Anatomical Landmark for Intraarticular Knee Steroid Injection
The superolateral (lateral midpatellar) approach is the recommended anatomical landmark for intraarticular knee steroid injection, achieving the highest accuracy rate of 91-93% when using anatomical landmarks alone. 1
Primary Approach: Superolateral (Lateral Midpatellar) Portal
The lateral midpatellar approach is superior to other anatomical landmarks based on systematic review evidence showing it achieves 91% pooled accuracy (95% CI 84-99%) across patients with different arthropathies. 1
Technical Details for Lateral Midpatellar Injection:
Patient positioning: Place the patient supine on an examination table with the knee extended, as this approach is most practical and accurate with the knee in extension 2, 3
Needle insertion point: Insert the needle at the lateral border of the patella at its midpoint, directing it posteriorly and slightly medially into the patellofemoral joint space 2
Needle specifications: Use a 20-24 gauge needle that is 2.0 inches (5.1 cm) in length to ensure adequate depth to reach the synovial space 4, 2
Confirmation of placement: Aspirate slightly before injection—obtaining even a few drops of synovial fluid confirms intra-articular placement 4
Alternative Approach: Modified Anterolateral Portal
A modified anterolateral approach with the knee bent, targeting the synovial membrane of the medial femoral condyle, achieves 97% accuracy and is an effective alternative when the lateral midpatellar approach is not practical. 3
This approach allows the knee to be in a bent position, which may be more comfortable for some patients 3
The anterolateral portal produces equivalent clinical outcomes to the lateral midpatellar approach in terms of pain relief and duration of effect 3
Comparative Accuracy of Different Approaches
The evidence demonstrates clear differences in accuracy between approaches:
- Lateral midpatellar: 93% accuracy 2
- Anterolateral (modified bent knee): 97% accuracy 3
- Anteromedial: 75% accuracy 2
- Standard anterolateral: 71% accuracy 2
The medial approach, despite having a larger anatomical joint opening on MRI, has lower accuracy rates in clinical practice compared to lateral approaches. 2, 5
Role of Ultrasound Guidance
Ultrasound guidance improves accuracy to 95.8% versus 77.8% with anatomical landmarks alone (odds ratio 6.4,95% CI 2.9-14) 6
However, ultrasound guidance is optional for knee injections, as the lateral midpatellar approach already achieves high accuracy rates with anatomical landmarks alone 7, 8
The EULAR guidelines note that while ultrasound improves accuracy, clinical outcomes are similar between ultrasound-guided and landmark-guided injections for the knee 1
Critical Technical Requirements
Strict aseptic technique is mandatory for all intraarticular injections to minimize infection risk (0.035% or 3 per 7,900 procedures). 1
Aseptic Procedure:
- Use surgical gloves 1
- Prepare skin with alcohol, iodine disinfectant, or chlorhexidine 1
- Change needles between drawing the medication and injecting into the joint 1
Ensuring Intra-articular Placement:
The injection must be made into the synovial space for full anti-inflammatory effect—injection into surrounding tissue provides little to no benefit 7, 4
After needle insertion, aspirate to confirm intra-articular placement before injecting 4
After injection, move the joint gently a few times to aid mixing of synovial fluid and the suspension 4
Common Pitfalls to Avoid
Failure to enter the joint space is the most frequent cause of treatment failure—if the injection is certain to be intra-articular (confirmed by aspiration) but fails, repeated injections are usually futile 4
Avoid injecting sufficient material to cause blanching of tissue, as this may be followed by tissue slough 4
Do not inject into the substance of the tendon itself; ensure the needle is in the joint space, not periarticular structures 4