Ferrero E, et al. - In a multicenter cohort of adolescent idiopathic scoliosis (AIS) patient, experts evaluated the incidence of proximal junctional kyphosis (PJK). They also ascertained the risk factor for PJK. In thoracic AIS, PJK is a frequent complication, occurring 16%, but remains often asymptomatic (less than 3% of revisions in the entire cohort). A greater risk of PJK was seen in the patients with high pelvic incidence and consequently large LL and TK. Postoperative posterior imbalance that can be due to increased LL, insufficient TK or inflection point shift during surgery may be one of the causes of PJK; as demonstrated in ASD.