Assessment of a novel biomechanical fracture model for distal radius fractures
1 Department of Surgery, Experimental Surgery and Regenerative Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
2 Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria
3 Lorenz Boehler Trauma Hospital, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Cluster for Tissue Regeneration, Vienna, Austria
4 Center of Anatomy and Cell Biology,Department of Systematic Anatomy, Medical University Vienna, Vienna, Austria
5 Munich Cancer Registry; IBE / Clinic Großhadern, Ludwig-Maximilians University Munich, Munich, Germany
6 Institute of Surgical Technology and Biomechanics, University of Bern, Bern, Switzerland
BMC Musculoskeletal Disorders 2012, 13:252 doi:10.1186/1471-2474-13-252Published: 18 December 2012
Distal radius fractures (DRF) are one of the most common fractures and often need surgical treatment, which has been validated through biomechanical tests. Currently a number of different fracture models are used, none of which resemble the in vivo fracture location. The aim of the study was to develop a new standardized fracture model for DRF (AO-23.A3) and compare its biomechanical behavior to the current gold standard.
Variable angle locking volar plates (ADAPTIVE, Medartis) were mounted on 10 pairs of fresh-frozen radii. The osteotomy location was alternated within each pair (New: 10 mm wedge 8 mm / 12 mm proximal to the dorsal / volar apex of the articular surface; Gold standard: 10 mm wedge 20 mm proximal to the articular surface). Each specimen was tested in cyclic axial compression (increasing load by 100 N per cycle) until failure or −3 mm displacement. Parameters assessed were stiffness, displacement and dissipated work calculated for each cycle and ultimate load. Significance was tested using a linear mixed model and Wald test as well as t-tests.
7 female and 3 male pairs of radii aged 74 ± 9 years were tested. In most cases (7/10), the two groups showed similar mechanical behavior at low loads with increasing differences at increasing loads. Overall the novel fracture model showed a significant different biomechanical behavior than the gold standard model (p < 0,001). The average final loads resisted were significantly lower in the novel model (860 N ± 232 N vs. 1250 N ± 341 N; p = 0.001).
The novel biomechanical fracture model for DRF more closely mimics the in vivo fracture site and shows a significantly different biomechanical behavior with increasing loads when compared to the current gold standard.