Purpose <p>Traumatic bone defects are complex injuries associated with prolonged disability and limited reconstructive options. Three-dimensional printed (3DP) patient-specific implants provide anatomically matched, mechanically tailored solutions. This review synthesizes current clinical evidence regarding their use, effectiveness, and safety in trauma-related bone defects.</p> Methods <p>MEDLINE, Embase, and Scopus were searched from inception to February 17, 2025. Human studies reporting clinical outcomes of custom 3DP implants for traumatic bone defects were included. Two reviewers independently screened studies, extracted data, and assessed methodological quality using the MINORS tool. Owing to heterogeneity in anatomy, defect characteristics, adjunctive procedures, and outcome definitions, a meta-analysis was not performed.</p> Results <p>Twelve studies comprising 108 patients met inclusion criteria; most were retrospective, non-comparative case series (predominantly Level IV evidence). Titanium-based implants were most common (92 patients), followed by tantalum (9) and polyetheretherketone (5). Defect sites included the humerus, forearm, femur, tibia, and calcaneus. Union assessment methods varied, but confirmed union was frequently reported. For tibial defects, union was confirmed in 13/20 patients; four had indeterminate imaging and three declined a planned second-stage procedure. Functional outcomes generally improved. Reported complications were typically manageable, and no catastrophic implant failures were described, although follow-up duration was limited.</p> Conclusion <p>Current evidence suggests that patient-specific 3DP implants are a feasible reconstructive option for selected traumatic bone defects. However, evidence certainty remains very low, and prospective comparative studies with standardized reporting are required.</p> Level of evidence <p>IV (systematic review of primarily Level IV case series and retrospective studies).</p>