Comparison of the Stress Relaxation of Biodegradable Surgical Threads Made of Mg and Zn Alloys and Some Commercial Synthetic Materials

The mechanical properties of the commercial synthetic surgical threads (i.e., monofilament Monosyn^R and polyfilament Polysorb^TM) and threads made of pure zinc and selected magnesium alloys were compared. Tensile and relaxation tests of fine fibers/wires without and with a surgical knot were performed on a Zwick 250 tensile machine and on the specially constructed tensile machine dedicated for ultra-thin samples. An about 50% decrease in the maximum tensile load was registered for both synthetic and Mg-based threads due to the presence of a surgical knot while only an about 10% decrease was documented for the zinc threads.