Safety of dorsolateral talonavicular joint fixation in modified double arthrodesis: An anatomic study

Background: Augmentation of talonavicular fusion with a retrograde percutaneous naviculocalcaneal screw has been shown to increase fixation stiffness of double (subtalar and talonavicular joint) arthrodesis. However, previous authors have speculated that neurovascular structures could be at risk in a percutaneous procedure. We investigated the safety of this procedure. We hypothesized that a high risk of neurovascular injury would be found. Methods: Dorsolateral talonaviculocalcaneal screw fixation was performed in 17 fresh-frozen cadaver limbs. A 1.5-cm incision was created over the lateral third of the navicular. Using percutaneous technique, a 4.5-mm cannulated screw was inserted using a guide wire. Blunt dissection and careful soft-tissue retraction were performed. The incision was extended, and a caliper was used to measure the distance from the guide wire to the superficial peroneal nerve (SPN), extensor hallucis longus, extensor digitorum longus, deep peroneal nerve (DPN), and deep peroneal artery (DPA). All injuries were recorded. Results: Injury to the deep neurovascular bundle occurred in five of 17 specimens. These injuries involved four insults to the DPN, two to the DPA, and one to branches of the SPN. Conclusions: Use of a retrograde naviculocalcaneal screw to augment talonavicular fusion in the setting of double arthrodesis was associated with high risk of injury to anatomic structures, including the deep neurovascular bundle. Clinical Relevance: An open procedure with careful dissection along the neurovascular bundle should be considered with use of a retrograde naviculocalcaneal screw to augment talonavicular fusion to avoid risk to nearby anatomic structures.