Accuracy of ultrasound guided injections in the foot and ankle.

BACKGROUND: Ultrasonography is an emerging imaging modality which affords dynamic, real-time, cost-effective and surgeon controlled visualization of the foot and ankle. The purpose of this study was to evaluate the accuracy of ultrasound guided injections for common injection sites in the foot and ankle.

MATERIALS AND METHODS: In 10 fresh cadaver feet, ultrasound guidance was utilized to inject a methylene blue-saline mixture into (1) the first MTP joint, (2) the second MTP joint, (3) the tibiotalar joint, (4) the Achilles peritendinous space, (5) the flexor hallucis longus sheath, (6) the posterior tibial tendon sheath, and (7) the subtalar joint. Dissection was then undertaken to assess injection accuracy.

RESULTS: Ultrasound guidance allowed the avoidance of intervening neurovascular and tendinous structures. Ultrasound guided MTP, ankle, Achilles, PTT and FHL peritendinous injections were 100% accurate. Ultrasound guided subtalar injection was 90% accurate.

CONCLUSION: Ultrasound appears to be a highly accurate method of localizing injections into a variety of locations in the foot and ankle.

CLINICAL RELEVANCE: Ultrasound's ability to display soft-tissue structures may be an advantage over blind injection and fluoroscopic injection techniques.