What are the risks of frequent cortisone (corticosteroid) knee injections?

Risks of Frequent Cortisone Knee Injections

Frequent cortisone knee injections should be limited to no more than 3-4 injections per year in the same joint due to potential risks of accelerated cartilage loss, increased risk of requiring knee arthroplasty, and other local and systemic complications. 1

Major Risks of Frequent Cortisone Injections

Local Complications

• Accelerated osteoarthritis progression: Recent evidence suggests that repeated corticosteroid injections may lead to greater progression of cartilage volume loss in the knee joint 1
• Increased risk of requiring knee arthroplasty: Each additional injection increases the absolute risk of requiring knee arthroplasty by approximately 9.4% at nine years follow-up 2
• Dose-dependent risk: Multiple injections show a dose-dependent relationship with the need for total knee arthroplasty - two injections nearly double the odds (OR 1.98) and three or more injections triple the odds (OR 3.22) compared to no injections 3
• Joint infection risk: In patients with prosthetic knees, there is a 0.6% infection rate (1 infection per 625 infiltrations) 1
• Local tissue atrophy and skin hypopigmentation: Repeated injections can cause subcutaneous tissue atrophy and skin color changes 4
• Tendon rupture: Especially with injections near tendons 4

Systemic Complications

• Transient hyperglycemia: Particularly important in diabetic patients, blood glucose levels can increase significantly during the first 3 days post-injection 1
• Adrenal suppression: Repeated injections can lead to hypothalamic-pituitary-adrenal axis suppression 5
• Cardiovascular effects: Corticosteroids can cause elevation of blood pressure, salt and water retention 5
• Immunosuppression: Increased risk of infection with any pathogen and potential reactivation of latent infections 5
• Osteoporosis: Long-term use may contribute to bone density loss 4

Timing Considerations

• Pre-surgical timing: Cortisone injections should be avoided within 3 months prior to knee replacement surgery due to increased risk of prosthetic infections (infection rate increases from 0.5% to 1.0%) 1
• Duration of effect: Benefits of cortisone injections are typically short-lived:
  • Moderate benefits at 1-2 weeks post-injection
  • Small to moderate benefits at 4-6 weeks
  • Small benefits at 13 weeks
  • No evidence of effect by 26 weeks 6

Recommendations for Safe Use

• Frequency limitation: Although not based on strong research evidence, the general accepted guideline is to avoid more than 3-4 corticosteroid injections in the same joint per year 1
• Patient-specific considerations: The decision to reinject should take into consideration benefits from previous injections, treatment alternatives, and individual patient factors (comorbidities, other medications) 1
• Post-injection care: Avoid overuse of the injected joint for 24 hours following injection, though complete immobilization is not recommended 1
• Special populations:
  • Diabetic patients should monitor glucose levels for 1-3 days post-injection 1
  • Patients with prosthetic joints should generally avoid routine injections unless performed by orthopedic surgeons after careful screening for infection 1

Clinical Approach to Repeated Injections

• Evaluate response: Consider the benefit from previous injections when deciding on repeat treatment 1
• Consider alternatives: If requiring frequent injections, consider other treatment modalities 1
• Monitor for complications: Watch for signs of accelerated joint deterioration with repeated injections 4
• Long-term planning: Be aware that patients receiving multiple injections may have a shortened time to knee replacement (time to TKA nearly halved with three injections compared to one) 3

Despite historical views that repeated injections are safe 7, more recent evidence suggests caution is warranted, particularly regarding the potential for accelerated osteoarthritis progression and increased risk of requiring knee arthroplasty 2, 3.