Related Experiment Video
Updated: May 13, 2026
06:41
A Novel Arthroscopic Medial Knot-Tying Suture-Bridge Repair with Rip-Stop Technique for Rotator Cuff Tears
Published on: January 13, 2026
Surgical knot tightening: how much pull is necessary?
Stefan Neuhofer1, Karl Wieser, Georg Lajtai
1Orthopaedic Department, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland, dr.stefan.neuhofer@gmail.com.
Summary
Excessive surgical knot tightening is unnecessary and can damage skin. Proper knot tying technique, not excessive force, is crucial for secure surgical knots, minimizing slippage and failure.
Area of Science:
- Surgical Materials Science
- Biomechanics
- Wound Closure Technology
Background:
- High-strength sutures enable knot tightening beyond surgeon's capacity, potentially causing iatrogenic tissue damage.
- The necessity and optimal tensioning for surgical knots remain incompletely understood.
Purpose of the Study:
- To evaluate the utility of excessive surgical knot tensioning.
- To determine the necessary tension for surgical knots.
Main Methods:
- Tested three suture materials: Vicryl, FibreWire, and PDS.
- Measured surgeon-applied "tying load" during knot tightening.
- Tied standardized square knots with increasing loads (0.5-50 N) and evaluated knot seating, failure mode, and failure load.
Main Results:
- FibreWire knots consistently failed by slipping, irrespective of tying load.
- Increasing tying load reduced knot slippage and increased failure load nonlinearly for all sutures.
- Significant differences in slippage were observed between 0.5-10 N (FibreWire, PDS) and 0.5-2 N (Vicryl).
Conclusions:
- Knot slippage and self-seating occur even with maximal tying loads.
- Tying loads exceeding 2 N (Vicryl) and 10 N (PDS, FibreWire) show minor but potentially significant improvements in failure load and slippage.
- Proper knot tying technique and number of throws are more critical than excessive tension for achieving maximum failure load.
