| Table 6-15 Physical Characteristics of Suture Material |
| | Physical Characteristic | | Definition | | Comment |
| | Coefficient of friction (COF) | | Ease with which suture will pull through tissue | | Polypropylene slides easily (↓ COF) Knot strength directly proportional to COF (↑ knot strength with ↑ COF) |
| | Suture configuration | | Monofilament – single strand
(nylon or polypropylene)
Multifilament – made of several strands either twisted or braided | | ↓ Coefficient of friction (COF) so slides easily through tissue causing less trauma |
| | | | Handle/tie more easily, ↑ tensile strength, but ↑ COF, ↑ risk infection (organisms may be harbored between filaments) |
| | Capillarity | | Ability of suture to absorb and transfer fluid | | Multifilament has ↑ capillarity, which also increases risk of harboring bacteria |
| | USP size | | Diameter of suture material
{Choose smallest suture providing adequate tensile repair} | | Related to tensile strength (smaller the number, greater tensile strength/diameter) |
| | Elasticity | | Ability of suture to regain former shape (original size/shape) after being stretched | | ↑ Elasticity means suture can stretch with tissue and will recoil when swelling subsides |
| | Knot strength | | Security of tied knot and degree of slippage occurring in a knot | | Polyglycolic acid has one of highest knot strengths |
| | Memory | | Suture’s tendency to retain natural configuration after deformation (determined by elasticity and plasticity of material) | | High memory sutures like polypropylene and nylon have greater tendency to untie themselves (do not handle easily, lower knot strength requiring greater number of ties); silk w/ ↓ memory (rarely unties) |
| | Plasticity | | Ability of suture to retain new length and form after being stretched | | Important in tissue edema – as sutures with plasticity (polypropylene) will accommodate edema without cutting into tissue; ↑ plasticity may lead to ↑ knot security |
| | Pliability | | How easily suture can be bent | | Braided suture (silk) most pliable |
| | Tensile strength | | Force required to snap the suture (determined by diameter and composition of suture) | | Larger sutures usually have more tensile strength; synthetic material usually stronger than natural materials like silk |
| | Tissue reactivity | | Degree of inflammation elicited by placement of suture in wound (degree of foreign body reaction) | | Natural suture w/ ↑ inflammatory response vs. synthetic materials (nylon); ↑ suture diameter w/ ↑ tissue reaction; ↓ reactivity with monofilament (unlike multifilament) |
| | Absorption | | Absorbable sutures lose tensile strength over time by absorption | | Proteolysis – natural materials (cat gut or silk)
Hydrolysis – synthetic absorbable sutures |
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