New research funded by the National Institute for Health Research (NIHR) has identified which groups of people are most likely to develop a severe infection after knee replacement surgery and therefore need the joint replacement redone.

The study, which was the largest ever carried out, found that patients who are under 60 years of age, males, those with chronic pulmonary disease, diabetes, or liver disease, and people with a higher body mass index are at increased risk of having the joint replacement redone due to infection.

The NIHR researchers at the University of Bristol also showed that the reason for surgery, the type of procedure performed and the type of prosthesis and its fixation also influenced the risk of needing revision surgery for infection.

The research “identified key patient and surgical characteristics which influence the risk of revision for infection following knee replacement, and specifically the risk of further surgery for infection two years or more after the initial operation”, commented Michael Whitehouse, reader and consultant in Trauma and Orthopaedic Surgery in the Musculoskeletal Research Unit of the Bristol Medical School

“This information provides me with the strong evidence I need to discuss the risk of infection with my patients undergoing knee replacement and helps us identify strategies to minimise that risk for them”, he continued.

The research was funded by NIHR Programme Grants for Applied Research and supported by the NIHR Bristol Biomedical Research Centre.

Knee replacement, used mainly to treat pain and disability caused by osteoarthritis, is a common procedure, with around 110,000 operations performed annually in the UK. Around 1% of patients experience deep infection - a rare but serious complication of the surgery.