Abstract:[Objective] To investigate the characteristics and significance of variation in spinal-pelvic sagittal parameters of post-trau-matic thoracolumbar kyphosis (PTK) in elderly. [Methods] A retrospective study was conducted on 65 patients who visited our hospital forsingle-segment PTK patients from January 2018 to December 2020. In addition, 50 patients who visited our hospital for simple osteoporosis(OP) during the same period were used as the control. The spinal-pelvic sagittal parameters measured on X-ray films were analyzed to ex-plore the characteristics and relationship among them. [Results] The PTK group was measured significantly greater thoracic kyphosis (TK)[(40.1±10.1)° vs (34.0±11.8)°, P＜0.05], thoracolumbar kyphosis (TLK) [(38.1±10.8)° vs (19.1±6.6)°, P＜0.05] and pelvic tilt (PT) [(29.5±12.0)° vs (21.2 ±5.9)°, P＜0.05] and sagittal vertical axis (SVA) [(54.4±23.8) mm vs (26.4±18.3) mm, P＜0.05] than the OP group. However,the former had significantly less lumbar lordosis (LL) [(31.7±10.5)° vs (49.7±13.8)°, P＜0.05] and sacral slope (SS) [(20.9±6.4)° vs (30.3±8.3)°, P＜0.05] than the latter. The sagittal imbalance rate proved 53.9% in the PTK group, while 20.0% in the OP group, which was statisti-cally significant (P＜0.05). Regarding correlation analysis, TK was positively correlated with TLK and SVA (P＜0.05), whereas PI was posi-tively correlated with PT and SS (P＜0.05) in the PTK patients. [Conclusion] Elderly patients with PTK do have considerable variation inspinal-pelvic sagittal parameters, and are prone to sagittal imbalance, with forward shift of center of gravity and backward rotation of pelvis.