Overview of Corticosteroid Injections

Musculoskeletal Corticosteroid Injections

Corticosteroid injections are a cornerstone in the management of various musculoskeletal conditions, offering significant relief from pain and inflammation. This webpage is designed to provide an in-depth understanding of corticosteroid injections, tailored for healthcare professionals and specialists in orthopedics and radiology.

Our comprehensive guide delves into the different types of corticosteroids used, such as Triamcinolone Acetonide (Kenalog), Methylprednisolone Acetate (Depo-Medrone), and Dexamethasone (Decadron). Each steroid is discussed in detail, considering its dosage, administration, particle size, and specific clinical notes.

Corticosteroid Types and Usage:

Corticosteroid	Dosage and Use	Particle Size	Specific Notes
Triamcinolone Acetonide	1. Dose: Adjust according to injection site, up to 40 mg per site, maximum 80 mg per procedure. 2. Use: Preferred for large/deep joints (e.g., hip, glenohumeral joints) and deep soft tissue targets.	15-60 µm, Microcrystalline structure.	1. Large particle size, densely packed; can coalesce with bupivacaine (> 100 µm particle), causing clouding of solution. 2. High potency, long duration. 3. Not recommended for superficial injections due to risk of tissue atrophy and hypopigmentation.
Methylprednisolone Acetate	1. Dose: Up to 40 mg for large joints and bursae; 5-20 mg for superficial soft tissues or small joints (e.g., metacarpophalangeal). 2. Use: Recommended for both large and small joints, intralesional, intrabursal, and tendon sheath injections.	Uniformly sized, <5% particles are >50 µm	1. Greater anti-inflammatory potency than prednisolone; particles do not form many aggregations. 2. Moderate potency, prolonged duration. 3. Lesser risk of tissue atrophy compared to Triamcinolone.
Dexamethasone	1. Dose: Variable, based on clinical scenario - 4-10 mg. 2. Administration: Broad use including intra-articular, soft tissue, and epidural injections.	<5 µm	1. Lowest density, minimal aggregation; rapid absorption leading to short duration of action. 2. Rapid onset but shorter action. 3. Lower risk of tissue and neurologic complications.

Understanding Corticosteroids:

Category	Sub-Category	Details
Mechanism of Action and Pharmacokinetics	Anti-inflammatory/Analgesic Mechanisms	1. Decrease in synovial blood flow and alteration of synovial fluid composition. 2. Suppression of leukocyte gene expression, cytokine and protease production, and altered collagen synthesis.
	Solubility and Duration	1. Less soluble steroids (e.g., Triamcinolone) have a prolonged therapeutic duration due to longer retention at the injection site. 2. More soluble steroids (e.g., Dexamethasone) are rapidly absorbed from the joint, with a shorter half-life.
Indications		1. Inflammatory, traumatic, or degenerative joint conditions e.g Osteoarthritis, rheumatoid arthritis, bursitis, tendinitis, synovitis, gout, and other inflammatory arthropathies. 2. Useful in targeted therapy, reducing systemic drug dosages, improving function and pain relief. 3. Adjunct to physical therapy and systemic medications.
Contraindications		1. Active joint infection (septic arthritis). 2. Recent joint surgery. 3. Periarticular fractures, skin conditions at injection site. 4. Uncontrolled diabetes, systemic infection, coagulopathy. 5. Relative contraindications include anticoagulant therapy, unstable joints. 6. Special consideration in immunocompromised patients.
Potential Adverse Effects	Steroid-induced Arthropathy	1. Possible worsening of joint conditions post-injection; early studies suggest a chondrotoxic effect but not clinically substantiated. 2. Radiographic evidence of worsening arthropathy.
	Septic Arthritis	1. Rare but serious; adherence to aseptic technique crucial. 2. Acute joint pain, swelling, fever post-injection.
	Steroid-mediated systemic sequelae	1. Includes facial flushing, vasovagal reactions, transient hyperglycemia in diabetics, and adrenal suppression. 2. Monitor blood sugar in diabetics. 3. Educate patients about possible flushing.
	Cutaneous Effects	1. Potential for dermal/subcutaneous tissue atrophy, hypopigmentation, and fat necrosis at injection site. 2. Avoid superficial injections with certain steroids (e.g., Triamcinolone).
	Tendon Rupture	1. Risk due to possible weakening of tendon strength; less than 1% incidence. 2. Avoid injections directly into tendons. 3. Educate patients on risk and symptoms.
	Steroid Flare	1. Post-injection synovitis in 1%-10% of cases; temporary worsening of symptoms with increased pain and inflammation in the joint following injection. 2. Typically self-limiting; NSAIDs can be used for management.
	Miscellaneous	1. Includes peri-articular joint capsule calcification, hypersensitivity, osteonecrosis, lactation suppression, and drug interactions. 2. Individualised risk assessment and patient education

Specific Considerations and Recommendations:

Consideration	Details
Epidural Steroid Injections	1. Controversy over effectiveness; particulate steroids linked with higher neurologic risks. Non-particulate steroids like Dexamethasone preferred for reduced risk.
When and Why	1. Repeat injections suggested at minimum intervals of 2-3 weeks (at different injection site) and 6 weeks (at same injection site), not exceeding 3 times a year in the same joint to minimize risks.
Guidelines and Practices	1. Lack of universal guidelines; choice often based on anecdotal evidence.

References