Revision knee arthroplasty involves removing some or all of the parts of the original prosthesis and replacing them with new often specialized implants. These specialized implants have longer thicker stems that fit deeper into the inside of the bone for extra support.
The main reason by far for revision knee surgery is loosening of the components. Occasionally an unstable knee that is giving way will need revised to a special hinged type implant. Also infection is a reason for revision surgery and this will frequently involve a two stage procedure. The first stage involves removal of all the components, a radical debridement and a temporary spacer until the infection has subsided. The second operation then involves putting back in a new replacement a few weeks later. Occasionally a nasty fracture near an existing knee replacement will mean that the knee replacement itself needs to be changed.
Many revision knee replacements are still performed under a spinal anaesthetic, where the legs are numbed from an injection of local anaesthetic into the back. This can be combined with sedation if you prefer not to be aware of the surgery. If a more prolonged procedure is anticipated, then a general anaesthetic may be used but ultimately this is the decision of the Anaesthetist looking after you and can be discussed with them prior to surgery.
The extent of surgery required in a revision knee replacement varies hugely from case to case. In the majority of patients, both components will need to be changed. Occasionally it is possible to replace these with standard components but mostly special revision implants will be required. These implants have stems which sit down snugly in the centre of each bone and provide additional support. Additionally if the knee does not have intact colllateral ligaments, then a special hinged type prosthesis will be needed.
Pre-operative x-rays demonstrating loose femoral component with some femoral bone loss.
Post-operative x-rays with stems on femoral and tibial sides and augments to femur.
Pre-operative x-rays demonstrating a grossly unstable knee
Post-operative x-rays following insertion of a hinged prosthesis
Compiled  October 2015
Review date: March 2016