Development of a discrete choice experiment design to explore how patient characteristics influence preferred...

Currently it is unclear how patient characteristics influence orthopaedic surgeons' decision-making in choice of implant and fixation. The aim of this study was to develop a discrete choice experiment (DCE) design to explore how patient characteristics influence surgeons' choices of implant fixation in total hip replacement (THR) in a national survey in the UK.

We followed a three-stage process to develop the DCE design. In stage 1, we used evidence from a literature review, expert panel of five surgeons, and Think-Aloud interviews with two surgeons to develop attributes and levels to describe patient profiles. In the stage 2, we developed a D-efficient experimental design for the survey. In stage 3, we pre-tested the survey using cognitive de-briefing with three surgeons and piloted the survey with ten surgeons.

Final attributes and levels were: age (55,65,75,85 years), sex (female, male), medical condition measured by ASA grade and BMI (3 levels: ASA III and BMI is ≥ 40; ASA III and BMI <40; ASA I or II and BMI < 40), patients' expected physical activity level after the surgery including sports, everyday activities and employment (mostly inactive, moderately active, very active), and surgeons' perception of the risk of periprosthetic fracture (high risk: yes, no). We generated an efficient experimental design with 40 patient profiles divided into 4 blocks of 10 profiles to be randomly distributed across respondents. Pre-test of the survey with cognitive debriefing confirmed the feasibility of the DCE task.

We co-developed a DCE design with orthopaedic surgeons to explore how patient characteristics influence THR fixation methods in a survey among UK orthopaedic surgeons. Results of the DCE will inform 1) the design of a large randomised controlled trial (HIPPY) that aims to find out which hip implant fixation (cemented, uncemented, or hybrid) is the most effective and cost-effective for patients aged under 70 years, undergoing primary elective THR and 2) the implementation strategy of trial findings into clinical practice.