Bosse M J, Holmes C, Vossoughi J, Alter D
Department of Orthopaedic Surgery, National Naval Medical Center, Bethesda, Maryland.
J Orthop Trauma. 1994;8(2):119-26. doi: 10.1097/00005131-199404000-00008.
To direct the U.S. military purchase of deployable external fixation gear, a project was designed to compare the biomechanical properties and ease of clinical application of military external fixators developed by Synthes and Howmedica. The project assessed (a) ease of application, (b) biomechanics, (c) heat stability, and (d) product line compatibility. Pretrained general surgery residents were provided with fresh cadaver limbs with simulated grade IIIB tibial fractures and 5-cm middiaphyseal defects. All chose the Howmedica Ultra-X for its ease of application but, on manual testing, noted that the Synthes Trauma-Fix was more stable. The frames were biomechanically tested in a previously validated model with strictly controlled parameters. The Howmedica Ultra-X demonstrated only 75% of the compressive stiffness, 29% of the anteroposterior bending stiffness, and 51% of the torsional stiffness of the Synthes Trauma-Fix. The Ultra-X failed to withstand steam sterilization and was significantly weaker than, and incompatible with, Howmedica's commercially available product. The Trauma-Fix demonstrated no statistically significant difference from Synthes' commercially available product. The Howmedica Ultra-X is unsuitable for military external fixation: The biomechanical properties are not equivalent to those of the unilateral Hoffmann frame, it is incompatible with commercially available Howmedica external fixators, and it fails to withstand heat sterilization.
为指导美国军方采购可部署的外固定装置，设计了一个项目，以比较辛迪思公司（Synthes）和豪美医疗器械公司（Howmedica）研发的军事外固定器的生物力学性能和临床应用便利性。该项目评估了：（a）应用便利性；（b）生物力学性能；（c）热稳定性；（d）产品线兼容性。为经过预培训的普通外科住院医师提供带有模拟ⅢB级胫骨骨折和5厘米骨干中段缺损的新鲜尸体肢体。所有人都因应用便利而选择了豪美医疗器械公司的Ultra-X，但在手动测试中发现，辛迪思公司的创伤固定器（Trauma-Fix）更稳定。在一个参数严格受控的先前经验证的模型中对这些框架进行了生物力学测试。豪美医疗器械公司的Ultra-X的抗压刚度仅为辛迪思公司创伤固定器的75%，前后弯曲刚度为29%，扭转刚度为51%。Ultra-X无法承受蒸汽灭菌，且明显比豪美医疗器械公司的市售产品更脆弱，且与之不兼容。创伤固定器与辛迪思公司的市售产品相比，没有统计学上的显著差异。豪美医疗器械公司的Ultra-X不适合用于军事外固定：其生物力学性能与单侧霍夫曼架不等同，与豪美医疗器械公司的市售外固定器不兼容，且无法承受热灭菌。
