INTRODUCTION
Tibiotalocalcaneal (TTC) fusion surgery is performed to relieve pain and correct severe foot deformity
by achieving solid bony union, often the only remaining treatment option before limb amputation.
According to the Association for the Study of Internal Fixation principles, compression across a
fusion site is important for promoting bone healing and achieving a solid union. Compression also
provides stability by maximizing bone-to-bone contact and limiting micro-motion. External fixation
frames allow for compression to be applied and adjusted during the course of treatment, but these
systems are surgically complex, associated with poor patient compliance, and have a relatively high
rate of pin tract infections. Intramedullary (IM) nails are a rigid, internal fixation option and are less
invasive and technically demanding to implant than external frames. Traditional IM nails apply
external compression at the time of surgery, but compression is lost once the instrumentation is
removed. Third-generation IM nails contain an internal compression mechanism that helps maintain
compression after instrument removal. However, these nail systems lose compression
over time post-surgery due to bone resorption and joint settling. 1
The DynaNail TTC Fusion System is the only fusion approach that offers the compression-sustaining
performance of an external fixator inside an intramedullary nail. Due to its proprietary internal
NiTiNOL element, DynaNail provides sustained, active compression to the bones maintaining them
in close apposition while also providing immediate dynamization. After implanting DynaNail, the
Compressive Element is stretched 6 mm and fixed in the stretched position with two screws (one
posterior-anterior and one lateral-medial) in the calcaneus allowing for 6 mm of post-operative
compression. External manual compression can then be applied for an additional 6 mm of
adjustment. Two medial-lateral screws are then inserted through the proximal portion of the nail
body across the tibia to maintain compression and provide additional stability. Post-surgery once
the Targeting Frame is removed, the Compressive Element will hold its stretched activated position
until any bone resorption and/or joint settling occurs, whereby the Element will automatically recover
its stretched length, maintaining compression across the joints. 1
The DynaNail TTC Fusion System is available in different diameters and lengths to accommodate for
varying patient anatomies. The Compressive Element is housed inside a rigid outer titanium body
with 7 mm End Cap. The system also features a rigid, radiolucent carbon fiber-filled polyether ether
ketone (PEEK) Targeting Frame that is used to precisely position the Nail Implant across the joints,
stretch the Compressive Element and then accurately drill and place the screws. Housed in a single
sterilization tray, the Frame and accompanying color-coded instrumentation provides the surgeon
with a simple, reliable surgical approach.
Compressive
Element
Sliding
Element
1
4
Yakacki et al. Pseudoelastic nailing for tibio-talo-calcaneal arthrodesis.
Expert Rev Med Devices, 2011; 8(2):159-166.