Knot holding capacity of two different high-strength sutures-a biomechanical analysis.

Abstract

The number of seven required throws per knot was previously reported asproviding sufficient security against slippage. A novel high-strength suture featuring dynamic tightening may allow for throw number reduction without compromising stability. Theaimsof this study were to (1) investigate the influence of thethrow numberand the effect of different ambient conditions on theknot security of two different high-strength sutures, and (2) compare their biomechanical competence. Two sutures (FiberWire (FW) and DynaCord (DC)) were considered for preparing alternating surgical knots. Thespecimens were stratified for exposure to different media during biomechanical testing-namely air(dry), saline solution(wet), and fat(fatty-wet). A monotonic tensile ramp loading to failure was applied in each test run. For each suture and ambient condition, seven specimens with three to seven throws each were tested (n = 7), evaluating their slippage and ultimate force to failure. The minimum number of throws preventing suture unraveling was determined for each suture type and condition. For each suture type and condition, failure occurred via rupture in all specimens for the following minimum number of throws: FW-dry-7, wet-7, fatty-wet-7; DC-dry-6, wet-4, fatty-wet-5. When applying seven throws, FW demonstrated significantly larger slippage (6.5 ± 2.2 mm) versus DC (3.5 ± 0.4 mm) in wet (p = 0.004) but not in dry and fatty-wet conditions (p ≥ 0.313). The lower number of throws providing knot security of DC versus FW in themore realistic wet and fatty-wet conditions indicates that thenovel DCsuture may allow to decrease the foreign body volumeand save surgical time without compromising the biomechanical competence.