SLR - April 2016 - Zachary Criswell

Title: Sonographically Guided Posterior Subtalar Joint Injections via the Sinus Tarsi Approach

Reference: Smith J, Maida E, Murthy NS, Kissin EY, Jacobson, JA. Sonographically Guided Posterior Subtalar Joint Injections via the Sinus Tarsi Approach. J Ultrasound Med. 2015 Jan; 3(1): 83-93.

Scientific Literature Review

Reviewed By: Zachary Criswell, DPM
Residency Program: University Hospital, Newark, NJ

Podiatric Relevance: Ultrasonography is becoming increasingly utilized as a diagnostic tool to many practicing physicians who treat a variety of musculoskeletal pathologies. In addition to its use as a diagnostic tool, it is also commonly utilized in podiatric practice for certain interventional procedures, such as arthrocentesis of deep joints of the lower extremity including the posterior subtalar joint. This technique is popular due to its availability for bedside procedures, lack of ionizing radiation (as seen with conventional CT guided injections), and real-time visualization of medication administration into the targeted joint. In this article, the authors endeavor to assess the accuracy of an ultrasound guided injection of the posterior subtalar joint (PSTJ) via the approach through the sinus tarsi.

Methods: A single investigator performed ten ultrasound-guided posterior subtalar joint injections with 2 and 4 mL of tap water via the sinus tarsi approach in ten cadaveric lower extremity specimens using an out-of-plane approach. After the arthrocentesis was performed, sonographic assessment of fluid within the posterior and lateral recesses of the PSTJ, the sinus tarsi, and the peroneal tendon sheath was performed in order to assess for accuracy of the injection technique. In addition, the subtalar joints of two separate cadaveric specimens were injected with contrast dye using the standard lateral approach; one specimen under sonographic guidance and the other under computed tomographic guidance.

Results: All ten ultrasound-guided PSTJ injections were accurate, meaning that both the lateral and posterior subtalar joint recesses were distended after administration of 2 and 4 mL of tap water. None of the ten specimens demonstrated fluid within the peroneal tendon sheath after arthrocentesis, thus re-affirming accurate placement within the joint itself. Finally, both arthrograms using contrast dye (CT-guided and ultrasound-guided) demonstrated similar joint distension.

Conclusions: This article makes the conclusion that ultrasound-guided injection of the subtalar joint via the sinus tarsi approach is an accurate way to deliver medication or imaging dye into the specific articulation in question. While ultrasonography is a very utilitarian tool for any podiatric practice, it is very operator dependent. In addition, the second part of the study, which tested flouroscopic guided vs sonographically guided injection of the PSTJ via a completely different approach, did nothing to confirm the accuracy of the sinus tarsi approach, which was the article’s main goal. Overall an interesting study, but somewhat lacking in scientific rigor. 

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