- 作者：Sven-Oliver Dietz ; MD ; sven-oliver.dietz@unimedizin-mainz.de ; Frank Hartmann ; MD ; Thomas Schwarz ; Tobias E. Nowak ; MD ; Annalisa Enders ; MD ; Sebastian Kuhn ; MD ; Alexander Hofmann ; MD ; Pol Maria Rommens ; MD
- 关键词：Basic Science Study ; Biomechanical Study
- 刊名：Journal of Shoulder and Elbow Surgery
- 出版年：2012
- 出版时间：May, 2012
- 年：2012
- 卷：21
- 期：5
- 页码：618-624
- 全文大小：470 K
Background
In locking plate osteosynthesis of proximal humeral fractures, secondary varus malalignment is a specific complication. Retron nails (Tantum AG, Neumunster, Germany), among others, have been designed to improve medial support of the calcar humeri. The aim of our biomechanical study was to examine whether Retron nails provide increased stiffness for axial loads and adequate stiffness for torsional loads when compared with Philos plates (Synthes AG, Umkirch, Germany).Materials and methods
Twenty-two fresh-frozen paired humeri were collected. After potting the specimens, intact bones were exposed to sinusoidal axial (10-120 N) and torsional (¡À2.5 Nm) loading for 8 cycles to calculate the initial stiffness and exclude pairs with differences. Afterward, an unstable proximal humeral fracture (AO 11-A3) was created by means of an oscillating saw, and the respective osteosynthesis devices were implanted. After another 4 cycles, initial changes in stiffness were measured. Subsequently, all specimens were tested for 1,000 cycles of loading before final stiffness was assessed.
Results
We found no statistically significant differences between Retron and Philos specimens after 4 or 1,000 cycles of loading.
Conclusion
Our study suggests that retrograde nailing provides sufficient stability for axial and torsional loading in 2-part fractures of proximal humeri.