Synthetic sutures such as nylon and Orion are coming to the fore because they are stronger than silk and, thus, can be used in smaller diameters. Also, claims have been made that these synthetic materials are less irritating.
However, their coefficient of friction is less that that of silk, and if they are tied, even with three or more "squared" single loops, the suture will not hold. Slippage can be prevented by using double-loop ties. But many surgeons are accustomed to tie knots with the so-called one-hand methods to speed up the procedure. Another advantage of "one-hand" tying is that each tie is customarily "squared" in relation to the preceding tie. To tie a knot with a double loop, it has been necessary to use "two-hands" which is much slower. Also, a tight "first" tie can be maintained more easily with a double loop.
The accompanying photographs describe a "one-hand"
SEIGER HW. New "One Hand" Double-Loop Method of Tying Knots. Arch Surg. 1963;87(6):986–987. doi:10.1001/archsurg.1963.01310180102017