Department of Orthopaedic Surgery, University of Missouri-Columbia, One Hospital Drive, MC213, Columbia, MO 65212, USA.
J Orthop Trauma. 2009 Oct;23(9):622-7. doi: 10.1097/BOT.0b013e3181a2a31d.
The angled blade plate has been the historical standard in fixed-angle extramedullary subtrochanteric femur fracture fixation, but it requires an extensile lateral approach to the femur. Little formal evaluation exists for specifically designed percutaneous extramedullary implants. The purpose of this study was to compare 3 locked plating constructs, all with percutaneous insertion capability, with the standard 95-degree angled blade plate to determine whether specifically designed fixed-angle extramedullary implants for subtrochanteric femur fractures were biomechanically comparable to the angled blade plate.
Forty composite adult femurs were divided into 4 equal groups. The constructs evaluated included a 95-degree angled blade plate, a broad 4.5-mm combination locking plate, and a precontoured proximal femoral locking plate (PFLP) with and without an oblique, angled strut or "kickstand" screw. A 30-degree wedge osteotomy was used to create a subtrochanteric fracture gap model. Each specimen underwent axial and torsional stiffness testing along with cyclic axial loading to failure.
Axial stiffness testing revealed that the PFLP with the "kickstand" screw was the stiffest construct (92.2 +/- 17.4 Nm/m), which was 211% stiffer than the blade plate, 309% stiffer than the broad plate, and 194% stiffer than the PFLP without the kickstand screw. The blade plate had the highest torsional stiffness (2.42 +/- 0.08 Nm/degree), which was 151% stiffer than the broad plate, 128% stiffer than the PFLP with the kickstand, and 138% stiffer than the PFLP without the kickstand screw. The PFLP with the kickstand screw had the least irreversible deformation (6.3 mm), which was 52% less than the broad plate and 61% less than the PFLP without the kickstand screw.
Our data reveal that the PFLP with the "kickstand" screw provides more axial stiffness, less torsional stiffness, and equivalent irreversible deformation to cyclic axial loading when compared with the blade plate.
角度钢板一直是固定角度髓外股骨转子下骨折固定的历史标准，但它需要对股骨进行广泛的外侧入路。专门设计的经皮髓外植入物的正式评估很少。本研究的目的是比较 3 种具有经皮插入能力的锁定钢板结构，与标准的 95 度角度钢板，以确定专为转子下股骨骨折设计的固定角度髓外植入物在生物力学上是否与角度钢板相当。
将 40 个复合成人股骨分为 4 组。评估的结构包括 95 度角度钢板、宽 4.5 毫米的组合锁定钢板以及带有和不带有斜向、角度支撑螺钉的预成型股骨近端锁定钢板（PFLP）。使用 30 度楔形截骨术创建转子下骨折间隙模型。每个标本都进行轴向和扭转刚度测试以及循环轴向加载至失效。
轴向刚度测试显示，带有“支撑钉”螺钉的 PFLP 是最坚固的结构（92.2 ± 17.4 Nm/m），比钢板坚固 211%，比宽板坚固 309%，比不带支撑钉的 PFLP 坚固 194%。钢板具有最高的扭转刚度（2.42 ± 0.08 Nm/度），比宽板坚固 151%，比带有支撑钉的 PFLP 坚固 128%，比不带支撑钉的 PFLP 坚固 138%。带有支撑钉的 PFLP 具有最小的不可逆变形（6.3 毫米），比宽板少 52%，比不带支撑钉的 PFLP 少 61%。
我们的数据显示，与钢板相比，带有“支撑钉”螺钉的 PFLP 在轴向刚度、扭转刚度和对循环轴向加载的不可逆变形方面提供了更多的支撑。
