Title: Feasibility study for a comparative trial of hybrid or cemented implants for total hip replacement. Acronym: HipHOP (Hip arthroplasty with Hybrid Or cemented implants: Patient reported outcomes)
Funder: Department of Health and Social Care

Abstract: Background Total Hip Arthroplasty (THA) is a successful operation with currently 90,000 procedures performed every year in the UK. Due to the ageing population and increasing demand from patients, the numbers of THA performed is predicted to significantly increase over the next 5 years. However, whilst the majority of patients do well following surgery, studies have shown that 10-30% may not improve following THA. Most research investigating factors that affect outcome are cohort studies and analyses of registry data which focus on survivorship of the implants rather than patient function. An NIHR Health Technology appraisal on hip replacement concluded that they were unable to advise on the best prosthesis due to lack of evidence and poor trial quality. The appraisal called for well-designed pragmatic randomised controlled trials (RCTs) and data linking patient-reported outcome measures (PROMs) to implant type. Aim We aim to perform a feasibility study to assess whether a two arm, single-blinded, pragmatic RCT comparing fully cemented versus hybrid THA can be undertaken. Embedded qualitative research and health economic analysis will be conducted to optimise the design of the main trial. Methods Sixty patients with primary osteoarthritis will be recruited and randomised to THA with either a fully cemented or hybrid prosthesis. Surgeons at Wrightington Hospital, UK and Royal Devon and Exeter Hospital, UK will aim to recruit 10 patients each into the study. The primary outcome of this feasibility study will be the ability to recruit the required number of patients within a 12-month period. Recruitment of 80% of our intended sample (48 patients) within 12 months will be considered a successful outcome in that a future full trial would be considered feasible. This feasibility study will also examine several quantitative parameters in the two groups including, but not limited to, the assessment of the Oxford Hip Score, Forgotten Hip Score, Self-Administered Patient Satisfaction Scale, EQ5D-5L and demographic data. Qualitative interviews with patients and surgeons will inform the design and implementation of the larger trial. Output The primary output of the quantitative workstream will be a decision as to whether or not to proceed with the full trial. The data collected will facilitate the design and methodology of the full trial and allow the calculation of an appropriate sample size. The outputs of the qualitative workstream will be an understanding of barriers and facilitators to recruitment for patients and surgeons so that effective interventions, tools and support can be provided during the full trial. This study will inform the submission of a HTA grant application for the full trial. The secondary outputs from the trial will be to publicise the results in scientific meetings, peer reviewed journals and on social media. We will use our PPI group to advise on dissemination via non-scientific media.

Lay abstract: Hip replacement is a common procedure but patients vary in how well their hip works after surgery. The type of hip implant used may affect how successful the surgery is, but there is no clear evidence on which is the best type of implant. We wish to undertake a trial of two types of implant. This application is for a feasibility study to see if the full trial is possible. Sixty patients from a two hospitals will receive either a cemented or a hybrid hip replacement. Patients hip function will be assessed at 6 weeks and 6 months later using standard questionnaires. Our main outcome is the rate of recruitment. We want to know how many patients will agree to take part, how long recruitment will take, and whether patients will complete the follow-up assessments after surgery. We will also learn how many patients will be needed for the full trial. In interviews, we will ask patients about their experiences of the trial and their reasons for taking part; we will also ask people who declined about their thoughts. We will ask surgeons about their willingness to take part in a trial and about any barriers there might be to changing their surgery practice following the full trial results. This topic of research has been discussed with patients at our patient and public involvement (PPI) group and we have received positive feedback that it is important and that patients would be happy to take part. The PPI group will be involved throughout the study, giving guidance with patient information sheets and letters. We will present the findings in scientific meetings and peer reviewed journals and share with professional bodies. Our PPI group will advise on sharing the research findings in social media, newspapers and radio. We would then apply for funding to complete the main trial.

Research activity codes: 6.4 SURGERY
Health categories: MUSCULOSKELETAL