Barriers to recruitment in paediatric orthopaedic surgical trials : a qualitative study embedded in the Big BOSS trial

Recruitment to randomized controlled trials (RCTs) remains a widely recognized challenge, particularly in surgical and paediatric contexts. The British Orthopaedic Surgery Surveillance (Big BOSS) trial aimed to compare surgical approaches for treating severe stable slipped capital femoral epiphysis (SCFE), a relatively rare but serious adolescent hip condition. Despite national estimates suggesting feasibility, recruitment fell significantly short of targets, and Big BOSS was discontinued. This embedded qualitative study explored the perspectives of consultant surgeons to understand the barriers that contributed to the low recruitment for the trial.

Semistructured interviews were carried out with 24 consultant surgeons from 21 NHS sites, including recruiting, non-recruiting, and setup sites. Participants were purposely sampled to ensure variation in experience and involvement in trials. Data were analyzed inductively and thematically, guided by constant comparative methods.

Five overarching themes were identified: 1) limited availability of eligible patients, with many cases of SCFE either unstable, too mild or managed outside trial centres; 2) challenges in interpreting and standardizing the eligibility criteria; 3) difficulty maintaining clinical equipoise, as surgeons often relied on personal experience and preferred treatment pathways; 4) systemic and logistical barriers, including limited research infrastructure, scheduling complexity, and demands on the resources for trials; and 5) patient-level factors, such as aversion to invasive procedures, logistical constraints, and predetermined expectations of treatment. Together, these themes revealed how clinical, practical, and ethical tensions limited participation in the trial.

This nested qualitative study highlighted the multifaceted barriers to recruitment in complex surgical RCTs, and showed how embedded qualitative research can help to uncover these challenges and guide the management decisions for trials. The findings emphasize the value of a qualitative investigation to understand the underlying processes and challenges within a trial. This approach facilitates the development of adaptive recruitment strategies, and supports more realistic planning when designing RCTs involving rare conditions or preference-sensitive treatments.