A secure Aberdeen knot: in vitro assessment of knot security in plasma and fat

Abstract

OBJECTIVES: To determine the minimum number of throws/turns to form a secure Aberdeen knot and the maximum ear slippage for these knots using three metric polydioxanone coated in fat or plasma. To compare plasma and novel canine liquefi ed fat as suture coating mediums for in vitro knot security testing. METHODS: Throws/turns were incrementally added until a secure knot was found for plasma and fat. Knots were tensioned until failure and remaining ear length measured. A secure knot was defi ned as ear slippage 3 mm or less in 20 consecutively tested knots. Ear slippages were statistically analysed. RESULTS: Minimum secure confi guration was a 3+1 knot in plasma and fat, and its ear slipped a maximum of 2 mm in plasma and 2·5 mm in fat. A secure 4+1 knot had a maximum ear slippage of 0·5 mm, which was signifi cantly less than that of the 3+1 knot (P<0·0001). Fat coating suture signifi cantly decreases in vitro knot security compared with plasma (P=0·0035). CLINICAL SIGNIFICANCE: The novel fat coating medium should be considered when testing in vitro knot security as it simulates a clinical knot tying environment. A 4+1 Aberdeen knot with a 3 mm ear is recommended to tie a secure Aberdeen knot in any body fl uid environment.