Ultrasound-Guided Talonavicular Arthrocentesis.

Background: Joint arthrocentesis is a commonly performed procedure by the emergency physician (EP). Point of care ultrasound (POCUS) has demonstrated promise in identifying joint effusions and guiding arthrocentesis procedures. EP-performed talonavicular joint arthrocentesis has not been previously described in the literature. We present a case in which an isolated talonavicular joint effusion was identified and then subsequently aspirated using POCUS.

Case Report: A 65-year-old man presented with atraumatic right ankle pain. On arrival, he was noted to have diffuse warmth and edema around the ankle and midfoot. POCUS was performed to evaluate for an ankle joint effusion, which was not present. The ultrasound was then moved distally, where a talonavicular joint effusion was noted. Inflammatory markers were found to be elevated. A magnetic resonance imaging scan revealed an isolated talonavicular joint effusion without additional acute findings. POCUS was then used to perform an arthrocentesis, which revealed monosodium urate crystals consistent with an initial episode of gouty arthritis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: POCUS provides the EP with an efficient tool to diagnose joint effusions and guide arthrocentesis procedures. The foot is composed of several small joints where ultrasound can be particularly helpful. Similar to the ankle joint, these joints can be afflicted with pyogenic infections and crystalline arthropathies. To our knowledge, we present the first report of EP-performed talonavicular arthrocentesis guided by POCUS. The approach to this joint and technique for arthrocentesis are presented.