Posterior fixation is usually performed to restore spinal stability and decompress the spinal canal for unstable thoracolumbar burst fractures. The purpose of this study was to compare trunk and lower extremity kinematics during gait between healthy adults and patients who underwent posterior fixation surgery after thoracolumbar fractures. Optical motion capture was used to record joint kinematics during walking. The angles and excursions of the trunk, hip, knee, and ankle joints in sagittal, frontal, and transverse planes were calculated, averaged, and compared between the patient and control groups. The patient group had significantly reduced hip extension and increased total excursion in the frontal plane, with mean differences of 7.0° in hip extension and 4.2° in total excursion. In the ankle joint, dorsiflexion was significantly reduced with increased plantarflexion, and internal rotation was also increased in the patient group. However, there were no differences in knee joint kinematics. The patient group exhibited a more upright trunk position during walking than the control group, where both peak trunk flexion and extension were significantly different, possibly indicating a stiffer trunk movement. This study provides fundamentals of the joint kinematics of the trunk and lower extremities after posterior surgical operation for thoracolumbar fracture, which may help to evaluate the surgical outcomes.