Current Insights On Augmenting Lateral Ankle Ligament Repair In Athletes

Ankle sprains are among the most common injuries that foot and ankle specialists treat. These injuries most frequently involve the lateral ankle ligament complex. The majority of lateral ankle sprains will not require surgical intervention but the risk of functional and/or mechanical ankle instability in the athletic patient may be detrimental in the individual’s return to a high level of activity.

The mainstay of treatment for lateral ankle sprains continues to be conservative care. This includes immobilization, rest, ice, anti-inflammatory medication and physical therapy. According to the literature, patients who have a history of a previous ankle sprain are at high risk of developing chronic ankle instability.¹ This instability manifests as functional, mechanical or both. The loss of proprioception from a prior injury to the ankle further increases the chances of a patient to have a recurring ankle sprain, which will continue to weaken and destabilize the lateral ankle ligament complex. These patients, particularly athletes, will not respond well to conventional physical therapy and will likely require surgical intervention to return to their baseline function.  

There are various surgical procedures that have emerged to address chronic lateral ankle instability. One should base the choice of procedure first on the pathology of injury and second on the patient’s history and desired functional outcome. Certainly, when treating a competitive athlete, the goal of the surgeon should be to return the patient to normal physical activity in a timely manner without deviating from the standard of care. In determining the pathology of injury, I use three components: history and physical examination, radiographic stress testing of the ankle and magnetic resonance imaging (MRI) findings.  

Evaluating Chronic Lateral Ankle Instability

The foot and ankle surgeon must take into account the history (including age, sex, weight) and any comorbidities of the patient. The physical examination will reveal tenderness on direct palpation of the anterior talofibular and/or calcaneofibular ligament. There can be increased edema to the affected ankle even in the chronic state. One will also find increased inversion of the injured ankle in comparison to the contralateral ankle. Crepitus on range of motion may be a sign of intra-articular injury or synovitis of the ankle. Circumduction range of motion may be difficult for the patient to perform and the clinician must also pay close attention to peroneal tendon pathology such as peroneal subluxation or entrapment.  

Employing a regional anesthetic block for the patient, one can perform radiographic stress tests in the office. The talar tilt test will identify injury or laxity to the calcaneofibular ligament and the anterior drawer test will examine the integrity of the anterior talofibular ligament. The anterior talofibular ligament is the most common ligament disrupted in an ankle sprain and routinely will be insufficient if the talus is displaced anterior relative to the distal tibial plafond.²  

Obtaining magnetic resonance imaging (MRI) is important for thoroughly evaluating chronic lateral ankle instability. Ligaments will most often be torn or attenuated in nature. One must also evaluate for possible osteochondral lesions of the talus as well as peroneal tendon pathology. This will assist the surgeon in determining the type of procedure and surgical approach required to repair the chronically unstable ankle.

Pertinent Tips On Procedure Selection

In a recent Podiatry Today article, Baravarian and colleagues thoroughly outlined the surgical options to treat lateral ankle instability.³ These options include direct repair of torn lateral ankle ligaments, minimally invasive arthroscopic repair or the use of tendon autografts and allografts. As they stated in their article, these repairs can be either anatomic or non-anatomic in nature. The anatomic repair approach has the advantage of maintaining normal ankle anatomy and biomechanics. Therefore, I only advise non-anatomic surgical approaches for revision ankle stabilization surgery in which the normal anatomy of the lateral ankle has been compromised from previous surgery.

Authors have historically described a multitude of procedures to reconstruct the lateral ankle ligament complex. These include the Lee, Nilsonne, Evans, Watson-Jones and Chrisman-Snook procedures.^4-7 These reconstructive procedures have generally been indicated only for revision of previously failed direct repairs or patients with conditions such as obesity.   

Currently, the most common procedure performed for lateral ankle instability is the Brostrom procedure, which allows direct repair of the anterior talofibular ligament and indirect fibroadhesion of the calcaneofibular ligament. The disadvantage of this approach is the utilization of damaged ligament and/or capsular tissue, which may compromise the strength of repair. This in turn can pose a serious setback in the rehabilitation and return to sports for an athlete.  

Due to this notion, I no longer perform just a direct repair of torn ankle ligaments in an athletic patient but prefer to augment the repair with either peroneal tendon allograft or non-absorbable suture tape.  

Debating The Use Of Allograft Versus Non-Absorbable Suture Tape

The use of an allograft can be technically challenging for various reasons. It is imperative to choose and prepare the proper length for use in bone tunnels in order to prevent “bunching” of the tendon graft and obtain physiologic tension. It is also often necessary to drill a bone tunnel not only into the talus and fibula, but also into the calcaneus, which can lead to further complications and error. Other disadvantages include risk of disease transmission, graft rejection, host immune response and overall cost.

Non-absorbable suture tape (FiberTape, Arthrex) is a construct that offers a new way to augment lateral ankle ligament repairs. The suture tape is a braided construction of ultra-high molecular weight polyethylene fiber blended with the fibers of one or more long chain synthetic polymers such as polyester. The suture tape is indicated for high demand orthopedic repairs and surgeons have used it for rotator cuff repair in the shoulder and anterior cruciate ligament (ACL) repair in the knee. Initial studies of the use of suture tape for augmenting direct ankle ligament repair have been promising with results indicating a higher strength and stiffness in comparison to just the Brostrom procedure alone.⁸   

The InternalBrace system (Arthrex) includes everything necessary for a surgeon to perform the augmentation technique in a reproducible manner. The system includes #2 suture tape (FiberTape), biocomposite knotless anchors (SwiveLock, Arthrex) for attachment of the suture tape to the talus and fibula, and necessary drill bits and guides.  

Essential Surgical Pearls

I prefer to insert suture tape from the talus to the fibula because it is technically easier with more exposure of the augmentation interface. Biomechanical testing performed on cadaveric specimens has shown that starting in the fibula first has a stronger pullout strength but both fibula-to-talus and talus-to-fibula approaches are significantly stronger than using suture tape for the native anterior talofibular ligament alone.⁸

Ensure supine positioning of the patient on the operating room table with a bump under the ipsilateral hip for access to the lateral ankle and apply a well-padded thigh tourniquet. Perform ankle arthroscopy prior to open repair when necessary to treat any concomitant injuries such as synovitis and osteochondral lesions of the talus.  

Base the incision on whether there is any peroneal tendon pathology. If there is no peroneal tendon injury, I prefer a curvilinear incision along the anterior border of the distal fibula approximately 4 cm in length. Deepen the incision through subcutaneous tissue, taking care to protect the intermediate dorsal cutaneous nerve superiorly and the sural nerve inferiorly. Ligate branches from the lesser saphenous vein as necessary. Identify the inferior extensor retinaculum along the anterior edge of the operative site and separate it from the deep fascia. Tag capsular tissue for later use for an additional layer of augmentation. The peroneal tendon sheath should be visible along the inferior edge of the exposure. If there is concern for injury, incise the peroneal sheath to visualize the brevis and longus tendons at the level of the distal fibula. Retract the tendons inferiorly to inspect the calcaneofibular ligament, which is extracapsular.  

Then direct attention to the anterior lateral aspect of the distal fibula. Perform a capsulotomy in line with the initial curvilinear skin incision from the distal edge of the anterior fibula. The anterior talofibular ligament will be visible since it is intracapsular. Attempt to preserve the anterior talofibular ligament and incorporate it into the repair if possible. Use a periosteal elevator to create a periosteal-capsular flap along the anterolateral fibula that you can use to imbricate and tighten the lateral capsule. Similarly, resect a flap from the non-articulating surface of the lateral talus to allow for tightening of the lateral capsule. Use a hand rasp to roughen the anterior distal surface of the fibula until bleeding to induce healing and fibroadhesion.  

Now perform a standard Brostrom procedure, holding the foot in a dorsiflexed and everted position. A surgical pearl is to place a bump made of towels superior to the heel to allow posterior displacement of the talus in the ankle mortise for optimal position during repair. Then place metallic bone anchors with attached suture needles into the anterolateral aspect of the fibula. Most athletes will require two to three anchors into the fibula for a strong construct.

It is recommended to use intraoperative fluoroscopy as one should take care to direct the bone anchors slightly superior and midline to the shaft of the fibula in order to prevent penetration into the lateral ankle gutter or shearing of the distal fibular colliculus. Then use the suture needles attached to the bone anchors to imbricate the lateral ankle capsule in a pants-over-vest technique by re-approximating the anterior talofibular ligament and talar capsular flap with the fibular capsular flap. The repair will be tighter with less bulk if one passes the sutures in an “inside-outside” manner and when suture knots lie along the fibular portion of the joint. Use 2-0 non-absorbable sutures to reinforce the repair along the lateral capsule in a simple suture technique.

The surgeon can now use FiberTape to reinforce the Brostrom procedure. It is important to place the suture tape extracapsular to avoid lateral ankle impingement postoperatively. The orientation of the suture tape is in line with the anterior talofibular ligament. Direct attention to the lateral aspect of the talus and use a #15 blade to incise the capsule (be aware to dissect along the non-articulating portion of the talus). This creates the entry for a drill guide and 3.4 mm drill bit. Under fluoroscopic guidance, drill a hole into the body of the talus down to the drill guide laser line with the orientation being posterior medial and approximately 45 degrees to the lateral aspect of the foot. Remove the drill and use the included 4.75 mm tap to create a bone tunnel. Proceed to place the 4.75 mm SwiveLock biocomposite anchor loaded with #2 FiberTape into the talus. Be sure to screw all the way down to the laser line on the handle to prevent any screw protrusion. Both limbs of the suture tape should now be well seated into the talus.

Then direct attention to the fibula and use a 2.7 mm drill bit to create a hole 1.5 cm proximal from the distal tip of the fibula. The orientation should follow that of the anterior talofibular ligament with a slight proximal-superior direction. Again, use the laser-lined drill guide to measure the exact depth of drilling. Then use a 3.5 mm tap to create a bone tunnel into the distal fibula and pass the two limbs of FiberTape through the eyelet on the 3.5 mm Swivelock anchor handle.  

As is the case with the use of tendon graft, tensioning is the key to augmenting the repair of the lateral ankle. While holding the foot in a dorsiflexed and everted position, place the 3.5 mm SwiveLock near the fibular bone tunnel. It is useful to place a Freer elevator between the FiberTape limbs and fibula to prevent over-tightening of the suture tape. Insert the interference screw down to the laser line on the handle until you have achieved the desired tension. Cut the residual portion of suture tape from the fibular end.  

Now assess the inversion of the ankle. It is important not to over-tighten the suture tape construct to avoid postoperative stiffness. (I believe it is not necessary to attempt direct repair of an attenuated or torn calcaneofibular ligament when using the InternalBrace system since normal ankle range of motion and kinematics have still occurred). One can achieve further reinforcement of the lateral ankle by suturing the lateral margin of the inferior extensor retinaculum to the fibular capsule with non-absorbable suture. Flush the area with copious amounts of normal saline. Close the peroneal tendon sheath along with the subcutaneous tissue using absorbable sutures and re-approximate the skin using non-absorbable subcuticular sutures. Deflate the tourniquet and administer a regional anesthetic block. Place the patient in a well-padded posterior splint and provide instructions on remaining non-weightbearing with crutches.

Facilitating An Improved Postoperative Protocol

I have found that this technique decreases the time a patient has to remain non-weightbearing postoperatively. The post-op protocol consists of seven days non-weightbearing in a slightly dorsiflexed and everted posterior splint, seven days non-weightbearing in a removable boot cast, and 14 days partial weightbearing in a removable boot cast. On average, athletic patients begin passive range of motion exercises earlier than they would with just a direct repair at 14 days post-op. Accordingly, this allows a quicker return to full activity and sports.

Normally, one would prescribe a formal physical therapy regimen at three weeks post-op and allow the patient to wear a lace-up ankle brace at five weeks post-op with supportive sneakers. Patients normally tolerate running and impact activities at eight to 10 weeks post-op if they have had a Brostrom procedure with suture tape augmentation.  

In Conclusion

The Arthrex InternalBrace system for use in lateral ankle stabilization procedures may serve as a reliable alternative to allograft reconstruction. Long-term clinical results are not yet available. However, there are many reasons why surgeons might find this system attractive including: ease of use, reproducibility, low physiologic reactivity, potential in cost savings and, of course, strength of repair. The InternalBrace can be particularly useful in the scenario of the athletic patient for whom returning to full activity (with the least amount of down time) may be the difference between success and failure.

Dr. Basra is in private practice with Complete Foot and Ankle in Ridgewood, NJ. He is a Fellow of the American College of Foot and Ankle Surgeons.   

References
1. DiGiovanni BF, Partal G, Baumhauer J. Acute ankle injury and chronic lateral instability in the athlete. Clin Sports Med. 2004; 23(1):1-19.
2. Berlet G, Anderson RB, Davis W. Chronic lateral ankle instability. Foot Ankle Clin. 1999; 20(4):713-728.
3. Baravarian B, Rotem BA. Exploring surgical options of chronic lateral ankle instability. Podiatry Today. 2014; 27(5):74-76
4. Chrisman OD, Snook GA. Reconstruction of lateral ligament tears of the ankle. An experimental study and clinical evaluation of seven patients treated by a new modification of the Elmslie procedure. J Bone Joint Surg Am. 1969; 51(5):904–12.
5. Zenni EJ Jr, Grefer M, Krieg JK, et al. Lateral ligamentous instability of the ankle: a method of surgical reconstruction by a modified Watson-Jones technique. Am J Sports Med. 1977; 5(2):78–83.
6. Hedeboe J, Johannsen A. Recurrent instability of the ankle joint. Surgical repair by the Watson-Jones method. Acta Orthop Scand. 1979; 50(3):337–40.
7. Horstman JK, Kantor GS, Samuelson KM. Investigation of lateral ankle ligament reconstruction. Foot Ankle. 1981; 1(6):338–42.
8. Viens N, Wijdicks C, Campbell KJ. Anterior talofibular ligament ruptures, part 1: biomechanical comparison of augmented Brostrom repair techniques with the intact anterior talofibular ligament. Am J Sports Med. 2014; 42(2):405-11.

Editor’s note: For related articles, see “What The Emerging Literature Reveals About Treating Lateral Ankle Injuries” in the September 2014 issue or “A Closer Look At The Use Of Interference Screws For Lateral Ankle Stabilization” in the August 2012 issue.