SURFACE OF KNOTS AND KNOT HOLDING CAPACITY IN POLYPROPYLENE MONOFILAMENTS

Knots form the weakest sections in suture materials. The addition of forces in the knot caused by bend and tension exceed the strength of the suture material and lead to rupture in the knot. Furthermore the most pronounced tissue reactions occur in the surrounding of knots because of their relatively large surface as compared to the linear filament. With a higher knot holding capacity a secure fixation can be achieved with less knots. As a reduced number of knots leads to a smaller surface a reduced tissue reaction can be expected. Because of high rigidity and a low coefficient of friction synthetic monofilaments achieve only a low knot holding capacity. To improve the knot holding capacity a usually large number of knots is being used. With increasing surface of exogenous materials the extent of foreign-body reactions increases, e. g. formation of granuloma. Results of in-vitro experiments are reported that were conducted to identify the smallest secure knot in polypropylene filaments of various diameters.