Accuracy of a Single Tunnel Technique for Reconstruction of the Interosseous Talocalcaneal Ligament

Abstract

Category: Ankle Introduction/Purpose: Numerous reconstructive techniques to address subtalar joint instability have been described. Interest has focused on direct anatomic repair of the interosseous talocalcaneal ligament (ITCL) with tendon autograft, which is passed through osseous tunnels of the talus and calcaneus within the native anatomic boundaries of the compromised ITCL. To our knowledge, the technique employed to accurately place a guidewire and create a percutaneously developed tunnel through the anatomical footprint of the ITCL to restore it has not been described. The purpose of this study was to confirm that an osseous tunnel could be positioned within the ligamentous footprints accurately and safely, to define anatomic landmarks that can be used as reference points to reproduce an accurate tunnel, and assess the structures at risk during percutaneous reconstruction. Methods: Ten fresh cadaveric below-knee specimens were utilized. Under fluoroscopy, an anterior cruciate ligament guide was utilized to place a drill tunnel from the plantar lateral aspect of the calcaneus, across the sinus tarsi, and through the dorsal medial talus. The monofilament wire was passed through this tunnel to serve as a simulated model for cortical button fixation within the footprint of the ITCL. The first five specimens (group 1) were dissected; structures at risk and wire distance to the center of the ITCL were recorded. The procedure was then performed on the second set of five specimens (group 2) to assess for improvement in our technique. Results: The mean distances from the wire to the ITCL on the calcaneus and talus were 2.92 mm and 4.04 mm, respectively. Mean distances from the wire to ITCL on the calcaneus in groups 1 and 2 were 4.04 mm and 1.80 mm, respectively (p = .04). Mean distances from the wire to ITCL on the talus in groups 1 and 2 were 6.23 mm and 1.84 mm, respectively (p = .08). Violated structures included the tibialis anterior tendon in one specimen, and the most dorsal aspect of the talar head cartilage in 2 specimens. Conclusion: Under fluoroscopic guidance, and with minimal technique experience, a tunnel can be directed across the ITCL footprints accurately and safely. In our last five specimens, we were within 2 mm of the ITCL center, and well within the typical 8.5 mm average ITCL width. In our practice, we have reconstructed the ITCL with a cortical button fixation device using this technique and found it to be efficient and effective.