DESIGNING A PRAGMATIC ORTHOPAEDIC TRIAL FOR PATIENTS RECEIVING TOTAL HIP ARTHROPLASTY

Pragmatic randomised controlled trials (RCTs) are designed to test the effectiveness of interventions in real-life settings, and it is notoriously difficult to achieve clinical equipoise in surgical trials. The HIPPY RCT aims to recruit 7,866 patients to three groups. Surgeon engagement and an efficient use of the budget is paramount for its success. HIPPY is a pragmatic RCT in 60–100 hospitals to determine whether cemented, uncemented, or hybrid implants are better for patients under 70 in terms of revision rates at 10-years post-surgery. Surgeons were invited to take part in a survey and optional interviews to inform the trial design. The survey included questions on clinical practice and surgeon preference. We engaged with a third-party randomisation provider (Sealed Envelope) to discuss different randomisation options; held initial feasibility meetings with sites who had expressed an interest in taking part; and liaised with National Joint Registry (NJR) and Outcome Registries Platform to collect the primary outcome (revision) at 10 years. Primary outcome data will be collected by linking trial patients to routine national databases (NJR and Hospital Episode Statistics), which will reduce data collection burden at sites. Of the 101 surgeons who responded to the survey, 28 would randomise between all implants, 28 to uncemented or hybrid, 19 to cemented or hybrid, and 12 would not randomise. Feasibility meetings highlighted different preferences across surgeons within the same hospital. Randomisation for the trial has been stratified by surgeon and site to enable surgeons to individually choose which implants they would be willing to randomise between at each hospital they work at. The randomisation system allows surgeons to choose between only two of the three implants compared. The balance of participants across the three groups will be closely monitored and randomisation ratios adjusted if necessary. The HIPPY trial is now open to recruitment until June 2027. The HIPPY RCT was designed to minimize the burden of data collection and processes for sites and patients, and to maximize surgeon engagement by accounting for their preferences for implants in their usual clinical practice.