Recommended Volume for Kenacort A-10 Subacromial Bursa Injection
For subacromial bursa injection, use 2 mL of Kenacort A-10 (10 mg/mL triamcinolone), providing a total dose of 20 mg, diluted with 3-5 mL of lidocaine for a total injectate volume of 5-7 mL.
Dosing Rationale
The most recent high-quality guideline evidence demonstrates that 20 mg triamcinolone is as effective as 40 mg for subacromial subdeltoid bursa corticosteroid injections 1. This 2025 multi-society guideline from ASRA, AAPM, ASIPP, ISIS, and NASS provides the strongest recommendation to use lower doses than traditionally employed.
Since Kenacort A-10 contains 10 mg/mL triamcinolone 2, you need 2 mL to achieve the recommended 20 mg dose.
Total Injectate Volume
Current practice patterns show that sports medicine physicians predominantly use 5-7 mL total injectate volume for shoulder injections 3. This aligns with:
- 2 mL Kenacort A-10 (20 mg triamcinolone)
- 3-5 mL lidocaine 1% for dilution
The addition of local anesthetic (lidocaine is most commonly used by 79-87% of physicians) provides immediate pain relief and increases total volume for better bursal distribution 3.
Key Supporting Evidence
Recent 2025 data comparing doses found that 20 mg triamcinolone provided more sustained pain relief than 10 mg in subacromial bursitis, with NRS scores improving from 8.1 to 2.4 at six months versus 7.9 to 3.5 with the lower dose 4. However, the multi-society guideline's recommendation of 20 mg as equivalent to 40 mg takes precedence, as it represents consensus across multiple specialties and addresses the balance between efficacy and adverse events 1.
Important Caveats
- Ultrasound guidance is strongly recommended - it increases injection accuracy and reduces procedural pain 1
- Avoid doses >40 mg - while 36% of physicians report using higher doses, evidence does not support this practice and increases risk of adverse events including hyperglycemia, adrenal suppression, and cartilage damage 3, 1
- Short-term benefit expected - corticosteroid injections typically provide relief for weeks to months, not permanent resolution 1
- Consider rotator cuff pathology - the evidence for subacromial injections in patients with rotator cuff tears is inconclusive, though short-term improvement may occur 5