Research Update - Orthopaedic Infection Trial

September, 2020

Over 114,000 joint replacement procedures were performed in Australia in 2015 and demand for this surgery will likely double over the coming decades.

A devastating complication of joint replacement surgery is surgical site infections (SSIs) which occur in 5-7% of patients. These infections are associated with significant patient morbidity including prolonged hospitalisation, reoperation, immobility, pain and, in recalcitrant cases, amputation of the affected limb. Furthermore, SSIs are associated with a five-fold increase in mortality.

A four-year multi-centre trial in Australia is searching for a preventative answer to reduce the risk of infection for patients undergoing hip and knee replacement surgery. The Australian Surgical Antimicrobial Prophylaxis (ASAP) Trial is being led by the Infectious Diseases Department at Monash University and is being undertaken across 11 hospitals. Launceston orthopaedic surgeon, Dr Jonathon Mulford is the site investigator for the LGH and Calvary St Lukes and locally supported by the Clifford Craig research team.

Study Design
This randomised, multicentre, double-blind, placebo-controlled trial compares the incidence of SSIs, safety and cost-effectiveness of surgical treatment to prevent disease (prophylaxis) with cefazolin antibiotic plus vancomycin antibiotic to that with cefazolin plus placebo. The study will be performed in 4450 enrolled patients undergoing elective or expedited joint replacement surgery.

Methods
All patients will receive cefazolin as part of standard care. Participants will be randomly assigned in a ratio of 1:1 to either the standard care arm or the intervention arm. The intervention group will receive 1.5g intravenous vancomycin prior to surgical incision as a single prophylactic dose. The control group will receive normal saline placebo prior to surgical incision as a single prophylactic dose. Participants will be followed for 180 days following index surgery to capture all relevant clinical and health economic outcomes.

What will impact will this research have in 5 years’ time?

This study may change standard antibiotic prophylaxis for hip and knee arthroplasty patients around the world. It may also assist in reducing the risk of infection following arthroplasty surgery. Given the rising amount of hip and knee arthroplasty, this could benefit many patients and save countless health dollars.

The ASAP Trial has enrolled 2360 patients to date across the 11 sites with Launceston aiming to contribute 450-500 patients.