A secure Aberdeen knot: in vitro assessment of knot security in plasma and fat.
OBJECTIVE
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 liquefied 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 defined as ear slippage 3 mm or less in 20 consecutively tested knots. Ear slippages were statistically analysed.


RESULTS
Minimum secure configuration 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 significantly less than that of the 3+1 knot (P<0.0001). Fat coating suture significantly decreases in vitro knot security compared with plasma (P=0.0035).


CONCLUSIONS
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 fluid environment.
Schaaf
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O
Biological Sciences, Murdoch University Veterinary Hospital, Perth, Western Australia, Australia.
Glyde
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M
Day
R E
RE
D000273:Adipose Tissue; D000818:Animals; D004285:Dogs; D066298:In Vitro Techniques; D010949:Plasma; D013536:Suture Techniques / Q000662:veterinary*; D013537:Sutures / Q000662:veterinary; D013718:Tensile Strength