Clinical and biomechanical analysis of a dynamic compression intramedullary nail for hindfoot and ankle arthrodesis

Tibiotalocalcaneal (TTC) arthrodesis and tibiocalcaneal (TC) arthrodesis are salvage procedures indicated to maintain stability and ambulation in the setting of various debilitating lower extremity conditions. Intramedullary nail fixation has proven to be highly effective in achieving stable union when performing TTC and TC arthrodesis procedures. Newer generation intramedullary nail implants feature dynamic compression technology, offering continuous compression across the desired fusion interfaces. Although published data is scarce, emerging literature suggests use of dynamic compression implants may be favorable to static implants, particularly in patients with increased risk of non-union. The primary aim of this paper is to review clinically relevant mechanical testing data that outlines specific mechanical properties of a particular TTC implant (Phantom ActivCore). Specifically, we describe various properties of the implant through objective testing data and describe these findings in a clinically relevant format to provide surgeons with closer insight into dynamic compression technology. Secondarily, we feature three case examples in which this flex coil intramedullary nail was employed by the senior authors (BH &TC) to achieve functional TTC arthrodesis in salvage scenarios.