Investigating fracture mechanisms of some non-absorbable sutures in vivo

Abstract

The change of two important mechanical properties, tensile strength and knot strength reduction and fracture mechanisms of four different nonabsorbable sutures, namely silk, polyester, polyamide6 and polypropylene in vivo were evaluated. Three different sizes (0,2/0,3/0) were also used for each suture type. In the experiments in vivo conditions, rats Rattus norvegicus in race obtained from University of Uludag Medical Faculty Experimental Animals Breeding and Research Centre, have been used. The experiments were carried out before and after implantation. Effect of in vivo conditions on tensile strenth, knot strength, knot security and fracture mechanisim were evaluated.Effect of fibrous tissue (a capsule) around the suture and knot plays an important role on both tensile and knot strength retention, knot security and fracture mechanism. As a protein based natural material showed great deal of knot and tensile strentgth reduction as it is effected by the water absorbtion from the body fluid. Due to fibrous tissue, however, the rate of reduction was not as high as expected. Broken ends showed no scattering of the filaments and the knot was not opend. This was not the case for braided polyester suture. No fibrous tissue was observed around the suture and the knot. The knot was opened and the filaments were scattered at the broken ends. Polyamide and Polypropylene sutures were in monofilament form. Typical ductile fracture for PA suture and typical anisotropic fracture for polypropylene suture were observed. No effect of in vivo was recorded for the both sutures in terms of fracture mechanism. However a reduction in knot and tensile strength was clear for PA suture as water efects the molecule chain due to amide linkages. © 2010 Woodhead Publishing Limited. All rights reserved.