PURPOSE: Supracondylar fractures of the humerus cause significant morbidity in children. Nerve damage and loss of fracture reduction are common recognised complications in patients with this injury. Uncertainty surrounds the optimal Kirschner wire configuration and diameter for closed reduction and pinning of these fractures. This study describes current practice and examined the association between wire configuration or diameter and outcomes (clinical and radiological) in the operative management of paediatric supracondylar fractures. METHODS: Children presenting with Gartland II or III supracondylar fractures at five hospitals in south-west England were eligible for inclusion. Collaborators scrutinised paper and electronic case notes. Outcome measures were maintenance of reduction and iatrogenic nerve injury. RESULTS: Altogether 209 patients were eligible for inclusion: 15.7% had a documented neurological deficit at presentation; 3.9% who were neurologically intact at presentation sustained a new deficit caused by treatment and 13.4% experienced a clinically significant loss of reduction following fixation. Maintenance of reduction was significantly better in patients treated specifically with crossed ×3 Kirschner wire configuration compared to all other configurations. The incidence of iatrogenic nerve injury was not significantly different between groups treated with different wire configurations. CONCLUSION We present a large multicentre cohort study showing that crossed ×3 Kirschner wires are associated with better maintenance of reduction than crossed ×2 or lateral entry wires. Greater numbers would be required to properly investigate nerve injury relating to operative management of supracondylar fractures. We found significant variations in practice and compliance with the British Orthopaedic Association Standard for Trauma (BOAST) 11 guidelines.