Sidhu Navjit, Huntington Lachlan S, Richardson Martin, Ackland David C
Department of Biomedical Engineering, The University of Melbourne, Melbourne, Victoria, Australia.
Melbourne Medical School, The University of Melbourne, Melbourne, Victoria, Australia.
ANZ J Surg. 2019 Oct;89(10):1308-1313. doi: 10.1111/ans.15392. Epub 2019 Sep 3.
Surgical fixation of comminuted mid-shaft clavicle fractures commonly employs intramedullary devices; however, pins with smooth surfaces are prone to migration, whilst threaded pins can be challenging to remove post-operatively. The aim of this study was to evaluate the biomechanical performance of fractured clavicles repaired using a novel intramedullary Echidna pin device and a non-threaded Knowles pin. The Echidna pin features retractable spines that engage with the bone to minimize migration and facilitate ease of device removal.
A total of 28 cadaveric clavicle specimens were harvested and a mid-shaft wedge-shaped osteotomy was performed to simulate a comminuted butterfly fragment. Specimens were allocated randomly to either the Echidna pin or Knowles pin fracture repair groups. Following surgery, eight specimens in each group underwent 200 cycles of four-point bending, whilst six specimens in each group underwent torsional testing and pull-out. Cyclic construct bending stiffness, torsional stiffness and ultimate strength were recorded.
Echidna pin intramedullary repair constructs showed significantly greater bending stiffness (mean difference 0.55 N.m/°, 95% confidence interval -0.96, -0.14, P = 0.01) and pull-out strength (mean difference 146.03 N, 95% confidence interval 29.14, 262.92, P = 0.019) in comparison to Knowles pin constructs. There was no significant difference in torsional stiffness between Echidna pin and Knowles pin repair constructs (P > 0.05).
The intramedullary Echidna pin device, which exhibits greater bending strength and pull-out strength than that of the Knowles pin, may produce a more stable clavicle fracture reduction compared to that of commercially available threadless intramedullary pins.
粉碎性锁骨中段骨折的手术固定通常采用髓内装置；然而，表面光滑的髓内针容易移位，而带螺纹的髓内针术后取出可能具有挑战性。本研究的目的是评估使用新型髓内针鼹鼠针装置和无螺纹诺尔斯针修复锁骨骨折的生物力学性能。鼹鼠针具有可伸缩的棘刺，可与骨骼接合，以尽量减少移位并便于取出装置。
总共采集了28个尸体锁骨标本，并进行了中段楔形截骨术以模拟粉碎性蝶形骨折块。标本被随机分配到鼹鼠针或诺尔斯针骨折修复组。手术后，每组中的8个标本进行200次四点弯曲循环，而每组中的6个标本进行扭转测试和拔出测试。记录循环结构的弯曲刚度、扭转刚度和极限强度。
与诺尔斯针结构相比，鼹鼠针髓内修复结构显示出显著更高的弯曲刚度（平均差异0.55N.m/°，95%置信区间-0.96，-0.14，P = 0.01）和拔出强度（平均差异146.03N，95%置信区间29.14，262.92，P = 0.019）。鼹鼠针和诺尔斯针修复结构之间的扭转刚度没有显著差异（P>0.05）。
与市售的无螺纹髓内针相比，髓内鼹鼠针装置具有比诺尔斯针更大的弯曲强度和拔出强度，可能会使锁骨骨折复位更稳定。
