Estudo biomecânico do terceiro metacarpiano de eqüinos

Abstract

Bone properties determined by biomechanical testing are extremely important for both metallic implants and osteosyntesis protocols development. The objective of this study was determining the biomechanical properties of some different regions of third metacarpal bone submitted to compression and bending tensions, using thirty pairs divided into two groups, each group formed by one limb of each pair. During the three points bending test the dorsal surface of the entire bone was placed upon two cylindrical bases 150 mm far from each one, and load was applied in the mid point on the palmar aspect of the bone, 75 mm far from each cylindrical base, until bone's failure. For the compression test samples of different bone regions were used. The mid diaphysis was used as samples (cp1), which its height was twice its latero-lateral thickness at the mid point of the bone length. All cp1 were submitted to proximodistal compressive loads until it reached 4000kgf. Using a trefina the others samples were obtained from the fragments of bone not used for the cp1 confection. Two of them were collected from the trabecular portion of proximal (cp2) and distal (cp3) epiphysis, and the others from lateral (cp4L) and medial (cp4m) cortex region of diaphysis. All of them were submitted to proximo-distal compressive load until their failure. By the analysis of the results obtained was concluded that the medial cortex is more resistant to tensions and has greater elastic modulus than the medial cortex, at the diaphyseal region; the trabecular bone at the distal epiphysis has the same elastic modulus than at the proximal epiphysis, however its failures occurs at greater loads.

Placas ósseas confeccionadas a partir de diáfise cortical equina na osteossíntese femoral em coelhos

“…O metacarpo equino é considerado como um dos elementos mais fortes do esqueleto nesta espécie (Moreira 2008). Sua capacidade em suportar diferentes cargas o torna um material de grande interesse.…”