Total knee replacement is a life-changing surgical procedure that enables people with severe knee pain to start living an active life once more. But, over time – often many years – the artificial knee implant may start to loosen and wear. When this happens, the implant needs to be replaced using a surgical procedure called a revision knee replacement.
What is a revision total knee replacement?
Sometimes only one part of the knee implant needs to be replaced but often all three components need to be removed and replaced with a new implant. This is called a revision total knee replacement. The bone around the knee may also need to be rebuilt using metal components called augments, or using a bone graft.
Because of the likelihood of bone damage, it may be impossible for the orthopaedic surgeon to use a standard implant during a revision knee replacement. In this case, they may need to use specialised implants with longer stems that fit deeper inside the bone for extra support. Due to these additional complexities and the length of time required for surgery, the risks of developing complications after revision total knee replacements tend to be higher than with primary total knee replacements. Infection is a potential complication and this can occur during the surgery itself or afterwards – sometimes many years afterwards. If excessive scar tissue builds up around your knee joint it can limit the range of motion, also leading to the need for revision surgery.
The fact that revision surgery can be more risky, with potentially poorer outcomes than primary knee replacements, is why patients are encouraged to delay for as long as possible before having surgery. We prefer patients to try less invasive treatments like painkilling injections and medication before going down a surgical route as this means there is less chance of requiring a revision knee replacement in the future.
What increases the chances of needing revision knee replacement surgery?
But are there certain factors that make it more likely you’ll need a revision knee replacement?
A team of researchers at the University of Edinburgh set out to explore this question, publishing its findings in The Bone and Joint Journal in 2022. They looked at patients from the Scottish Arthroplasty Project who had undergone total knee replacement surgery between 1 January 1998 and 31 December. The researchers calculated cumulative incidence function for revision surgery and death and used cause-specific Cox regression modelling to determine the impact of individual factors.
Research study
They found that the risk of needing a revision knee replacement ranged between 32.7% for patients aged 45-49 years and 0.6% for patients aged over 90. Men were more likely than women to need to undergo revision surgery (HR1.1 (95%CI1.1to1.2);p<0.001) or to die (HR1.4 (95%CI 1.3to1.4);p<0.001). Having inflammatory arthritis meant patient were more likely to die during the study period, but less likely to need a revision joint replacement.
The researchers found that patients with the highest number of comorbidities (HR 1.4 (95%CI 1.3 to 1.4)) and the most socioeconomic deprivation (HR 1.4 (95% CI 1.4 to 1.5)) had the greatest chance of dying within the study period but were not at increased risk of needing revision surgery.
What the study shows
This study showed that younger patients have a one in three chance of needing to have revision surgery in their lifetime, compared with a one in 159 risk in patients aged 90 or more. This is largely in line with what we would expect, as most artificial implants last 15-20 years so older patients tend to outlive them in many cases. It backs up the current practice of delaying primary knee replacement surgery for as long as possible.
Can I prevent the need for a revision knee replacement?
It is not always possible to avoid having to have a revision knee replacement, unfortunately. While some implants fail as a result of natural wear and tear, others may become infected. A condition called osteolysis can lead to the implant becoming loose or unstable. We generally advise patients to follow the exercises recommended by their physiotherapist after surgery and to avoid doing high impact exercise which can increase the chance of the implant loosening. Maintaining a healthy body weight can help to avoid putting too much pressure on the artificial implant. After surgery, you will be advised of any warning signs to look out for which could indicate the possibility of infection. In some cases, this can be treated by washing out any bacteria and replacing the plastic spacer in the implant. However, some serious infections require the implant to be removed altogether.
If you have serious knee pain and would like to discuss a total knee replacement or if you have previous undergone knee replacement surgery and think you may require a revision knee replacement, contact us for more information.
