Assessment of a novel biomechanical fracture model for distal radius fractures

• Published in: BMC musculoskeletal disorders 2012-12, Vol.13 (1), p.252-252, Article 252
• Main Authors: Baumbach, Sebastian Felix, Dall'Ara, Enrico, Weninger, Patrick, Antoni, Anna, Traxler, Hannes, Dörr, Martin, Zysset, Philippe K
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Biomechanical fracture model; Biomechanical Phenomena; Biomechanics; Bone Density; Bone Plates; Confidence intervals; Distal radius fracture; Editing; Elasticity; Female; Fresh-frozen; Humans; Linear Models; Male; Medical imaging; Middle Aged; Musculoskeletal diseases; Osteotomy; Plate osteosynthesis; Radius Fractures - diagnostic imaging; Radius Fractures - physiopathology; Radius Fractures - surgery; Stress, Mechanical; Surgery; Weight-Bearing; X-Ray Microtomography
• ISSN: 1471-2474; 1471-2474
• DOI: 10.1186/1471-2474-13-252

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.