Joint Injection and Aspiration

Indications for joint aspiration

Joint aspiration is indicated in a number of joint conditions where it can be either therapeutic or diagnostic, or both:

• Septic arthritis; sampling synovial fluid for culture and sensitivity, also pus is destructive of joint structures
• Haemarthrosis; blood in aspirate is diagnostic and blood itself is inflammatory
• Crystal arthropathy; identifies crystal involved
• Large joint effusions; rapidly relieves pain and improves mobility

Indications for joint injection

Corticosteroid is usually injected to reduce inflammation in acutely inflamed structures:

• Rheumatoid arthritis¹
• Osteoarthritis of the knee (although hyaluronic acid injections have a more durable effect)^2,3

Often beneficial in one or two joints in RA where joint is warm and swollen with morning stiffness. Other conditions where it is widely used include psoriatic arthritis, ankylosing spondylitis and pyrophosphate arthritis.
Benefit is experienced within a few days if successful, and can last for months, but is often short lived. Injection can be repeated, but effect is diminished. Failure may be due to not entering joint or incorrect diagnosis.

Contraindications to joint injection

• Sepsis, or risk of
• Skin lesions
• Bleeding disorder or anticoagulant use

Complications of steroid injection

• Septic arthritis
• Worsening of pain next day
• Local skin atrophy
• Facial flushing
• Joint destruction is rare, but occasionally occurs after repeated injection (avoid weight bearing after injection). Allow at least 4 months between injections.

Therapeutic injections (lignocaine plus a corticosteroid) are useful both because they are therapeutic and also because they can help differentiate impingement from other problems. For example, if a patient does not improve after a sub-acromial injection, has normal x-rays and an inconclusive examination, the rotator cuff may not be the problem.

Indications for soft tissue injection

• Shoulder impingement;^4,5 there are several entry points for shoulder injections, but the posterior subacromial approach is perhaps the easiest.
• Synovitis
• Tenosynovitis
• Bursitis e.g. housemaids knee
• Tendinitis e.g. tennis elbow^6,7,8
• Nerve compression, e.g. carpal tunnel syndrome

Complications of steroid injection

• Rupture of tendon with injection into tendon.⁹ May be seen after injection in athletic injury.
• Worsening of pain next day
• Local skin atrophy
• Facial flushing