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Internal Fixation of the Distal Humerus: A Comprehensive Biomechanical Study Evaluating Current Fixation Techniques.
J Orthop Trauma. 2013 Jul 29;
Authors: Caravaggi P, Laratta JL, Yoon RS, Biasio JD, Ingargiola M, Frank MA, Capo JT, Liporace FA
Abstract
OBJECTIVES:: The purpose of this study was to evaluate current fixation techniques in the operative fixation of distal humerus fractures, both with conventional and locked plating in both parallel and orthogonal orientation.
METHODS:: Twenty-eight upper extremities from fourteen cadavers were prepared to create four implant testing constructs: Synthes locking plates (IMP1), medial and posterolateral with lateral flange), Acumed parallel locking plates (IMP2), Smith & Nephew orthogonal locking plates (IMP3), and Synthes orthogonal 3.5-reconstruction plating (IMP4), one posterolateral and one medial). A 5mm supracondylar osteotomy was made to simulate the fracture. Stiffness in axial and sagittal-plane loading, fatigue properties (over 5000 cycles), and ultimate strength were determined for each construct via biomechanical testing.
RESULTS:: The parallel locking plates (IMP2) exhibited the highest stiffness in axial load and the highest ultimate strength (p<0.05). No significant differences in sagittal-plane stiffness and in the fatigue properties were seen across the locking plate groups, regardless of orientation. Locked plating constructs performed significantly better in all categories when compared to conventional non-locked plating. Plastic deformation and implant loosening were the main modes of failure following ultimate strength test.
CONCLUSION:: Parallel locking plate configuration showed significantly higher stiffness to axial load and ultimate failure strength when compared to orthogonal locked and non-locked plating. Locked plating configurations performed significantly better than non-locked plating configurations, regardless of orientation. While parallel orientation seems biomechanically superior, translation to the clinical setting may prove difficult when taking surrounding soft tissue and exposure into consideration.
PMID: 23899767 [PubMed - as supplied by publisher]
Read more... http://www.ncbi.nlm.nih.gov/pubmed/23899767?dopt=Abstract
