The British Orthopaedic SCFE Surgery Study for Severe Stable Slips (The Big BOSS Study): A multi-centre prospective randomised superiority trial of an acute deformity correction versus pinning in-situ for severe stable SCFE in children

Slipped Capital Femoral Epiphysis (SCFE) is the most common hip disease of adolescence, akin to a hip fracture. There is strong evidence that childhood obesity is the major cause. In the short-term it requires surgery to stabilise the hip, and typically results in deformity. In the long-term it accelerates the development of osteoarthritis and disability, often necessitating hip replacement in early adulthood. Patient’s with severe deformity face particular uncertainty. Traditionally, the approach to managing severe SCFE is to stabilise the hip with minor surgery, albeit accepting the deformity that may cause pain and arthritis. However, the newer ‘major’ surgical techniques of ‘open reduction’ immediately restores normal anatomy, though this comes with the notable risk of complete collapse of the femoral head with immediate pain and disability. There is growing uncertainty regarding the optimal surgical approach, i.e. traditional ‘minor surgery’ vs. newer ‘major surgery’, which has driven members of the British Society of Children’s Orthopedic Surgery to make this as their top research priority. We propose a multi-centre prospective randomised superiority trial of acute deformity correction versus pinning-in-situ for stable severely SCFE in children aged 8 years and above. We will use well-established networks of children’s orthopaedic surgeons engaged in research; many of whom have contributed to a preceding study in this disease area. The primary outcome is the Patient Reported Outcomes Measurement Information System Mobility Score for Children (PROMIS Mobility). The proposed project is a two-phased study. An internal pilot will confirm the expected rate of recruitment to this trial, and will take place at 30 centres over 12 months. The pilot will determine the number of eligible and recruited patients in centres, optimise electronic data collection procedures and enable qualitative work. The pilot will seek to recruit >0.2 patients/ month/ centre, and has clear stop/go criteria. The main trial will continue to recruit from these centres. With consent, a research associate will collect baseline demographic data, PROMIS Mobility, Wong Baker Faces Pain Score, EQ-5DY, complications, cost-effectiveness and satisfaction. A randomisation sequence, using a minimisation algorithm with stratification factors: age group (8-10 years, 11-16 years) and bilateral disease (presence or absence) will be produced by the trial statistician. Patients will be randomly allocated (1:1) to interventions. Follow-up will occur at 8 weeks during routine clinical care, and thereafter electronically (by email or text message) or by telephone. Outcomes will be collected at 8 weeks, 3 months, 6 months, 1 year and 2 years (Primary outcome time-point). Electronic follow-up will be administered centrally. An embedded qualitative study will occur throughout the trial to inform the development of trial materials and to identify barriers and facilitators to recruitment. This information will be used to develop practical strategies that can be implemented in the main trial to improve recruitment and enhance acceptability of the trial. Consent will be sought from participants to allow potential future follow up through efficient means using linkage to routine healthcare databases, such as the hospital episode statistics, National Joint Registry of England and Wales, and joint registries in Scotland and Northern Ireland.