MRCS Part B Revision · Procedural and technical skills
Joint Aspiration — MRCS Part B Procedural and technical skills
By Dr Richard Miller, MBChB FRCS · Reviewed
Joint Aspiration 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 Joint Aspiration station
Knee Aspiration
• Wash your hands
• Introduce yourself and explain the procedure gaining verbal consent
• Palpate effusion with the knee extended
• Assemble equipment using sterile technique
• Prep the superolateral area around 2cm (finger breadths) above the superolateral margin of the patella
• Make a hole in the isolation drape and place it over this area
• Insert the white needle at 45 degrees aspirating as you go beneath the patella
• Aspirate the effusion to dry
• Place aspirate into x2 sterile pots
• Gently reeve the needle placing a swab over the entry point
• Place a plaster over the wound
• Thank the patient and dispose of sharps
• Label and send the samples
What are you asked at the Joint Aspiration station?
The station runs to 7 questions over nine minutes. These are the questions as they are put to you; the model answers are in the question bank.
- Describe the equipment you would assemble
- Describe how you would perform the knee aspiration
- Explain your choice of needle used
- What is your differential diagnosis for the above patient?
- What tests would you send the samples for?
- What other investigations would be helpful in this patient?
- The aspirate result is shown below Fluid: straw-coloured fluid Organisms: No organisms identified WCC: ++ WCCs Crystals: pending How would you proceed?
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 Joint Aspiration station ask?
It opens with "Describe the equipment you would assemble" and runs to 7 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