- 作者：Stefano Brianza ; Michael Plecko ; Boyko Gueorguiev ; Markus Windolf ; Karsten Schwieger
- 关键词：Cadaveric model ; Humerus ; Proximal humerus fracture ; Intramedullary nail ; Locking implants ; Plate ; Biomechanics
- 刊名：Clinical Biomechanics
- 出版年：2010
- 出版时间：November 2010
- 年：2010
- 卷：25
- 期：9
- 页码：886-892
- 全文大小：1677 K
BackgroundThe optimal surgical treatment for displaced proximal humeral fractures is still controversial. A new implant for the treatment of three-part fractures has been recently designed. It supplements the existing Expert Humeral Nail with a locking plate. We developed a novel humeral cadaveric model and the existing implant and the prototype were biomechanically compared to determine their ability in maintaining interfragmentary stability.Methods
The bone mineral density of eight pairs of cadaveric humeri was assessed and a three-part proximal humeral fracture was simulated with a Greater Tuberosity osteotomy and a surgical neck wedge ostectomy. The specimens were randomly assigned to either treatment. A bone anchor simulated part of a rotator cuff tendon pulling on the Greater Tuberosity. Specimens were initially tested in axial compression and afterward with a compound cyclic load to failure. An optical 3D motion tracking system continuously monitored the relative interfragmentary movements.
Findings
The specimen stabilized with the prototype demonstrated higher stiffness (P = 0.036) and better interfragmentary stability (P values < 0.028) than the contralateral treated with the existing implant. There was no correlation between the bone mineral density and any of the investigated variables.
Interpretation
The convenience of this new IM-nail and locking plate assembly must be confirmed in vivo but the current study provides a biomechanical rationale for its use in the treatment of three-part proximal humeral fractures. The improved stability could be advantageous in particular when medial buttress is missing, even in osteoporotic bone.