MRCS Part B Revision · Procedural and technical skills
Knot Tying — MRCS Part B Procedural and technical skills
By Dr Richard Miller, MBChB FRCS · Reviewed
Knot Tying is a procedural station. Two of the seventeen examined stations in the MRCS Part B OSCE are procedural. The procedural stations ask you to perform a practical task, usually on a model, while explaining what you are doing and why.
What you need to know for the Knot Tying station
Knot Tying
The key to tying knots is practise. Use your surgical skills manual and try to practise in theatre to skills labs. You can even use pieces or suture material or string and practise at home.
The surgeon's knot is a simple modification to the reef knot. It adds an extra twist when tying the first throw, forming a double overhand knot. The additional turn provides more friction and can reduce loosening while the second half of the knot is tied.
- Hold one end of the rope in your left hand and the other end in your right hand.
- Cross ends Cross the end of the rope in your left hand over the end in your right hand to form an “X.”
- Entwine ends Bring the end of rope in your left hand down behind the end in your right hand, then back up, so that the two ends are entwined—the left-hand rope is now in your right hand and vice-versa
- Immediately throw another loop doubling the throw
- Form another "X" Use your right hand to pass the same end back over the end now in your left hand, forming another “X.”
- Pull end through loop Bring that end down behind the other end again, and continue pulling it through the loop that forms.
- Pull ends Pull the two ends to a symmetrical length
- Hold one end of the rope in your left hand and the other end in your right hand.
- Cross ends Cross the end of the rope in your left hand over the end in your right hand to form an “X.”
- Entwine ends Bring the end of rope in your left hand down behind the end in your right hand, then back up, so that the two ends are entwined—the left-hand rope is now in your right hand and vice-versa
- Immediately throw another loop doubling the throw
- Form another "X" Use your right hand to pass the same end back over the end now in your left hand, forming another “X.”
- Pull end through loop Bring that end down behind the other end again, and continue pulling it through the loop that forms.
- Pull ends Pull the two ends to a symmetrical length
What are you asked at the Knot Tying station?
The station runs to 5 questions over nine minutes. These are the questions as they are put to you; the model answers are in the question bank.
- Describe how you would tie a Reef Knot
- Please tie a surgeon's knot
- Please perform a reef knot at depth
- Describe the most secure way of tying off a bleeding vessel
- Please perform a simple instrument tie
How is the procedural and technical skills station marked in MRCS Part B?
The two procedural stations are marked differently from each other. Procedural skills with a patient carries 8 marks for clinical and technical skill and 4 each for knowledge, communication and professionalism. Procedural skills, technical, performed on a model rather than a person, carries 12 for skill and 8 for knowledge, with no communication or professionalism marks available.
FAQ
What does the Knot Tying station ask?
It opens with "Describe how you would tie a Reef Knot" and runs to 5 questions over nine minutes. The two procedural stations are marked differently from each other. Procedural skills with a patient carries 8 marks for clinical and technical skill and 4 each for knowledge, communication and professionalism. Procedural skills, technical, performed on a model rather than a person, carries 12 for skill and 8 for knowledge, with no communication or professionalism marks available.
What procedural skills are tested in MRCS Part B?
Two of the seventeen examined stations are procedural: one with a patient and one purely technical. Candidates most often report suturing, abscess incision and drainage, catheterisation and chest drain insertion.
How is a procedural station marked?
The station with a patient carries 8 of its 20 marks for clinical and technical skill and 4 each for knowledge, communication and professionalism. The technical station carries 12 for skill and 8 for knowledge, with no communication marks.
Should I talk while I perform the procedure?
At the station with a patient, yes: a third of the marks there are for communication and professionalism, and they are gone if you work in silence. At the purely technical station those marks do not exist, so the technique itself is what counts.
How many stations are in the MRCS Part B OSCE?
Seventeen examined stations of nine minutes each, with a minute to read the task before each one. Two preparation stations and at least one rest station bring the circuit to about twenty, and the exam takes about three and a half hours.
What is the pass mark for MRCS Part B?
There is no published pass mark. The cut score is set separately for Applied Knowledge and Applied Skills, for each circuit, by borderline regression. Published pass rates across the 2024/25 diets ranged from 51% to 66%.
Can I fail a station and still pass?
Yes. There is no rule about how many stations you may fail: the cut score applies to your total mark in each component, so a weak station costs the marks you lost on it and strong stations elsewhere can make them back. Applied Knowledge and Applied Skills are passed separately and must both be passed at the same sitting, so a strong anatomy performance cannot rescue a weak communication one.
Dr Richard Miller, MBChB FRCS
Station summaries are reviewed against the current intercollegiate MRCS syllabus and the published marking blueprint. Guidance changes between diets: check the royal colleges' own pages before relying on a date, a fee or a threshold.
Practise this station
The question bank carries the model answer to every question above, with the rest of the procedural and technical skills stations.
More procedural and technical skills stations