Talar Arthroscopic Reduction and Internal Fixation (TARIF): A Novel All-Inside Soft-Tissue-Preserving Technique.

Abstract

Background: Talar arthroscopic reduction and internal fixation (TARIF) is an alternative approach for the operative fixation of talar fractures that may be utilized instead of more traditional open approaches such as medial, lateral, or even dual anterolateral. The TARIF approach allows for nearly anatomic fracture reduction and fixation of talar neck, body, and posterior dome fractures while minimizing the soft-tissue stripping and vascular injury associated with the standard anterolateral approach.

Description: Following initial closed fracture reduction and any associated procedures, we recommend obtaining computed tomography scans of the injured ankle in order to evaluate the fracture pattern and allow for preoperative planning. Most patients can be positioned prone for this procedure, except for those with fractures associated with anterior loose bodies and those with neck fractures requiring reduction, which are both amenable to lateral positioning¹. The feet are positioned off the end of the bed in a neutral position with room to plantar flex and dorsiflex the ankle freely for reduction maneuvers. Following induction of anesthesia and positioning of the patient, the fluoroscopic screen and arthroscopy equipment are positioned on the side opposite the surgeon. A mini C-arm is utilized for the fluoroscopy. The team may then proceed with preparing and draping the surgical field. The surgeon proceeds with creating posteromedial and posterolateral portals to view the fracture site. For talar neck fractures, we utilize standard posterolateral and posteromedial portals directly adjacent to the Achilles tendon at the level of the tip of the medial malleolus, which have previously been established as safe with respect to neurovascular structures⁴. Of note, for talar body fractures these portals are placed slightly more distal at the level of the distal fibula, allowing the screws to be placed perpendicular to the fracture site. An accessory sinus tarsi portal can be established if further reduction to correct varus is needed. The flexor hallucis longus tendon serves as a landmark throughout the case to maintain orientation. We prefer to utilize a 1.9-mm malleable arthroscopic NanoScope (Arthrex), which maximizes our view in the small subtalar space and allows for visualization over the talar dome. A shaver is then utilized to clear out the deep joint capsule and remove fracture hematoma. In our experience, after the initial primary reduction attempt by the orthopaedic trauma provider, the fracture is relatively stable and often held by an external fixator. The remaining reduction is performed with use of manipulation of the ankle in combination with an accessory sinus tarsi portal, utilizing an elevator or a small reduction tool in 1 of the posterior portals. We have also utilized percutaneous Kirschner wires to "joystick" the fragments prior to the placement of the guidewires. We then place multiple 1.1-mm guidewires under direct arthroscopic and fluoroscopic visualization, utilizing the flexor hallucis longus tendon as our safe margin to ensure that we are lateral on the posterior talar dome. This approach in turn allows us to ensure the integrity of the neurovascular structures, such as the tibial artery and nerve medially as well as the sural nerve laterally. Finally, cannulated headless compression screws are passed over the guidewire to achieve fixation. The senior author (K.D.M.) prefers fully threaded, cannulated 3.5-mm titanium headless compression screws because the cannulation allows the guidewires to be placed through the posterolateral and posteromedial portals, while the headless design allows the screws to be placed under the articular cartilage. Additionally, the use of titanium allows for improved postoperative magnetic resonance imaging quality as well as favorable biomechanics as titanium has a modulus of elasticity similar to bone. After drilling is complete, we sequentially tighten the screws by hand to prevent varus or valgus angulation. Although we have not experienced failure or a poor bite when utilizing the 3.5-mm fully threaded compression screw, we have found that the partially threaded screw can at times have a poorer bite. Additionally, we select a 3.5-mm screw rather than a larger screw-say 5.5 mm-as we have found that the larger screws do not easily pass through our portals, which are minimal in size when utilizing this approach. Throughout this process, fluoroscopy, in tandem with arthroscopy, is obtained in multiple views to ensure that fixation and orientation are appropriate and the screws are in the optimal position, off of the articular surface. If large osseous defects or collapse are encountered, an accessory anteromedial portal is utilized to add grafting material. Following confirmation of adequate fracture fixation, final arthroscopic images of the talar dome continuity, subtalar continuity, and ankle joint during range of motion are obtained. The portal sites are closed with use of 3-0 nonabsorbable sutures, and a well-padded L and U splint is applied postoperatively.

Alternatives: Alternatives include the standard anterolateral approach to fixation or dual anterior approach, a medial or lateral approach, and external fixation with interval operative fixation.

Rationale: TARIF is indicated for reduction of a wide variety of talar fractures, including neck, body, and posterior facet fractures, and offers the added advantage of minimizing the soft-tissue stripping and vascular injury associated with the standard anterolateral approach. Additionally, TARIF is well suited for patients with a compromised soft-tissue envelope or associated vascular injury, such as those with open-fracture pathology, because the approach avoids further disruption of these tissues. The overall aim of the procedure is to obtain adequate fracture reduction while avoiding the neurovasculature and soft-tissue envelope that would commonly be encountered anteriorly. The procedure is completed through 2 incisions, a posteromedial portal and a posterolateral portal, through which the fracture is visualized, reduced, and fixated using cannulated screws. The fixated talus is tested through its range of motion while under arthroscopy and fluoroscopy to ensure adequate fixation while preserving range of motion.

Expected outcomes: The TARIF procedure has been shown to successfully treat many complex talar fractures². We theorize that this procedure produces equivalent outcomes when compared with the standard approaches to fracture fixation, with the added benefit of avoiding excessive soft-tissue disruption and neurovascular compromise. Our arthroscopic approach allows for direct visualization of articular injuries and reduction, with the ability to evacuate loose bodies and fracture hematoma, reducing matrix metalloproteinases (MMPs) known to cause posttraumatic ankle arthritis^1,3. Multiple case series have assessed the use of this technique, showing preserved range of motion and minimal residual pain or disability, as measured with use of multiple scoring systems such as the American Orthopaedic Foot & Ankle Society Ankle-Hindfoot scale^1,2.

Important tips: Immediately after accessing the ankle via the operative portals, identify the flexor hallucis longus tendon to prevent iatrogenic injury to the neurovascular bundle.Plantar flexion of the ankle while applying anterior force to the talar body often aids in reduction.Place the medial guidewire directly adjacent to the flexor hallucis tendon in order to ensure that it is medial enough.Utilize anterior-to-posterior fluoroscopic images of the foot and ankle to ensure screw placement.Directly visualize the fracture site as the screws are sequentially tightened in order to prevent malalignment.Countersink all screw heads and directly verify with arthroscopic visualization.

Acronyms & abbreviations: MVC = motor vehicle collisionXR = x-ray (radiograph)CT = computed tomographyEx-fix = external fixatorMRI = magnetic resonance imagingFT = fully threadedFHL = flexor hallucis longusAP = anteroposteriorROM = range of motionDVT = deep vein thrombosisBID = bis in die (twice daily dosing).