Weak ankles. They are the bane of all athletes, dancers and, well … everyone. What do I mean when I say “weak ankles”? This refers to instability of the surrounding ligaments or tendons due to an acute injury or repeated injuries, leading to a chronic problem. We sometimes confuse sprain and strain. Ligaments/tendons are sprained while muscles are strained. Now there is much to discuss concerning lateral ankle sprains and subsequent instability.
To quickly review the basic anatomy with these injuries, there are three major ligaments that are responsible for the strength and stability of the lateral ankle.1
The anterior talofibular ligament attaches to the neck of the talus and the distal anterior fibula. It is the weakest of the three ligaments. It provides anterior stability to the ankle joint, especially during plantarflexion of the foot.
The calcaneofibular ligament attaches to the calcaneus and the distal tip of the fibula. It stabilizes both the ankle and the subtalar joint.
The posterior talofibular ligament attaches to the calcaneus and the posterior aspect of the distal fibula. It is the strongest of the three ligaments and secures the talus posteriorly.
There are multiple factors that may predispose someone to an injury to the lateral ankle ligament complex but 85 percent of the time, the injury is from a plantarflexed and inverted foot.2
Lateral ankle injuries account for 15 percent of all sporting injuries, specifically 45 percent of basketball injuries, 31 percent of soccer injuries and 10 to 15 percent of football injuries.3,4 Lateral ankle injuries are also responsible for one-third of all military recruit injuries.4 Chronic instability of the ankle may occur in 40 to 60 percent of those injured.3,4
What causes lateral ankle injuries? The aforementioned ligaments do their best to resist an abnormal force placed upon them but in many instances are unable to resist, and they either stretch or tear.
If you remember, the anterior talofibular ligament is the weakest of the three ligaments and ruptures in almost all lateral ankle sprains. The calcaneofibular ligament ruptures in 50 to 70 percent of injuries and the posterior talofibular ligament ruptures in less than 10 percent.5
There are multiple systems to classify lateral ankle sprains. The most basic system is based on how many ligaments are injured.6
• Grade 1 – injury to the anterior talofibular ligament
• Grade 2 – injury to the anterior talofibular ligament and calcaneofibular ligament
• Grade 3 – injury to all three ligaments
I believe Thordarson’s system is better because it gives you a better sense of the treatment plan.4
• Grade 1 – mild stretching with minimal swelling and tenderness, but no instability or functional loss
• Grade 2 – partial tear with increased swelling and tenderness, and mild to moderate instability
• Grade 3 – complete rupture of the anterior talofibular ligament with variable injury to the calcaneofibular ligament. Severe swelling and tenderness with complete loss of function and significant instability.
The following system grades instability based on a manual diagnostic exam that occurs with X-ray.7
• Grade 0 – normal (<5 mm) displacement
• Grade 1 – 5 to 10 mm displacement
• Grade 2 – 10 to 15 mm displacement
• Grade 3 - >15 mm displacement
With an acute ankle injury, patients might experience a popping/tearing sensation in the ankle with an audible sound at the time of the initial injury.6 The ankle will immediately begin to swell and pain will skyrocket. Walking may be difficult.
In regard to chronic injuries, one might continue to experience moments of ankle inversion or rolling the ankle following the initial injury. Often patients might complain about the ankle constantly feeling as if it is going to give way or a looseness.8,9 Chronic instability is defined as having signs and symptoms for at least six months’ duration.10
Once one has diagnosed the injury, the severity of injury will determine the aggressiveness of the treatment.
Conservative care. Rest, ice, compression and elevation (RICE) are mainstays of conservative care. Physical therapy consists of range of motion, strengthening exercises and proprioceptive exercises.
Note that conservative care is very effective but up to 26 percent of patients may need more aggressive care.9
Surgical care. Most of the time, one reserves surgical care for more severe or chronic injuries.1,4,6,8 The two types of surgical repair are non-anatomical and anatomical.7 Non-anatomical repair uses other tissues besides the ligaments themselves for repair and reconstruction. Anatomical repair uses the ligament for repair and reconstruction.
One may prevent recurrence of injury by using good, appropriate shoe gear and taping/bracing. Research has shown that taping and bracing restrict ankle inversion by up to 16 degrees.3
1. Banks AS, Downey MS, Martin DE, et al. McGlamry’s Comprehensive Textbook of Foot and Ankle Surgery, third edition, volume 1. Lippincott, Williams and Wilkins, Philadelphia, 2001.
2. Nauck T, Lohrer H, Gollhofer A. Evaluation of arthrometer for ankle instability: a cadaveric study. Foot Ankle Int. 2010; 31(7):612-18
3. Hubbard T, Cordova M. Effect of ankle taping on mechanical laxity in chronic ankle instability. Foot Ankle Int. 2010; 31(6):499-504.
4. Thordarson D. Foot and Ankle, second edition. Lippincott, Williams and Wilkins, Philadelphia, 2012.
5. Phisitkul P, Chaichankul C, Sripongsai R, et al. Accuracy of anterolateral drawer test in lateral ankle instability. Foot Ankle Int. 2009; 30(7):690-5.
6. Coughlin M, Mann R, Saltzman C. Surgery of the Foot and Ankle, eighth edition. Mosby Elsevier, Philadelphia, 2007.
8. Easley M, Wiesel SW. Operative Techniques in Foot and Ankle Surgery. Lippincott Williams and Wilkins, Philadelphia, 2011.
9. Crim J, Beals TC, Nickisch F, et al. Deltoid ligament abnormalities in chronic lateral ankle instability. Foot Ankle Int. 2011; 32(9):873-8.
7. Lee K, Park YU, Kim JS, et al. Long-term results after modified Brostrom procedure without CFL reconstruction. Foot Ankle Int. 2011; 32(2):153-7.
10. Tourne Y, Mabit C, Moroney PJ, et al. Long-term follow-up of lateral reconstruction with extensor retinaculum flap for chronic ankle instability. Foot Ankle Int. 2012; 33(12):1079-86.