends for your operation.
It takes a long time to recover after a revision knee replacement: typically it takes a year to get full function back. It is important that you work with a physiotherapist to regain your range of motion, strength and stability after surgery.