Biomechanical Study of Medial Buttress Plate Combined with Cannulated Compression Screws for Pauwels Type III Femoral Neck Fractures Using Cadaveric Specimens

Purpose To investigate the biomechanical advantages of medial buttress plate (MBP) combined with inverted triangle cannulated compression screws (CCS) in the internal fixation of Pauwels type III femoral neck fractures, and to provide experimental evidence for optimizing treatment strategies for vertically unstable femoral neck fractures. Methods Twelve adult embalmed femoral specimens were used to create Pauwels type III femoral neck fracture models and randomly assigned to two groups: CCS group and CCS + MBP group (n = 6 each). After standardized internal fixation procedures, axial compression, torsional stiffness, and failure load were tested using a Bose ElectroForce 3510 biomechanical testing system, and all measurements were recorded. Differences between groups were analyzed with independent-samples t-tests, with statistical significance set at P  < 0.05. Results Compared with the CCS group, the CCS + MBP group demonstrated significantly higher axial stiffness (562.95 ± 88.26 N/mm vs. 171.02 ± 44.98 N/mm), torsional stiffness (3.24 ± 0.43 N·m/° vs. 2.28 ± 0.51 N·m/°), and failure load (2523.08 ± 432.71 N vs. 1567.88 ± 209.96 N) ( P  < 0.05 for all). Conclusion The combination of MBP and CCS provides significantly greater mechanical stability than CCS alone in Pauwels type III femoral neck fractures. This construct disperses shear forces, improves the biomechanical environment for fracture healing, and may reduce postoperative complications and implant failure risk. These findings provide experimental evidence for optimizing internal fixation design and surgical strategies for vertically unstable femoral neck fractures. Level of evidence: I