Siffri Paul C, Peindl Richard D, Coley Edward R, Norton James, Connor Patrick M, Kellam James F
Department of Orthopaedic Surgery, Carolinas Medical Center, Charlotte, NC 28232, USA.
J Orthop Trauma. 2006 Sep;20(8):547-54. doi: 10.1097/01.bot.0000244997.52751.58.
To compare the mechanical stability of a fixed-angle blade plate with that of a locking plate in a cadaveric proximal humerus fracture-fixation model subjected to cyclic loading. A secondary objective was to evaluate whether the use of synthetic humerus specimens would replicate significant differences found during cadaveric tests.
Mechanical evaluation of constructs in bending and torsion.
Biomechanical laboratory in an academic medical center.
Simulated humeral neck fractures (Orthopaedic Trauma Association (OTA) classification 11A3), in matched-pair cadaveric and synthetic specimens underwent fixation using either a 3.5-mm, 90-degree cannulated LC-Angled Blade Plate or a 3.5-mm LCP Proximal Humerus Locking Plate. Cadaveric specimen constructs were cyclically loaded in bending and torsion; synthetic specimens were tested in torsion.
Humeral shaft-bending displacements and angular rotations for respective cyclic bending loads and axial torques were recorded and compared at repeated cyclic intervals to evaluate construct loosening.
Locking-plate constructs exhibited significantly less loosening than blade-plate constructs for torsional loading in cadaveric specimens (P = 0.036). The two types of constructs performed similarly for torsional loading in synthetic specimens (P = 0.100). Under cyclic, closed-bending load conditions in which the plates served as tension members, both types of constructs performed similarly in cadaveric specimens (P = 0.079).
For simulated humeral neck fractures subjected to cyclic loading, locking-plate constructs demonstrated significantly greater torsional stability and similar bending stability to blade plates in a cadaveric specimen model. In contrast, these same constructs performed similarly with torsional loading when using synthetic humerus specimens. These results indicate potential advantages for locking-plate fixation. They also indicate that the synthetic specimens tested may not be appropriate for evaluating fixation stability in the humeral head, where cancellous bone fixation predominates.
在尸体近端肱骨骨折固定模型中，对固定角度接骨板和锁定接骨板在循环加载情况下的力学稳定性进行比较。第二个目的是评估使用合成肱骨标本是否能重现尸体试验中发现的显著差异。
对构建物进行弯曲和扭转的力学评估。
一所学术医学中心的生物力学实验室。
在配对的尸体和合成标本中模拟肱骨颈骨折（骨科创伤协会（OTA）分类11A3），使用3.5毫米、90度空心LC角接骨板或3.5毫米LCP近端肱骨锁定接骨板进行固定。尸体标本构建物在弯曲和扭转状态下进行循环加载；合成标本进行扭转测试。
记录并比较在重复循环间隔下，对应循环弯曲载荷和轴向扭矩时肱骨干的弯曲位移和角旋转，以评估构建物的松动情况。
在尸体标本中，锁定接骨板构建物在扭转载荷下的松动明显少于接骨板构建物（P = 0.036）。在合成标本中，两种类型的构建物在扭转载荷下表现相似（P = 0.100）。在循环闭合弯曲载荷条件下，即接骨板作为受拉构件时，两种类型的构建物在尸体标本中的表现相似（P = 0.079）。
对于承受循环加载的模拟肱骨颈骨折，在尸体标本模型中，锁定接骨板构建物表现出显著更高的扭转稳定性，且弯曲稳定性与接骨板相似。相比之下，使用合成肱骨标本时，这些构建物在扭转载荷下表现相似。这些结果表明锁定接骨板固定具有潜在优势。它们还表明，所测试的合成标本可能不适用于评估以松质骨固定为主的肱骨头的固定稳定性。
