How Much Subtalar and Ankle Joint Surface are Actually Destroyed when Reaming for Tibiotalocalcaneal (TTC) Nailing? A Cadaveric Study

Abstract

Category: Ankle; Trauma Introduction/Purpose: Tibiotalocalcaneal (TTC) nailing in the setting of acute ankle trauma has become increasingly popular over the last decade, with expanding indications. Potential advantages of TTC nailing include: less soft tissue dissection, decreased wound burden, and earlier weightbearing. No consensus exists as to whether formal joint preparation is necessary, and at one or both joints. While some argue that joint preparation is not necessary due to inherent joint destruction from the injury and reaming during TTC nailing, others advocate for preparation to facilitate fusion and ensure no further motion occurs at the joint which could lead to nonunion and/or hardware failure. The purpose of this study was to quantify the proportion of ankle and subtalar joint articular surface destruction associated with reaming for TTC nail fixation. Methods: Twelve cadaver feet from 6 specimens were procured. The specimens were reduced and pinned into neutral ankle dorsiflexion and neutral hindfoot alignment. Prior to reaming, each specimen was secured in a simulated supine position. Per standard TTC nailing technique, a 3.0 millimeter (mm) guide wire was inserted under fluoroscopy, retrograde from the calcaneus, through the talus, and into the tibia, followed by a 12mm opening reamer. The specimens were then dissected, exposing the tibial plafond (TP), talar dome (TD), posterior facet of the talus (PFT), and posterior facet of the calcaneus (PFC). Clinical images of each joint were obtained at an angle of 90 degrees and 12 centimeters (cm) from the joint surface. The images were processed using the ImageJ software platform. The total joint surface area, area of articular destruction, and the remaining joint surface area were calculated. The percentage of joint destruction associated with reaming was then calculated. Results: The mean surface area values and percentages of articular surface destruction are summarized in Table 1. The mean surface area (cm 2 ) after reaming was 11.82, 13.70, 9.23, and 7.79 for the TP, TD, PFT, PFC, respectively. The percentage of articular cartilage destruction was 9.32%, 10.33%, 8.89%, and 10.28% for the TP, TD, PFT, PFC, respectively. No joint destruction was observed in the middle facets of the subtalar joint. Conclusion: This study demonstrates that reaming for TTC nail placement involves only a small portion (roughly 8-10%) of each of the articular surfaces of the ankle and subtalar joints. Violation of the middle facet of the subtalar joint did not occur. These results suggest that a significant portion of hindfoot articular surface remains after reaming for TTC nail. Formal joint preparation may be beneficial to aid with fusion after TTC nail placement, particularly when used in younger, more active individuals who sustain hindfoot and ankle trauma.