Introduction: Surgical stabilization of Pauwels Type III femoral neck fractures remains a significant challenge due to high vertical shear forces. While the medial buttress plate is a recognized solution, it requires extensive deep dissection. This study aims to compare the biomechanical performance of various screw configurations combined with either a medial buttress or anteromedial support plate. Materials and methods: Twenty-five third-generation synthetic femurs were used to create a standardized 70-degree (Pauwels III) fracture model. Specimens were divided into five groups ( n = 5): (A) Inverted triangle (IT) screws with a Pauwels screw, (B) Inverted triangle (IT) with medial buttress plate (MBP), (C) Inverted triangle with anteromedial support plate (ASP), (D) L-configuration with medial buttress plate (MBP), and (E) L-configuration with anteromedial support plate (ASP). Axial loading was applied at 2 mm/min until construct failure, defined objectively by the real-time force-distance curve. Results: Although no statistically significant difference was found between groups ( p = 0.102), a large effect size was observed (η² = 0.309). Group C (IT + ASP) demonstrated the highest mean failure load (1695 ± 494.6 N). Conversely, Group E (L-configuration + ASP) exhibited the lowest stability (977.2 ± 195.4 N) with a remarkably narrow standard deviation. The majority of failures occurred as transverse subtrochanteric fractures distal to the implants. Conclusion: The combination of an inverted triangle screw arrangement with an anteromedial support plate demonstrated comparable biomechanical stability to the medial buttress plate, while offering a potentially safer surgical corridor. Conversely, pairing L-shaped screw configurations with anteromedial support plates resulted in the lowest mean ultimate load-to-failure among the tested constructs, likely due to potential stress riser effects.

Introduction: The purpose of this study was to perform biomechanical pull-out comparisons between composite bone blocks and additively manufactured bone models using locked plate and screw systems. The hypothesis posited that the mean pull-out force of the 3D-printed models would demonstrate non-inferior pull-out strength compared to standard composite bones within a clinically acceptable 15% margin. A standardized pull-out mechanism was developed to evaluate its biomechanical reliability and its potential as a customizable alternative. Materials and methods: The study compared three groups: standard composite (Sawbones) blocks and two types of additively manufactured polylactic acid (PLA) blocks (grid and gyroid infill pattern), each measuring the same dimensions with 30% infill and mimicking a Sawbones block with 2 mm cortical thickness. A 6-hole LC-DCP titanium plate was fixed onto bone block models with dimensions of 29 × 170 × 42 mm using four screws, each measuring 36 mm in length, which were inserted perpendicularly and tightened to the same torque levels. Steel cables placed under the plate were connected to a mechanical testing setup, and pull-out tests were conducted to evaluate fixation strength. Seven replicate specimens were fabricated to ensure repeatability and reliability of the results. Results: Mean pull-out forces were 1784.4 ± 79.9 N for Sawbones, 1698.5 ± 134.3 N for Grid PLA ( n = 7), and 1908.7 ± 335.2 N for Gyroid PLA ( n = 7). Statistical analysis using a one-sample t-test showed that both 3D-printed models were non-inferior to the standard Sawbones model within a clinical acceptance margin of 15% ( p < 0.05). Conclusions: Additively manufactured models exhibit mechanical pull-out performance that is statistically non-inferior to traditional composite bone block models. These findings confirm that 3D-printed PLA-based grid and gyroid structures serve as reliable, cost-effective alternatives for orthopaedic mechanical research without compromising mechanical integrity.