Labèr Raffael, Jann David, Behm Pascal, Ferguson Stephen J, Frueh Florian S, Calcagni Maurizio
Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland.
Institute for Biomechanics, ETH Zurich, Zurich, Switzerland.
J Hand Surg Eur Vol. 2020 Jul;45(6):595-600. doi: 10.1177/1753193419898066. Epub 2020 Jan 16.
Intramedullary cannulated compression screws have been introduced for the fixation of unstable metacarpal fractures. In the present study, this technique was compared with dorsal compression plating to evaluate its biomechanical performance in stabilizing metacarpal shaft fractures. In a first set of experiments, the biomechanical characteristics of the screws were analysed in an artificial bone model. In subsequent experiments, midshaft osteotomies were performed in human cadaver metacarpals, followed by plating or intramedullary screw osteosynthesis. The metacarpals were tested to failure in cantilever bending, following a stepwise increasing cyclic loading protocol. We found a significantly lower load at failure and a significantly lower number of cycles to failure in the intramedullary screw group, but both methods offered sufficient stability under these loads. With reference to published loads on the metacarpals during use of the hand, we conclude that intramedullary osteosynthesis yields sufficient strength and stiffness for early active motion. A difference in its fixation stability is noted compared with plate fixation, which may not be clinically relevant.
髓内空心加压螺钉已被用于不稳定掌骨骨折的固定。在本研究中，将该技术与背侧加压钢板固定进行比较，以评估其在稳定掌骨干骨折方面的生物力学性能。在第一组实验中，在人工骨模型中分析螺钉的生物力学特性。在随后的实验中，对人体尸体掌骨进行中段截骨，然后进行钢板固定或髓内螺钉接骨术。按照逐步增加的循环加载方案，对掌骨进行悬臂弯曲试验直至失效。我们发现髓内螺钉组的失效载荷显著较低，失效循环次数也显著较少，但两种方法在这些载荷下均提供了足够的稳定性。参照已发表的手部使用过程中掌骨所承受的载荷，我们得出结论，髓内接骨术可为早期主动活动提供足够的强度和刚度。与钢板固定相比，其固定稳定性存在差异，但这可能在临床上并无相关性。
