NEW GENERATION NAIL VS. PLATE IN THE TREATMENT OF UNSTABLE INTERTROCHANTERIC FEMORAL FRACTURE

ABSTRACT Objective: To compare antirotator proximal femoral nail (A-PFN) with antirotator dynamic hip screw (A-DHS). Methods: Fourteen proximal femur models with type 31/A2 fracture, according to the AO Foundation/Orthopaedic Trauma Association (AO/OTA) classification, were separated into two groups. Group 1 bones (n = 7) were fixed with A-PFN and Group 2 (n = 7) with A-DHS. A 5 mm/min axial load was applied to femur heads using a testing device. Results: Two of the seven models in the A-PFN group fractured at the proximal, and the other five at distal locking screw level. All models in the A-DHS group fractured at the tightened distal screw region. The median fracture load for the A-PFN group was 132.1 N (97.1-173.69 N range), and for the A-DHS group it was 81.7 N (75.15-89.12 N range). Conclusion: A-PFN-treated unstable intertrochanteric fractured models resisted to higher levels of axial load than the A-DHS-treated group, with statistically significant difference. However, clinical studies are required to support these results. Level of Evidence V, Biomechanical study.摘要 目的：对比防旋股骨近端髓内钉（antirotator proximal femoral nail, A-PFN）与防旋动力髋螺钉（antirotator dynamic hip screw, A-DHS）的生物力学性能。 方法：将14例符合AO创伤协会（AO Foundation/Orthopaedic Trauma Association, AO/OTA）31/A2型分型的股骨近端骨折模型分为两组。组1（n=7）采用A-PFN固定，组2（n=7）采用A-DHS固定。通过测试装置以5mm/min的速率对股骨头施加轴向载荷。 结果：A-PFN组的7个模型中，2个于近端发生断裂，其余5个在远端锁定螺钉处断裂；A-DHS组所有模型均在远端紧固螺钉区域发生断裂。A-PFN组的中位断裂载荷为132.1N（范围97.1~173.69N），A-DHS组为81.7N（范围75.15~89.12N）。 结论：A-PFN固定的不稳定转子间骨折模型所能承受的轴向载荷显著高于A-DHS固定组，差异具有统计学意义。但仍需开展临床研究以佐证该实验结果。本研究为生物力学研究，证据等级为V级。