Resumo

MURATORE, Álvaro et al. Biomecánica de la fijación distal en fracturas extrarticulares de radio: tornillos versus pernos: Estudio en modelos cadavéricos. Rev. Asoc. Argent. Ortop. Traumatol. [online]. 2015, vol.80, n.4, pp.292-302. ISSN 1852-7434.

Objective: To perform a biomechanical comparison in cadaveric models between locking screws and locking smooth pegs in extra-articular distal radius fractures stabilized with volar locking plates. Methods: We reproduced extra-articular dorsal comminuted fractures in 12 cadaveric radius. We divided them into two groups according to the use of locking screws or locking smooth pegs in distal fixation. Biomechanical tests were conducted evaluating changes in the rigidity of the systems after performing an axial load. Finally, the systems were led to the failure. Radiological controls were performed in all instances. Results: When the systems fixed with locking screws were led to the failure, a greater dorsal inclination of the articular facet was observed. A separation of the plate relative to the bone was observed in those plates fixed with locking smooth pegs. Moreover, the maximum tolerated load was 1659 N and 1905 N in the systems with locking screws and with locking smooth pegs, respectively. Conclusions: In both systems the load force moves from the epiphysis to the diaphysis through the osteosynthesis (boneplate- bone), bridging the fracture and deforming the plate which pushes the articular facet to dorsal deviation. However, in models with locking smooth pegs we found a second time of load transmission in which the plate is removed from the system due to slippage of the locking smooth peg, allowing a transmission directly from the distal to the proximal fragment (bone-bone) generating in all cases an incomplete and longitudinal fracture of the volar cortex, but avoiding deformation of the plate to dorsal deviation.

Palavras-chave : Distal radius fracture; Volar locking plate; Locking screws; Locking smooth pegs.

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