What is knee joint aspiration, and when is it performed?

Knee joint aspiration is a procedure that removes synovial fluid with a hollow needle for diagnosis or symptom relief. It is performed when a knee is swollen, painful, or contains a suspected effusion. Common indications include suspected septic arthritis, crystal arthritis, unexplained inflammation, traumatic haemarthrosis, and tense swelling causing discomfort. The procedure may also reduce pressure and improve movement. Always explain the purpose, obtain consent, check allergies, and use strict aseptic technique. Introducing infection into a previously sterile joint is the feared complication.)

Which approach is commonly used for knee arthrocentesis?

The superolateral approach is commonly used because it accesses the suprapatellar pouch with the knee extended. Palpate the superolateral border of the patella, then insert the needle approximately one finger breadth above and lateral to it. Direct the needle medially and posteriorly, at about 45 degrees, while applying gentle aspiration. Other approaches include the anterolateral and anteromedial routes. Use local anaesthetic where appropriate, but avoid contaminating the specimen. Consider ultrasound guidance when landmarks are unclear, the effusion is small, or previous attempts have failed.

What does aspirated knee fluid reveal?

Synovial fluid analysis can distinguish infection, crystal arthritis, inflammatory disease, and bleeding. Send fluid urgently for Gram stain, microscopy for crystals, culture, and cell count with differential. Turbid or purulent fluid and a high white-cell count raise concern for septic arthritis, although no single result excludes infection. Needle-shaped, negatively birefringent monosodium urate crystals support gout. Calcium pyrophosphate crystals support pseudogout. Blood suggests haemarthrosis, which may follow trauma, anticoagulation, a bleeding disorder, or a vascular injury. Always interpret results alongside the clinical examination and blood tests.

Can a knee injection be given at the same time?

A knee injection may follow aspiration, but corticosteroid must not be injected until infection has been reasonably excluded. Aspiration alone is usually appropriate when septic arthritis is possible. If infection is unlikely, a local anaesthetic or corticosteroid injection may provide symptom relief for selected inflammatory conditions. Use a new sterile syringe and needle for the injection. Do not inject through infected skin, into a prosthetic joint without specialist advice, or when the diagnosis remains uncertain. Document the drug, dose, route, batch number, and patient response.

What are the contraindications and complications?

Avoid aspiration through infected skin and correct significant bleeding risk before inserting the needle. A suspected bleeding disorder or anticoagulation requires an individual risk assessment rather than automatic exclusion. Prosthetic joints, severe coagulopathy, and an uncooperative patient may require specialist input. Complications include pain, bleeding, vasovagal symptoms, damage to cartilage or nearby structures, and persistent leakage. The most serious complication is septic arthritis caused by inoculating bacteria into the joint. Strict hand hygiene, sterile gloves, skin preparation, and a no-touch technique reduce this risk.

When should ultrasound guidance be considered, and how is a septic knee managed?

Use ultrasound guidance for a small, deep, loculated, or difficult-to-localise effusion, but treat suspected septic arthritis as an emergency. After aspiration, send samples immediately and start appropriate intravenous antibiotics after cultures are obtained, unless the patient is unstable. Urgently involve orthopaedics or the relevant surgical team for washout or repeated drainage. Do not delay treatment while awaiting culture results. Record observations, obtain blood cultures, and assess for sepsis. A negative initial aspiration does not exclude infection if clinical suspicion remains high. Aspirate safely, analyse the fluid urgently, and never inject steroids into a poten

Joint Aspiration for MRCS Part B: MRCS Part B Revision

Knee joint aspiration is a minimally invasive procedure that removes synovial fluid with a sterile needle to diagnose conditions or relieve pressure. A clinician may perform an aspiration injection knee joint procedure separately or combine aspiration with a carefully selected joint injection after infection has been reasonably excluded. For exam-focused procedural revision, Mrcspartbquestions highlights the importance of combining technical accuracy with safe clinical decision-making.

Key takeaways

Strict asepsis is the whole point: introducing infection into a joint is the feared complication.
Send synovial fluid for urgent Gram stain, microscopy for crystals, culture and cell count.
Aspirate before giving any intra-articular steroid, and never inject steroid into a joint you suspect is septic.
A superolateral approach with the knee extended is the usual route for the knee.
Say out loud that you would treat a hot, swollen joint as septic arthritis until the fluid proves otherwise.

What Is Knee Joint Aspiration?

Knee joint aspiration is the sterile removal of synovial fluid from the knee for laboratory diagnosis or pressure relief. Knee joint aspiration is a procedure that uses a needle and syringe to remove excess fluid from inside the knee joint. It is also called knee arthrocentesis. The fluid may be removed to reduce pressure and pain, or sent for laboratory testing. See this overview of joint aspiration for diagnosing rheumatoid arthritis and osteoarthritis.

This procedure has both diagnostic and therapeutic roles. Synovial fluid can reveal infection, bleeding, crystals, or inflammatory disease. Removing a large effusion may improve pain and movement.

Knee joint aspiration injection describes aspiration followed by medicine placed inside the knee. An aspiration injection knee joint sequence can decompress a swollen knee before selected intra-articular injections. These terms describe two linked procedures, not one identical procedure.

Aspiration, Injection, and Causes of Effusion

Aspiration removes fluid from the joint. An intra-articular injection places medicine into the joint, such as a local anaesthetic or corticosteroid. These procedures may occur during the same appointment, but they have different purposes. An injection treats symptoms or inflammation; aspiration obtains fluid or relieves pressure.

Common causes of a knee effusion include:

Trauma, including haemarthrosis after ligament or meniscal injury
Infection, including septic arthritis
Crystal arthritis, such as gout or pseudogout
Inflammatory arthritis, such as rheumatoid arthritis
Osteoarthritis, especially during an acute flare

Before any needle approach, the clinician confirms the indication, checks allergies and contraindications, and explains the procedure. Strict aseptic technique is essential because introducing infection into the joint is the feared complication. Fluid should be sent urgently for Gram stain, microscopy for crystals, culture, and cell count.

An aspiration injection removes excess synovial material before a therapeutic medicine is considered. In a planned aspiration injection knee appointment, clinicians should document whether the purpose is diagnosis, decompression, or treatment. A knee joint aspiration injection should never delay urgent assessment for suspected septic arthritis.

The terms aspiration injection knee, injection knee joint, and injection knee may appear in patient searches for different treatments. Clinically, needle aspiration collects a specimen, while injections deliver an anaesthetic, corticosteroid, or another prescribed medicine. The distinction matters when discussing consent and risk.

Anatomy and MRCS Part B Relevance

Candidates must identify the patella, patellar tendon, joint line, and the soft tissue around the knee. A common approach uses the superolateral area, above the superolateral patellar margin. The needle enters the joint while avoiding the patellar tendon and other tendons.

The examiner may also expect awareness of nearby vessels and nerves. The popliteal neurovascular bundle lies posteriorly, while the saphenous nerve and vessels require consideration on the medial side. Good surface anatomy supports a safe needle approach and reduces complications. Mrcspartbquestions similarly recommends linking each anatomical landmark to the practical reason for identifying it during an MRCS station.

For MRCS Part B, treat this as both a technical and communication station. Explain the indication, gain consent, maintain sterility, and describe how you would label and send the sample. The procedural station assesses clinical knowledge, technique, communication, and professionalism.

Relevant anatomy includes the patellofemoral compartment, suprapatellar pouch, tibiofemoral joint line, quadriceps tendon, and patellar tendon. The medial and lateral landmarks determine whether a medial approach, lateral approach, or superomedial approach is suitable.

Clinical insight: The safest approach is the one that provides a clear path into the synovial space while avoiding skin disease, tendons, cartilage, vessels, and nerves.

Is knee aspiration the same as a steroid injection? No. Aspiration removes joint fluid, while an injection introduces medication. Knee joint aspiration uses a sterile needle to remove knee fluid for diagnosis or symptom relief, while an injection delivers medication into the joint.

When Is Knee Arthrocentesis Indicated?

Knee arthrocentesis is indicated when synovial fluid is needed for diagnosis or when a tense collection is causing pressure and restricted movement. Knee arthrocentesis is the removal of synovial fluid from the knee using a sterile needle and syringe. It can provide a diagnosis, relieve pressure, or support treatment. The decision depends on the history, examination, systemic symptoms, skin condition, and relevant imaging.

A hot, acutely swollen knee with fever or systemic illness requires urgent aspiration to investigate potentially limb-threatening septic arthritis.
Synovial fluid analysis distinguishes infection from gout, pseudogout, inflammatory arthritis, and haemarthrosis when acute monoarthritis has no clear cause.
Aspiration is indicated for an unexplained effusion, especially when history and examination cannot establish a safe, convincing diagnosis.
Therapeutic aspiration can relieve pressure from a tense, painful effusion and improve movement while the underlying cause is treated.
A corticosteroid injection may follow aspiration only after infection is reasonably excluded and the needle path avoids infected skin.
Before inserting a needle, assess history, systemic symptoms, skin integrity, examination findings, and relevant imaging to guide the approach.

A diagnostic aspiration injection knee joint plan is particularly important when there are large effusions, unexplained knee pain, or concern about hemarthrosis. Electronic records such as Epic and Cerner can help document the indication, specimen destination, and follow-up plan.

Diagnostic indications

Septic arthritis is the most urgent indication. A painful, hot, swollen knee with restricted movement may represent infection, even without fever. Delaying aspiration can delay antibiotics and source control. Acute monoarthritis or an acute non-traumatic effusion with septic concern warrants diagnostic aspiration.

Send the sample promptly for four core investigations: Gram stain, microscopy for crystals, culture, and cell count. Crystal identification supports gout or pseudogout. The clinical picture and cell count help assess inflammation, but no single result excludes infection.

Aspiration can also investigate inflammatory arthritis, including rheumatoid arthritis, and bleeding into the joint. Haemarthrosis may follow trauma, an operation, anticoagulation, or a bleeding disorder. An unexplained knee effusion may need aspiration when imaging and examination do not provide the diagnosis.

A hemarthrosis is blood within the knee cavity. Recurrent hemarthrosis can occur after injury, surgery, anticoagulant use, or a clotting disorder. Aspiration injection knee assessment should distinguish blood-stained material from traumatic needle contamination whenever possible.

Large effusions can occur with septic arthritis, crystal disease, trauma, and inflammatory conditions. The presence of large effusions does not establish a cause, so laboratory analysis remains essential.

Therapeutic indications and safety

A large, tense effusion can cause severe pain and limit knee movement. Removing fluid with a needle may provide rapid relief. Following an acute injury, aspiration of haemarthrosis may also reduce inflammatory exposure within the joint.

A local anaesthetic or corticosteroid injection may be considered after aspiration for selected non-infective conditions. Never inject through cellulitis or into a joint where infection remains possible. Strict asepsis is essential because introducing infection is the feared complication. Only clinicians familiar with the anatomy, indications, and complications should perform the procedure.

A joint aspiration injection may be followed by an injection knee treatment for knee osteoarthritis, inflammatory synovitis, or selected patellofemoral disorders. The clinician must first consider whether osteoarthritis, trauma, crystal disease, or infection explains the swelling.

A corticosteroid injection is not a substitute for diagnostic sampling. For knee osteoarthritis, an aspiration injection may temporarily improve pressure-related symptoms, but it does not repair cartilage or reverse osteoarthritis.

Can aspiration and injection happen during the same appointment? Yes, but only after appropriate fluid has been collected and infection is not suspected. Use a new sterile needle for the injection when required by local policy.

Knee joint aspiration is indicated when fluid analysis is needed, pressure requires relief, or septic arthritis must be excluded urgently.

Which approach and landmarks do you use?

Knee joint aspiration approaches are selected according to the effusion, landmarks, patient positioning, and relevant anatomy. A swollen knee can obscure the joint line, patellar tendon, and femoral condyles. The wrong needle approach may strike cartilage, bone, or a tendon. It may also produce a dry tap despite a large effusion. Knee joint aspiration is needle access to the synovial cavity to remove fluid for diagnosis or treatment.

The direct answer is to choose a lateral route when possible. The superolateral approach is usually preferred for a large effusion. With the knee extended, insert the needle about 1 cm above and 1 cm lateral to the superolateral patellar margin. Aim posterior to the patella and superiorly, at approximately 45 degrees, toward the suprapatellar pouch.

For an aspiration injection knee joint procedure, positioning should make the patella, joint line, and intended portal easy to palpate. The knee may be extended or slightly flexed according to the chosen approach and local technique.

Comparing the main approaches

The superolateral route is effective because fluid collects in the suprapatellar pouch. A large effusion expands this pouch and moves it closer to the skin. The needle can pass beneath the articular surface of the patella, helping avoid cartilage. Studies and procedural guidance support this approach for knee aspiration.

For any injection or aspiration, identify the patella first. Trace its superior and inferior borders, then locate the patellar tendon below it. Identify the quadriceps tendon above it. Palpate the medial and lateral femoral condyles and the joint line. Avoid directing the needle through the patellar tendon, quadriceps tendon, or directly into the patella.

The superomedial approach and superomedial portal can be useful alternatives when the lateral side is unsuitable. A medial approach may be considered when the medial recess is more accessible, but the operator must account for medial vessels, nerves, scars, and tenderness.

Patellofemoral disease can alter the perceived landmarks. Patellofemoral pain, patellofemoral osteoarthritis, and patellofemoral maltracking should not be diagnosed solely from the route chosen for aspiration. Patello-femoral approaches require careful palpation and a clear understanding of the intended compartment.

MRCS anatomy checklist

Before choosing an approach, confirm:

Is the knee extended, and is the effusion easier to palpate?
Where are the patella, patellar tendon, and quadriceps tendon?
Can you identify the joint line and femoral condyles?
Is there a clear soft spot lateral or medial to the patella?
Would a large effusion make the superolateral pouch accessible?
Is the needle directed posteriorly, away from the patella’s articular surface?
Have you avoided infected skin, scars, and neurovascular structures?

For examination scenarios, select the superolateral approach when a large effusion makes the suprapatellar pouch prominent; select a lateral approach for a smaller, localised joint collection or injection.

Symptoms of other approaches include anteromedial, anterolateral, medial, lateral, and superomedial routes. The best technique depends on the collection’s location, the patient’s positioning, and the operator’s experience. The approach portals used in arthroscopy are not automatically the correct portals for aspiration injection procedures.

How Is Knee Joint Aspiration Performed?

Knee joint aspiration is performed with consent, antisepsis, local anaesthetic when appropriate, controlled needle placement, specimen handling, and safety-netting.

Knee joint aspiration involves consent, strict asepsis, local anaesthetic, accurate needle placement, fluid collection, and safe aftercare. Send synovial fluid promptly for cell count, Gram stain, culture, and crystal analysis when infection or crystal arthritis is possible.

Preparation and consent

Confirm the patient’s identity, procedure, side, indication, allergies, anticoagulant use, and relevant bleeding or infection risks. Explain the purpose, steps, discomfort, benefits, and possible complications. These include bleeding, pain, failed aspiration, and introducing infection into the joint. Obtain verbal consent and offer a chaperone where appropriate.

Position the patient supine with the knee extended or slightly flexed. Palpate for an effusion and identify the planned approach. The superolateral approach is commonly used, but the approach should follow local guidance and the patient’s anatomy.

Prepare sterile gloves, an antiseptic solution, sterile drapes, gauze, a dressing, a sharps bin, and suitable syringes. A larger syringe may be needed for a tense effusion. For a midpoint approach, an 18-gauge needle with a 30–60 mL syringe may enter approximately 1 cm medial or lateral to the patella. Direct it posteriorly and horizontally towards the intercondylar notch.

Perform a procedural time-out before skin puncture. Confirm the patient, side, planned approach, equipment, allergies, and specimen containers. Use strict aseptic technique because infection introduced into a joint is the feared complication. Mrcspartbquestions also encourages candidates to verbalise these safety checks rather than treating them as assumed steps.

Symptoms of the equipment may include a 10 mL syringe for anaesthetic, a 20–60 mL syringe for collection, an 18- or 20-gauge needle, sterile containers, and a label printer. The precise equipment and needle size depend on the patient, suspected diagnosis, and local policy.

Needle placement and fluid collection

Clean the skin with antiseptic and allow it to dry. Apply a sterile drape, exposing only the intended puncture site. Infiltrate local anaesthetic into the skin and deeper tissues, avoiding contamination of the joint or specimen. Allow time for the anaesthetic injection to work.

Insert the needle through the anaesthetised skin using the selected approach. Advance slowly while applying gentle negative pressure with the syringe. Avoid excessive force. If bone is contacted, withdraw slightly and redirect rather than pushing deeper.

When fluid enters the syringe, maintain the needle position and continue aspiration. Large effusions may require more than one syringe. Observe the fluid’s colour, clarity, and presence of blood or pus. Stop if the patient develops severe pain, resistance, or neurological symptoms.

Release negative pressure before withdrawing the needle. Remove it smoothly and immediately apply sterile gauze and a small dressing. Never reinsert a contaminated needle or pass it back across the sterile field. A steroid injection should only follow appropriate diagnosis, exclusion of infection, and separate consent.

A needle aspiration should use controlled advancement and gentle suction. The technique is not a forceful search for fluid. If the first placement fails, stop, reassess positioning, and consider ultrasound guidance rather than making repeated blind passes.

The same principles apply to aspiration injection procedures and intra-articular injections: correct placement, sterile handling, appropriate anaesthetic, and documented medication. The injection knee technique should never be performed through cellulitis or when septic arthritis remains a realistic possibility.

Specimens and aftercare

Divide the sample into correctly labelled containers at the bedside. Record the patient’s details, joint and side, date and time, and the tests requested. Send synovial fluid urgently for Gram stain, microscopy, culture, and white cell count when infection is possible. Request crystal analysis using polarised light microscopy when gout or pseudogout is suspected.

Symptoms of other tests may include differential cell count, protein, glucose, or specialised microbiology. Follow local laboratory requirements because the correct container and transport method affect results. Do not delay urgent specimens while waiting for additional paperwork.

After the procedure, check pain, swelling, bleeding, distal circulation, and movement. Document the indication, consent, position, approach, needle size, anaesthetic, fluid appearance and volume, specimens, complications, and patient response.

Give safety-netting advice. The patient should seek urgent review for increasing pain, redness, warmth, swelling, fever, rigors, or reduced movement. Suspected septic arthritis requires immediate senior review, urgent microbiology communication, blood tests, and appropriate treatment. In an MRCS station, clear communication, asepsis, technical control, and escalation all demonstrate safe practice.

What is the safest key principle? Strict asepsis is essential because contamination can cause septic arthritis. What should synovial fluid be tested for? Send it for cell count, Gram stain, culture, and crystal analysis, with further tests guided by the clinical situation.

Safe knee joint aspiration combines informed consent, strict asepsis, controlled needle placement, prompt fluid analysis, complete documentation, and rapid escalation of suspected infection.

How do you avoid the complications?

Accuracy improves when the clinician combines palpable landmarks, appropriate positioning, an atraumatic technique, and ultrasound when necessary.

What improves procedural accuracy?

Landmark-guided aspiration uses palpable anatomy, usually through a superolateral approach with the knee extended. The needle enters above and lateral to the patella, aiming beneath it. This is suitable when the effusion and landmarks are clear.

Ultrasound guidance visualises the effusion, needle, and surrounding structures in real time. It may improve accuracy in obesity, small or loculated effusions, altered anatomy, prosthetic joints, or after a failed landmark-guided attempt. Ultrasound can also guide an injection into the intended compartment.

Use strict aseptic technique for every approach. Clean the skin, use sterile gloves and equipment, and avoid touching the needle or prepared field. Send fluid promptly for urgent Gram stain, microscopy for crystals, culture, and cell count.

Ultrasound systems from GE HealthCare, Philips, and Mindray can display the target recess and needle in real time. The technology does not replace relevant anatomy, consent, specimen handling, or clinical judgement. It improves placement when the target is deep, small, loculated, or difficult to palpate.

Why must clinicians assess risk first?

Do not pass a needle through overlying cellulitis or an open wound. This can introduce bacteria into the joint. Suspected prosthetic joint infection requires urgent orthopaedic assessment and a specialist aspiration pathway. Avoid unnecessary injection before infection has been excluded.

Check bleeding risk, including thrombocytopenia, coagulopathy, and anticoagulant treatment. Anticoagulation is not always an absolute contraindication, but the decision should consider the drug, dose, INR, renal function, and bleeding risk. Correct significant coagulopathy where appropriate.

Difficult anatomy, previous surgery, severe swelling, or a joint replacement may justify ultrasound guidance or senior help. Only clinicians familiar with the anatomy, indications, and complications should perform the procedure.

Symptoms of common pitfalls include failing to identify the correct side, confusing an injection knee portal with an aspiration portal, contaminating the anaesthetic, and sending an unlabeled specimen. A pre-procedure checklist reduces preventable errors.

Intra-articular injections require additional caution. A corticosteroid injection can worsen an unrecognised septic process, while an anaesthetic injection can temporarily mask worsening symptoms. Electronic consent and barcode specimen systems may support safety, but they do not replace direct patient checks.

How are complications recognised and managed?

Possible complications include:

Bleeding: increasing swelling, bruising, or haemarthrosis. Stop, apply pressure, reassess circulation, and escalate if swelling is severe.
Infection: worsening pain, warmth, fever, or purulent fluid. Arrange urgent review and cultures.
Pain or cartilage injury: stop advancing the needle if the patient reports sharp pain or resistance.
Vasovagal episode: lay the patient flat, maintain observation, and check vital signs.
Dry tap: stop rather than repeatedly redirecting the needle. Recheck landmarks, assess whether fluid is present, and consider ultrasound or senior assistance.

A dry tap means no fluid is obtained despite entering or attempting to enter the joint. It does not exclude infection. > Safety insight: A dry tap is a result, not a diagnosis. Reassess the landmarks, review the imaging, and escalate when clinical suspicion remains high.

What is the MRCS response to an unsuccessful aspiration? Acknowledge the result, explain that repeated blind passes increase pain and injury risk, maintain asepsis, and seek senior or ultrasound-guided assistance. In a patient station, communicate bleeding, infection, pain, and fainting risks clearly. The procedure is marked across knowledge, technical skill, communication, and professionalism; a patient procedure carries 8 marks for clinical and technical skill, plus 4 marks each for knowledge, communication, and professionalism.

Safe knee joint aspiration combines accurate anatomy, strict asepsis, risk assessment, clear consent, and a calm plan for complications or a dry tap.

How does aspiration differ from injection?

Aspiration removes synovial material, injection delivers medicine, and imaging or blood tests provide complementary information rather than replacing fluid analysis.

Knee joint aspiration is the insertion of a sterile needle into the knee joint to remove synovial fluid for analysis or symptom relief.

Aspiration versus injection

Diagnostic aspiration removes fluid to investigate an unexplained effusion. Send the sample urgently for Gram stain, microscopy for crystals, culture, and cell count. This helps identify septic arthritis, gout, pseudogout, or inflammatory disease.

Therapeutic aspiration removes a large or painful effusion. It may reduce pressure and improve movement, but fluid can reaccumulate. Use strict aseptic technique because introducing infection into the joint is the feared complication.

An intra-articular injection places medicine into the joint using a needle. Corticosteroid may reduce inflammation, while local anaesthetic can provide temporary pain relief. However, avoid injection until septic arthritis has been excluded. Steroid may worsen infection, and local anaesthetic may mask clinical deterioration.

Aspiration and injection can occur during the same procedure, but the indication must be clear. In an acutely hot, swollen knee, aspirate first and await appropriate microbiology advice. Do not inject simply because the patient has pain.

A knee joint aspiration injection is therefore different from an aspiration injection knee joint search phrase used in online treatment information. Likewise, an aspiration injection knee may refer broadly to removing pressure and then injecting medicine, while injection knee joint can refer to medication delivery alone.

For knee osteoarthritis, a joint injection may contain corticosteroid, anaesthetic, or another clinician-selected medicine. Evidence and suitability vary by patient. Discuss expected duration, alternatives, risks, and the possibility that osteoarthritis symptoms may return.

Comparing investigations

MRCS Part B application

In a patient station, explain the indication, benefits, discomfort, bleeding, infection, failed aspiration, and possible need for further treatment. Check allergies, obtain consent, confirm the correct knee, and maintain asepsis. The needle approach should be described clearly before insertion.

A patient-based procedural station carries 8 marks for clinical and technical skill, plus 4 each for knowledge, communication, and professionalism. A model-based procedural station carries 12 marks for skill and 8 for knowledge.

Should you inject before aspirating? Usually not when infection is possible. Aspirate first and exclude septic arthritis before therapeutic injection. Aspiration diagnoses or decompresses the knee, injection treats selected conditions, and imaging or blood tests cannot replace synovial fluid analysis when septic arthritis is suspected.

How is this topic marked in MRCS Part B?

MRCS Part B marks the procedural stations out of 20. Procedural skills with a patient carries 8 marks for clinical and technical skill and 4 each for clinical knowledge, communication and professionalism. Procedural skills (technical), performed on a model, carries 12 marks for skill and 8 for knowledge, with no communication or professionalism marks. Two of the seventeen examined stations are procedural.

Joint Aspiration for MRCS Part B: Asepsis, Technique and Synovial Fluid