steps and direction ends pulled must alternate to make a square knot.
failure to alternate the steps results in a granny knot (best at first to always start an instrument tie with the needle holders in the center of the knot)
as each throw is tightened, even tension must be applied to each suture strands keeping the ends at the same level as the knot (ie. hands down near the surface of the "patient").
uneven tension while tightening or holding hands high results in the knot flipping into a half-hitch (tendency to slip and fail)
avoid seesawing motion when tightening as this may cause the strands to break
handle only the ends of the suture strands with instruments to avoid damaging the suture
tighten throws firmly (ensure tight knot) but not too aggressively (damage or tear tissues)
knots for surgery need a minimum of 4 throws (see knot security)
check knot is tight and square with ends lying flat
when first learning to tie knots, watch each throw until tight and critically examine the finished knot to make sure it is square
with practice, you develop a feel for when a square knot is tied
trying to go too fast too soon often leads to tying slip or granny knots
