A novel non-bridging external fixator construct versus volar angular stable plating for the fixation of intra-articular fractures of the distal radius--a biomechanical study.
ABSTRACT Non-bridging external fixation has recently been introduced as an alternative to volar angular stable plating for the fixation of unstable intra-articular distal radial fractures. The purpose of this study was to biomechanically compare a new non-bridging external fixator construct to volar angular stable plate fixation in a dorsally comminuted intra-articular fracture model of the distal radius.
Five pairs of fresh frozen human cadaveric radii were randomly supplied with either a non-bridging external fixator or a stainless steel volar locking plate. A three-fragmental AO 23-C2.1 fracture was created by removing a 15 degrees dorsal wedge with remaining volar cortical contact and by an intra-articular osteotomy lateral to the lister-tubercle. Physiological load transfer via the wrist was simulated by means of a custom-made seesaw. For biomechanical testing, the bones were loaded in cyclic axial compression. Starting at 100N, the load was monotonically increased at 0.025 degrees N per cycle until failure of the construct. Motion of the lunate and scaphoid fragments with respect to the radial diaphysis was acquired by optical three-dimensional (3D) motion tracking. Plastic wedge deformation was determined after 2000, 4000 and 6000 cycles.
The amplitude of wedge motion at the beginning of the test as a measure for construct stiffness was significantly lower for the fixator group (P=0.003, power=0.99). Plastic wedge deformation after 2000, 4000 and 6000 cycles was found significantly lower for the external fixator (repeated measures analysis of variance (ANOVA), P=0.009, power=0.86). Displacement of the intra-articular gap was found below 0.6mm (mean) for both groups (P>0.05).
The study revealed superior biomechanical properties of the proposed non-bridging external fixation compared to volar locked plating in an unstable intra-articular fracture model with volar cortical support. However, both fixation techniques seem to apply sufficient stabilisation to restore and retain anatomy after fracture of the most distal part of the radius and should be individually chosen according to distinct criteria.
- SourceAvailable from: Srecko Sabalic[Show abstract] [Hide abstract]
ABSTRACT: Pločica na zaključavanje za ekstraartikularne prijelome distalnog humerusa -biomehanička studija na osteoporotičnom modelu Doktorska disertacija Osijek, 2012.11/2012, Degree: PhD, Full Professor, Supervisor: Ante Muljačić, Janoš Kodvanj
- [Show abstract] [Hide abstract]
ABSTRACT: Distal radius fractures are a common disorder in industrialized nations associated with osteoporosis, with a reported incidence of two fractures per thousand patients per year. We performed a retrospective study comparing two sets of 40 patients, with fracture of the distal radius treated with Penning external fixator, compared to 40 patients treated with fixed-angle volar-locking plate (Plate Depuy ® DVR), with the objective of finding differences between both treatment methods in anatomical values, functional outcomes and complication rates. All fractures were classified according to the AO classification. Postero-anterior and lateral radiographs of the wrist were taken after fracture, after surgery and at 6 months after surgery. We also assessed functional outcome. Minimum follow up was of 10 months. We compared complications between both groups. In the group of patients treated with fixed-angle volar-locked plate, radiological results are found to be closer to the anatomical references. Final outcomes revealed similar functional scores between both groups. The complications rate was statistically higher in the group of patients who underwent external fixation. In the fixed-angle volar-locked plate group, most of complications were related to patient discomfort due to the volar-locking plate.Journal of Hand and Microsurgery. 12/2012; 4(2).
- [Show abstract] [Hide abstract]
ABSTRACT: IntroductionAnatomicaly preformed variable-angle locking plates are technologically mature and appear to be optimal for the fixation of distal radius fractures. However, there is still much argument about whether volar plating is equivalent to dorsal (buttressing) plating, especially in the management of intra-articular extension fractures. This biomechanical study was performed to determine, in a simple intra-articular fracture model, whether dorsal or volar plate constructs would be more stable.Materials and methodsSix pairs of fresh frozen radii were examined with dual-energy absorptiometry (DXA) to determine their bone mineral density (BMD). An AO type 23 C2.1 fracture was created. Volar fixation was with a 2.4 mm Variable-Angle LCP Two-Column Volar Distal Radius Plate; dorsal fixation was with two orthogonal 2.4 mm Variable-Angle LCP Dorsal Distal Radius Plates (both devices: Synthes, Oberdorf, Switzerland). Biomechanical testing used a proven protocol involving static tests of stiffness, and a cyclic test to obtain range of motion (ROM), maximum deformation, and subsidence data.ResultsNone of the constructs failed during biomechanical testing. The two groups (volar and dorsal plating, respectively) did not differ significantly in terms of initial (pre-cyclic-testing) and final (post-cyclic-testing) stiffness. Equally, there was no significant difference between the subsidence values in the two groups. The post-cyclic-testing ROM was significantly greater in the dorsal-plate group as compared with the volar-plate group. The volar constructs showed a significant decrease in the ROM between pre- and post-cyclic testing.Conclusion Biomechanically, volar plating with a modern variable-angle locking plate is equivalent to dorsal plating with two modern variable-angle locking plates.Injury 04/2013; 44(4):523–526. · 2.46 Impact Factor