Division of Orthopaedic Trauma, Department of Orthopaedics, R Adams Cowley Shock Trauma Center, University of Maryland, Baltimore, Maryland.
Division of Neuromechanics, Department of Physical Therapy and Rehabilitation Science, University of Maryland, Baltimore, Maryland.
J Orthop Res. 2020 Dec;38(12):2573-2579. doi: 10.1002/jor.24756. Epub 2020 Jun 23.
To assess whether far-cortical locking (FCL) screws alter the fracture site strain environment and allow shorter bridge plate constructs for supracondylar femoral fractures, we tested the fracture site displacement under force of synthetic left femora with a 5-cm metaphyseal fracture gap, modeling comminution. Five models of nine constructs were tested (three types of diaphyseal screws [nonlocking, locking, and FCL] and two plate lengths [13 holes and 5 holes]). Long plate models using three or four diaphyseal screws (working length 13.5 or 7.5 cm, respectively) were compared with short plates with three diaphyseal screws (working length 7.5 cm). Models were loaded axially and torsionally; 100 cycles in random order. Primary outcome measures were axial and torsional fracture site stiffness. FCL screws decreased rotational stiffness 19% (P < .01) compared with baseline nonlocking screws in the same plate and working length construct, mirroring the effect (20% decrease in stiffness, P < .01) of nearly doubling the nonlocking construct working length (7.5-13.5 cm). Similarly, FCL screws decreased axial stiffness 23% (P < .01) in the same baseline comparison. Fracture site displacement under loading comparable to a long working length nonlocked plate construct was achieved using a shorter FCL plate construct. By closely replicating the biomechanical properties of a long plate construct, a fracture site strain environment considered favorable in promoting fracture healing might still be achievable using a shorter plate length. Clinical Significance: It might be possible to optimize fracture site strain environment and displacement under loading using shorter FCL plate constructs. Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 00:00-00, 2020.
为了评估远皮质锁定（FCL）螺钉是否会改变骨折部位的应变环境，并允许使用更短的桥接钢板治疗股骨髁上骨折，我们测试了具有 5cm 骨干骨折间隙的合成左侧股骨在受力下的骨折部位位移，模拟了粉碎性骨折。我们测试了 5 种 9 种构建模型（三种类型的骨干螺钉[非锁定、锁定和 FCL]和两种钢板长度[13 孔和 5 孔]）。使用三根或四根骨干螺钉的长钢板模型（工作长度分别为 13.5 或 7.5cm）与使用三根骨干螺钉的短钢板（工作长度 7.5cm）进行比较。模型在轴向和扭转方向加载；以随机顺序进行 100 个循环。主要观察指标为轴向和扭转骨折部位刚度。与同一钢板和工作长度构建中的基线非锁定螺钉相比，FCL 螺钉使旋转刚度降低了 19%（P<.01），这与几乎将非锁定构建工作长度增加一倍（7.5-13.5cm）的效果（刚度降低 20%，P<.01）相匹配。同样，FCL 螺钉在相同的基线比较中使轴向刚度降低了 23%（P<.01）。使用较短的 FCL 钢板构建，实现了与长工作长度非锁定钢板构建相似的加载下骨折部位位移。通过紧密复制长钢板构建的生物力学特性，仍可以使用较短的钢板长度来实现有利于促进骨折愈合的骨折部位应变环境。矫形研究协会。由 Wiley 期刊出版公司出版。J Orthop Res 00:00-00，2020 年。
使用较短的 FCL 钢板构建，可能有可能优化骨折部位的应变环境和加载下的位移。
