Joint aspirations and injections

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

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

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

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

• 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

• 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

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

• See above 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

• See What you do — knees or What you do — shoulders

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