Surgical Management of Lateral Ankle Instability in Athletes

The assessment of the patient with CAI begins with a focused history and physical examination. The history should address the mechanism of the most recent injury, the ability to bear weight, the frequency of instability episodes and ankle sprains, and previous treatments. The physical examination includes an evaluation of gait and standing alignment during which the examiner looks for varus hindfoot alignment, which leads to lateral foot overload and can result in ankle instability, peroneal tendon injury, and fifth metatarsal stress fracture.¹⁶  Subtle hindfoot varus is often not recognized when viewing the foot from behind but instead can be recognized by the “peek-a-boo” heel sign, in which the medial border of the heel is seen from in front of the patient. Inspection and palpation of the hindfoot focuses on determining the degree of swelling, location of ecchymosis, point of maximal tenderness (ATFL, CFL, peroneal tendons, or syndesmosis), and whether the peroneal tendons click or are prominent. Range of motion of both the ankle and subtalar joints is assessed with the patient seated and the knee flexed to 90° to eliminate the pull of the gastrocnemius. A neurologic examination evaluates sensation in the distributions of the deep and superficial peroneal nerves and the sural, saphenous, and tibial nerves. The strength of the peroneus brevis is assessed by resisted eversion with the ankle in maximal plantar flexion to prevent the ankle extensors from assisting. The anterior drawer test (Figure 2A) addresses ATFL laxity: the examiner pulls the calcaneus anteriorly and internally, rotating it slightly with the ankle in 15° of plantar flexion. The test is positive when excessive anterior translation of the talus compared with the contralateral side occurs. The talar tilt test (Figure 2B) evaluates the integrity of both the ATFL and CFL: the examiner applies a varus moment to the calcaneus with the ankle in neutral position. As it can be difficult to differentiate physiological subtalar motion from varus tilting at the ankle joint, the test is often performed using fluoroscopy or radiography. A difference ≥15° in inversion of the hindfoot compared with the contralateral ankle is associated with complete rupture of both the ATFL and the CFL.¹⁷  The Coleman block test should be performed in patients exhibiting varus alignment to determine whether the hindfoot varus is forefoot driven (Figure 2C) and thus can be corrected by realigning the forefoot and accommodating the plantar-flexed first ray via an orthosis (such as the Arch Rival; DJO Global, Dallas, TX). The squeeze test (compression between the proximal tibia and fibula produces pain at the ankle) and the external-rotation stress test are used to evaluate syndesmosis injury (high ankle sprain).

The assessment of CAI also includes standing 3-view (anteroposterior, mortise, and lateral) radiographs of the ankle to evaluate alignment and identify the presence of arthritis, avulsion fracture, syndesmotic widening, or osteochondral lesion. Stress radiographs can be added to assess ligament function when the physical examination is equivocal. Magnetic resonance imaging or ultrasound should be obtained to assess the lateral ankle ligaments, peroneal tendons, peroneal retinacula, and syndesmotic ligaments. Magnetic resonance imaging is also used to determine the presence of an osteochondral lesion, whereas ultrasound is better for detecting transient subluxation or dislocation of the peroneal tendons.¹⁸ 

Lateral ankle pain that persists for more than 3 months after an acute inversion injury should lead to the search for not only CAI but also any of a number of other injuries that can occur concomitantly with LAS. Collectively, these disorders are often referred to as “the ankle sprain that will not heal”; they include peroneal tendinitis, peroneal tendon tear, peroneal subluxation, osteochondral lesion of the talus (OLT), high ankle sprain (syndesmotic injury), and ankle impingement.

Peroneal tendon injuries occur commonly with LASs, as the peroneus brevis is an active stabilizer of the lateral ankle and fires reflexively to prevent excessive inversion of the ankle. Longitudinal-split tears of the peroneus brevis (Figure 3A) can occur when the brevis tendon pulls forcefully against the distal fibula, causing lateral translation within the fibular groove. This same mechanism is thought to lead to peroneal subluxation (Figure 3B) or dislocation due to tearing or avulsion of the superior peroneal retinaculum, which restrains the peroneal tendons within the fibular groove. Peroneal tendinitis and tenosynovitis occur from ineffective or incomplete healing of the overloaded peroneal tendons.

Osteochondral lesions of the talus also commonly occur with lateral ankle ligament injuries. The incidence has been reported¹⁹  to be as high as 89%; fortunately, the majority of these lesions are asymptomatic. The mechanism of OLT involves impaction of the shoulder of the centromedial talar dome on the tibial plafond with ankle inversion, leading to subchondral fracture and chondral compromise.

High ankle sprains involve injury to the syndesmotic ligaments, which bind the tibia to the fibula and maintain the stability of the ankle mortise. High ankle sprains often occur from excessive external rotation of the talus, which acts as a wedge to drive the ankle mortise apart.²⁰  High ankle sprains are less common, take longer to heal, and have a higher morbidity than LASs. Untreated syndesmotic injury can lead to incongruity of the ankle joint and early arthritis.

The medial ankle ligaments are concomitantly injured in 2.8% of lateral ankle injuries.²¹  Medial-sided ecchymosis or tenderness should alert the examiner to the possibility of medial ankle-ligament injury. Medial ankle symptoms indicate a more severe injury, portend a poorer prognosis, and necessitate a longer healing time. Patients with medial-sided injuries are frequently immobilized in a cast for the first few weeks postinjury to prevent attenuation of the deltoid and spring ligaments during the healing process.

Ankle impingement can occur after ankle-ligament injury when synovial hypertrophy or fibrous bands form between the talus and tibia, resulting in pain or a feeling of giving way (or both) without ligamentous laxity. The diagnosis of impingement is made once other causes of the symptoms have been eliminated. The initial treatment for impingement should be directed at decreasing inflammation and relieving symptoms. Patients who do not respond to initial treatment may benefit from ankle arthroscopy with partial synovectomy.

These disorders should be suspected in any patient with an ankle sprain whose symptoms have persisted for 3 months or more. The workup for each disorder involves eliciting the characteristic physical examination findings and then confirming the diagnosis using magnetic resonance imaging or ultrasound. Treatment details for the associated disorders are beyond the scope of this review; however, a number of articles on these topics are available.^20,22,23  The remainder of this review will focus on CAI treatment.

The initial management of CAI consists of functional rehabilitation and the use of bracing or taping. Rehabilitative exercises include proprioceptive training and eversion (peroneus brevis) strengthening. Ankle bracing or taping improves mechanical and functional stability in athletes with CAI.²⁴  Both taping and bracing restrict range of motion, reduce reinjury rates, improve proprioception, have minimal negative effects on other joints, and do not affect athletic performance. Bracing with an ankle-stabilizing orthosis (a soft brace that provides compression and has straps crossing the ankle joint) limits varus angulation and provides proprioceptive feedback that helps to improve active stabilization by the peroneus brevis. Taping is less bulky than bracing and may cater to unusual anatomy; however, bracing has the advantage of being reusable and easily adjustable. Approximately 80% of patients improve with functional rehabilitation and bracing. Nonsteroidal anti-inflammatory drugs, either taken orally or applied topically, may be used to provided short-term (1–3 weeks) pain relief and a reduction in swelling, but they have no long-term effects on the symptoms of CAI. A detailed description of the nonoperative treatment of CAI is beyond the scope of this review.

Operative treatment of CAI is indicated in patients who have failed to improve on a 3- to 6-month trial of nonoperative management because of either persistent pain or mechanical instability. The operative treatments for lateral CAI include a variety of procedures ranging from simple repairs to complex reconstructions. Repairs consist of either reattaching or imbricating (shortening) the injured native tissues, whereas reconstructions involve replacing the ligaments with either autologous or allograft tissue. Furthermore, reconstructions may be either anatomic or nonanatomic. Anatomic reconstructions maintain the physiological orientation of the ATFL or CFL or both by attempting to preserve native ankle anatomy and normal joint kinematics. Nonanatomic reconstructions involve recreating the lateral ankle support using tissue that does not follow the physiological orientation of the ATFL and CFL.

Lateral ankle ligament surgery is generally performed as an outpatient procedure under general anesthesia and often supplemented with a popliteal nerve block. The patient is positioned in the lateral decubitus position. Laxity of the ATFL and CFL should be confirmed while the patient is under anesthesia by performing the anterior drawer and talar tilt tests under fluoroscopy. Equivocal results can be resolved by comparison with the contralateral side²⁵ ; thus, the examination should be done before the surgical site is prepared.

Anatomic repair of the lateral ligamentous complex remains the criterion standard for recurrent ankle instability, effectively restoring native ankle anatomy and joint kinematics while preserving motion. The Broström procedure and its modifications are the most common of the anatomic-repair procedures.

First described in 1966, the Broström repair⁵  has evolved over the last 50 years to include several modifications, including those by Gould and Karlsson, and has recently been combined with ankle arthroscopy to identify and treat the concomitant osteochondral lesions.²⁶ 

The Broström technique was designed to repair both the ATFL and CFL while retaining the anatomic relationship of the lateral ankle structures. The procedure can be performed using either a curved incision over the anterior border of the lateral malleolus (for isolated ligament repair) or an extensile longitudinal incision along the distal fibula (when concomitant tendon or retinacular repair is planned). The subcutaneous tissues are retracted anteriorly and the ATFL and CFL are identified as thickenings of the lateral aspect of the ankle-joint capsule (Figure 4A). The ATFL and CFL are then dissected free of the surrounding tissue, cut in the midsubstance, and repaired in a pants-over-vest fashion.^5,25  After the repair has been completed, ankle stability should be reexamined using the anterior drawer and talar tilt tests. Once stability is confirmed, the ankle should be taken through a full range of plantar-flexion and dorsiflexion exercises to confirm that the repair has not limited the ankle range of motion.²⁶ 

The Broström is a highly effective and durable procedure. A long-term follow-up study²⁷  identified 31 male patients who had undergone a Broström procedure for CAI as midshipmen enrolled in the US Naval Academy. The mean follow-up time in this study was 26.3 years. Using a self-report questionnaire, these patients were found to have high-functioning ankle joints with a mean numeric score for overall ankle function of 91.2 out of 100.²⁷  Ninety-one percent of these patients also reported good or excellent results using the Good Ankle Function Scale.²⁸  A total of 87% of the patients had full motion of the ankle joint restored postoperatively, and none cited ankle symptoms as affecting the length of their military career.²⁹ 

In a recent study³⁰  of patients with CAI, all had improved stability after the Broström procedure and reoperation rates were low. The mean follow-up time in this study was 3.6 years (range = 1–6.2 years). Among the 20 patients studied, only 3 had reoperations; 2 for probable subcutaneous nerve entrapment and 1 for posttraumatic osteoarthritis of the ankle joint.³⁰  Overall, the Broström procedure has shown excellent results in restoring ankle stability, with relatively low reoperation rates and good longevity.³¹ 

In 1980, Gould et al³²  described a modification to the Broström technique in which the repair of the lateral ankle ligaments was reinforced by pulling the extensor retinaculum proximally and suturing it to the distal fibula (Figure 4B). This has the effect of both reinforcing the ATFL repair and limiting inversion to stabilize the subtalar joint.³²  This modification has been shown to increase the strength of the repair by 50%.³³ 

The Karlsson procedure³⁴  is a variation of the Broström technique that was initially designed for late repair of LASs. The rationale behind this procedure was that the ATFL and CFL often heal after injury with increased length, which then causes laxity. This procedure eliminates the laxity by sectioning the ligaments 3 to 5 mm from their insertions on the fibula, excising the intervening scar tissue, and then reattaching the ligaments to the fibula using drill holes or, more recently, suture anchors³⁴  (Figure 4C). The advantage of the Karlsson over the Broström procedure is its ligament-to-bone healing, as opposed to the ligament-to-ligament healing that occurs with the Broström procedure. A 3-year follow-up study of 60 patients who underwent the Karlsson procedure showed that functional results, including functional stability, pain, activity levels, and swelling, were good to excellent among 88% of patients. Commonly, both the ATFL and CFL are repaired, as 95% of patients undergoing repair of both had good to excellent results compared to 75% of those who underwent isolated ATFL repair.³⁴ 

Anatomic repairs (Broström and related procedures) address lateral ankle-ligament instability by shortening, tightening, or reattaching the native ligaments. Although these techniques are effective in most patients, they are not effective in those with severely attenuated or absent ligaments. In these situations, the surgeon must choose between nonanatomic and anatomic reconstruction using either local tendon transfer or free allograft- or autograft-tendon reconstruction.

Nonanatomic reconstructions stabilize the lateral ankle without repair of the native ligaments. These techniques involve rerouting the peroneus brevis tendon through bone tunnels in the distal fibula. Examples of nonanatomic reconstructions include the Watson-Jones,³⁵  Evans,³⁶  and Chrisman-Snook³⁷  procedures (Figure 5). These procedures are included for historic interest as they alter hindfoot biomechanics, limit motion, and lead to the development of early arthritis. As a result, they have largely been supplanted by anatomic reconstructions.^35–37 

Researchers in several long-term outcome studies have looked at the efficacy of these nonanatomic repairs for return of ankle function and performance. A 5-year follow-up study³⁸  of a modified Evans procedure did not show promising results: only half of patients reported their ankles were fully recovered or much better than before surgery. Performance testing demonstrated even worse outcomes, with only 35% of the 48 ankles attaining a score of good to excellent. In addition, ankle range of motion was significantly impaired, and the incidence of ankle swelling and calf-muscle atrophy increased. Another study³⁹  with a 14-year follow-up period also showed similar poor results for the Evans procedure: only 50% of patients endorsed satisfactory function and stability of the ankle. The majority of those with poor results complained of pain, instability, swelling, and restricted activity. In a prospective study⁴⁰  comparing the modified Broström and Chrisman-Snook procedures among 40 patients with CAI, more than 80% had good to excellent stability. Patients who underwent the modified Broström procedure had better ankle-function scores with significantly fewer complications.

The long-term outcomes of nonanatomic reconstruction include alterations in ankle and hindfoot kinematics and the frequent loss of subtalar motion, leading to greater risks of progression to arthritis and further sequelae.^41–43  Comparison studies with longer follow-ups mostly indicated that anatomic repair was favored over nonanatomic tenodesis reconstruction. Long-term studies of nonanatomic tenodesis have shown that these procedures resulted in ankle laxity, limited range of motion, decreased function, increased pain, increased need for revision procedures, and higher degrees of osteoarthritis compared with anatomic reconstruction.⁴¹  Their role as revision procedures when anatomic repair has failed has been replaced with anatomic graft–based reconstructions.

For anatomic graft reconstructions, autogenous or allogenic tendon grafts are placed at the native ligament insertion sites to recreate both the anatomy and mechanics of the ATFL and CFL. These techniques are especially useful in patients with long-standing instability that has resulted in poor tissue quality, failed previous repair, generalized ligamentous laxity, and cavovarus foot deformity.⁴⁴ 

A variety of reconstruction procedures have been described using different graft types, fixation methods, and materials.^45–53  In these procedures, the graft is routed through tunnels in the distal fibula, the talus, and the calcaneus to recreate both the ATFL and CFL (Figure 6). The tendon grafts can be affixed either through sutures to themselves or by placing interference screws into the tunnels.

These procedures have demonstrated excellent results. One study⁴⁵  of 28 patients undergoing gracilis autograft reconstruction showed that all patients rated their level of satisfaction as good to excellent. Seventy-nine percent of patients remained pain free at final follow-up, with a mean follow-up duration of 23 months. The remaining patients experienced mild pain, with morning stiffness among 24% and mild swelling postexercise in 21%. In another investigation⁵³  of 38 patients who underwent reconstruction with semitendinosus allograft performed by a single surgeon over 8 years, all were satisfied with the procedure, mean Ankle-Hindfoot Scale scores increased by nearly 30 points, and overall pain scores decreased. A total of 71% of patients returned to preinjury or near preinjury activity levels; in addition, laxity improved among all patients. Other authors⁵⁴  followed 19 patients for 30 months after allograft tendon reconstruction and observed that all had returned to activity without instability, pain, or decreased range of motion. One potential risk of these surgeries is fracture through the fibular tunnels, which are large (4–6 mm) in comparison with the tip of the fibula.⁵⁵ 

Ankle arthroscopy has commonly been performed in conjunction with open lateral ankle ligament reconstruction on patients who have concomitant lesions such as OLT, anterior ankle impingement, or a loose intra-articular body. Symptomatic OLT is treated with chondral debridement, microfracture, or retrograde drilling.

The arthroscopic Broström procedure was developed to address a number of challenges that arose when performing open repair after arthroscopy, such as soft tissue swelling from extravasated fluid that obscured tissue planes and the additional surgery time for patient repositioning between ankle arthroscopy and open lateral ankle-ligament repair. A number of techniques have been described for arthroscopic lateral ankle-ligament repair.^56–58  These procedures are similar to the modified Broström procedure, except that the surgeon places the anchors while viewing the distal fibula through an arthroscope rather than through an open exposure of the distal fibula. The technical details of the arthroscopic Broström are beyond the scope of this review. Arthroscopic repair has been shown to restore equivalent function as open repair but with the advantages of smaller scars, less pain, less swelling, less disturbance of cutaneous sensation,⁵⁶  and possibly faster recovery.⁵⁷  Despite these reported advantages, arthroscopic repair has not yet gained widespread acceptance, perhaps because of the simplicity, reliability, and rapidity of the standard open-repair techniques.

Postoperative protocols vary among surgeons and depend on the specific repair or reconstruction performed (Table). Generally, the postoperative protocol consists of an initial 2- to 6-week period of cast, splint, or boot immobilization to prevent stressing of the repaired or reconstructed tissue by inversion. Rehabilitative exercises are started after this initial period of immobilization. Initial therapy focuses on restoring ankle range of motion. Proprioceptive training and strength training begin once complete range of motion has been restored.

The timing of and specific criteria for return to activity and return to play have not been well defined but depend on the specific injury and the surgery performed. Patients may return to running on level ground once they demonstrate that 90% of their ankle strength has been restored, usually around 3 months after surgery. Cutting and jumping may then resume 4 to 6 months after surgery if balance and proprioception have been adequately restored.²⁵ 

Return to play can be considered when an athlete no longer experiences pain or swelling; demonstrates normal ankle stability, strength, and neuromuscular control; and is able to perform a set of relevant functional tests. Ankle stability is assessed with the anterior drawer and talar tilt tests and by questioning the patient about episodes of giving way, swelling, or pain. The evaluation of neuromuscular control includes proprioception, balance, and postural control. Strength deficits in all muscle groups are assessed, but particular attention is paid to inversion and eversion.⁵⁸  A large number of functional tests have been used to evaluate athletes with lateral ankle injuries, including lateral- and forward-hop tests, timed single-legged–stance tests, and heel-rocker tests to assess dorsiflexion of the ankle.²⁴  However, because no consensus exists as to the specific functional tests an athlete would need to pass before returning to sport, many authors have suggested reasonable alternatives that accommodate individual athletes rather than a generalized population of athletes. For example, in 1 protocol, an athlete may be cleared to return to play simply by performing a full-speed figure of 8.⁵⁶  Other protocols deem an athlete ready to return to sport if he or she can perform both cutting exercises and drills pertaining to the desired sport—for example, karaoke drills in soccer, double jumps in basketball, or burpees in football.⁶⁰  Furthermore, some researchers⁴⁰  who used casts for 6 weeks as their postoperative immobilization protocol suggested that an athlete may return to play 3 months after cast removal without mention of passing any functional tests. Ankle bracing or taping should be considered for all athletes returning to play, as these interventions were associated with a 70% decrease in recurrent ankle sprains.⁶¹  Ankle bracing or taping should be continued for at least 6 months after injury or surgery to allow time for ligamentous healing.

Our preferred postoperative protocol for lateral ligament reconstruction and repair involves cast placement in the operating room and the patient weight bearing as tolerated. At 3 weeks, the patient is seen for cast and suture removal. He or she is then placed in a removable boot for 3 weeks and asked to remove the boot 3 times a day for ankle range-of-motion exercises. At 6 weeks postsurgery, physical therapy and subtalar-joint range of motion may begin with proprioceptive training and eversion strengthening. Inversion stretching is not permitted until 3 months postsurgery. An ankle-stirrup splint is worn from 6 weeks to 3 months to prevent accidental inversion, which could injure the healing ligaments. At 3 months, the athlete is allowed to return to play in a functional brace.

Lateral ankle instability is initially treated nonoperatively. Athletes who have failed to improve after 3 to 6 months of bracing and functional rehabilitation may benefit from surgery to restore ankle stability, reduce pain, and improve function. The preferred operative treatment is primary repair using a modified Broström technique because of its simplicity and strong reproducible outcomes. Anatomic reconstruction using tendon graft is performed when patients lack adequate tissue for repair. Nonanatomic reconstructions are performed infrequently, as they alter ankle mechanics and thus can lead to early arthritis. Postoperative protocols vary but generally involve a short period of immobilization followed by bracing and functional rehabilitation. Return to play should be considered when an athlete no longer experiences pain or swelling; demonstrates normal ankle stability, strength, and neuromuscular control; and is able to perform a set of relevant functional tests.