Effect of strain rate on tensile strength and strain of surgical suture materials

The present work demonstrates the influence of the strain rate on the mechanical characteristics of Prolene and Ethilon loops. The testing of the loops was performed on a materials testing machine and complete load deformation curves were recorded. Various mechanical parameters were calculated and analysed by computer. The present study demonstrates that calculating energy absorption (areas L/S and S/S) is necessary, and that isolated measurements of breaking strength (Fmax) and tensile strength (delta max) values are misleading as measures of functional suture strength. The investigation showed that the mechanical characteristics of the thread and the knot, and thus the loop, depend on the strain rate and examples are given on the practical importance of this. It is emphasized that the in vivo situation with its varying strain rate necessitates an international standard with more detailed and clinically applicable test procedures for surgical suture material.