Joint and Soft Tissue Injections

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It has long been recognised that injecting corticosteroids locally at a site of inflammation is superior to large oral doses.

Indications

Corticosteroid injection can be considered when there are few joints affected in the context of active inflammation. It is also useful in joint involvement that is preventing active rehabilitation

For soft tissues it can be considered in pain that is unresponsive to other measures - NSAIDs, physical therapy (See Tendinopathy Management), time, etc.

• Joints
  • Chronic inflammatory joint disease
  • Rheumatoid arthritis
  • Spondyloarthritis
  • Crystal arthritis - gout/pseudogout
  • Traumatic synovitis
  • Osteoarthritis - acute flare
• Soft tissues
  • Enthesopathies
  • Tensosynovitis, bursitis
  • Mononeuropathies - e.g. carpal tunnel syndrome

Contraindications

• Infection
• Intra-articular fracture
• Haemarthrosis
• Patient reluctance or other psychological issues
• Before a specific diagnosis is made (relative contraindication)
• Late stage joint disease with irreparable mechanical damage (relative contraindication)
• Prosthetic or unstable joint

Frequency

Injections should be done as infrequently as possible.

In inflammatory arthritis a maximum of 3-4 per individual joint per year, at least four weeks apart, and no more than 2-3 joints in one sitting.

For soft tissues maximum 3 at least one month apart per year depending on response. If no response after two injections do not continue and consider alternative treatment

Corticosteroids

Long acting corticosteroids are preferred

Triamcinolone acetonide (Kenacort-A): A10 (10mg/ml) low dose, A40 (40mg/ml) high dose. Intra-articular and deep soft tissue injections. Caution with superficial injection e.g. lateral elbow tendinopathy due to tissue atrophy.

Triamcinolone hexacetonide: particularly good for children where it is a first line intraarticular steroid.

Methylprednisolone (Depomedrol): useful alternative, preferred for superficial injections.

Dexamethasone: this is more commonly used for epidural injections.

Doses

	Joint	Dose	Needle
Large Joints	Knee, shoulder	Triamcinolone 40mg Methylprednisolone 40mg Dexamethasone 6mg	22G
Medium Joints	Ankle, elbow	Triamcinolone 20mg Methylprednisolone 20mg Dexamethasone 3mg	23G
Small Joints	Hands, feet, wrist, superficial soft tissues	Triamcinolone 10-20mg Methylprednisolone 10-20mg Dexamethasone 1.5mg	25G 1"

Local Anaesthetic

Using a local anaesthetic such as lidocaine 1% is often mixed with corticosteroid. For larger joints it allows for creating a greater volume for distribution. It can ease post-injection pain. It is useful in determining whether the injection was given to the correct area. Smaller joints do not allow for much local anaesthetic to be used.

Complications

• Post-injection flare
• Infection - rare 1/50,000
• Acute crystal synovitis
• Skin atrophy
• Tendon rupture
• Allergic reaction

Pre-Procedural Evaluation

Explain the likely benefit and risks. For risks discuss systemic, local, specific to site, and specific to other comorbidities (e.g. diabetes mellitus). Discuss how the procedure is performed.

Obtain verbal or written consent as appropriate.

Technique

• Have the patient in a relaxed position
• Doctor also in a relaxed position such as sitting down
• Identify the injection site by palpation and landmarks or with ultrasound guidance
• Use strict aseptic technique
  • Wash hands
  • Pre-packaged sterilised disposable needles and syringes
  • Single dose ampoules of local anaesthetic and steroid
  • Swab injection site with chlorhexidine or chlorhexidine + alcohol mixture (to be dry)
  • No touch technique after swabbing
  • Change needles between drawing up and administering.
• Aspirate any synovial fluid (use 10mL syringe for large joints). Send for routine analysis of cell count, crystals, and culture in a pink pottle and purple top tube.
• Do not inject against resistance, this usually means it isn't in the right place for example within a tendon
• After injection move joint gently to disperse the injectate throughout the joint

Post-Advice

Advise that the joint may be painful for up to 24 hours post injection, and it may take several days to a week for the full benefit. The injected site should be rested for 24 hours with no heavy lifting or excessive walking. No sporting activity for at least 5 days. Supportive splints are sometimes needed e.g. for the wrist.

Follow up

Explain what to do in the event of a complication.

Contact again in the next few days to assess response and ensure no complications.

If failure to respond this could mean technical failure or a non-inflammatory condition.

A routine follow up appointment is appropriate in some settings.

Overview

The acronym INJECTION can be used

• Indications: inflammation
• Negative outcomes
• Juice
• Expected outcomes and efficacy
• Contraindications
• Telephone the following day if worried
• Infection
• Opportunity for questions and consent
• Number of injections, NNT

References

Courtney P, Doherty M. Joint aspiration and injection. Best Pract Res Clin Rheumatol. 2005 Jun;19(3):345-69. doi: 10.1016/j.berh.2005.01.009. PMID: 15939363.

Speed CA. Injection therapies for soft-tissue lesions. Best Pract Res Clin Rheumatol. 2007 Apr;21(2):333-47. doi: 10.1016/j.berh.2006.11.001. PMID: 17512486.

Stephens MB, Beutler AI, O'Connor FG. Musculoskeletal injections: a review of the evidence. Am Fam Physician. 2008 Oct 15;78(8):971-6. PMID: 18953975.