How should I perform an intra‑articular injection for an adult with symptomatic knee osteoarthritis refractory to oral analgesics, physical therapy, and activity modification?

How to Perform a Knee Injection for Osteoarthritis

Injection Technique and Preparation

For symptomatic knee OA refractory to conservative measures, inject 5-15 mg of triamcinolone acetonide (or equivalent long-acting corticosteroid) into the knee joint using strict aseptic technique, with dosing based on joint size—use 5-10 mg for smaller joints and up to 40 mg for larger joints like the knee. 1

Pre-Injection Steps

• Aspirate excessive synovial fluid if present before injecting the corticosteroid, as this aids pain relief and prevents undue dilution of the steroid 1
• Shake the vial thoroughly before use to ensure uniform suspension, and inspect for clumping or granular appearance (agglomeration)—discard if agglomerated 1
• Consider using a local anesthetic prior to injection, which is often desirable for patient comfort 1
• Inject without delay after withdrawal to prevent settling in the syringe 1

Injection Technique Specifics

• Use the standard intra-articular injection approach with careful technique to avoid entering a blood vessel or introducing infection 1
• Avoid injecting into surrounding tissues (particularly in the deltoid region if treating other joints), as this may lead to tissue atrophy 1
• For acute nonspecific tenosynovitis, ensure injection into the tendon sheath rather than the tendon substance itself 1

Clinical Indications and Timing

Intra-articular corticosteroid injection is specifically indicated for acute exacerbations of knee pain, especially when accompanied by effusion. 2

• This intervention is appropriate for patients with moderate to severe pain flares who have failed oral analgesics, physical therapy, and activity modification 3
• Benefits typically last only 3 months, and repeated injections can be considered for recurrent flares 3

Critical Pitfalls to Avoid

• Do not use hyaluronic acid as the next step after failed steroid injections—the American Academy of Orthopaedic Surgeons recommends against routine use due to inconsistent evidence, high number needed to treat, and inability to identify responders 3
• Do not neglect core non-pharmacological treatments (strengthening exercises, low-impact aerobic exercise, weight loss if BMI ≥25 kg/m²) even when performing injections 3, 4
• Avoid repeated injections in the same site without allowing adequate time between injections to prevent tissue atrophy 1

What to Do If Injection Fails

If corticosteroid injection provides inadequate relief:

• Optimize topical NSAIDs first (diclofenac gel), which offer effective pain relief with minimal systemic toxicity, particularly appropriate for elderly patients or those with cardiovascular/GI risk factors 3, 4
• Consider oral NSAIDs or COX-2 inhibitors at the lowest effective dose for the shortest duration, with mandatory proton pump inhibitor co-prescription for gastroprotection 3, 4
• Tramadol is conditionally recommended as an alternative analgesic 3
• Refer for joint replacement when symptoms substantially affect quality of life and remain refractory to comprehensive non-surgical treatment for 3-6 months 3

Treatments to Avoid

• Do not offer hyaluronic acid injections routinely—they should only be considered as a last resort after failure of all conservative treatments, and only in patients with mild radiographic disease and significant surgical risk factors 3
• The American College of Rheumatology strongly recommends against PRP due to lack of standardization and unclear benefit-to-risk ratio 3
• Do not recommend glucosamine, chondroitin, or acupuncture, as they lack clinically important outcomes compared to placebo 4, 5