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.
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ABSTRACT: Networks are known to improve performance and create synergies. A research network can provide a significant advantage for all parties involved in research in surgery by systematically tracking the outcome of a huge number of patients over a long period of time. The aim of the present study was to investigate the experiences of surgeons with respect to research activities, to evaluate the opinions of surgeons with regard to the development of a national network for research in the field of surgery in Switzerland and to obtain data on how such a network should be designed. An anonymous postal survey of board-certified surgeons practising in Switzerland was conducted during summer 2007. The questionnaire included questions related to research activities, the desire to develop a national research network and the design and potential advantages of such a network. Qualitative analyses were performed using Mayring's content analysis. A total of 337 out of 749 (45%) questionnaires were returned. In all, 156/337 (46.3%) surgeons were engaged in research activities. During the past five years, 212/337 (62.9%) of the participants had participated at least in one multi-centre study. Out of 337, 88 (26.1%) surgeons were members of an established research association in Switzerland. Interest in a national surgical research network was reported by 266 (78.9%) participants. The reported advantages were "power" (53.1%), "teamwork effects" (23.7%), "efficiency" (12.2%) and "quality aspects" (8.0%). The most frequently named design proposal was based on a clinic for coordinating research, while the younger participants also suggested a web-based platform. Due to the significant interest of participants, the establishment of a national research network should be considered. An established clinic for coordinating research alongside an additional web-based platform to target young surgeons could function as an umbrella organisation.Schweizerische medizinische Wochenschrift 11/2011; 141:w13295. DOI:10.4414/smw.2011.13295 · 1.88 Impact Factor
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ABSTRACT: Polyaxial angle-stable plating is thought to be particularly beneficial in the management of complex intra-articular fractures of the distal radius. The purpose of the present study was to investigate whether the technique provides stability to match that of conventional (fixed-angle) angle-stable constructs. In seven pairs of human cadaver radii, an Arbeitsgemeinschaft für Osteosynthese (AO) 23 C2.1 intra-articular fracture was created. One radius of each pair received a juxta-articular 2.4-mm locking compression plate (LCP) Volar Distal Radius Plate, whilst the contralateral one received a 2.4-mm Variable Angle Locking Compression Plate (LCP) Two-Column Volar Distal Radius Plate (both plates: Synthes, Oberdorf, Switzerland). Parameters tested were construct stiffness (static axial loading with 150 N), range of motion and secondary loss of reduction (dynamic 150 N axial loading over 5000 cycles). Stiffness and range of motion were measured both pre- and post-cycling. The polyaxial constructs were significantly stiffer, both before and after cyclic testing. However, the two-column plates showed a significant loss of stiffness during cyclic testing. The range of motion was significantly greater, both initially and at the end of cyclic testing, in the fixed-angle constructs. The conventional constructs had significantly greater secondary loss of reduction. The polyaxial two-column plate tested in this study provides a biomechanically sound construct for the management of intra-articular fractures of the distal radius.Injury 02/2011; 42(11):1248-52. DOI:10.1016/j.injury.2010.12.005 · 2.46 Impact Factor
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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. DOI:10.1016/j.injury.2012.08.048 · 2.46 Impact Factor