Steinberg Ely L, Blumberg Nehemia, Dekel Shmuel
Department of Orthopaedic Surgery "B", Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, 6 Weizmann Street, Tel-Aviv 64239, Israel.
J Biomech. 2005 Jan;38(1):63-8. doi: 10.1016/j.jbiomech.2004.03.014.
The treatment of choice for early mobilization of hip fracture is surgery, which traditionally employs side plates and screws or intramedullary nails. We examined the biomechanical properties of a new proximal femoral nail system. The new expandable Fixion proximal femur nailing (PFN) system, made of stainless-steel alloy, consists of a nail, a peg and an anti-rotation pin. Upon positioning, the nail and peg are expanded to their maximal diameter. The current biomechanical study investigated: nail bending strength and stiffness, fatigue properties and hip peg strength. A cadaveric study that determined the effect of the expandable peg on the femoral head included subsidence testing, pull and torsion testing and intra-osseous pressure (IOP) measurements before and after expansion. Biomechanical properties of the new nail met ASTM F384 guideline requirements. The cadaver study yielded equivalent results for the pullout test between the peg and the hip screw, but found the peg superior in the torsion strength test. IOP during peg insertion and expansion was substantially lower than the threshold pressure that causes avascular necrosis. The biomechanical tests found the new system to be safe and able to provide good abutment of the nail to the bone. We conclude that the Fixion PFN system proved to be an effective proximal femur fracture fixation device.
髋部骨折早期活动的首选治疗方法是手术，传统上采用侧板和螺钉或髓内钉。我们研究了一种新型股骨近端钉系统的生物力学性能。新型可扩张的Fixion股骨近端髓内钉（PFN）系统由不锈钢合金制成，包括一根髓内钉、一个栓子和一个防旋转销。定位后，髓内钉和栓子会扩张至最大直径。当前的生物力学研究调查了：髓内钉的抗弯强度和刚度、疲劳性能以及髋部栓子强度。一项尸体研究确定了可扩张栓子对股骨头的影响，包括沉降测试、拉伸和扭转测试以及扩张前后的骨内压（IOP）测量。新型髓内钉的生物力学性能符合ASTM F384指南要求。尸体研究得出栓子和髋螺钉在拔出试验中的结果相当，但发现栓子在扭转强度试验中更具优势。栓子插入和扩张过程中的骨内压远低于导致缺血性坏死的阈值压力。生物力学测试发现新系统安全且能够使髓内钉与骨骼良好贴合。我们得出结论，Fixion PFN系统被证明是一种有效的股骨近端骨折固定装置。
