Arthroscopic Suture Material and Knot Type: an Updated Biomechanical Analysis

Background: Several new arthroscopic suture materials are available. It is important for surgeons to know which suture-knot combination provides the strongest construct.

Hypothesis: The newer, polyblend sutures have dissimilar load-to-failure characteristics.

Study Design: Controlled laboratory study.

Methods: The load to failure of 4 knots was evaluated (surgeon's, Duncan loop, Samsung Medical Center [SMC], and Roeder) using 5 No. 2 suture materials (Ethibond, Ticron, FiberWire, ForceFiber, MaxBraid). One surgeon tied all knots. Fifteen samples were tested for each suture-knot configuration. Knots were pretensioned to 10 N, then loaded to failure at a rate of 1.0 mm/s. Failure load recorded was the maximum load applied between 0 and 3 mm of displacement. Cyclic loading of suture-knot samples was performed on 3 knots (surgeon's, Duncan loop, and SMC) using 4 suture materials (Ethibond, FiberWire, ForceFiber, MaxBraid). Six samples were tested for each suture-knot configuration. Knots were cyclically loaded from 5 to 40 N at 0.5 Hz for 1000 cycles, then loaded to failure. Data were compared with analysis of variance and the Tukey multiple range test and considered significant at P < .05.

Results: The surgeon's and SMC knots were strongest, particularly if tied using MaxBraid or ForceFiber. With single load-to-failure testing, MaxBraid was significantly stronger than Ethibond, Ticron, or FiberWire, regardless of knot type used. ForceFiber was stronger than Ethibond and Ticron with any knot type, and stronger than FiberWire when tied with a surgeon's knot or Roeder knot. The MaxBraid surgeon's knot (246 N) and MaxBraid SMC knot (239 N) were more than twice as strong as the Ethibond surgeon's knot (111 N) and Ethibond SMC (118 N). With cyclic loading, MaxBraid and ForceFiber were stronger than FiberWire and Ethibond, regardless of knot type tied. The SMC knot using MaxBraid withstood the highest load, and was stronger than the Duncan loop tied with MaxBraid. When stricter criteria (1-mm and 2-mm displacement) for failure were used, MaxBraid and ForceFiber remained superior to other sutures, including FiberWire, but knot type became less significant.

Conclusion: Nonabsorbable polyblend sutures are stronger than traditional sutures, but not all polyblend sutures are alike. MaxBraid and ForceFiber provide a stronger knot than FiberWire, Ethibond, and Ticron, particularly if tied using a surgeon's or SMC knot.

Clinical Relevance: The SMC knot using MaxBraid provides the strongest knot/suture combination of knots and sutures tested.