Osteoporotic vertebral fracture (OVF) usually occurs in the thoracolumbar region and rarely affects the low lumbar region. The characteristics of osteoporotic low lumbar fracture (OLLF) have not been reported. Lumbosacral sagittal balance plays an important role in preserving the normal physiologic function of the spine. However, it is unknown how lumbosacral parameters vary in patients with OLLF. The authors retrospectively analyzed the clinical and radiologic characteristics of patients with OLLF and osteoporotic thoracolumbar vertebral fracture (OTVF) who were treated at their institution. Vertebral height, local deformity angle, and visual analog scale and Oswestry Disability Index scores were assessed preoperatively and postoperatively for both groups. The changes in lumbosacral parameters were measured for patients with OLLF. The results showed that OLLF was more likely to occur at L3 (53.66%) and that the prevalence of severe trauma (29.27%) was higher among patients with OLLF (P<.05). The most common morphologic type of the vertebrae affected by OLLF was biconcave (58.54%, P<.05). Patients who had OLLF showed an apparent increase in pelvic tilt and a decrease in local lordosis and sacral slope. Postoperatively, vertebral height, local deformity angle, and visual analog scale and Oswestry Disability Index scores were significantly improved compared with preoperative values (P<.05). Among patients with OLLF, local lordosis and sacral slope increased significantly, whereas pelvic tilt decreased significantly after percutaneous kyphoplasty. Restoration of local lordosis had a mean value of 6.29 degrees +/- 4.80 degrees. These results indicate that OLLF has unique characteristics compared with OTVF and that it results in lumbosacral sagittal imbalance. Percutaneous kyphoplasty is effective and safe for the treatment of OLLF and plays an important role in postoperative improvement of sagittal imbalance.