DEFINITION

Lateral ligament instability occurs in some patients after an inversion injury.38 Although an inversion injury is common, only a few patients have ongoing ankle instability severe enough to require surgery.

Persistent instability may occur in 15% to 48% of patients.7,10,15,45

Lateral ligament disruption may occur in combination with osteochondral defects, hindfoot varus, peroneal tendon tears, anterior lateral joint impingement, or a tight heel cord.29,43,48 Any of these concomitant pathologies needs to be sought during the clinical examination and treated if it represents a

significant component of the ongoing symptoms.

Medial ankle instability may occur in combination with lateral ankle instability.23 In these cases, the medial ligament instability may need to be addressed at the same time.

 

 

ANATOMY

 

The lateral collateral ligaments include the calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL).11 These are condensations within the lateral capsule.

 

The CFL runs from the anterior tip of the fibula to the lateral wall of the calcaneus. The ligament passes superficial to the lateral margin of the posterior facet of the subtalar joint and courses deep to the peroneal tendons to insert via a broad base onto the lateral side of the calcaneus.

 

The ATFL arises from the anterior portion of the distal fibula and inserts onto the lateral side of the talar neck (FIG 1).

 

 

 

FIG 1 • Anatomy of the CFL and ATFL.

 

PATHOGENESIS

 

Lateral ankle instability occurs after an inversion injury to the lateral ligament complex. The injury typically occurs in plantarflexion. Traditionally, the ATFL ruptures first and the CFL second.

 

A cavus foot may predispose the ankle to recurrent instability.

 

 

Osteochondral defects of the talus and peroneal tendon tears are known associated pathologies.5,23

 

NATURAL HISTORY

 

Most ankle sprains resolve without the need for surgery. However, a recurrently unstable ankle treated with appropriate physical therapy protocols may benefit from lateral ankle ligament repair or reconstructions.

 

Left untreated, persistent lateral ankle instability may result in fixed varus tilt to the talus within the ankle mortise and eventual ankle arthritis. Most patients present because of the disability associated with the recurrent sprains.

 

 

Physiotherapy and bracing will improve symptoms in some patients with recurrent instability. There does not appear to be a role for immediate surgery on ruptures of the lateral ligaments.26

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Patients should remove their socks and shoes before the history is taken so they can directly point to where the symptoms occur. Patients should be asked about pain and its relationship to activity and instability.

Pointing to the foot or ankle with one finger will help focus the patient on the area of maximum discomfort and focuses the examination.

 

Ankle instability may be difficult for the patient to convey; it may be more subtle than recurrent inversion injuries. Patients should be asked if the ankle gives way; if possible, the position of the foot during the instability episode and circumstances (running, cutting left, cutting right, etc.) should be determined.

 

The impact of the instability on sports and work should be determined.

 

On physical examination, the patient should be examined standing and walking. He or she should be asked to heel walk and toe walk. The examiner should look for a cavus alignment to the foot. A “peek-a-boo” heel sign may assist in the diagnosis.

 

Using the Coleman block: If heel varus corrects, the hindfoot is considered flexible; if heel varus does not correct, the cavus deformity is secondary to a forefoot varus and correction of forefoot will correct the hindfoot through the mobile midfoot. A severe cavus deformity that is rigid may require a calcaneus osteotomy in addition to forefoot correction.

 

 

22

 

The area of maximum discomfort and instability should be elicited. We take the ankle and hindfoot through a range of motion independent of one another to determine the joint of maximum discomfort.

 

Peroneal tendon pathology may accompany lateral ankle instability. A resisted contraction of ankle eversion should be performed and the tendons palpated for pain and fullness (suggestive of tenosynovitis). The peroneal tendons, which are flexors, are best isolated with the ankle in plantarflexion and testing eversion against resistance. Peroneal tendon weakness accompanies most peroneal pathology due to pain; marked weakness may signify a peroneal tendon tear. In our experience, the combination of chronic ankle instability, varus hindfoot, and marked peroneal tendon weakness should raise the suspicion for a peroneal tendon tear. Occasionally, an equinus contracture may be associated with lateral ankle instability. A Silfverskiöld test (ankle dorsiflexion with the knee flexed contrasted with ankle dorsiflexion with the knee extended) allows the examiner to determine whether the contracture is isolated to the gastrocnemius or involves both the gastrocnemius and soleus components of the Achilles complex.

 

The ATFL resists anterior translation and medial rotation of the talus on the tibia. A direct anterior draw (pulling the talus anteriorly without plantarflexion and internal rotation) may fail to elicit instability in an unstable ankle as an intact deltoid ligament medially will prevent translation. Instead, the examiner should hold the tibia posteriorly with the left hand while translating the calcaneus anteriorly and internally rotating the foot at the same time. Side-to-side comparison to the contralateral, physiologically stable ankle assists in identifying ankle instability.

 

An inversion stress test determines the integrity of the CFL.

 

An injury to the syndesmosis (ie, “high ankle sprain”) may be elicited with a squeeze test and by rotating and translating the talus in the ankle mortise in dorsiflexion. A syndesmotic injury must be distinguished from lateral ankle instability because treatment is different.

 

We also routinely examine the medial ankle for deltoid instability because medial and lateral instability may coexist.

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

We routinely obtain weight-bearing anteroposterior (AP) and lateral ankle radiographs; if more information is required, we add a mortise view. Osteochondral defects, anterior osteophytes, and tibiotalar arthritis associated with recurrent instability are generally visualized on standard radiographs of the ankle (FIG 2A).

 

On occasion, we add a calcaneal axial view, Saltzman view, or tibial views if we need additional information on limb alignment. Recurrent ankle instability may be secondary to tarsal coalition; if the hindfoot is stiff on clinical examination, then calcaneal axial view and standard foot radiographs may identify the coalition. Computed tomography (CT) provides greater detail of osteochondral defects, osteophytes, arthritis, and tarsal coalition and should be obtained if these associated findings are suggested on plain radiographs.

 

A magnetic resonance imaging (MRI), particularly an MRI arthrogram, may provide detail of the deficient ligaments. Associated chondral and osteochondral defects as well as soft tissue impingement lesions may also be visualized by an MRI examination (FIG 2B).

 

Selective, diagnostic local anesthetic blocks of the ankle, subtalar, or talonavicular joints may be required to determine localized joint pain.

 

When the diagnosis of ankle instability is suspected but remains in question, an inversion stress test done under fluoroscopy, compared to the physiologically stable contralateral ankle, may be useful. Bone scans can assist in determining associated pathology.

 

DIFFERENTIAL DIAGNOSIS

Loose body in ankle Osteochondral defect Syndesmotic instability

Peroneal tendinopathy or rupture Medial ankle instability

Cavus foot Tarsal coalition

 

 

NONOPERATIVE MANAGEMENT

 

Nonoperative treatment includes bracing and physiotherapy. Patients with recurrent ankle instability may develop peroneal tendon weakness and loss of proprioception.33,37 Physiotherapy via proprioceptive training and strengthening can resolve the ankle instability. Bracing may help a patient to recover from a sprain and

prevent future

 

23

sprains by strengthening the dynamic, stabilizing peroneal tendons.

 

 

 

FIG 2 • A. Radiologic finding of osteochondral lesion of talar dome. B. MRI finding of osteochondral lesion of posteromedial talar dome.

 

 

Nonoperative treatment is less effective if ankle instability is associated with fixed hindfoot varus. Flexible hindfoot varus may be compensated for with a lateral wedge orthotic. If hindfoot varus is driven by a plantarflexed first ray (as determined by the Coleman block test), the orthotic should be “welled out” under the first metatarsal head, permitting further progression of the hindfoot into physiologic valgus.

 

SURGICAL MANAGEMENT

 

The indication for surgical management of lateral ligament instability is chronic symptoms despite appropriate nonoperative management, including physiotherapy and bracing.

 

Surgical management of lateral ankle ligament instability includes repair (anatomic tightening of the lateral ankle ligaments) and reconstruction (reconstitution of the lateral ankle ligaments using more than the local physiologic tissue in the lateral ankle ligamentous complex).

 

Lateral ankle ligament reconstruction may be anatomic or nonanatomic.11 Anatomic reconstruction implies that the ligaments are rebuilt in the physiologically occurring orientation. Nonanatomic reconstruction suggests that lateral ankle support is reconstituted with tissue (typically tendon transfer to substitute for ligament deficiency) that does not follow a physiologic orientation of the ATFL and CFL.

 

In our opinion, the literature on this topic favors anatomic over nonanatomic reconstruction; examples of nonanatomic reconstruction include the Evans2,4,13,17,18,19,20,21,27,28,30,31,32,34,35,36,39,40,42 and Watson-Jones procedures.3,5,13,16,30,31,32

 

We recommend repairing the lateral ankle ligaments when possible. If the ligaments are not repairable or require an augmentation, however, we perform an anatomic reconstruction.

 

 

Graft options for reconstruction include autograft (peroneus brevis, plantaris, gracilis) or allograft tendon.

 

Preoperative Planning

 

Plain radiographs, and if further detail is needed other imaging studies of the ankle, must be evaluated for associated conditions, such as malalignment, osteochondral defects, tendon pathology, and arthritis. Adjuvant procedures must be planned so that they may be safely performed in concert with ligament reconstruction.

 

We recommend performing stress testing with the patient under anesthesia. In our opinion, the gold standard tests to determine lateral collateral ligament integrity are open anterior drawer and inversion stress tests on the table.

 

Positioning

 

Apply a wide thigh tourniquet. Prepare and drape the leg to just above the knee. Perform anterior drawer and inversion stress tests on the table to confirm the diagnosis.

 

 

 

FIG 3 • Patient positioned using beanbag to allow good exposure to the lateral aspect of the ankle.

 

 

We routinely use a beanbag or large bump under the ipsilateral hip to rotate the operated extremity and allow full access to the lateral ankle (FIG 3).

 

A full lateral position is avoided, as it limits access to the proximal medial tibia, making harvest of the gracilis tendon autograft more challenging.

 

Use regional anesthetic blocks if possible to ensure appropriate postoperative pain relief.

 

Approach

 

We recommend an extensile approach (ie, a longitudinal curvilinear approach) in lieu of the traditional J-shaped incision popularized by Brostrom. The extensile approach affords access to not only the lateral ankle ligaments but also the distal tibia, peroneal tendons, sinus tarsi, and lateral calcaneus for adjuvant procedures that may be warranted.

 

We prefer a gracilis autograft tendon, anchored via drill holes, for the anatomic lateral ankle reconstruction

and aim to obtain immediate stable fixation, biologic ingrowth to bone in time, and an anatomic reconstruction. The technique is a modification of the plantaris reconstruction described by Anderson1 (FIG 4A).

 

If intra-articular pathology has been preoperatively identified or is suspected, we routinely address this with ankle arthroscopy before lateral ankle reconstruction (FIG 4B).

 

 

24

 

 

 

 

FIG 4 • A. Free gracilis lateral ligament reconstruction. B. Osteochondral defect of the talus found on arthroscopy before ligament reconstruction.

 

TECHNIQUES

• Gracilis Reconstruction through Drill Holes

Exposure

Start the extensile longitudinal lateral incision on the distal fibula, continue it over the lateral malleolus, and curve it anteriorly toward the sinus tarsi (TECH FIG 1A).

Expose the superior extensor retinaculum anterior to the fibula while protecting the deep branch of the peroneal nerve, which has variable anatomy. Strip the extensor retinaculum off the fibula so that the extensor compartment is exposed. Carry the dissection distally toward the ankle joint to the junction between the tibia, talus, and fibula. Open the joint at this level. This dissection will ensure that no ligaments are damaged during the exposure (TECH FIG 1B).

 

 

 

 

TECH FIG 1 • A. Lateral incision (solid line) with course of sural and superficial peroneal nerves marked (dotted lines). B. Lateral dissection anterior to the fibula, sparing the ATFL.

 

 

Remove anterior osteophytes using an osteotome.

Stress Testing

 

Perform an open anterior drawer and inversion stress tests (TECH FIG 2) to assess the integrity of the lateral collateral ligaments as a final check before proceeding with reconstruction. We will perform a repair if the ligaments are clearly torn off bone, if they are not obviously scarred or thickened, if there is

enough length to bridge the gap, or if they have been avulsed with a bone fragment.9

 

If the ligaments are not considered repairable, reconstruction is warranted. We favor an autograft gracilis reconstruction, and therefore optimal patient positioning and preparation and draping of the operated extremity are important.

Tendon Harvest and Drill Hole Creation

 

Perform a standard gracilis tendon harvest with an incision over the medial aspect of the tibial tubercle at

the pes anserinus

 

25

insertion. Carry dissection down through the sartorius fascia and onto the gracilis tendon. Isolate the gracilis with the knee flexed, and use a tendon stripper to release it from its muscle proximally. Reef the tendon using a baseball whipstitch.

 

 

 

TECH FIG 2 • Open anterior drawer test. Talus is anterior and internally rotated relative to fibula, indicating a positive test and insufficiency of the ATFL.

 

 

Divide the tendon at its insertion into bone and measure it. Select a drill bit matching the size of the tendon (typically a 3.5-, 4.5-, or 6-mm drill bit).

 

Alternatively, a tendon-anchoring interference screw system may be used, size matched to the harvested tendon's diameter.

 

Expose the fibula first by removing part of the peroneal fascia so that the peroneal tendons and the posterior fibula are exposed (TECH FIG 3A). We typically examine the peroneal tendons at this time to rule out or treat associated peroneal tendon pathology.

 

If needed, the peroneal retinaculum is incised with a step cut to allow complete exposure of the peroneal tendons for débridement or repair.29

 

Incise the collateral ligaments and expose the insertions of the CFL and ATFL. Dissect to the origin of both ligaments on the calcaneus and talus. Both areas are dissected clear onto bone (TECH FIG 3B). Use a curette to clear the area of the junction of the body and neck of the talus.

 

 

 

TECH FIG 3 • A. Dissection of the talus with exposure of the insertion of the ATFL. B. Dissection posterior to the fibula to expose the peroneal tendons. C. Location of medial incision. D. Postoperative CT demonstrating drill path through calcaneus. (continued)

 

 

Make a medial incision at the anterior border of the Achilles tendon and carry the dissection down to the bone and tendon at this level (TECH FIG 3C).

 

Drill through the calcaneus from medial to lateral, adjacent to the Achilles tendon, with the appropriately sized drill bit (depending on harvest tendon diameter), exiting laterally at the origin of the CFL (TECH FIG 3D). A cannulated drill or a combined aiming device can be used to target this drill to the calcaneofibular footprint on the calcaneus.

 

Make a fibular drill hole starting at the insertion of the CFL and exiting the posterior fibula. Make another fibular drill hole starting at the insertion of the talofibular ligament and exiting in the posterior fibula about 1 cm above the exit point of the previous fibular drill hole (TECH FIG 3E).

 

Then, make a 2.5-mm drill hole in the center of the junction between the talar body and neck (TECH FIG 3F). Measure its depth. A fully threaded cancellous small fragment screw with a small and large fragment washer is readied on the back table.

Passing and Securing the Graft

 

With a no. 2 braided nonabsorbable polyester suture, suture the tendon onto the edge of the Achilles

medially, using a Kessler

 

26

stitch on the nonbraided end of the gracilis tendon. Leave 1 cm of loop between the Achilles and the end of the gracilis to prevent buildup of suture and ligament medially, which may cause irritation. Place the knot in the middle of this segment.

 

 

 

TECH FIG 3 • (continued) E. Drill paths through calcaneus and fibula. F. Postoperative CT scan demonstrating orientation of screw in talus.

 

 

 

Use a tendon passer to pass the tendon graft through the calcaneal tunnel to the lateral calcaneus. Cycle the tendon a few times to make it tight.

 

Pass the tendon through to the posterior aspect of the fibula and pull it tight with the ankle in eversion. Suture the tendon to any remaining tissue on the fibula (TECH FIG 4A).

 

Bring the tendon back through the fibula so that it exits anteriorly at the second drill hole.

 

Cycle the tendon in tension and suture it to the cuff of tissue on the fibula at the insertion of the talofibular ligament.

 

Start the selected small fragment screw with the large and small washer into the 2.5-mm hole in the talar neck.

 

 

 

TECH FIG 4 • A. Gracilis graft passed from calcaneus to fibula. B. Gracilis graft tensioned from fibula to talus.

 

 

Place the split tendon end over the washer (right side) and under the washer (left side) and secure it around the washer in a clockwise direction. Hold the foot in dorsiflexion and eversion.

 

Hold the tendon tight around the washer and screw and tighten the screw home. The tendon will tighten as the screw is placed home (TECH FIG 4B). Although interference screw systems are effective, our method using standard screws and a simple ligament washer is cost-effective and consistently affords immediate ankle stability.

 

Suture the free end of the tendon back onto the tendon segment between the fibula and washer.

 

Suture the remainder of the tendon back onto the lateral side of the fibula and trim the residual tendon end.

 

 

To confirm stability and proper ligament tension of the reconstruction, place the ankle through repeat open anterior drawer and inversion stress tests. Close the wounds using nylon or staples. Use of a drain is at the surgeon's discretion.

 

• Coughlin Drill Holes in Bone

  27

   

   

  An alternative technique is to use drill holes through the bone made on the lateral side only.14 This is a variation of the Emslie technique (TECH FIG 5).

   

  Use a similar exposure, with no medial incision.

   

   

  Make two drill holes on the lateral wall of the calcaneus on each side of the origin of the CFL. Pass the tendon through the drill boles and suture it back onto itself.

   

   

  Make a single drill hole on the tip of the fibula, joining the insertion of both lateral collateral ligaments. Make two drill holes on each side of the insertion of the talofibular ligament.

   

  Pass the tendon through the fibula and through the drill holes on the talus and tension it and suture it

  back onto itself.

   

  We consider this variation more challenging than our described technique, specifically in passing the tendon through bone without fracturing the bone bridges. Moreover, we find it more difficult to ensure anatomic location of the ligaments and optimal tendon tensioning. In our opinion, prolonged postoperative immobilization may be required, depending on the strength of the bone bridges.

   

   

   

  TECH FIG 5 • Coughlin drill holes in bone technique.

• Biotenodesis Screw Technique

   

  With this technique, a similar exposure and tendon harvest are used (TECH FIG 6). No medial exposure is required.

   

  Make a drill hole on the lateral side of the calcaneus at the CFL origin. Place the tendon over the tip of a tenodesis screw and secure it to the lateral wall of the calcaneus.

   

  Pass the tendon through two fibular tunnels at the anatomic locations of the CFL and talofibular ligament, exiting over a posterior fibular bone bridge as described in our technique.

   

  Make a second drill hole on the lateral side of the talus at the junction of the body and neck to accommodate the tendon and a second biotenodesis screw.

   

  Our concerns with this alternative are as follows:

   

   

  Quality of fixation via interference screw in the relatively weak cancellous bone of the calcaneus The relatively large talar drill hole, which may serve as a stress riser and cause of talar neck fracture

   

   

   

  TECH FIG 6 • Biotenodesis screw fixation technique.

• Myerson Minimal Incision Technique

 

This technique (TECH FIG 7) is similar to the Coughlin technique but is performed through two small incisions.

 

Make one incision over the calcaneal drill holes and a second over the region of the talar drill holes. Carry dissection down to bone. Make two connecting drill holes in each location. Tunnel a drill bit and guide subcutaneously to drill the pathway through the fibula.

 

Harvest the graft and route it in the same fashion as in the Coughlin technique described earlier.

 

Although this is a reasonable alternative, as for the Coughlin technique, we have difficulty passing and tensioning the tendon using this technique.

 

28

 

 

 

TECH FIG 7 • Myerson minimally invasive technique. Red lines indicate skin incisions.

 

PEARLS AND PITFALLS

Exposure

• Ensure that the exposure goes through the anterior compartment and down into

the ankle. This will avoid damage to the ligaments before the open anterior drawer test.

Positioning

• Use a beanbag to ensure that the ankle is internally rotated to allow access to the

lateral side of the ankle. Different patients have different amounts of internal rotation, and this needs to be accommodated. However, avoid a full lateral position if you plan a gracilis tendon harvest.

Drill holes

• Drill the calcaneal hole from medial to lateral. The vector guide can be used to

 

 

	ensure correct positioning of the exit hole and the CFL footprint on the lateral calcaneus.     Drill hole ▪ The drill hole should closely match the size of the graft to ensure osseous size integration. The drills and taps from the anterior cruciate ligament set can be used. The drill hole should be large enough to pass the tendon.     Graft ▪ The graft should be prepared with a whipstitch to ensure that it passes easily preparation through the bone tunnels.     Graft ▪ Avoid anterior translation of the talus within the ankle mortise when the tendon tensioning reconstruction is tensioned. In particular, place a bump under the distal tibia and avoid placing a bump under the heel, which tends to translate the foot and talus anteriorly. Also, after each pass of the tendon through a tunnel, cycle the ankle with the tendon under tension to gain optimal final tension.

 

 

POSTOPERATIVE CARE

 

 

With our preferred technique, patients are placed in a walker boot at the time of surgery. At 1 week, they are allowed to bear weight as tolerated.

 

The sutures are removed at 2 weeks. Ankle range of motion, supervised by physiotherapy, is initiated at this time.

 

Patients are kept in the walker boot until 10 weeks after surgery during weight bearing. Gait training is started 8 weeks after surgery.

 

 

Proprioception and single toe raises are started 12 weeks out. Patients may return to sports after 4 months.

 

 

OUTCOMES

There are few retrospective reviews of anatomic reconstructions using various autografts. Despite the paucity of literature, all studies have reported good results, with 88% to 100% of patients reporting good outcomes.1,12,15,46

Few studies have specifically looked at the outcome of a gracilis ligament reconstruction. A review of 29

ankles in 28 patients by Coughlin et al15 reported a successful outcome in terms of American Orthopaedic Foot and Ankle Society (AOFAS) and Karlsson scores in all patients. Postoperative followup averaged 23 months.

Sammarco and DiRaimondo44 used a portion of peroneus brevis through drill holes; 91% good and excellent results were seen in 43 ankles.

One study looked at the outcome of a semitendinosus graft reconstructing the ATFL; 81% of 23 patients reported an improved outcome.41

There are sufficient studies with poor outcomes in the literature to recommend against nonanatomic reconstruction of the lateral ankle ligaments. Eleven papers in a recent review of lateral ligament

reconstructions argued against nonanatomic reconstruction, including the Evans and Watson-Jones

procedures.6,8,22,24,25,28,35,36,39,40,47

 

 

 

29

 

COMPLICATIONS

Wound healing Recurrent instability Nerve injury

Loss of range of motion

 

 

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30. Karlsson J, Lansinger O. Chronic lateral instability of the ankle in athletes. Sports Med 1993;16:355-365.

     

     

31. Karlsson J, Lansinger O. Lateral instability of the ankle joint. Clin Orthop Relat Res 1992;(276):253-261.

     

     

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34. Kennedy MP, Coughlin MJ. Peroneus longus rupture following a modified Evans lateral ankle ligament reconstruction. Orthopedics 2003;26:1059-1060.

     

     

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36. Labs K, Perka C, Lang T. Clinical and gait-analytical results of the modified Evans tenodesis in chronic fibulotalar ligament instability. Knee Surg Sports Traumatol Arthrosc 2001;9:116-122.

     

     

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