Revision deformity surgery in the growing child is a complex clinical problem. Excellent outcomes can be obtained with meticulous patient evaluation followed by well-planned and well-executed treatment. A multidisciplinary team is crucial to a satisfactory overall outcome. Diagnosis of failed index spine fusion requires a thorough patient history and physical examination, careful patient assessment, and imaging between the index procedure and the presentation for revision and confirmatory testing that validates the diagnosis. Revision surgery may include irrigation and débridement, implant removal, or revision spine fusion with deformity correction. Correction may require either an anterior approach or a posterior approach with osteotomy. For best results, the planned revision must address the mechanism of the failure of the index procedure. If the symptoms or observations are not explained by the diagnosis, then alternative etiologies should be considered.