Safety and Expectations
Most musculoskeletal injections are low-risk when used appropriately, but every injection should have a clear indication and realistic goal.
Possible risks
Potential risks include temporary pain flare, injection-site pain, swelling, bruising, bleeding, skin depigmentation, subcutaneous fat atrophy, transient facial flushing, temporary stiffness, rare allergic or inflammatory reaction, and infection. Infection is rare but serious.
Corticosteroid can temporarily elevate blood glucose in patients with diabetes. Corticosteroid should generally not be injected directly into tendon tissue because of the risk of tendon weakening. Frequent repeated intra-articular corticosteroid injections may raise cartilage concerns and should be used thoughtfully.
Timing before surgery
Injections may affect the timing of future surgery, especially joint replacement. If surgery is being considered, patients should tell the surgeon about any recent injections, the medication used, the exact location injected, and the date of injection.
For a corticosteroid injection into the same hip or knee that may be replaced, the current practical recommendation is to avoid elective joint replacement within 3 months of the injection. Several systematic reviews and meta-analyses have found a higher risk of periprosthetic joint infection when hip or knee replacement is performed within 3 months after an ipsilateral intra-articular corticosteroid injection. The evidence is less consistent once the interval is longer than 3 months.
If hip or knee replacement may be needed soon, a steroid injection into that joint should not be used as a short-term bridge to surgery without discussing the timing with the surgeon. Patients should keep a record of the injection date, the joint injected, and the medication used.
- AAOS Diagnosis and Prevention of Periprosthetic Joint Infections guideline, 2021.
- Lai et al. Prior intra-articular corticosteroid injection within 3 months may increase infection risk after hip or knee arthroplasty. Clinical Orthopaedics and Related Research, 2022.
- Kim, Joo, and Song. Preoperative steroid injections within 3 months increase infection risk in total knee arthroplasty. Journal of Orthopaedic Surgery and Research, 2023.
- Albanese et al. Infection risk increases after total hip arthroplasty within 3 months following intra-articular corticosteroid injection. Journal of Arthroplasty, 2023.
When aspiration is more important than injection
If infection is suspected, the priority is evaluation, aspiration when appropriate, and laboratory testing. Corticosteroid injection should generally be avoided when infection has not been excluded.
What injections can and cannot do
Injections can sometimes reduce pain, calm inflammation, help confirm the pain source, or help a patient participate more effectively in rehabilitation. They do not reliably reverse advanced arthritis, rebuild a destroyed joint surface, regrow a meniscus, or heal a major full-thickness tendon tear.