Tehran University of Medical Sciences Journal of Orthopedic and Spine Trauma 2538-2330 12 1 2026 03 06 37 42 Seyyed Hadi Kalantar Assistant Professor, Department of Orthopedic Surgery, Joint Reconstruction Research Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Omid Salkhori Assistant Professor, Department of Orthopedic Surgery, Joint Reconstruction Research Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Nima Bagheri Associate Professor, Department of Orthopedic Surgery, Joint Reconstruction Research Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Seyyed Saeed Khabiri Assistant Professor, Department of Orthopedic Surgery, Joint Reconstruction Research Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Aidin Arabzadeh Assistant Professor, Department of Orthopedic Surgery, Joint Reconstruction Research Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Alireza Talebi Orthopedic Surgeon, Department of Orthopedic Surgery, Joint Reconstruction Research Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Hadi Jahanbin Orthopedic Surgeon, Department of Orthopedic Surgery, Joint Reconstruction Research Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Seyed Mohammadjavad Mortazavi Professor, Department of Orthopedic Surgery, Joint Reconstruction Research Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Hamed Naghizadeh Orthopedic Surgeon, Department of Orthopedic Surgery, Joint Reconstruction Research Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran 2025 09 13 2026 01 26 Background: Segmental bone defects of the lower extremity, particularly involving the femur and tibia, remain a major reconstructive challenge. Traditional techniques such as the Ilizarov method, Masquelet’s induced membrane, and vascularized fibular grafts are effective but often associated with prolonged treatment duration and significant morbidity. Recent advances in additive manufacturing have introduced patient-specific three-dimensional (3D)-printed implants as a promising alternative. Methods: This systematic review and meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was conducted to collect current knowledge on 3D-printed implants of the tibia and femur. Databases including PubMed, Scopus, Embase, and Web of Science were searched from January 2000 to April 2025 for studies reporting outcomes of treatment of tibial or femoral segmental bone defects. Primary outcomes included bone union rate and complications. Study quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) tool, and pooled data were analyzed using a random-effects model. Results: Seventeen studies involving 174 patients were included. The mean bone defect length was 12.3 cm, and the mean follow-up was 27.2 months. The pooled union rate was 92.4% [95% confidence interval (CI): 89.0%-94.8%], with no statistically significant heterogeneity (I2 = 0%). The mean time to radiological union was 7.66 months. The pooled complication rate was 23.5% (95% CI: 15.6%- 33.8%), with reoperation, deep infection, and device-related events being the most common. Assessment of publication bias revealed no statistically significant effect. Conclusion: Custom-made 3D-printed implants represent a highly effective and safe option for the reconstruction of segmental bone defects in the lower extremity. The high union rate and acceptable complication profile support their utility in managing complex cases. Further prospective studies are needed to confirm these findings and define optimal indications.   https://jost.tums.ac.ir/index.php/jost/article/view/712 https://jost.tums.ac.ir/index.php/jost/article/download/712/461