AIM: To investigate which pedicle level and wall were most affected by screw malposition in osteoporotic and non-osteoporotic patients undergoing thoracolumbar stabilization, and to determine whether significant differences existed between the groups. MATERIAL and METHODS: This retrospective study analyzed pedicle screw malpositions and the specific walls involved in thoracolumbar stabilization procedures performed between 2014 and 2025 using the freehand technique with fluoroscopic guidance by the same surgical team. A total of 972 patients were included: those with a T-score ≤−2.5 (osteoporotic group) and those with a T-score > −2.5 (non-osteoporotic group). Indications for surgery included traumatic vertebral fracture, spinal stenosis, recurrent disc herniation, spinal tumor, or spondylolisthesis. All patients underwent preoperative MRI, CT, bone mineral densitometry, and X-rays, as well as postoperative CT and X-rays. Patients with acute decompression without preoperative densitometry and those treated with vertebroplasty/kyphoplasty were excluded. In cases of malposition, postoperative CT scans were used to evaluate superior, inferior, lateral, medial, and anterior cortical breaches, and comparisons were made between groups. RESULTS: Screw malposition rates were significantly higher in osteoporotic patients across all levels, particularly in thoracic vertebrae. The medial pedicle wall was most frequently affected in this group. CONCLUSION: In osteoporotic patients, transpedicular screw fixation using the freehand technique with fluoroscopic guidance was associated with higher malposition rates, especially involving the medial pedicle wall. These complications may be reduced through greater surgical experience and careful intraoperative technique.