Paul J. Hecht, Justin S. Cummins, Mark E. Easley, and Dean C. Taylor
DEFINITION
Lateral ankle injuries are among the most common musculoskeletal injuries in the athletic population.
Rates as high as 7 per 1000 person-years have been reported in the general population.
From 10% to 20% of sprains progress to some kind of chronic symptoms.
Determining whether the patient’s instability is functional (ie, subjective giving way) or mechanical (ie, motion beyond the normal physiologic limits) is important for formulating treatment recommendations.
ANATOMY
The lateral ankle ligament complex consists of the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL).
The ATFL originates from the anterior aspect of the distal fibula and inserts on the lateral aspect of the talar neck. It is often ill defined and, in the chronically sprained ankle, may be manifest as a capsular expansion.
The ATFL limits anterior translation of the talus with the ankle in neutral and becomes the primary restraint to inversion when the ankle is plantarflexed.
The CFL originates from the distal tip of the fibula and inserts on the lateral wall of the calcaneus (FIG 1A,B).
The CFL measures 4 to 6 mm in diameter and 13 mm in length, and is directed posteriorly 10 to 45 degrees from the tip of the fibula.
The CFL functions to resist inversion with the ankle in neutral.
The anterior margin of the talus is wider than the posterior margin, which makes the ankle more susceptible to inversion injuries while in plantarflexion.
The peroneal tendons provide dynamic stability to the ankle joint.
PATHOGENESIS
An inversion force with the ankle in plantarflexion is the most common mechanism of injury.
The ATFL typically is the first ligament injured, followed by the CFL.
Ligament ruptures are most commonly midsubstance tears or avulsions off of the talus.
NATURAL HISTORY
Despite a relatively high incidence of lateral ankle injuries, most patients do well with nonoperative management.
Patients are at increased risk for recurrent lateral ankle sprains after sustaining the initial injury and failing to rehabilitate completely.
Chronic lateral instability may lead to progressive loss of function and osteoarthritic changes of the ankle.
PATIENT HISTORY AND PHYSICAL FINDINGS
Patients with chronic ankle instability frequently present with pain as well as complaints of multiple sprains caused by minor provocation.
Duration of symptoms, the type of incidents that cause sprains, the need for functional bracing, and previous treatments are important for determining treatment recommendations.
If pain is present between episodes of instability, other lesions about the ankle should also be considered.
An anterior drawer test with a bony endpoint that is distinctly different from that of the contralateral ankle is considered markedly positive.
Physical examination techniques include the following:
Palpation. Palpate the ATFL, CFL, syndesmosis, medial and lateral malleoli, peroneal tendons, base of the fifth metatarsal, and anterior process of the calcaneus.
FIG 1 • The CFL is directly deep to the peroneal tendons as demonstrated by this surgery to repair peroneal tendon dislocation. A. Peroneal tendons in their anatomic location. B. CFL identified when peroneal tendons are retracted.
FIG 2 • Anterior drawer test. A. Ankle reduced. B. Anterior subluxation.
Grading ATFL injuries. I, stretching; II, partial tearing; III, complete rupture. This is most useful in the acute setting to determine which structures are injured.
Anterior drawer test (FIG 2A,B) . The ankle is held in plantarflexion, and the talus is translated forward relative to the tibia. With intact medial structures, the displacement is rotatory. Translation of 5 mm more than the contralateral ankle or absolute translation of 9 to 10 mm is a positive test and suggests an incompetent ATFL. Grading ATFL injuries: I, stretching; II, partial tearing; III, complete rupture; most useful in the acute setting to determine which structures are injured.
Talar tilt. The heel is inverted with the ankle in neutral. Range of motion is compared to the contralateral ankle. Increased inversion is suggestive of a CFL injury.
Alignment. Assess the standing alignment of the hindfoot. Varus hindfoot alignment predisposes the ankle to inversion injury.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Standard radiographs should include standing anteroposterior (AP), lateral, and mortise views to evaluate for anterior tibial marginal osteophytes, talar exostoses, osteochondral lesions of the talus, or intra-articular loose bodies.
Talar tilt can be assessed with inversion stress mortise views of the ankle (FIG 3A).
Comparison views of the contralateral ankle should also be obtained.
A talar tilt angle greater than 10 degrees, or 5 degrees greater than the contralateral ankle, is considered pathologic laxity.
Anterior translation stress radiographs can be obtained by performing the anterior drawer test and shooting a lateral radiograph (FIG 3B).
Comparison stress views of the contralateral ankle should also be obtained.
Anterior translation 5 mm greater than the contralateral ankle, or an absolute value of greater than 9 mm is suggestive of instability.
Stress radiographs may be helpful, but physical examination remains the gold standard for evaluation of instability.
MRI can be useful to evaluate the ligamentous injury, as well as peroneal tendon pathology and suspected osteochondral injuries.
DIFFERENTIAL DIAGNOSIS
Lateral process talar fracture
Anterior process calcaneus fracture
Base of the fifth metatarsal fracture
Tarsal coalition
Osteochondral lesion of the talus or tibia
Subtalar instability
Syndesmosis injury
Neurapraxia of the superficial peroneal or sural nerve
Peroneal tendon tear
Peroneal instability
Sinus tarsi syndrome
Anterolateral ankle soft tissue impingement
NONOPERATIVE MANAGEMENT
Physical therapy should be the initial treatment for patients with chronic instability.
Proprioceptive training and peroneal tendon strengthening are the most important features.
FIG 3 • Radiographic stress tests. A. Positive talar tilt test. B.
Positive anterior drawer test.
FIG 4 • With the patient in the lateral decubitus position, the nonoperated extremity should be well padded. A. Nonoperated leg in a gel pad. B. With the nonoperated leg protected, a platform may be used to facilitate positioning of the operated leg. C. Alternatively: positioning in the lateral decubitus position, using a stack of folded sheets to serve as a rest for the operated leg.
The duration of therapy varies based on strength deficiencies and the intensity of the program.
External stabilization of the ankle with taping or bracing can be effective.
Taping provides tibiotalar stability, but quickly deteriorates with activity.
Reusable braces provide similar stability, but do not lose effectiveness with activity.
Orthotic devices and shoe wear modification can also be used when foot or ankle malalignment contributes to the instability.
SURGICAL MANAGEMENT
If the patient fails 3 to 6 months of conservative treatment and has persistent signs and symptoms of functional and mechanical instability, he or she becomes a candidate for surgery.
Preoperative Planning
The history must be considered. A relative contraindication for this anatomic repair is generalized ligamentous laxity as might be encountered in Ehlers-Danlos syndrome.
Carefully review the physical examination. If a varus heel exists, a Dwyer type calcaneal osteotomy should be considered.
If an osteochondral lesion is present, the ligamentous reconstruction should be done in conjunction with arthroscopic or open treatment of the osteochondral defect.
Positioning
The patient is placed in the lateral decubitus position with appropriate padding at bony prominences to avoid damage to subcutaneous structures (FIG 4A,B).
An operative platform is created using bolsters or blankets.
A “bump” made of four or five towels is used either proximal to the ankle to create a varus or inverted position for better exposure or distal to the ankle to create a valgus or everted position to approximate the edges of the repair (FIG 4C).
Approach
Two commonly used approaches
J incision (FIG 5A)
The incision is made from the distal tip of the fibula along its anterior margin proximally to the level of the ankle mortise.
Does not afford optimal access to the peroneal tendons
Curvilinear extensile exposure (FIG 5B)
Cuvilinear incision over posterior tip of fibular, extending to sinus tarsi area
Affords comprehensive exposure to anterior ankle, ATFL, CFL, and peroneal tendons
FIG 5 • A. A traditional J approach on the anterior distal fibula. B. An extensile curvilinear exposure to the lateral ankle. This approach facilitates access to the peroneal tendons should there be associated peroneal tendon pathology.
TECHNIQUES
MODIFIED BROSTROM ANATOMIC LATERAL ANKLE LIGAMENT REPAIR WITH SUTURE ANCHORS
Perioperative antibiotics are given.
The patient is positioned as described, a thigh tourniquet is placed, and a standard orthopaedic prep and drape is carried out. The tourniquet is inflated.
The incision is made as described under Approach in the Surgical Management section (TECH FIG 1A).
With the bump placed proximal to the ankle, a dissection is carried out to isolate the inferior extensor retinaculum.
The joint capsule is then incised in line with the skin incision and just distal to the leading edge of the fibula. The anterior talofibular (ATF) ligament may or may not be visible as a capsular expansion.
The CFL is inspected. This inspection, along with the preoperative evaluation, is used to decide whether or not a repair of this ligament is needed.
The joint is inspected for chondral injury.
A subperiosteal dissection is carried out at the anterior and lateral aspect of the fibula, raising a flap 3 to 6 mm wide.
Using curettes and rongeurs, a trough is made in the anterior and lateral aspect of the fibula at its leading edge, about 3 mm deep and 3 mm wide.
If no CFL repair is needed, a single corkscrew anchor double-armed with no. 2 FiberWire (Arthrex, Inc., Naples, FL) suture is inserted centrally in the trough. If a CFL repair is performed, a second anchor, with no. 2 Fiberwire, is used (TECH FIG 1B).
The joint is thoroughly irrigated, and the actual repair begins. Move the bump so it sits under the lateral border of the foot, placing the subtalar and ankle joints into an everted position before repairing the CFL if necessary.
The capsular and ATF ligament repair is now performed by bringing the sutures from deep to superficial in a horizontal mattress pattern. The “ligament” is shortened by creating the trough at the fibula. If further shortening is needed, the capsule may be trimmed from the distal cut edge.
A second reinforcing layer of repair is created by suturing the inferior extensor retinaculum to the periosteal flap with absorbable 2-0 figure 8 sutures.
The skin is closed in layers with 3-0 absorbable suture in the subcutaneous suture and staples or subcuticular suture used in the skin.
Dressings are applied, and a short-leg non–weight-bearing splint is applied.
Modified Brostrom Anatomic Lateral Ankle Ligament Repair with Suture Anchor(s) (Courtesy of Mark E. Easley)
Confirm ankle instability with exam under anesthesia.
Approach and exposure
Curvilinear incision over posterior tip of the fibula and extending to the sinus tarsi (TECH FIG 2)
Protect sural nerve posteriorly and superficial peroneal nerve anteriorly.
Prepare the inferior extensor retinaculum.
Identify and mobilize the inferior extensor retinaculum (TECH FIG 3AB).
Relatively thin superficial structure
Identify, inspect, and protect the peroneal tendons (TECH FIG 3CD).
Anterior arthrotomy
Detach the capsule, including the ATFL and CFL (TECH FIG 4AB).
Protect the peroneal tendons (TECH FIG 4C).
Excise the anterior inferior tibiofibular ligament (Bassett’s ligament) (TECH FIG 4D).
Usually present in patients after ankle sprain.
Potential for anterolateral soft-tissue ankle impingement.
Inspect the lateral talar dome for cartilage defect.
TECH FIG 1 • A. Traditional approach to perform the modified Brostrom repair. B. Suture anchors placed in the distal fibula.
TECH FIG 2 • Curvilinear extensile exposure to the lateral ankle ligaments.
Identify the ATFL and CFL (TECH FIG 5A–D); these are condensations within the capsular sleeve.
Develop a distal fibular periosteal flap (TECH FIG 6AB) to use as an additional reinforcement of the repair.
Prepare anterior distal fibula for reattachment of capsule and ligaments.
Create a trough using a rongeur (TECH FIG 6C).
Predrill anatomic footprints for ATFL and CFL suture anchor placement (TECH FIG 6DE).
Place suture anchors (TECH FIG 7AB).
Orient them so that they do not:
Interfere with one another
Violate the joint
Violate the posterior cortex of the fibula and irritate the peroneus brevis
Test the stability of the suture anchors (TECH FIG 7C).
Lift the limb by the anchors; if the anchors are going to fail, we want them to do so now so the problem can be rectified.
Pass the respective sutures through the CFL, the ajacent capsule, and the ATFL (TECH FIG 7D–F).
Test the sutures to ensure that they indeed advance the appropriate portion of the capsule to the desired location on the distal fibula (TECH FIG 7G)
Position the ankle properly for securing the sutures (TECH FIG 8A).
Reduce the talus within the ankle mortise
Avoid anterior translation of the talus within the mortise
Dorsiflex the ankle to neutral
Maintain slight hindfoot valgus
Tie the sutures (TECH FIG 8B–D).
Check the stability of the repair after the anchor sutures have been tied (TECH FIG 8E).
Pass the anchor sutures through the distal fibular periosteal flap (TECH FIG 9A–C).
This reinforces the repair
Place additional sutures from the periosteum to the capsule that has been advanced to the distal fibula (TECH FIG 9D,E)
Augment the repair further with the inferior extensor retinaculum
TECH FIG 3 • A,B. Mobilize the inferior extensor retinaculum to be used to augment the repair (Gould modification of the Brostrom procedure). A. Identify the inferior extensor retinaculum. B. Demonstrate that the retinaculum can be advanced. C,D. Identify, inspect, and protect the peroneal tendons. C. Identify the tendons. D. Inspect the tendons.
TECH FIG 4 • Anterior arthrotomy. A–C. The anterolateral capsule is elevated from the distal fibula. D. With the anterolateral tibiotalar joint exposed, the talar articular cartilage may be inspected and the hypertrophied anterior inferior tibiofibular ligament (Basset’s ligament) may be excised. (Following multiple ankle sprains, anterolateral soft tissue ankle impingement frequently develops).
TECH FIG 5 • Identify the ATFL and CFL within the lateral capsule; these structures represent condensations within the lateral capsule. A,B. ATFL and its anatomic location on the fibula identified. C,D.CFL identified and its competency tested with ankle/hindfoot inversion.
TECH FIG 6 • Distal fibular periosteal flap. This flap may be developed to create another layer for repair. A,B. Mobilizing distal fibular flap. C. Using a rongeur to prepare the distal fibula for reattachment of the capsule. D,E. Predrill holes for suture anchors. D. First, drill hole in anatomic footprint of ATFL. E. Second, drill hole in anatomic footprint of CFL.
TECH FIG 7 • Suture anchors. A. First anchor in anatomic footprint of ATFL. B. Second anchor in anatomic footprint of CFL. C. Stability of suture anchors tested by lifting limb from the operating room table by the anchor sutures. D–G. Anchor sutures passed through respective capsular condensations. D. Suture through CFL. E. Suture through posterior aspect of capsule adjacent to CFL. F,G. Suture through ATFL.
TECH FIG 8 • A. Reduce the talus within the ankle mortise before reattaching the ligaments and capsule. The ankle is held in dorsiflexion, with a posterior force maintaining the talus within the ankle mortise. Although covered, a bump has been placed under the distal tibia to allow the heel to translate posteriorly without interfering with the operating table. The heel is maintained in slight valgus. B–D.Secure the sutures while ankle is maintained in optimal position. B. Protect the peroneal tendons. C. Secure the CFL and more posterior capsule. D. Secure the ATFL. E. Recheck the anterior drawer test to determine if the primary sutures are securely maintaining ankle stability.
TECH FIG 9 • Anchor sutures passed through the periosteal flap to reinforce the repair. A. Sutures through the periosteal flap. B. Check the stability. C. Secure the sutures. D,E. Reinforce the repair with additional sutures. D.Pass sutures from the capsule through the periosteal flap. E. Secure these sutures.
TECH FIG 10 • Gould modification of the Brostrom procedure. A. Protect peroneal tendons. B. More posterior advancement of the inferior extensor retinaculum. C. Anterior advancement. D. Attempt to cover the permanent anchor sutures with the retinaculum.
Protect the peroneal tendons because they are in close proximity to the inferior extensor retinaculum (TECH FIG 10A).
Advancing the inferior retinaculum to the distal fibula over the capsular advancement is the (Nathaniel) Gould modification of the Brostrom lateral ankle ligament reconstruction (TECH FIG 10B–D).
If possible. advance the inferior retinaculum so that the tissue covers the sometimes prominent permanent anchors suture knots. Final check of the anterior drawer and talar tilt to ensure that ankle stability has been reestablished (TECH FIG 11A).
Closure (TECH FIG 11B).
TECH FIG 11 • A. Final check of anterior drawer and talar tilt tests to be sure repair is satisfactory. B. Closure.
MODIFIED BROSTROM BROSTROM-EVANS PROCEDURE
Definition
This is a combination of the modified Brostrom procedure described above and the Evans procedure, tenodesing the anterior 50% of the peroneus brevis to the fibula
Indications
Athlete or patient in whom greater restraint against inversion is desired
For example, a football lineman who does not need as much hindfoot flexibility as a running back
Anatomic repair planned but greater than anticipated instability, particularly with inversion stress, and an intraoperative determination that more restraint to inversion is needed than can be afforded by the modified Brostrom procedure alone.
Lateral ankle instability in a patient with pre-exisiting longitudinal split tear of the peroneus brevis.
Technique
Same positioning and approach as for a modified Brostrom procedure
The ATFL and CFL are released with the capsular sleeve from the fibula the same way as for the modified Brostrom procedure (TECH FIG 12A)
Preparing the peroneus brevis tendon
The peroneus brevis (PR) is isolated distal and proximal to the superior peroneal retinaculum (SPR) that is left intact
The peroneus brevis is split longitudinally and the anterior 50% is released proximally (TECH FIG 12B)
While keeping the SPR intact, the PR is split using a suture that is passed beneath the SPR that is used to separate the PR into anterior and posterior limbs, acting as a “saw” to divide the tendon along its longitudinal fibers.
Ater being released proximally the anterior limb of the PR is passed beneath the SPR distally
Passing the anterior limb of the PR through the fibula
Drill an oblique tunnel in the distal fibula (TECH FIG 13A)
Pass the anterior 50% of the PR through the tunnel from distal to proximal (TECH FIG 13B)
Complete the modified Brostrom procedure (TECH FIG 13C,D)
The ankle is held in neutral position
The talus is maintained in the ankle mortise
TECH FIG 12 • A. Prepare the lateral ankle ligament complex as is done for the isolated modified Brostrom procedure. B. Isolate the anterior 50% of the peroneus brevis tendon.
TECH FIG 13 • A. Transect the anterior 50% of the tendon proximally and pass this half of the peroneus brevis tendon beneath the intact superficial peroneal retinaculum. Drill a fibular tunnel from distal to proximal. B. Pass the anterior slip of the peroneus brevis through the tunnel from distal to proximal. C, D. Complete the modified Brostrom procedure. E, F. After passing through the fibular tunnel, the anterior slip of the peroneus brevis may be folded distally over the fibula to augment the repair. Check the ankle stability: (G) Anterior drawer and (H) inversion stress test.
Slight valgus is maintained in the hindfoot
Augment the modified Brostrom with the Evans modification
The anterior slip of the PR is secured to the fibular periosteum, both at the anterior and posterior aspects of the tunnel
Avoid excessive valgus or excessive tensioning as overtightening could occur; the goal is to have a restraint to inversion, not a complete lack of inversion
Typically, the anterior slip of the PR can be sewn over the fibula after being passed through the tunnel to further augment the repair (TECH FIG 13E,F)
Check ankle stability with anterior drawer and particularly inversion stress (TECH FIG 13G,H)
Postoperative Protocol
Same as for modified Brostrom
POSTOPERATIVE CARE
The patient is to remain non–weight-bearing until seen in the clinic for the first cast change in 10 to 14 days.
At this first postoperative visit, the splint is removed and wound evaluated. If no problems are seen, the skin closure is removed and the patient is placed in a short-leg weightbearing cast for the subsequent 4 to 5 weeks.
At the next visit the cast is removed and a physical therapy program is initiated for range of motion, proprioceptive training, and progressive resistive exercise.
Gradual return to sport is possible at 12 to 16 weeks following surgery.
COMPLICATIONS
Minimal; avoid injury to the superficial peroneal and sural nerves
Infection
Wound dehiscence
Failure of repair
Peroneal weakness (postoperative physical therapy program important)
If the talus was not reduced within the ankle mortise when the sutures were secured, then the repair may prove inadequate.
With an anatomic repair, overtightening is unlikely.
REFERENCES
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