Development of a discrete choice experiment design to explore how patient characteristics influence preferred fixation method in total hip replacement in the UK

Background

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.

Methods

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.

Results

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.

Conclusion

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.