Custom Three-Dimensional-Printed Implants for Tibial and Femoral Segmental Defects: A Systematic Review and Meta-Analysis

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.