Smith Sean D, Wijdicks Coen A, Jansson Kyle S, Boykin Robert E, Martetschlaeger Frank, de Meijer Peter-Paul, Millett Peter J, Hackett Tom R
Department of BioMedical Engineering, Steadman Philippon Research Institute, Vail, CO, USA.
Knee Surg Sports Traumatol Arthrosc. 2014 Feb;22(2):448-55. doi: 10.1007/s00167-013-2411-5. Epub 2013 Jan 31.
Operative treatment for middle-third clavicle fractures has been increasing as recent data has demonstrated growing patient dissatisfaction and functional deficits after non-operative management. A controlled biomechanical comparison of the characteristics of locked intramedullary (IM) fixation versus superior pre-contoured plating for fracture repair and hardware removal is warranted. Therefore, the purpose of the present study was to investigate potential differences between these devices in a biomechanical model.
Thirty fourth-generation composite clavicles were randomized to one of five groups with 6 specimens each and tested in a random order. The groups tested were intact, repair with plate, repair with IM device, plate removal, and IM device removal. The lateral end of the clavicles was loaded to failure at a rate of 60 mm/min in a cantilever bending setup. Failure mechanism, energy (J), and torque (Nm) at the site of failure were recorded.
Failure torque of the intact clavicle (mean ± standard deviation) was 36.5 ± 7.3 Nm. Failure torques of the IM repair (21.5 ± 9.0 Nm) and plate repair (18.2 ± 1.6 Nm) were not significantly different (n.s.) but were significantly less than the intact group (P < 0.05). Failure torque following IM device removal (30.2 ± 6.5 Nm) was significantly greater than plate removal (12.9 ± 2.0 Nm) (P < 0.05). No significant differences were observed between the intact and IM device removal groups (n.s.).
The results of the current study demonstrate that IM and plate devices provide similar repair strength for middle-third clavicle fractures. However, testing of the hardware removal groups found the IM device removal group to be significantly stronger than the plate removal group.
随着近期数据表明非手术治疗后患者不满情绪增加且功能出现缺陷，锁骨中1/3骨折的手术治疗一直在增加。对锁定髓内（IM）固定与预塑形钢板治疗骨折及取出内固定装置的特性进行对照生物力学比较是有必要的。因此，本研究的目的是在生物力学模型中研究这些装置之间的潜在差异。
30根第四代复合锁骨随机分为五组，每组6个标本，并按随机顺序进行测试。测试的组包括完整组、钢板修复组、IM装置修复组、钢板取出组和IM装置取出组。在悬臂弯曲装置中，以60mm/min的速率对锁骨外侧端加载直至失效。记录失效部位的失效机制、能量（焦耳）和扭矩（牛顿米）。
完整锁骨的失效扭矩（平均值±标准差）为36.5±7.3牛顿米。IM修复组（21.5±9.0牛顿米）和钢板修复组（18.2±1.6牛顿米）的失效扭矩无显著差异，但显著低于完整组（P<0.05）。IM装置取出后的失效扭矩（30.2±6.5牛顿米）显著大于钢板取出后的失效扭矩（12.9±2.0牛顿米）（P<0.05）。完整组与IM装置取出组之间未观察到显著差异（无统计学意义）。
本研究结果表明，IM装置和钢板装置对锁骨中1/3骨折提供相似的修复强度。然而，对内固定装置取出组的测试发现，IM装置取出组明显比钢板取出组更坚固。
