Department of Orthopaedics, Tianjin Hospital, Tianjin, China.
Department of Orthopaedics Institute, Tianjin Hospital, Tianjin, China.
Orthop Surg. 2022 Aug;14(8):1884-1891. doi: 10.1111/os.13364. Epub 2022 Jun 15.
To compare the biomechanical performance of proximal femoral nail anti-rotation (PFNA), the "upside-down" less invasive plating system (LISS), and proximal femoral locking plate (PFLP) in fixing different fracture models of subtrochanteric fractures.
Thirty composite femurs were divided into three equal groups (PFNA, PFLP, and reverse LISS). The implant-femur constructs were tested under axial compression load (0-1400 N) from models I to IV, which represented the Seinsheimer type I subtrochanteric fracture, type IIIa subtrochanteric fracture with the posteromedial fragment reduced; type IIIa subtrochanteric fracture with the posteromedial fragment lost; and type IV subtrochanteric fracture, respectively. Axial stiffness was analyzed for each group. Each group was then divided into two subgroups, one of which underwent torsional and axial compression failure testing, while the other subgroup underwent axial compression fatigue testing. The torsional stiffness, failure load, and cycles to failure were analyzed.
PFNA had the highest axial stiffness (F = 761.265, p < 0.0001) and failure load (F = 48.801, p < 0.0001) in model IV. The axial stiffness and failure load of the PFLP were significantly higher than those of the LISS (p < 0.0001, p = 0.001). However, no significant difference in axial stiffness was found between models I to III (model I: F = 2.439, p = 0.106; model II: F = 2.745, p = 0.082; model III: F = 0.852, p = 0.438) or torsional stiffness in model IV (F = 1.784, p = 0.187). In fatigue testing, PFNA did not suffer from construct failure after 90,000 cycles of axial compression. PFLP and LISS were damaged within 14,000 cycles, although LISS withstood more cycles than PFLP (t = 3.328, p = 0.01).
The axial stiffness of the three implants was similar in models I to III. The biomechanical properties of PFNA were the best of the three implants in terms of axial stiffness, failure load, and fatigue testing cycles in model IV. The axial stiffness and failure load of the PFLP were better than those of the reverse LISS, but PFLP had fewer cycles in the fatigue tests than the reverse LISS.
比较股骨近端防旋髓内钉（PFNA）、“倒置”微创接骨板系统（LISS）和股骨近端锁定钢板（PFLP）在固定不同类型股骨转子下骨折模型中的生物力学性能。
将 30 个复合材料股骨分为三组（PFNA、PFLP 和反向 LISS）。从模型 I 到 IV 对植入物-股骨结构进行轴向压缩载荷（0-1400 N）测试，分别代表 Seinsheimer Ⅰ型转子下骨折、伴有后内侧骨块复位的 Ⅲa 型转子下骨折、伴有后内侧骨块丢失的 Ⅲa 型转子下骨折和 Ⅳ型转子下骨折。分析每组的轴向刚度。每组随后分为两个亚组，其中一个进行扭转和轴向压缩失效测试，另一个进行轴向压缩疲劳测试。分析扭转刚度、失效载荷和失效循环数。
在模型 IV 中，PFNA 具有最高的轴向刚度（F=761.265，p<0.0001）和失效载荷（F=48.801，p<0.0001）。PFLP 的轴向刚度和失效载荷明显高于 LISS（p<0.0001，p=0.001）。然而，在模型 I 到 III 中，轴向刚度（模型 I：F=2.439，p=0.106；模型 II：F=2.745，p=0.082；模型 III：F=0.852，p=0.438）或模型 IV 中的扭转刚度（F=1.784，p=0.187）均无显著差异。在疲劳测试中，PFNA 在 90000 次轴向压缩循环后未发生结构失效。尽管 LISS 承受的循环次数多于 PFLP，但 PFLP 和 LISS 均在 14000 次循环内损坏（t=3.328，p=0.01）。
在模型 I 到 III 中，三种植入物的轴向刚度相似。在模型 IV 中，PFNA 的轴向刚度、失效载荷和疲劳循环数的生物力学性能最佳。PFLP 的轴向刚度和失效载荷优于反向 LISS，但 PFLP 的疲劳试验循环数少于反向 LISS。
