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Volar versus dorsal locking plates with and without radial styloid locking plates for the fixation of dorsally comminuted distal radius fractures: A biomechanical study in cadavers

Murray Blythe, Karl Stoffel, Paul Jarrett & Markus Kuster

abstract PURPOSE: To compare the stability and stiffness of dorsal and volar fixed-angle distal radius constructs in a cadaveric model. METHODS: A locking distal radius system was used in a combination of a dorsal and styloid plate (group 1), a single volar plate (group 2), and a combination of a volar and styloid plate (group 3) configuration. In addition a single volar 3.5-mm steel locking plate was used in group 4. Each construct was tested on 6 fresh-frozen radii with simulated unstable dorsally comminuted extra-articular distal radius fractures. Specimens were tested on a material testing machine with an extensometer and subjected to axial compression fatigue and load-to-failure testing. RESULTS: No construct failed in fatigue testing of 250 N for 5,000 cycles. Two specimens in each group were tested for 20,000 cycles without failure. The plastic deformation in the double-plate groups was lower compared with the single-plate groups, although the difference was not statistically significant. Group 1 had the highest and group 4 the lowest failure load and stiffness, respectively. The differences between group 1 and the other groups, except failure load compared with group 3, were statistically significant. Groups 2 and 3 had a significantly higher load to failure and group 3 had a significantly higher stiffness compared with group 4. CONCLUSIONS: All constructs offer adequate stability with minimal deformation on fatigue testing under physiologic conditions. Dorsal fixed-angle constructs are stiffer and stronger than volar constructs. The addition of a styloid plate to a volar plate did not significantly improve stability in this model of simulated extra-articular dorsal comminution loaded in axial compression.
   
citation Blythe M, Stoffel K, Jarrett P, kuster m. Volar versus dorsal locking plates with and without radial styloid locking plates for the fixation of dorsally comminuted distal radius fractures: A biomechanical study in cadavers. The Journal of hand surgery 2006; 31:1587-93.
   
type journal paper/review (English)
date of publishing 12-2006
journal title The Journal of hand surgery (31/10)
ISSN print 0363-5023
pages 1587-93
PubMed 17145377
DOI 10.1016/j.jhsa.2006.09.011