RESUMO
The aim of this study was to evaluate the biomechanical role of both a non-locking two-hole small fragment dynamic compression plate with 3.5-mm screws and a 4.5-mm cortical screw with a washer applied to a Schatzker type-I tibial plateau fracture. Sixteen right synthetic tibiae were used to create an anterolateral shear tibial plateau fracture (Schatzker type-I fracture). Eight models were fixed with a small fragment non-locked straight dynamic compression plate with one 3.5-mm bicortical screw (plate-screw construction) and eight models were fixed with a 4.5-mm cortical screw and a washer (screw-washer construction), both inserted at 1.0 mm distal to the apex of the fracture. Specimens were tested up to the onset of yielding at a constant strain rate of 5.0-mm/min. Stiffness ranged from 311.83 N/mm to 199.54 N/mm, with a mean + SD of 260.32 + 33.8 N/mm in the plate-screw construction, and from 290.34 N/mm to 99.16 N/mm, with a mean + SD of 220.46 + 63.12 N/mm in screw-washer construction. There was no significant difference (p=0.172). Use of a two-hole small-fragment non-locked plate with one 3.5-mm cortical screw or a 4.5-mm cortical screw with a washer applied at 1.0 mm distal to the apex of the fracture as buttressing present similar stiffness in terms of preventing axial displacement in synthetic tibiae models tested up to the onset of yielding.
Assuntos
Fixação Interna de Fraturas/métodos , Fraturas da Tíbia/cirurgia , Placas Ósseas , Parafusos Ósseos , Humanos , Modelos AnatômicosRESUMO
ABSTRACT The aim of this study was to evaluate the biomechanical role of both a non-locking two-hole small fragment dynamic compression plate with 3.5-mm screws and a 4.5-mm cortical screw with a washer applied to a Schatzker type-I tibial plateau fracture. Sixteen right synthetic tibiae were used to create an anterolateral shear tibial plateau fracture (Schatzker type-I fracture). Eight models were fixed with a small fragment non-locked straight dynamic compression plate with one 3.5-mm bicortical screw (plate-screw construction) and eight models were fixed with a 4.5-mm cortical screw and a washer (screw-washer construction), both inserted at 1.0 mm distal to the apex of the fracture. Specimens were tested up to the onset of yielding at a constant strain rate of 5.0-mm/min. Stiffness ranged from 311.83 N/mm to 199.54 N/mm, with a mean + SD of 260.32 + 33.8 N/mm in the plate-screw construction, and from 290.34 N/mm to 99.16 N/mm, with a mean + SD of 220.46 + 63.12 N/mm in screw-washer construction. There was no significant difference (p=0.172). Use of a two-hole small-fragment non-locked plate with one 3.5-mm cortical screw or a 4.5-mm cortical screw with a washer applied at 1.0 mm distal to the apex of the fracture as buttressing present similar stiffness in terms of preventing axial displacement in synthetic tibiae models tested up to the onset of yielding.
RESUMO O objetivo do estudo foi avaliar o comportamento biomecânico de dois tipos de fixação: placa de compressão dinâmica de pequenos fragmentos, não bloqueada com parafuso de 3,5mm e parafuso cortical de 4,5mm com arruela, ambos posicionados no vértice de fratura do platô tibial do tipo I de Schatzker. Dezesseis tíbias sintéticas foram utilizadas para criar uma fratura por cisalhamento na face ântero-lateral do platô tibial (tipo I de Schatzker). Oito modelos foram fixados com placa de compressão dinâmica de pequenos fragmentos não bloqueada com parafuso de 3,5mm, inserido 1,0mm distal ao vértice da fratura (construção placa-parafuso), e oito modelos foram fixados com parafuso cortical de 4,5mm com arruela, inserido 1,0mm distal ao vértice da fratura (construção parafuso-arruela). Os modelos foram testados em compressão axial até o início da falha mecânica na interface construção-osso, com taxa de deformação constante de 5,0mm/min. A rigidez variou de 311,83 N/mm a 199,54 N/mm, com média + DP de 260,32 + 33,8 N/mm nos modelos da construção placa-parafuso, e de 290,34 N/mm a 99,16 N/mm, com média + DP de 220,46 + 63,12 N/mm nos modelos da construção parafuso-arruela. Não houve diferença estatisticamente significativa (p=0,172). A utilização de placa de compressão dinâmica de pequenos fragmentos não bloqueada com parafuso de 3,5mm ou de parafuso cortical de 4,5mm com arruela, posicionados no vértice da fratura do platô tibial do tipo I de Schatzker, apresenta rigidez similar na prevenção do desvio axial da fratura.