Cortisone Injection for Knee Pain After Total Knee Replacement
Cortisone injections into a prosthetic knee should generally be avoided in routine practice and only considered in exceptional circumstances after rigorous exclusion of prosthetic joint infection and direct consultation with the orthopedic surgeon who performed the replacement. 1
The Infection Risk is Real and Significant
The primary concern with cortisone injections into a prosthetic knee is periprosthetic joint infection (PJI):
The infection rate is 0.6% (1 in every 625 injections) based on a large retrospective review of 1,845 injections in 736 patients with total knee prostheses. 2, 1
A more recent systematic review found the infection rate after intra-articular steroid injection into a TKR was 2.1% at 12 months, compared to 1.4% in controls—a statistically significant increase. 3
EULAR guidelines explicitly state that intra-articular glucocorticoid injections in prosthetic joints should be avoided in routine practice and only considered after strict screening for prosthetic infection in consultation with the orthopedic surgical team. 2, 1
When It Might Be Considered (Rarely)
If you are contemplating this intervention despite the risks, the following strict criteria must be met:
Mandatory rigorous exclusion of prosthetic joint infection through clinical examination, laboratory analysis (ESR, CRP, synovial fluid analysis if indicated), and radiographic evaluation. 4
Direct consultation and approval from the orthopedic surgeon who performed the replacement is essential. 1, 5
The patient must have failed other conservative measures and the expected benefit must clearly outweigh the infection risk in this specific clinical scenario. 4
Evidence of Potential Benefit (Limited)
One retrospective study showed that among patients who received cortisone injections into their TKR:
76.6% reported decreased pain, 57.9% reported increased motion, and 84.1% reported overall improvement (slight to great). 4
56.1% experienced improvement lasting greater than 1 month. 4
Importantly, no patient developed PJI within 1 year of injection in this single-surgeon series, though this contradicts larger database studies. 4
Critical Safety Protocols If Proceeding
Should you decide to proceed after careful consideration:
Use strict aseptic technique with surgical gloves, skin preparation with alcohol or chlorhexidine, and consider changing needles between drawing and injecting. 1
Counsel diabetic patients to monitor glucose levels closely for 1-3 days post-injection due to transient hyperglycemia risk, particularly in those with suboptimal glycemic control. 1, 5
Advise patients to avoid overuse of the injected joint for 24 hours, but discourage immobilization. Normal activity after 24 hours is appropriate. 1
Limit to no more than 3-4 injections per year maximum in the same joint, though even this guideline is not based on strong research evidence for prosthetic joints. 5
Common Pitfalls to Avoid
Never inject without first ruling out infection—this is the most critical error and can lead to catastrophic outcomes. 1, 4
Do not perform this as a "routine" intervention—it should be exceptional, not standard practice. 2, 1
Avoid if the patient is within 3 months of any planned revision surgery, as preoperative injections within this timeframe significantly increase infection risk. 5, 6
The Bottom Line
The weight of guideline evidence strongly discourages this practice. While some patients may experience symptomatic relief, the infection risk in a prosthetic joint is substantially higher than in a native joint, and PJI is a devastating complication with significant morbidity. 2, 1, 3 Alternative pain management strategies (physical therapy, oral analgesics, evaluation for component malposition or loosening, assessment for referred pain) should be exhausted before considering this high-risk intervention.