What causes tendon pain and numbness after a steroid (corticosteroid) injection?

Tendon Pain and Numbness After Steroid Injection: Causes and Management

Steroid injections into or near tendons can cause tendon pain, weakening, and even rupture due to their inhibitory effects on tendon healing and reduced tensile strength, potentially leading to nerve compression and associated numbness. 1

Mechanisms of Post-Injection Tendon Pain and Numbness

Direct Tendon Effects

• Tendon Weakening: Corticosteroids can inhibit collagen production and reduce tensile strength of the tendon tissue 1
• Inhibited Healing: Steroids may suppress the natural healing process in tendons, particularly when injected directly into the tendon substance 1
• Tissue Atrophy: Local tissue atrophy can occur around the injection site, affecting both the tendon and surrounding structures 2

Nerve-Related Causes of Numbness

• Post-injection inflammation: Initial inflammatory response can cause swelling that compresses nearby nerves
• Tendon rupture complications: When steroids contribute to tendon rupture, the resulting anatomical changes can cause nerve compression 3
• Direct neurotoxicity: In some cases, the steroid or its carrier may have direct effects on peripheral nerves

Risk Factors for Adverse Outcomes

1. Injection Technique

   • Direct injection into tendon substance (highest risk) 1
   • Multiple repeated injections in the same area 4
   • Improper sterile technique (risk of infection) 5

2. Patient Factors

   • Pre-existing tendon degeneration
   • Concurrent anabolic steroid use 4
   • High physical demands on the affected tendon
   • Age and comorbidities affecting tissue healing

3. Steroid-Related Factors

   • Type of corticosteroid used (longer-acting preparations may pose higher risk) 3
   • Dosage (higher doses increase risk)
   • Frequency of injections (multiple injections increase risk) 2

Anatomical Considerations

Different tendons have varying risks of complications:

• Highest risk: Achilles tendon (should avoid steroid injections) 6
• Moderate risk: Rotator cuff tendons, particularly the supraspinatus 1
• Variable risk: Lateral epicondylar tendons, biceps tendons 3

Management of Post-Injection Complications

Immediate Management

• Rest: Relative rest of the affected area to prevent further damage
• Ice: Cryotherapy for 10-minute periods through a wet towel to reduce pain and inflammation 1
• Pain control: NSAIDs may help manage pain but won't alter long-term outcomes 1

Rehabilitation Approach

• Eccentric strengthening exercises: Particularly beneficial for tendon healing 1
• Gradual tensile loading: Stimulates collagen production and proper fiber alignment 1
• Avoid complete immobilization: Prevents muscle atrophy and deconditioning 1

When to Consider Surgical Intervention

• Persistent pain despite 3-6 months of conservative treatment
• Confirmed tendon rupture
• Progressive neurological symptoms (worsening numbness or weakness) 1

Prevention Strategies

To minimize risk of tendon pain and numbness after steroid injection:

1. Avoid direct tendon injection: Peritendinous injections are safer than intratendinous 1
2. Limit frequency: Minimize the number of injections to the same area
3. Use appropriate technique: Ensure proper needle placement with imaging guidance when necessary
4. Consider alternatives: Explore other treatment options before using corticosteroid injections, especially for Achilles tendon issues 6
5. Post-injection care: Advise patients to temporarily reduce activities that stress the injected tendon

Special Considerations

• Achilles tendon: Corticosteroid injections should generally be avoided due to high risk of rupture 6
• Rotator cuff: Evidence is inconclusive regarding benefits of subacromial injections for rotator cuff tears 1
• Trigger finger: One of the few tendon conditions with strong evidence supporting steroid injection 2

Clinicians should weigh the potential short-term benefits of pain relief against the risks of tendon weakening, rupture, and associated nerve complications when considering steroid injections for tendon disorders.