The “Flying V”: A Novel Construct to Address Concurrent Lateral Ankle and Syndesmotic Instability

Ankle sprains are one of the most commonly encountered sports medicine injuries. They involve disruption of the anterior talofibular ligament (ATFL) and/or the calcaneofibular ligament (CFL). Most injuries go on to heal with conservative treatment, and operative management is typically reserved for patients who have recurrent sprains despite appropriate functional rehabilitation. Numerous approaches exist, including ligament reconstruction or tendon transfers. The Broström technique is the most commonly utilized method, which involves a direct anatomic repair that imbricates the ATFL. The Gould modification integrates a periosteal flap in addition to the extensor retinaculum. A modified suture tape augmentation has been described as well, with data showing improved functional scores and rapid return to sport without increased morbidity.1

Syndesmotic ligament injuries are a separately described entity, known colloquially as a high ankle sprains. They are much less common and often overlooked. The syndesmosis is comprised of the anterior-inferior tibiofibular ligament (AITFL), interosseous ligament, inferior transverse ligament, and posterior-inferior tibiofibular ligament.2 Injury of the syndesmosis can potentially alter ankle joint congruity. This can lead to prolonged recovery, increased time away from sport, and early post-traumatic arthritis if not addressed.3 Thus, patients with syndesmosis disruption are often treated surgically. This was traditionally performed using screw fixation, but suture buttons have become a widely accepted alternative. A newer technique, involving suture tape augmentation of the AITFL, has strong biomechanical evidence to support its use in isolation or as an adjunct to traditional fixation.4

These injuries are typically encountered as separate entities, but in unique cases the pathologies may overlap. We have developed a novel technique to address concurrent lateral ankle and syndesmotic instability in an efficient manner. This technique, known as the “Flying V,” incorporates the use of suture tape to reconstruct both the ATFL and AITFL simultaneously in a single construct.

TECHNIQUE

A thorough history identifies patients at risk for this injury pattern. A comprehensive foot and ankle examination is performed, but we will emphasize maneuvers and findings pertinent to this pathology. Testing of the lateral ligaments is primarily done utilizing an anterior drawer test. This involves placing anterior pressure on the calcaneus while stabilizing the ankle with the other hand, looking for asymmetric translation of 3 to 5 mm more than the contralateral side. The test can be performed in plantarflexion to isolate the ATFL or in neutral position to test the CFL.5 The talar tilt test, placing inversion stress on the ankle, can serve as a useful adjunct.

A more thorough description of our evaluation of the syndesmosis has been described elsewhere for reference.4 This begins with the fibular translation test, which involves stabilizing the tibia with one hand and providing anterior/posterior stress to the fibula. Increased translation compared with the contralateral side or pain suggests sagittal plane instability, which is primarily provided by the AITFL component of the syndesmosis.6 External rotation stress, the crossed-leg test, and the “squeeze” test are all useful adjuncts if they reproduce pain proximal to the joint line.5 Ankle stabilization with coban wrapped at the level of the syndesmosis should provide relief of pain on dynamic examination.

Standard X-rays are part of our initial evaluation. A gravity stress external rotation view is added if syndesmosis disruption is suspected. However, both lateral ligament and syndesmotic instability are ultimately diagnosed clinically. We do not routinely order magnetic resonance imagings in our practice unless the underlying diagnosis is unclear. Ryan et al7 demonstrated that fluid extravasation proximally from the mortise (“Lambda sign”) was highly sensitive and specific for syndesmotic disruption. Representative images are shown in Figure 1 from a patient seen in our practice with these concomitant pathologies.

F1FIGURE 1:

Images A and B are coronal magnetic resonance imaging (MRI) cuts showing the “Lambda sign” in the circled area with fluid extravasation and disruption of the interosseous ligament. Image C is an axial MRI cut showing diastasis of the syndesmosis with disruption of the anteriorinferior tibiofibular ligament marked by the arrow. The posterior-inferior tibiofibular ligament remains intact. Image D is an axial MRI showing anterior-inferior tibiofibular ligament insufficiency in the same patient as indicated by the arrow.

On the day of surgery, physical exam is carried out under anesthesia as well to confirm these findings. Fluoroscopic examination with dorsiflexion and external rotation stress can show coronal instability with widening of the syndesmosis for additional evidence.

In regards to the procedure, a routine ankle arthroscopy is carried out to start. Anteromedial and anterolateral portals are established using a nick and spread technique. The talar dome is carefully examined for any chondral damage, and all concurrent pathology is addressed. The syndesmosis is carefully examined and stressed under direct arthroscopic visualization. An enlarged lateral gutter indicates that a patulous capsule is present, suggesting underlying lateral ankle instability. Placing an instrument of known size into the syndesmosis can estimate the diastasis, with 3 mm shown in cadaveric studies to reliably predict syndesmosis disruption8 (we elect to use a readily accessible 4.0 mm shaver).

Once the diagnosis is confirmed, we proceed with the lateral ligament reconstruction utilizing a modified Broström technique with suture tape augmentation. We described our technique for this procedure in detail in an earlier publication.1 Briefly, a curvilinear incision is made directly over the distal fibula aiming towards the fourth metatarsal. A periosteal cuff of tissue is elevated from the distal fibula. The bone is prepared with a rongeur and rasp to establish a bleeding zone. The residual ATFL and CFL are released from their fibular attachments. The proximal band of the ATFL is dissected out to its insertion on the lateral talus, creating an “L” shaped flap of tissue comprised of the inferior retinaculum, capsule, and residual ATFL. Next, a 4.75 mm knotless anchor as part of an internal ligament brace construct is inserted into the anatomic footprint of the ATFL, 5 mm distal to the terminal extent of the talar articular cartilage.9 We use a free needle to pass the suture tape through the inferior limb of our tissue cuff. We then turn our attention back to the fibula. Two 2.4 mm suture anchors are inserted 5 mm (anatomic footprint of the CFL)9 and 20 mm (approximate superior extent of ATFL fibers)2 from the tip of the fibula. This is demonstrated in Figure 2. With the foot in a neutral position, we use these smaller anchors to grasp the superior cuff of tissue and reapproximate the native ligaments to the fibula. The suture tape is then laid superficially and inserted 12 mm from the tip of the fibula (center of the ATFL footprint)2,9 with a 3.5 mm knotless anchor. The remaining suture tape is preserved for a later step. The periosteum flap is imbricated using the suture from the smaller anchors in a pants-over-vest technique. This flap covers the inferior limb of the suture tape and completes the lateral ligament reconstruction.

F2FIGURE 2:

Anchors are placed in the fibula at 5 and 20 mm from the tip to replicate native calcaneofibular ligament (CFL) and superior anterior-inferior tibiofibular ligament (ATFL) insertions, respectively. The suture tape has already been placed into the talus at this point. It will be inserted between the 2 smaller anchors at 12 mm to reinforce the anterior-inferior tibiofibular ligament reconstruction.

The novel addition to this technique involves integration of a syndesmosis reconstruction into this same construct. Through our original incision, we identify the tibial AITFL footprint on the Chaput tubercle, roughly 5 mm superomedial to the articular cartilage of the tibial plafond.2 After the marked site is drilled and tapped, we measure out the appropriate length of suture tape remaining from our distal repair. A point-to-point clamp is applied to the posterolateral fibula and anteromedial tibia to achieve reduction of the syndesmosis. This is confirmed on fluoroscopy, and the suture tape is inserted under appropriate tension using a 4.75 mm knotless anchor. The completed construct is shown in Figure 3. After cutting the excess suture material, a 2.0 Polyglactin 910 (Vicryl) is used to imbricate the inferior extensor retinaculum. A repeat physical and arthroscopic exam is performed to confirm stability of the syndesmosis. Restoration of the “Mercedes sign” indicates a restored spatial relationship between the fibula, tibia, and talus.4 The wound is irrigated. Subcutaneous tissue is closed with 3-0 Polyglactin 910 (Vicryl) and skin is closed with a running horizontal mattress 3-0 Polyamide (Nylon). A posterior slab and U splint are applied.

F3FIGURE 3:

The completed “Flying V” construct is shown here. The suture tape augmentation from the modified Broström technique is carried from the lateral talus to Wagstaffe tubercle on the fibula to recreate the native anterior-inferior tibiofibular ligament. This is then carried to the Chaput tubercle on the anterolateral tibia to recreate the native anterior-inferior tibiofibular ligament.

EXPECTED OUTCOMES

The “Flying V” technique aims to simultaneously address both lateral ankle and syndesmosis instability. The AITFL is the weakest, thus the most commonly disrupted component of the syndesmosis. However, it contributes the greatest amount to stability, particularly in resisting external rotation and posterior translation.6 Instead of performing 2 separate procedures, the surgeon will be able to achieve this desired outcome utilizing 1 incision and 1 construction. It also allows for direct visualization of an anatomic reconstruction of both the ATFL and AITFL. These patients will be able to participate in functional rehabilitation more quickly than the standard protocol, thus reducing the anticipated time until return to activity.

COMPLICATIONS

As with any procedure, there are complications that one must be aware of. Some of the causes of malreduction in traditional suture button or screw fixation techniques exist using this reconstruction as well. These include a shallow incisura, overcompression, and ineffective clamp positioning.4 A unique cause of malreduction in this technique can occur if the surgeon overtensions the suture tape. We recommend ensuring isometric length throughout all key portions of the procedure as well as confirming the reduction and stability through repeat arthroscopy, fluoroscopy, and physical exam as well. Traditional suture button fixation also places medial neurovascular structures, particularly the saphenous nerve and vein, at risk. These risks are decreased or entirely eliminated using the AITFL reconstruction method.

When drilling all anchors, particularly with the lateral wall of the talus, great care must be taken to avoid penetration into the joint and iatrogenic articular cartilage damage. Intraoperative fluoroscopy can be used to minimize this risk.

The lateral ligament reconstruction portion of the procedure and its associated complications have been well described in the literature. Stiffness can occur because of overtightening. We mark the length of the anchor on our suture tape before insertion to minimize this risk. Recurrent instability is rare but possible.1 Meticulous closure and the close attention paid to the imbrication of the extensor retinaculum can help to avoid symptomatic hardware or wound complications.

The talar and tibial ligament attachments can be precisely approximated using this technique. However, the construct design necessitates a single fibular origin for the ATFL and AITFL. In reality, the AITFL insertion lies on Wagstaffe’s tubercle of the fibula. Its center is roughly 3 cm above the tip of the fibula and is more proximal than that of the ATFL insertion, which lies closer to 12 mm.10 This is a limitation of the technique that must be acknowledged, but the clinical importance of this discrepancy is unknown. Fortunately, the anatomic footprint of the AITFL is very broad and is composed of several separate bands. Studies have shown that its inferior fascicle extends as inferior as 12 mm above the distal tip of the fibula.10 In the same study, the majority of specimens examined exhibited some degree of blending of the AITFL and ATFL fibers. A more distal insertion of the AITFL could theoretically lead to increased contact pressure on the talus and potential for chronic pain because of anterolateral impingement. However, further studies are needed to investigate the biomechanical repercussions in addition to long-term clinical follow-up for patients treated with this construct.

REFERENCES 1. Martin KD, Andres NN, Robinson WH. Suture tape augmented broström procedure and early accelerated rehabilitation. Foot Ankle Int. 2021;42:145–150. 2. Golanó P, Vega J, de Leeuw PAJ, et al. Anatomy of the ankle ligaments: a pictorial essay. Knee Surg Sports Traumatol Arthrosc. 2010;18:557–569. 3. Leeds HC, Ehrlich MG. Instability of the distal tibiofibular syndesmosis after bimalleolar and trimalleolar ankle fractures. J Bone Joint Surg Am. 1984;66:490–503. 4. Wake J, Martin KD. Syndesmosis injury from diagnosis to repair: physical examination, diagnosis, and arthroscopic-assisted reduction. J Am Acad Orthop Surg. 2020;28:517–527. 5. Larkins LW, Baker RT, Baker JG. Physical examination of the ankle: a review of the original orthopedic special test description and scientific validity of common tests for ankle examination. Arch Rehabil Res Clin Transl. 2020;2:100072. 6. Patel NK, Murphy CI, Pfeiffer TR, et al. Sagittal instability with inversion is important to evaluate after syndesmosis injury and repair: a cadaveric robotic study. J Exp Orthop. 2020;7:18. 7. Ryan LP, Hills MC, Chang J, et al. The lambda sign: a new radiographic indicator of latent syndesmosis instability. Foot Ankle Int. 2014;35:903–908. 8. Guyton GP, DeFontes K, Barr CR, et al. Arthroscopic correlates of subtle syndesmotic injury. Foot Ankle Int. 2017;38:502–506. 9. Dong Y, Qian Y, Liu L, et al. Anatomical study on the reconstruction of the anterior talofibular ligament. J Foot Ankle Surg. 2021;60:908–911. 10. Fisher A, Bond A, Philpott MDG, et al. The anatomy of the anterior inferior tibiofibular ligament and its relationship with the Wagstaffe fracture. Foot Ankle Surg. 2021;27:291–295.

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