Füchtmeier B, May R, Hente R, Maghsudi M, Völk M, Hammer J, Nerlich M, Prantl L
Department of Traumatology, University Clinic, Franz-Josef-Strauss Allee 11, 93053 Regensburg, Germany.
Arch Orthop Trauma Surg. 2007 Aug;127(6):441-7. doi: 10.1007/s00402-007-0319-6. Epub 2007 Apr 25.
The biomechanical stability of a newly developed humerus nail (Sirustrade mark) for the treatment of fractures of the proximal humerus was analyzed in comparison to established systems. In total, three randomized groups were formed (n = 4 pairs) from 12 matched pairs of human cadaver humeri.
All intact bones were mechanically characterized by five subsequent load cycles under bending and torsional loading. The bending moment at the osteotomy was 7.5 N m the torsional moment was 8.3 N m over the hole specimen length. Loading was consistently initiated at the distal epiphysis and the deformation at the distal epiphysis was continuously recorded. Prior to implant reinforcement, a defect of 5 mm was created to simulate an unstable subcapital humerus fracture. For paired comparison, one humerus of each pair was stabilized with the Sirus proximal humerus nail while the counterpart was stabilized by a reference implant. In detail, the following groups were created: Sirus versus Proximal humerus nail (PHN) with spiral blade (group I); Sirus versus PHILOS plate (group II); Sirus versus 4.5 mm AO T-plate (group III).
The Sirus nail demonstrated significantly higher stiffness values compared to the reference implants for both bending and torsional loading. The following distal epiphyseal displacements were recorded for a bending moment of 7.5 N m at the osteotomy: Sirus I: 8.8 mm, II: 8.4 mm, III: 7.7 mm (range 6.9-10.9), PHN 21.1 mm (range 15.7-25.2) (P = 0.005), PHILOS plate 27.5 mm (range 21.6-35.8) (P < 0.001), 4.5 AO T-plate 26.3 mm (range 24.3-33.9) (P = 0.01). The rotations corresponding to 8.3 N m torsional moment were: Sirus I: 9.1 degrees , II: 9.3 degrees , III: 10.6 degrees (range 7.5-12.2), PHN 13.5 degrees (range 10.3-15.6) (P = 0.158), PHILOS plate 15.6 degrees (range 13.7-20.8) (P = 0.007), 4.5 AO T-Platte 14.1 degrees (range 11.5-19.7) (P = 0.158).
The intramedullary load carriers were biomechanically superior when compared to the plating systems in the fracture model presented here. Supplementary, the Sirus Nail showed higher stiffness values than the PHN. However, the latter are gaining in importance due to the possibility of minimal invasive implantation. Whether this will be associated with functional advantages requires further clinical investigation.
与现有系统相比，分析了一种新开发的用于治疗肱骨近端骨折的肱骨钉（Sirustrade商标）的生物力学稳定性。总共从12对匹配的人体尸体肱骨中形成了三个随机组（n = 4对）。
所有完整的骨骼通过在弯曲和扭转载荷下的五个连续加载循环进行力学表征。截骨处的弯矩为7.5 N·m，在孔标本长度上的扭矩为8.3 N·m。加载始终从远端骨骺开始，并连续记录远端骨骺处的变形。在植入物加固之前，制造一个5 mm的缺损以模拟不稳定的肱骨近端骨折。为了进行配对比较，每对中的一根肱骨用Sirus近端肱骨钉固定，而另一根则用参考植入物固定。详细来说，创建了以下几组：Sirus与带螺旋刀片的近端肱骨钉（PHN）（第一组）；Sirus与PHILOS钢板（第二组）；Sirus与4.5 mm AO T形钢板（第三组）。
与参考植入物相比，Sirus钉在弯曲和扭转载荷下均显示出明显更高的刚度值。在截骨处弯矩为7.5 N·m时记录到以下远端骨骺位移：Sirus I组：8.8 mm，II组：8.4 mm，III组：7.7 mm（范围6.9 - 10.9），PHN组21.1 mm（范围15.7 - 25.2）（P = 0.005），PHILOS钢板组27.5 mm（范围21.6 - 35.8）（P < 0.001），4.5 AO T形钢板组26.3 mm（范围24.3 - 33.9）（P = 0.01）。对应于8.3 N·m扭矩的旋转角度为：Sirus I组：9.1度，II组：9.3度，III组：10.6度（范围7.5 - 12.2），PHN组13.5度（范围10.3 - 15.6）（P = 0.158），PHILOS钢板组15.6度（范围13.7 - 20.8）（P = 0.007），4.5 AO T形钢板组14.1度（范围11.5 - 19.7）（P = 0.158）。
在此处呈现的骨折模型中，髓内载荷承载器在生物力学上优于钢板系统。此外，Sirus钉显示出比PHN更高的刚度值。然而，由于微创植入的可能性，后者正变得越来越重要。这是否会带来功能上的优势需要进一步的临床研究。
