Reinhardt Sophia, Martin Heiner, Ulmar Benjamin, Döbele Stefan, Zwipp Hans, Rammelt Stefan, Richter Martinus, Pompach Martin, Mittlmeier Thomas
Department of Trauma, Rostock University Medical Center, Hand and Reconstructive Surgery, Rostock, Germany
Department of Biomedical Engineering, Rostock University Medical Center, Rostock, Germany.
Foot Ankle Int. 2016 Aug;37(8):891-7. doi: 10.1177/1071100716643586. Epub 2016 Apr 8.
Open reduction and internal fixation with a plate is deemed to represent the gold standard of surgical treatment for displaced intra-articular calcaneal fractures. Standard plate fixation is usually placed through an extended lateral approach with high risk for wound complications. Minimally invasive techniques might avoid wound complications but provide limited construct stability. Therefore, 2 different types of locking nails were developed to allow for minimally invasive technique with sufficient stability. The aim of this study was to quantify primary stability of minimally invasive calcaneal interlocking nail systems in comparison to a variable-angle interlocking plate.
After quantitative CT analysis, a standardized Sanders type IIB fracture model was created in 21 fresh-frozen cadavers. For osteosynthesis, 2 different interlocking nail systems (C-Nail; Medin, Nov. Město n. Moravě, Czech Republic; Calcanail; FH Orthopedics SAS; Heimsbrunn, France) as well as a polyaxial interlocking plate (Rimbus; Intercus GmbH; Rudolstadt, Germany) were used. Biomechanical testing consisted of a dynamic load sequence (preload 20 N, 1000 N up to 2500 N, stepwise increase of 100 N every 100 cycles, 0.5 mm/s) and a load to failure sequence (max. load 5000 N, 0.5 mm/s). Interfragmentary movement was detected via a 3-D optical measurement system. Boehler angle was measured after osteosynthesis and after failure occurred.
No significant difference regarding load to failure, stiffness, Boehler angle, or interfragmentary motion was found between the different fixation systems. A significant difference was found with the dynamic failure testing sequence where 87.5% of the Calcanail implants failed in contrast to 14% of the C-Nail group (P < .01) and 66% of the Rimbus plate. The highest load to failure was observed for the C-Nail. Boehler angle showed physiologic range with all implants before and after the biomechanical tests.
Both minimally invasive interlocking nail systems displayed a high primary stability that was not inferior to an interlocking plate.
Based on our results, both interlocking nails appear to represent a viable option for treating displaced intra-articular calcaneal fractures.
切开复位钢板内固定被认为是移位性关节内跟骨骨折手术治疗的金标准。标准钢板固定通常通过延长外侧入路进行，伤口并发症风险高。微创技术可能避免伤口并发症，但提供的结构稳定性有限。因此，开发了两种不同类型的锁定钉，以允许采用具有足够稳定性的微创技术。本研究的目的是与可变角度锁定钢板相比，量化微创跟骨锁定钉系统的初始稳定性。
经过定量CT分析后，在21具新鲜冷冻尸体上建立标准化的Sanders IIB型骨折模型。为进行骨固定，使用了两种不同的锁定钉系统（C型钉；Medin，捷克共和国摩拉维亚州新梅斯托；跟骨钉；FH Orthopedics SAS；法国海姆斯布伦）以及一种多轴锁定钢板（Rimbus；Intercus GmbH；德国鲁多尔施塔特）。生物力学测试包括动态载荷序列（预加载20 N，从1000 N增加到2500 N，每100个循环逐步增加100 N，0.5 mm/s）和直至失效的载荷序列（最大载荷5000 N，0.5 mm/s）。通过三维光学测量系统检测骨折块间运动。在骨固定后以及出现失效后测量跟骨角。
不同固定系统在失效载荷、刚度、跟骨角或骨折块间运动方面未发现显著差异。在动态失效测试序列中发现了显著差异，其中跟骨钉植入物87.5%失效，相比之下，C型钉组为14%（P <.01），Rimbus钢板为66%。C型钉观察到最高的失效载荷。在生物力学测试前后，所有植入物的跟骨角均显示在生理范围内。
两种微创锁定钉系统均显示出较高的初始稳定性，并不亚于锁定钢板。
基于我们的结果，两种锁定钉似乎都是治疗移位性关节内跟骨骨折的可行选择。
