How to Tie Surgical Knots


Surgical knot tying is an important part of any surgical rotation. Let’s go over the basics to help you shine on your surgical rotations.

There are three ways to tie a knot that you will need to know

  1. Two handed: This is the bread and butter and you must master this. Some attendings will want you to demonstrate proficiency in two-handed ties before doing one-handed. I do not necessarily agree with this as you can be good at one handed and bad at two handed, but I understand their rationale. They want to make sure you understand the basic principles of tying strong, square knots.
  2. One handed: This is the most efficient but hardest to learn.
  3. Instrument: You will be doing instrument ties when you are suturing. It’s important to get proficient at instrument ties otherwise you may lose privilege closing incisions until you can do so appropriately.


General Principles

Knot security

It’s critically important that your knots to stay in place. Without getting into the theoretical details of stretch and friction, what you need to know is that proper technique is the most important factor. Throw solid square knots. Also, more throws leads to better knot security. The type of suture can also influence knot security. Monofilament, which is more slippery than braided suture, generally requires more throws to achieve the same knot security.

Surgeon’s knot

Sometimes you should use the surgeon’s knot, which is looping the suture twice in the same direction before locking it. This is generally used when tying under tension as it prevents slippage. Why do you not always use the surgeon’s knot? Because it uses excess material. You generally want to use the least amount of suture necessary for a secure knot.

Square knot vs slipknot

Square knot refers to tying in opposite directions to lock a knot. It also refers to laying down a throw squarely. You can see a demonstration of these concepts in the videos linked above.

Slipknot is when you throw two throws in the same direction. This allows you to secure it without locking, helping you prevent air knots.


Things to Keep in Mind

Efficiency is the name of the game in the operating room. All your movements should be deliberate and intentional. A mistake I often see is tying a one-handed knot while moving your post (stationary hand). This defeats the purpose of a one handed knot.

Once you get the hang of tying, focus on details like eliminating unnecessary movements and not tugging too hard. If you’re tying over a delicate vessel, you need to be able to tie a knot securely without damaging vital structures.

Practice! I would have ties on my water bottle or notebook and tie while watching TV or listening to lectures. Do what works best for you. Practice with both hands. Being able to tie one- and two-handed with either your left or right hand will serve you well in the OR.


The suturing kit I used in the videos can be found here. Parts 1 through 4 below:


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