Product Manual

Knot slippage is counteracted by the frictional forces of the knots. The

degree to which a knot slips can be influenced by a variety of factors

including the coefficient of friction of the suture material, suture diameter,

moisture, knot type and final geometry. Knots of the granny type (crossed)

usually exhibit more slippage than do knots with a square-type (parallel)

construction.

With each additional throw, incrementally greater forces are required for

knot untying. After a specified number of throws, failure will occur by knot

breakage, after which the knot breakage force will not be enhanced by the

addition of more throws. Consequently, these additional throws offer no

mechanical advantage and represent more foreign bodies in the wound that

damage host defenses and resistance to infection.

The human element in knot tying has considerable influence on the

magnitude of knot slippage.

The amount of tension exerted by the

surgeon on the “ears” of the knot significantly alters the degree of slippage.

The careless surgeon who applies minimal tension (10% of knot break

strength) to the “ears” of the knot constructs knots that fail by slippage.

Knot slippage can be minimized by applying more tensions (80% of knot

break strength) to the “ears” of the knot. Another serious error often made

by the inexperienced surgeon is not to change the position of his/her hands

appropriately during construction of square and/or granny type knots. The

resulting knot, a sliding or slip knot, will become untied regardless of the

suture material. The risk of forming a slip knot is greatest when tying one-

hand knots and/or with deep seated ligatures.

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knot slippage