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 1.40, 95% CI (1.08, 1.83), P = 0.01), 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. For patients with Lenke 5 AIS, larger preoperative TK (WMD 7.85, 95% CI (5.69, 10.00), P < 0.00001), larger postoperative TK (WMD 9.66, 95% CI (1.06, 18.26), P = 0.03, larger follow-up TK (WMD 11.92, 95% CI (6.99, 16.86), P < 0.00001, larger preoperative PJA (WMD 0.72, 95% CI (0.03, 1.41), P = 0.04, larger postoperative PJA (WMD 5.54, 95% CI (3.57, 7.52), P < 0.00001), larger follow-up PJA (WMD 12.42, 95% CI 9.24, 15.60), P < 0.00001, larger follow-up SVA (WMD 0.07, 95% CI (− 0.46, 0.60), P = 0.04), larger preoperative PT (WMD − 3.04, 95% CI (− 5.27, − 0.81), P = 0.008, larger follow-up PT (WMD − 3.69, 95% CI (− 6.66, − 0.72), P = 0.02) were identified as risk factors for PJK.