Cortisone Injections for Knee Pain: Safety, Risks, and Benefits Explained by Surgeons

Understanding Cortisone Injections

• 💡 Cortisone is a generic term for injectable corticosteroids, such as Devrol, Kenalog, or Triamcinolone, used to reduce inflammation.
• 💉 These are corticosteroids, distinct from anabolic steroids used for bodybuilding or athletic enhancement.
• 🎯 The primary purpose of injecting corticosteroids into a joint like the knee is to reduce inflammation.

Oral Corticosteroids vs. Injections

• 💊 Oral corticosteroids, like Prednisone, are used for various inflammatory conditions but carry significant risks, including osteopenia, osteoporosis, fragility fractures, and avascular necrosis.
• 🦴 Oral steroids can decrease osteoblast activity (bone-building cells) and increase osteoclast activity (bone-resorbing cells), leading to bone density loss.
• 📉 Systemic effects of oral steroids also include reduced calcium absorption, increased calcium loss via kidneys, and potential disruption of sex hormones, mimicking menopause or andropause.
• 🩸 In contrast, cortisone injections into the knee result in only about 1-2% absorption into the bloodstream, significantly reducing the risk of systemic side effects.

Safety and Efficacy of Knee Injections

• 🔬 While theoretically possible, the systemic risks associated with oral corticosteroids do not typically apply to knee injections due to the minimal absorption.
• 📈 Cortisone injections can cause a temporary increase in blood sugar for individuals with diabetes.
• ⚠️ There is no reliable evidence that repeated cortisone injections in the knee lead to decreased bone density, except in rare circumstances like severe pre-existing osteoporosis or excessive injections across multiple sites.
• 🧐 A subtle increase in cartilage thinning (0.1 mm over two years) was observed in one MRI study, but the accuracy of measurement and the fact that knees injected are often already damaged make this finding less conclusive.

Risks and Considerations

• ⚠️ Cortisone injections are generally not recommended for the hip due to a potential risk of rapid arthritis progression, though this is not observed in the knee.
• 🦴 In patients with severe osteoporosis, a low-dose cortisone injection might be considered if the benefit of reducing inflammation and fall risk outweighs the theoretical risk to bone density.
• ❓ The effectiveness of cortisone injections is highly variable from person to person, with some experiencing no relief and others significant symptom improvement.
• 🩹 Cortisone injections do not stop or reverse the underlying arthritis; they are primarily for symptom control.

Recommendations and Best Practices

• ✅ Most orthopedic and rheumatological societies recommend a maximum of three to four injections per year, using the lowest effective dose.
• 🗓️ A common practice is to administer injections no more frequently than once every six months to potentially prolong efficacy and manage expectations.
• 🩺 It is crucial to remember that cortisone injections are for symptom management and do not alter the progression of joint disease.