Abstract
Proximal humerus fractures are common and complex; despite advances, malunion, nonunion, and osteonecrosis remain concerns. Three-dimensional (3D) imaging/printing has emerged to improve classification, planning, and execution, especially in displaced patterns. METHODS: Multiple databases have been searched using predefined terms ("proximal humerus fractures/sequelae", "three-dimensional", and "3D printing"). Inclusion criteria targeted human longitudinal studies (retrospective/prospective) on 3D-assisted fracture or sequela management; expert opinion, prior reviews, and letters to editors were excluded. Data extracted included the design, the level of evidence (LoE), the sample size, 3D application (diagnostic, planning, intraoperative, and combined), outcomes, follow-up, and complications. RESULTS: Nineteen studies were included (fourteen fractures and five sequelae; 636 and 28 patients, respectively). In fractures, 3D imaging was used chiefly for preoperative planning (57.1%) and diagnostic support (35.7%); no intraoperative PSI was reported. In sequelae, intraoperative/PSI dominated (100%), with planning in 80% and combined uses in 80%. Fracture studies were mostly retrospective (50.0%; LoE III 78.6%), while all sequelae were LoE IV-V (60% of case reports). Standardized outcomes were reported in 42.1% of studies; follow-up was available in 42.1% (means ≈ 18 months). Complications occurred in 14.3% of fracture studies and in none of the sequelae. CONCLUSIONS: Three-dimensional printing is primarily applied for planning in fractures and intraoperative guidance in sequelae. While feasibility and potential perioperative benefits are evident, small heterogeneous cohorts and limited outcome reporting warrant larger prospective studies with standardized endpoints.