Evaluation of tension obtained by use of three knots for tying cerclage wires by surgeons of various abilities and experience

Simon C. Roe Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606.

Search for other papers by Simon C. Roe in
Current site
Google Scholar
PubMed
Close
 BVSc, PhD, DACVS

Abstract

Objective—To compare tension of 3 cerclage wire knots tied by surgeons of various abilities and experience.

Design—Cross-sectional study.

Sample Population—Participants and faculty at a postgraduate course in veterinary orthopedics.

Procedure—Subjects tied a cerclage of their choice on an instrumented tying stand that displayed the tension on a computer. Mean tensions in cerclage wires tied with twist, single loop, or double loop knots were compared. The relationship between level of surgeon experience and tension achieved was examined.

Results—29 twist, 30 single loop, and 16 double loop wires were analyzed. Mean ± SD tension for twist knots was significantly less than for single loop knots (82.3 ± 46.1 vs 166.6 ± 42.2 N, respectively). Double loop knots achieved significantly greater tension (392.0 ± 116.6 N) than twist and single loop knots did, even though few participants had ever tied this knot previously. There was no correlation with experience of the participant. For twist knots, wiggling the wire during cutting and pushing the twist over to flatten it to the bone further reduced tension.

Conclusions and Clinical Relevance—Cerclage applied with a twist knot does not compress fracture fragments as effectively as cerclage applied with single loop or double loop techniques. Because greater compression of fragments will improve the stability of a fracture, a surgeon should strive to maximize the tension in the cerclage that they use. Experience and abilities of the surgeon are not associated with ability to tie cerclage wires tightly. (J Am Vet Med Assoc 2002;220:334–336)

Abstract

Objective—To compare tension of 3 cerclage wire knots tied by surgeons of various abilities and experience.

Design—Cross-sectional study.

Sample Population—Participants and faculty at a postgraduate course in veterinary orthopedics.

Procedure—Subjects tied a cerclage of their choice on an instrumented tying stand that displayed the tension on a computer. Mean tensions in cerclage wires tied with twist, single loop, or double loop knots were compared. The relationship between level of surgeon experience and tension achieved was examined.

Results—29 twist, 30 single loop, and 16 double loop wires were analyzed. Mean ± SD tension for twist knots was significantly less than for single loop knots (82.3 ± 46.1 vs 166.6 ± 42.2 N, respectively). Double loop knots achieved significantly greater tension (392.0 ± 116.6 N) than twist and single loop knots did, even though few participants had ever tied this knot previously. There was no correlation with experience of the participant. For twist knots, wiggling the wire during cutting and pushing the twist over to flatten it to the bone further reduced tension.

Conclusions and Clinical Relevance—Cerclage applied with a twist knot does not compress fracture fragments as effectively as cerclage applied with single loop or double loop techniques. Because greater compression of fragments will improve the stability of a fracture, a surgeon should strive to maximize the tension in the cerclage that they use. Experience and abilities of the surgeon are not associated with ability to tie cerclage wires tightly. (J Am Vet Med Assoc 2002;220:334–336)

Advertisement