Alpha Defensin use in Periprosthetic Joint Infection revision surgery
Research type
Research Study
Full title
Alpha Defensin use in Periprosthetic Joint Infection revision surgery
IRAS ID
237090
Contact name
Lucy Walker
Contact email
Sponsor organisation
Newcastle-upon-Tyne Hospitals Foundation Trust
Clinicaltrials.gov Identifier
ISRCTN94873042, ISRCTN; 6415, Caldicott application
Duration of Study in the UK
1 years, 0 months, 1 days
Research summary
When the body is responding to infection is releases substances called biomarkers to help it fight the infection. One of these biomarkers is called Alpha defensin. It has been shown by previous research that the levels of alpha defensin increase when a patient has infection around a hip or knee replacement. Testing for alpha defensin has been shown to be as good, if not better, than the tests currently used to detect infection. Currently, the standard way of testing for infection is to take samples of fluid and tissue from around the joint and send them to the microbiology laboratory to see if they then grow any ‘bugs’. It can take several days for this to happen and to get the final result. The advantage of alpha defensin is that it can be tested using a ‘pregnancy test’ type device, called Synovasure, which gives you a result within ten minutes.
When a hip or knee replacement is infected it can be difficult to treat. The best chance of getting rid of the infection completely is to take out the joint replacement and thoroughly clean out the remaining bone and soft tissues – this is called ‘first stage revision surgery.’ The patient is then left without a joint replacement for a period of time, ranging from hours to several weeks depending on surgeon preference. During this time the patient is also given a course of antibiotics. Following this time period the surgical team use blood tests and assess how well the patient is, to decide whether they think the infection has been fully treated or if infection is still present in the joint. If these tests suggest the infection has gone the patient then has a new joint replacement – this is the ‘second stage revision surgery.’ If the surgeon thinks the infection is still there then the patient may need the joint washing out again, or more antibiotics. However, using blood tests and judging how the patient is, is not a very reliable way of deciding whether there is still infection or not.
At the moment, the best way we have of deciding if there is still infection present in the joint is to take more samples during the second operation, when a new joint might be being put in if the patient is well and has normal blood tests. These samples are currently then sent to the microbiology laboratory to see if any bugs are growing, but again this takes several days by which time the patient already has their new joint put in. If the samples taken do grow more bugs, and the patient has a new joint put in, this puts the patient at risk of the new joint replacement also getting infected, meaning that they may have to go through several more operations . If a test for infection could be done during the second operation that gave you a results within minutes, like the alpha defensin Synovasure test, this could stop a new joint replacement being put into a patient with ongoing infection. That would then mean that the patient would not be at risk of getting another hip or knee replacement infection leading to multiple further operations and even amputation.
The research team for this project are aiming to show whether the alpha defensin test shows positive when there is infection around a hip or knee replacement and then if it goes negative once the infection is successfully treated. Alpha defensin Synovasure tests could then be used to show that it is safe to put a new joint replacement in a patient at their second surgery.REC name
North East - Newcastle & North Tyneside 1 Research Ethics Committee
REC reference
18/NE/0063
Date of REC Opinion
19 Mar 2018
REC opinion
Further Information Favourable Opinion