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Locking, Jamming, and Ratchet Mechanisms of Sliding Surgical Knots Topologically Revisited



The geometry of lockable, ratchet, or jamming sliding surgical knots was assessed to enhance practical and topological understanding of knots among surgeons.


Using a database of more than 100 surgical knots, 29 knots that reportedly feature locking, ratchet, or jamming mechanisms were topologically assessed for their ability to lock antegradely or retrogradely, to lock by assuming their flat geometry, or to jam.


Eighteen of the 29 investigated surgical knots have previously been mistakenly categorized. Topologically, the concept of a true ratchet knot is a fallacy.


Surgical knots may be consistently classified on the basis of precise and detailed definition of various anti-backsliding geometrical characteristics of knots.

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The authors thank Mr. Adri Jans, medical illustrator and knot-tier, for his artwork, encouraging comments, and constructive criticism.

Financial Disclosure and Products

The authors hereby certify, that to the best of their knowledge:

1. This work has been executed as part of our regular appointment at the Netherlands Cancer Institute and VU Medical Center, and that there have been no external or commercial sources or funds supporting this work.

2. No financial support or benefits have been received by us, by any member of our immediate family or any individual or entity with whom or with which we have a significant relationship from any commercial source which is related directly or indirectly to the scientific work or any product that is reported on in the article.

3. We understand an example of such a financial interest would be a stock interest in any business entity which is included in the subject mater of the manuscript or which sells a product relating to the subject matter of the manuscript.

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Correspondence to J. Joris Hage.

Glossary Box

Sliding knot:

allows both forward and backward sliding, even after tightening the knot.

Ratchet knot:

allows only forward sliding toward the suture loop after tightening the working end.

Jamming knot:

prevents both forward and backward sliding, as a result of anything less than a bight in the standing part that was caused by traction on the working end.

Locking knot:

prevents both forward and backward sliding by change to a flat knot or by distortion of the straight standing part into a bight upon traction on the working end.

Retrograde locking knot:

locked by distortion upon traction on the loop part of the working end.

Antegrade locking knot:

locked by distortion upon traction on the tag end of the working end.

Proximal antegrade locking knot:

locked by a bight that is formed in the standing part by the most proximal turn of the working end, nearest to the knot-tier.

Middle antegrade locking knot:

locked by a bight that is formed in the standing part by an intermediate turn of the working end.

Distal antegrade locking knot:

locked by a bight being formed in the standing part by the most distal turn of the working, nearest to the suture loop.

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Hage, J.J., van der Steen, L.P.E. Locking, Jamming, and Ratchet Mechanisms of Sliding Surgical Knots Topologically Revisited. World J Surg 33, 751–757 (2009).

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  • Suture Loop
  • Consistent Classification
  • Ratchet Effect
  • Ratchet Mechanism
  • Loop Security