Joint aspirations and injections

Well lit area.
Wear mask.
Wear safety glasses.
Sterile technique.
Pathology collected.
 
Sharps disposal.

Attention

  • Do not do unless you have been trained. Medical consult prior to procedure
  • Most common joints to be injected/aspirated are knees, shoulders
    • Principles for joint injection and aspiration the same
    • Be aware of risk of introducing infection — always use aseptic technique
  • Before aspirating for diagnostic reasons — see Joint fluid analysis
  • If aspirating for healing (therapeutic) reasons — remove most of the fluid
  • Local anaesthetic not always needed. Depends on size of needle used
  • Always put needle in parallel to joint surfaces to prevent damage to cartilage
  • Use ultrasound guidance for shoulder injection if available

Note: Leave a bit of air in preloaded syringe. Air can easily be injected into joint but not tissue (strong resistance), helps you know if you are in joint

Circulation and sensation — when finished always check hands/feet (peripheries) for colour, warmth, sensation, movement, swelling, capillary refill, peripheral pulses — F 10.1, to make sure no damage to nerves, arteries or veins.

Syringes and needle sizes

  • Needle size depends on
    • Diagnostic or healing (therapeutic) aspiration
    • How much fluid and how thick
    • Size of joint
  • Always use smallest needle size possible
    • For aspiration usually 21G
    • For injection usually 23G
  • Needle length
    • Long — 32mm for shoulders or knees, 38mm for obese patients
  • Needle and syringe size for aspiration of toe/finger — 25G needle and 3mL syringe
  • Aspiration of knee/shoulder
    • 21G OR 18G needle/cannula if you expect thick or bloody fluid
    • 5mL syringe for diagnostic
    • 10–20mL syringe for healing (therapeutic) aspiration

Do not

  • Do not do joint aspirations if
    • Bacteraemia present
    • Skin infection or severe dermatitis over joint
    • Joint too difficult to reach
    • Severe lack of blood clotting (coagulopathy)
    • Gout in big toe (classic first metatarsophalangeal gout), very painful, not needed for diagnosis
  • Do not do steroid injection if
    • Bacteraemia present
    • Infectious arthritis
    • Close to bone infection (osteomyelitis)
    • Person having joint replacement surgery in less than a week
    • Bleeding into joint (haemarthrosis)

Indications (reasons) for joint aspiration

  • Therapeutic (to help with healing)
    • To relieve symptoms (pain, swelling)
    • To help stop damage to joint caused by infection
  • Diagnostic
    • To improve joint movement so swollen joint can be fully examined
    • To find reason for unexplained fluid build-up in joint

Types of effusions

Bloody effusions

  • Traumatic — most common
    • Bloody aspirate indicates soft tissue or bony injury
    • Fat globules in bloody aspirate indicate joint fracture
    • Usually contain streaks of clotted blood
  • Non-traumatic
    • Include haemophilia, anticoagulant therapy, malignant/benign tumours
    • Fluid is evenly bloody
    • May be caused by traumatic tap during joint aspiration — usually contains streaks and fresher looking blood
    • Don't need to send bloody aspirate to pathology unless you suspect septic arthritis, crystal arthropathy, malignant tumour
  • Non-traumatic effusions are usually non-bloody. Send aspirate to pathology for diagnosis
  • Single inflamed joint could be septic arthritis. Very damaging
    • 20% of people with septic arthritis don’t have a fever
    • 20% of cases of septic arthritis involve more than one joint

What you need

  • Blueys
  • Sterile dressing pack
  • Chlorhexidine 5% in 70% alcohol solution or povidone-iodine antiseptic solution
  • Syringes and needles
  • Sterile needle holder or haemostat clamp (to keep needle still when changing syringes)
  • Small sticking plaster
  • Compression bandage

May need

  • Large pillow
  • 3mL syringe preloaded with local anaesthetic and/or steroid for injection
  • Yellow cap sterile specimen container for aspirate
  • Crutches 

Knee injection/aspiration — medial and superolateral approach

Attention

  • Usually
    • Medial approach for injections and small (diagnostic) aspirations
    • Superolateral approach for large (healing/diagnostic) aspirations
  • Use method you are most comfortable with

What you do

Medial approach

  • Lie person on back with knee bent 45–90° over bluey-covered large pillow
  • Find site for aspiration/injection —  Figure 10.83
  • Mark injection site by making indentation with tip of syringe
  • Lay out dressing pack and equipment
  • Wash hands and put on sterile gloves
  • Disinfect site and drape with sterile towels
  • Put needle
    • Into triangular space made by edge of femoral condyle, tibial plateau (make sure you can palpate edge of tibial plateau) and patellar tendon, 1cm medial to patellar tendon — Figure 10.83
    • Behind patella, aiming for femoral notch. Direct inward and slightly backward toward person’s thigh for 2–3cm

Figure 10.83  

Triangle has apex at top of knee joint, long sides along femoral condyle and patellar tendon, base along tibial plateau.

Superolateral approach

  • Lie person on back with leg straight
  • Put in needle 1–2cm above (superior) and 1–2cm to outside (lateral) of upper outer aspect of patella at 45° angle, and at 45° to skin surface — Figure 10.84

Figure 10.84  

Injection site.

For both medial and superolateral approaches

  • If aspirating
    • Connect aspirating needle and syringe
    • Put spare hand (or have helper put their hand) on thigh above knee, press distally to milk effusion into joint. Take care to keep area sterile
    • Put in needle, pushing in slowly while aspirating until you see fluid, then aspirate
    • Don’t aspirate while needle being withdrawn through the skin. Can contaminate aspirate
  • If injecting
    • Inject skin and deeper tissues at needle insertion site with local anaesthetic
    • Use sterile needle holder/forceps (with non-dominant hand in pencil grip) to hold needle in joint, disconnect syringe, attach steroid/lidocaine (lignocaine) syringe
    • Put needle gently into centre of insertion site, push in slowly while aspirating until you see fluid or hit bone. If bone hit — pull back slightly
    • Inject
  • If aspirating and injecting
    • Do aspiration
    • Use sterile needle holder/forceps (with non-dominant hand in pencil grip) to hold needle in joint, disconnect aspiration syringe, attach steroid/lidocaine (lignocaine) syringe
    • Inject
Now
  • Take out needle, put firm pressure over site with thumb to stop any bleeding
  • Put on sticking-plaster dressing
  • If blood aspirated — put on firm bandage, arrange crutches
  • Put aspirate into specimen jar, store and transport under refrigeration
  • Check circulation and sensation

Shoulder joint injection/aspiration — lateral approach

What you do

  • Sit person comfortably on chair or couch facing you, arm hanging loosely by side, palm turned forward
  • To find site
    • Gently turn shoulder around from inside to outside to feel head of humerus
    • Find groove between head of humerus and glenoid rim
    • Needle entry site is in groove 1cm below and just lateral to coracoid process — Figure 10.85

Figure 10.85  

Injection site.

  • Mark site by indenting skin with tip of syringe
  • Lay out dressing pack and equipment
  • Wash hands and put on sterile gloves
  • Clean front of shoulder
  • Inject local anaesthetic into skin, if using
  • Connect syringe to needle. If injecting only — remember to start procedure with smaller needle
  • Put needle gently into shoulder at identified site. If you hit bone — pull back slightly
    • Aspirate fluid
    • Use sterile needle holder/forceps (with non-dominant hand in pencil grip) to hold needle in joint, disconnect aspiration syringe, attach steroid/lidocaine (lignocaine) syringe
    • Inject
    • Take out needle, put firm pressure over site with thumb to stop any bleeding
  • Put on sticking-plaster dressing
  • Put aspirate in specimen jar, store and transport under refrigeration
  • Check circulation and sensation

Shoulder joint — subacromial bursa injection

Attention

  • Do not inject into tendon. If needle enters tendon (gritty resistance) — pull out straight away
  • Aim to inject into soft tissue that lines non-cartilaginous surfaces (subacromial bursa)
  • If injection in right place — pain will be quickly relieved

What you need

  • Sterile dressing pack
  • Chlorhexidine 5% in 70% alcohol solution or povidone-iodine antiseptic solution
  • Local anaesthetic and equipment (if using)
  • 3mL syringe preloaded with lidocaine (lignocaine) 1% and 1mL of steroid for injection
  • Long 23G or 25G needle
  • Small sticking-plaster dressing

What you do

  • Ask person to put affected arm behind their back, with backs of fingers touching far waistline
  • Palpate acromial margin laterally or posterolaterally
    • Injection is below acromial margin, laterally, directed upward under acromion — aim for coracoid process
  • Mark injection site by indenting with end of syringe
  • Lay out dressing pack and equipment
  • Wash hands and put on sterile gloves
  • Clean site and drape with sterile towels
  • Inject local anaesthetic into skin, if using
  • Connect preloaded syringe and needle
  • Guide needle tip into site, beneath acromion, angled slightly upward and parallel to acromial under surface — Figure 10.86

Figure 10.86  

Injection site.

  • Inject air you have left in syringe to see if you are in joint. If no resistance felt — inject lidocaine (lignocaine) and steroid
  • Take out needle, put firm pressure over site with thumb to stop any bleeding
  • Put on sticking-plaster dressing
  • Check circulation and sensation

Steroid injection

  • Steroid injections give pain relief
  • Adding lidocaine (lignocaine) to steroid injection
    • Relieves pain at target site
    • Helps you work out if medicine has reached its target
    • Allows area to be re-examined while joint under anaesthesia
    • Helps to tell difference between local and referred pain
    • Gives volume to injection fluid
    • Distributes corticosteroid in large joints

Lidocaine (lignocaine) concentration

  • More concentrated (eg 2%) for small joints needing smaller volume
  • Less concentrated (eg 1%) for large joints needing larger volume

Attention

  • Infection after injection rare. Prevented by making sure person knows how to keep site clean
  • Post-injection flare (2–5%). Painful condition, starts 6–12 hours after injection, lasts 2–3 days. Easily confused with infection. Prevented by
    • Avoiding weight-bearing and vigorous activity with injected joint for 48 hours post-injection
    • Applying ice
    • NSAIDs — if no contraindications — Pain management (acute)
  • Steroid dose
    • Reduce dose for young people, the elderly, those in poor health
    • Be careful with short-acting steroids in people with diabetes. Risk of increased blood glucose levels for up to 3 weeks after injection

What you need

AND

  • 1mL betamethasone mixed with 3–5mL of lidocaine (lignocaine) 1%
  • OR 1mL methylprednisolone mixed with 3–5mL of lidocaine (lignocaine) 1%
  • 3mL syringe preloaded with lidocaine (lignocaine) and steroid
  • Small joints (eg wrists, ankle) — consider stronger steroids in smaller volumes

What you do

Joint fluid analysis

  • Send non-bloody fluid to pathology for cell count, gram stain, bacterial culture and if needed, special tests such as crystals, fluid-protein, fluid-glucose and fluid-LD levels
  • Do cultures on all synovial fluids. Bacterial infections can look like/be present with joint disease

Collection

  • Need a minimum of 2mL aspirate in sterile yellow container for gram stain, culture, WBC, crystals
  • For diagnosis
    • If enough fluid, put 1–2.5mL in EDTA tube (purple lid) — gives more accurate analysis of WBC. Important if delay in transport
    • If septic arthritis suspected and enough joint fluid — put 2.5mL in blood culture bottle (aseptic technique)

Transport

  • Best within 4 hours, but no later than 48 hours. Refrigerate if delay
  • Use blood culture bottle

Results

Joint fluid analysis will fall into one of 3 categories — Table 10.1

  • Non-inflammatory
    • Degenerative  (eg osteoarthritis, overuse syndrome)
    • Trauma, if no blood in fluid
  • Septic (eg infective mono-arthritis)
    • Non-gonococcal bacterial arthritis
    • Gonococcal bacterial arthritis
  • Inflammatory
    • Acute crystal arthropathy (eg gout, pseudogout)
    • Any type of arthritis

Synovial fluid findings

Table 10.1 Microscopic findings  

MC&S Normal Non- inflammatory Inflammatory Septic
WBC per mm 3 Less than 200 200–2,000 2,000–150,000
(likely less than 75,000)
15,000–200,000
(likely more than 100,000)
PMN Less than 10–25% Less than 25% Often more than 50% More than 75%
Gram stain +
Culture +
Crystals + Possible
Chemicals (eg protein, glucose, LD) not routinely requested, need an extra 0.5mL aspirate