'The unexpected journey': a qualitative interview study exploring patient and health professionals experiences of participating in the knee arthroplasty versus joint distraction study (KARDS).

Objective: The aim of the knee arthroplasty versus joint distraction (KARDS) randomised trial was to investigate whether knee joint distraction (KJD) is non-inferior to knee arthroplasty, also known as knee replacement (KR). Here we report the findings from qualitative interviews that were part of the planned KARDS process evaluation.

Design And Methods: Semi-structured qualitative interviews with staff and participants in secondary care. Data were analysed using thematic content analysis.

Findings: We were unable to complete the full-planned KARDS process evaluation as recruitment to the trial was closed early but key common themes emerged.Eleven members of staff were interviewed from two KARDS sites (eight initial interviews just after site opening and three follow-up interviews at 12 months). Eleven KARDS participants (six KR and five KJD) were interviewed. One overarching theme emerged: 'An unexpected journey'. This incorporated subthemes including 'an important research question', 'a roller coaster ride', 'lessons learnt', 'managing expectations' and 'a slow recovery'. These encapsulate experiences of both staff and participants.

Conclusion: The information that we were able to collect highlights that providing adequate and comprehensive information about all aspects of treatment including estimated timelines of recovery are essential in clinical trials of novel interventions. Incorporating a comprehensive rehabilitation package following KJD was a key learning. Process evaluations in these complex trials are essential to determine issues as early as possible so appropriate changes can be made to ensure participants have a smooth journey through the trial experience.

Trial Registration Number: ISRCTN14879004.