Side Effects of Intra-Articular Corticosteroid Knee Injections
Intra-articular corticosteroid injections into the knee are generally safe with most side effects being minor and self-limited, though serious complications including infection, transient hyperglycemia in diabetics, and potential cartilage damage with repeated use require careful patient counseling and monitoring. 1
Common Side Effects
Immediate and Early Reactions (0-72 hours)
- Injection site pain and soreness occurs in approximately 8-9% of patients and typically resolves within days 1
- Vasovagal reactions (lightheadedness, fainting) occur in 2.5% of procedures 1
- Post-injection flare (acute inflammatory response) manifests as increased pain, swelling, and warmth within 2-48 hours post-injection 2
- Most flares are mild and self-limited
- Severe flares mimicking septic arthritis are rare but can be disabling, caused by crystal-induced inflammation from the corticosteroid itself 2
- Facial flushing and sweating are corticosteroid-specific systemic effects occurring in approximately 2% of patients 1
Metabolic Effects
- Transient hyperglycemia in diabetic patients is the most clinically significant metabolic side effect 1
Serious but Rare Complications
Infection Risk
- Septic arthritis following intra-articular injection is rare but represents the most serious complication 1
- In native knees, infection rates are extremely low when proper aseptic technique is used 1
- In prosthetic knees, infection risk is 0.6% (1 infection per 625 injections) 1, 5, 4
- Injections within 3 months prior to total knee replacement increase prosthetic infection risk from 0.5% to 1.0% 1, 3
Nerve-Related Effects
- Transient sciatic nerve block can occur from anterior capsular disruption when local anesthetic is included in the injectate 1
- This creates temporary fall risk and typically resolves within hours 1
Long-Term Risks with Repeated Injections
Cartilage Effects
- Conflicting evidence exists regarding cartilage safety with repeated injections 1, 5
- The general accepted rule is to limit injections to no more than 3-4 per joint per year to minimize potential cartilage damage 1, 3, 5
Other Systemic Effects
- Adrenal suppression can occur with repeated injections 6
- Reduction in bone mineral density has been documented with frequent use 6
- Central serous chorioretinopathy (visual disturbances) is a rare but recognized complication 7
Critical Safety Precautions
Absolute Contraindications and High-Risk Scenarios
- Do not inject within 3 months of planned knee replacement surgery 1, 3
- Avoid routine injections in prosthetic joints; only consider after strict infection screening and orthopedic surgeon consultation 1, 5, 4
- Rule out infection before any injection—septic arthritis is an absolute contraindication 8
Post-Injection Instructions
- Avoid overuse of the injected joint for 24 hours, but do not immobilize 1, 4
- Immobilization (bed rest, splinting) provides no additional benefit and is discouraged 1
- Normal activity may resume after 24 hours 4
Frequency Limitations
- Maintain minimum 6-week intervals between injections 5
- Maximum 3-4 injections per joint per year based on expert consensus to balance efficacy with safety 1, 3, 5
- Consider alternative therapies if adequate relief is not achieved within this framework 3, 5
Common Pitfalls to Avoid
- Failing to counsel diabetic patients about glucose monitoring is a frequent oversight that can lead to uncontrolled hyperglycemia 1, 3, 4
- Injecting too frequently (more than 3-4 times per year) increases risk of cartilage damage and other complications 1, 5
- Not using strict aseptic technique including surgical gloves, skin preparation with chlorhexidine or alcohol, and changing needles between drawing and injecting 1, 4
- Dismissing severe post-injection flares as normal when they may represent crystal-induced inflammation requiring aspiration and symptomatic treatment 2