Now you can predict if a new knee will last prior to surgery

Patients contemplating getting a new knee to help relieve the pain of arthritic joints can now use a simple test to see whether the surgery will be a success. The Patient Decision Support Tool for Joint Replacement was developed by scientists at the University of Sheffield and the University of Bristol, and could prove to be a game changer.

The current system offers patients general information about the risks and benefits of the procedure, but nothing tailored to them as an individual. Deciding on when to get a knee replacement can be a tricky business and mistiming the operation can leave some recipients of the new joint feeling unhappy.

If knee surgery is performed too soon, patients are likely to consider the new joint inferior to their natural knee. Leave it too late and muscles can waste away, as well as deformities emerge, making it harder to recover from the surgery in the long run. Once you add a whole host of other factors in, such as age, weight, health, mobility and levels of pain, it can be difficult to hit the sweet spot in terms of timing.

Now, the new online test will predict how successful the new knee or hip will be and whether pain and day-to-day function will be improved. This will be plotted on a sliding scale from zero, where it is worse than before, up to 48, which will mark an improvement.

Other information supplied by the Patient Decision Support Tool for Joint Replacement includes an estimate of recovery time, the likelihood of a need for repeat surgery within a decade and the chances of dying in the 12 months after the procedure. All of this will help patients to make informed decisions about if and when to go ahead with a knee or hip replacement.

The test is based on data collected from more than a million UK patients that have had knee or hip replacement surgery. It was recorded in the National Joint Registry and has now been used to create an algorithm for the online tool.

More than 220,000 people in the UK receive a new knee or hip replacement every year, making it a very common procedure. Nearly all of the patients seek the surgery as a result of osteoarthritis, with the wear and tear of the joints leaving them in pain and with reduced mobility.

Professor Mark Wilkinson, a consultant orthopaedic surgeon and senior clinical lecturer at the University of Sheffield, hopes the new test will lead to more informed patient choice. They will be better able to decide on when to have the surgery, if it’s right for them and whether they should be trying to lose weight before going under the knife.

He said: “Patients considering a knee or hip replacement want to know how much better they are going to feel after the operation and how long the new joint is going to last. At the moment, it is impossible for GPs and consultants to give each individual patient tailored information about the risks and advantages of joint-replacement surgery specific to them and their lifestyle.

“With this new tool, rather than guessing the risk, they will get a true estimate based on their characteristics. That may totally change their mind about having the surgery.”