Incidence and risk factors of proximal junctional kyphosis in adolescent idiopathic scoliosis after correction surgery: a meta-analysis and systematic review

Abstract

Aim To analyze the risk factors of proximal junctional kyphosis (PJK) after correction surgery in patients with adolescent idiopathic scoliosis (AIS). Methods PubMed, Medline, Embase, Cochrane Library, Web of Science, CNKI, and EMCC databases were searched for retrospective studies utilizing all AIS patients with PJK after corrective surgery to collect preoperative, postoperative, and follow-up imaging parameters, including thoracic kyphosis (TK), lumbar lordosis (LL), proximal junctional angle (PJA), the sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), pelvic incidence-lumbar lordosis (PI-LL), sacral slope (SS), rod contour angle (RCA) and upper instrumented vertebra (UIV). Results Nineteen retrospective studies were included in this meta-analysis, including 550 patients in the intervention group and 3456 patients in the control group. Overall, sex (OR 1.34, 95% CI (1.03,1.76), P = 0.03), larger preoperative TK(WMD 6.82, 95% CI (5.48,8.16), P＜0.00001), larger follow-up TK(WMD 8.96, 95% CI (5.62,12.30), P＜0.00001), larger postoperative LL(WMD 2.31, 95% CI (0.91,3.71), P = 0.001), larger follow-up LL(WMD 2.51, 95% CI (1.19,3.84), P = 0.0002), great change in LL(WMD − 2.72, 95% CI (-4.69,-0.76), P = 0.006), larger postoperative PJA(WMD 4.94, 95% CI (3.62,6.26), P＜0.00001), larger follow-up PJA(WMD 13.39, 95% CI (11.09,15.69), P＜0.00001), larger postoperative PI-LL (WMD − 9.57, 95% CI (-17.42,-1.71), P = 0.02), larger follow-up PI-LL(WMD − 12.62, 95% CI (-17.62,-7.62), P＜0.00001), larger preoperative SVA(WMD 0.73, 95% CI (0.26,1.19), P = 0.002), larger preoperative SS(WMD − 3.43, 95% CI (-4.71,-2.14), P＜0.00001), RCA(WMD 1.66, 95% CI (0.48,2.84), P = 0.006) were identified as risk factors for PJK in patients with AIS. Conclusion The incidence of PJK in patients with AIS was 19%. Sex, larger preoperative TK, larger follow-up TK, larger postoperative LL, larger follow-up LL, great LL change, larger postoperative PJA, larger follow-up PJA, larger postoperative PI-LL, larger follow-up PI-LL, larger preoperative SVA, larger preoperative SS and RCA were identified as risk factors for PJK in AIS post-correction surgery.