Physical properties of self locking and conventional surgical knots.

OBJECTIVE

To assess some of the physical properties of three types of self locking knots and two types of conventional surgical knots.

DESIGN

Experimental in vitro study.

OUTCOME MEASURES

Knot efficiency (knot strength: suture strength ratio), slippage, and volume.

MATERIALS

Test knots tied with the suture materials polyglactin, polydioxanone and nylon in USP sizes 1,2/0, and 4/0.

RESULTS

Self locking knots performed significantly better (p < 0.01) than conventional knots in all combinations of material and size, except for 4/0 nylon. Efficiency of the self locking knots tied with the monofilament polydioxanone and nylon ranged from 0.88-0.96. With the multifilament polyglactin, it ranged from 0.71-0.90, and it increased proportionally with the thickness of the material. The mean efficiency of the conventional knots was 0.51 (0.06) for polyglactin, and 0.70 (0.17) for the monofilament materials. The self locking knots did not slip. The conventional starting knot often slipped partly, but came undone only when the conventional terminating knot was tied with monofilament material. The self locking knots were significantly smaller than the conventional knots.

CONCLUSION

Self locking knots are safer than conventional surgical knots, and considerably smaller.