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Joint aspiration/corticosteroid injection [advanced]

Please note this information is for educational purposes only and procedures should not conducted based on this information. OSCEstop takes no responsibility for use of any content.

Aspiration indications: diagnose cause of swollen joint; tense effusion symptom relief

Steroid injection indications: osteoarthritis, synovitis, inflammatory arthritis, crystalloid arthropathies, tendinopathy (except achilles/patellar), bursitis, entrapment syndromes

Relative contraindications: overlying cellulitis (IV antibiotics required); coagulopathy (INR >1.4, platelets <50, therapeutic anticoagulant <24 hours, clopidogrel <7days); skin lesion over joint; known bacteraemia; adjacent osteomyelitis; joint prosthesis

Joint sizes


Large = knee, ankle, shoulder

Medium = wrist, elbow

Small = MCP, ICP, sternoclavicular, acromioclavicular


  • Wash hands, Introduce self, Patients name & DOB, Explain procedure and get consent
    • Risks: pain, bleeding/haemarthrosis, infection, cartilage damage, damage to local structures
    • Corticosteroid risks: tendon atrophy/rupture, avascular necrosis, skin discoloration, local fat atrophy, soft tissue/pericapsular calcification, osteoporosis
  • **Check patients clotting screen, platelet count and if they have been on an therapeutic anticoagulant/clopidogrel**
  • Check drug allergies
  • Ensure assistant is available
  • Examine joint and confirm effusion

Preparation part

  • Wash hands and apply apron
  • Clean  a trolley
  • Gather equipment onto bottom of trolley (think through what you need in order)

Equipment list

  • Sterile pack
  • Cleansing snap-sponge (iodine or alcohol/chlorhexidine) x2
  • OPTIONAL: Sterile drape with hole in centre (or 2-3 drapes without holes in)
  • 10ml syringe and 2 needles (1 blunt fill 18G drawing-up needle, 1 orange 25G) for local anaesthetic
  • Injection/aspiration needle (green 21G if large joint, blue 23G needle if medium joint, orange 25G if small joint)
  • Syringe
    • 20-50ml syringe if doing aspiration (depending on size of effusion)
    • 1-5ml syringe if doing injection (5ml for large joint, 2.5ml for medium joint, 1ml for small joint)
  • Extra green 21G needle to draw up steroid if doing aspiration
  • Cotton gauze swabs (used whenever needed throughout procedure to dry/clean sterile area)
  • Sterile dressing
  • Equipment to be kept outside of the sterile field
    • Incontinence pad
    • Sterile gloves
    • 10ml 1% lidocaine (maximum 3mg/kg – note 1ml 1% lidocaine = 10mg)
    • Blood culture bottles or 2 white-topped sample collection bottles, and 1 purple EDTA tube if doing aspiration
    • 80mg Depo-Medrone (methylprednisolone acetate) in 2ml vial if doing large joint injection
    • 40mg Depo-Medrone (methylprednisolone acetate) in 1ml vial if doing medium/small joint injection

  • Walk to patient
  • Wash hands
  • Open sterile pack to form a sterile field on the top of the trolley
  • Open packets (without touching the instruments themselves) and drop sterile instruments neatly into the sterile field
  • Pick up waste bag from sterile pack without touching anything else and stick to side of trolley

Patient part

Positioning and exposure

  • Position patient
  • Expose joint and place incontinence pad below
  • Examine the surface anatomy of patient’s joint
  • Locate insertion point
  • Mark insertion point with a skin pen/indentation


  • Wash hands
  • Apply sterile gloves using sterile technique (open pack on a side surface)
  • Sterilize area
    • Work from middle outwards in one spiral motion (using cleansing snap-sponge)
    • Repeat with second cleansing snap-sponge
    • Discard used snap-sponges as they are no longer sterile, but note all equipment used after this (including all needles) can be returned to the sterile field after use
    • OPTIONAL: Apply the sterile drape over the patient’s body so that the hole is in the correct place to allow access to the insertion site (or apply 2-3 drapes centred around exposed insertion site if no holes)
  • Anaesthetise tract
    • Ask assistant to snap open lidocaine bottle and hold open upside-down
    • Draw up lidocaine using drawing-up needle on 10 ml syringe and expel any air (maximum 7ml if doing injection so the rest can be used with the injection)
    • Change to the orange needle and insert at an acute angle to form a single subcutaneous bleb around insertion site in order to anaesthetise the skin
    • Now use the same needle to anaesthetise the insertion tract up to the joint capsule
      • Always aspirate when advancing the needle (so you know if you enter the joint capsule) and aspirate before injecting lidocaine (to check you are not in a vessel)

Joint aspiration

  • With a 20-50ml syringe on the aspiration needle, stretch the skin and insert into the insertion tract
  • Aspirate during infiltration
  • As soon as fluid enters the syringe, stop advancing the needle and aspirate to fill the syringe/as much as possible
  • Withdraw the needle

Joint injection

  • Ask assistant to snap open Depo-Medrone bottle and hold this and the lidocaine bottle open upside-down
  • Draw up the Depo-Medrone and some lidocaine into the same syringe using a green needle and expel any air
    • Large joint: 2ml Depo-Medrone + 3ml lidocaine (in 5ml syringe)
    • Medium joint: 1ml Depo-Medrone + 1ml lidocaine (in 2.5ml syringe)
    • Small joint: 0.25ml Depo-Medrone + 0.25ml lidocaine (in 1ml syringe)
  • Change to the injection needle, stretch the skin and insert into the insertion tract
  • Aspirate during infiltration
  • When in place, aspirate to ensure you are not in a vessel and slowly expel the contents of the syringe
  • Withdraw needle


  • Dress wound

Joint specific techniques


  • Suprapatellar approach
    • Position patient lying supine with the knee extended
    • Identify the midpoint of the superolateral border of the patella
    • Insert needle 1cm above and 1cm lateral to this point
    • Direct the needle inferomedially and angle slightly posteriorly (at ~ 45˚ from horizontal plane), between the posterior surface of the patella and the intercondylar femoral notch
Knee aspirate – suprapatellar approach
  • Parapatellar approach (preferred aspiration approach)
    • Position patient lying supine with the knee extended
    • Identify the junction of the upper and middle third of the patella on its medial or lateral border
    • Apply pressure to the opposite border of the patella to open the joint space
    • Palpate the groove under the patella (~5-10mm laterally) and insert the needle here
    • Direct the needle medially and a little inferiorly in the horizontal plane, between the posterior surface of the patella and the intercondylar femoral notch
Knee aspirate – parapatellar approach
  • Infrapatellar approach
    • Position patient sitting on the side of the bed with knees at 90˚ over side
    • Identify the inferior border of the patella and the patella tendon
    • Insert the needle 5mm inferior to the inferior border of the patella, just lateral to the patella tendon
    • Direct the needle superomedially and angle slightly posteriorly (at ~ 45˚ from horizontal), between the posterior surface of the patella and the intercondylar femoral notch

Note: lateral approaches are described above but identical medial approaches may also be used


  • Anterior approach (preferred)
    • Position the patient in a seated position with their shoulder externally rotated
    • Palpate the coracoid from anteriorly
    • Insert the needle 1cm lateral to the coracoid (medial to head of humerus)
    • Direct the needle posteriorly and angle slightly superolaterally
Shoulder aspirate – anterior approach
  • Posterior approach
    • From posteriorly, palpate the acromium (posteriorly) and coracoid (anteriorly)
    • Insert the needle 1cm inferior to the posterior tip of the acromium
    • Direct the needle anteriorly and angle slightly medially towards the coracoid


  • Position the patients forearm on a stable surface, with their palm facing downwards
  • Ask the patient to extend their thumb to identify the extensor pollicis longus tendon, and also locate Lister’s tubercle (bony prominence at distal end of radius)
  • Insert the needle distal the Lister’s tubercle and lateral to extensor pollicis longus tendon
  • Direct the needle ventrally, perpendicular to the forearm
Wrist aspirate


  • Position the patients elbow at 90˚ flexion, rested on a stable surface
  • Palpate the olecranon process, the lateral epicondyle and the radial head
  • Insert the needle the centre point of this triangle, perpendicular to the skin
Elbow aspirate


  • Anterolateral approach (preferred)
    • Position the patient lying supine with ankle at 90˚
    • Palpate the space between the lateral malleolus (laterally) and the extensor digitorum longus (medially) in the ankle joint line
    • Insert the needle midway between
    • Aim the needle posteriorly, perpendicular to the fibular shaft
Ankle aspirate – anterolateral approach
  • Anteromedial approach (risks damage to dorsalis pedis and deep peroneal nerves)
    • Position the patient lying supine with ankle at 90˚
    • Palpate the space between the medial malleolus (medially) and the tibialis anterior tendon (laterally) in the ankle joint line (just above the talus)
    • Insert the needle midway between
    • Aim the needle posteriorly and slightly laterally, perpendicular to the tibial shaft

Note: you can ask patient to dorsiflex foot against resistance to help identify tendons

Metacarpophalangeal joint

  • Rest the hand on a stable surface, palm down with the fingers slightly flexed
  • Insert the needle dorsally, either medial or lateral to the extensor tendons
MCP joint aspirate

To complete

  • Thank patient and cover them
  • Bin waste and gloves, dispose of sharps safely in sharps bin, clean trolley and wash hands
  • If required, label sample tubes and send to lab:
    • MC&S (blood culture bottles or white-top x2) β†’ microbiology
    • Crystals (white-top) β†’ cytology
    • Cell count (purple EDTA tube) β†’ haematology – if the local hospital haematology laboratory do not do synovial fluid cell counts, the MC&S should be sent in a white-top, so microbiology can do cell count
  • Fully document procedure in patients notes

Learn how to interpret the results too…

Synovial fluid result interpretation is covered here!

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