Sulkar Hema J, Tashjian Robert Z, Chalmers Peter N, Henninger Heath B
Harold K. Dunn Orthopaedic Research Laboratory, Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA; Department of Bioengineering, University of Utah, Salt Lake City, UT, USA.
Harold K. Dunn Orthopaedic Research Laboratory, Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA.
Clin Biomech (Bristol). 2019 Jan;61:64-69. doi: 10.1016/j.clinbiomech.2018.11.007. Epub 2018 Nov 22.
Trauma can fracture the scapular neck. Typically, a single plate along the lateral scapula border affixes the glenoid fragment to the scapula. This method is limited by difficulty in screw placement, frequent excessive soft tissue dissection, and risk for neurovascular injury. Substituting 2 smaller plates bridging the scapular neck mitigates these limitations, but no comparative mechanical data between techniques exists. Therefore, we compared the mechanical properties of two constructs securing a simulated scapular neck fracture.
Twenty synthetic human scapulae underwent a templated scapular neck fracture. Repairs were performed with a single plate on the lateral scapular border (Column method), or two small plates parallel to the lateral border (Neck method). Measures of displacement, force, and stiffness were quantified during cyclic testing (20-150 N, 1 Hz, 1000 cycles) and loading to failure. Statistical comparisons were made with t-tests (p ≤ 0.050).
The column constructs had higher displacements than neck constructs after 1000 cycles, but differences were small (mean) 0.18 (SD 0.01) vs. 0.15 (0.02) mm (p ≤ 0.004). Cyclic stiffness was 655 (43) and 790 (88) N/mm for the column and neck constructs, respectively (p ≤ 0.003). Both techniques performed comparably in failure loading: at 1 mm of gap reduction the compressive loads were 426 (61) N and 428 (48) N and stiffness was 354 (129) and 334 (80) N/mm for the column and neck constructs, respectively.
Given the surgical advantages, the neck fixation may be more suitable without biomechanical compromise compared to traditional lateral column fixation.
创伤可导致肩胛颈骨折。通常，沿肩胛骨外侧缘使用一块钢板将关节盂碎片固定于肩胛骨。该方法存在螺钉置入困难、软组织剥离频繁以及神经血管损伤风险等局限性。采用两块较小的钢板跨越肩胛颈可减轻这些局限性，但目前尚无两种技术之间的比较力学数据。因此，我们比较了两种固定模拟肩胛颈骨折结构的力学性能。
对20个合成人体肩胛骨进行模板化肩胛颈骨折。分别采用沿肩胛骨外侧缘的单钢板（柱形法）或与外侧缘平行的两块小钢板（颈形法）进行修复。在循环测试（20 - 150 N，1 Hz，1000次循环）和加载至破坏过程中，对位移、力和刚度进行量化测量。采用t检验进行统计学比较（p≤0.050）。
在1000次循环后，柱形结构的位移高于颈形结构，但差异较小（均值）0.18（标准差0.01）对0.15（0.02）mm（p≤0.004）。柱形和颈形结构的循环刚度分别为655（43）和790（88）N/mm（p≤0.003）。两种技术在破坏载荷下表现相当：在间隙缩小1 mm时，柱形和颈形结构的压缩载荷分别为426（61）N和428（48）N，刚度分别为354（129）和334（80）N/mm。
考虑到手术优势，与传统的外侧柱固定相比，颈形固定在不影响生物力学的情况下可能更合适。
