The study describes a technique of tibial autograft to augment posterior instrumented spinal fusion in a population of paediatric patients with severe idiopathic, neuromuscular or syndromic scoliosis who are at a higher risk of postoperative pseudarthrosis and reports patient outcomes in terms of union rate, donor site morbidity and cost. Patients were identified from a review of waiting list and operating room records between 2007–2014. Surgery was performed by the senior author. Information on patient demographics, underlying diagnosis, age at surgery, revision surgery and length of follow-up was obtained from clinic notes. Parents of children were followed up with a structured telephone questionnaire regarding ambulatory status, post-operative pain, infection, further surgery and general satisfaction. Four hundred and nine patients underwent posterior instrumented spinal fusion, during the study period. Forty-two patients’ fusions were augmented with tibial graft, 40 of whom participated in the study. There were no cases of donor site infection, compartment syndrome, tibial fracture or perioperative mortality. In 85% of cases leg pain had resolved within 6 weeks, and 100% within 6 months of surgery. There were 6 cases of revision spinal surgery, 3 for infection, 2 for sacroiliac screw removal and 1 for sacroiliac screw revision. There were no clinical cases of spinal pseudarthrosis in this series. All parents were satisfied by the clinical outcome of both the tibial and spinal surgeries. Spinal fusion utilising tibial autograft is advocated as a simple, safe and cost-effective method of providing significant structural autograft to support fusion for a population of patients with high risk of junctional pseudarthrosis. With the exception of transient post-operative pain, the procedure was without any serious donor site morbidity. The outcomes of this study were as expected and in keeping with previous reports