Variability of Joint Communications in the Foot and Ankle Demonstrated by Contrast-Enhanced Diagnostic Injections

Background: The history and physical examination will usually direct a surgeon to the correct site of joint pathology. Imaging with plain radiographs and diagnostic injections help localize joint pathology more precisely. The presence of accessory communications between adjacent joints may reduce the sensitivity of these investigations. Material and Methods: We report on the findings of 389 arthrograms of the midfoot, hindfoot and ankle that were performed by a single radiologist over a 7-year period. Fluoroscopic guidance with radioopaque dye was used to confirm needle position before local anesthetic was injected. Images were closely studied to identify any communication between adjacent joints. Results: The passage of contrast into adjacent joints confirmed the presence of an additional communication. In 13.9% of cases there was a communication between the ankle and subtalar joint. A communication between the talonavicular and the calcaneocuboid joint was observed in 42.3% of local injections. We identified previously unreported communications between the anterior subtalar and the naviculocunieform joints (8%), the anterior subtalar and the calcaneocuboid joints (9%) and the naviculocunieform and tarsometatarsal joints (1.1%). Conclusion: This study reinforces the typical incidence of known joint communications, describes previously unreported communications and highlights the importance of these communications particularly with the small joints of the midfoot. The possible presence of accessory communications must always be considered when performing isolated midfoot fusions relying upon diagnostic local anesthetic injections.