In this first of a two part topic I will discuss the ankle sprain, how it happens, what structures are involved and the diagnosis. In part two I will discuss the immediate treatment and the proper rehabilitation for the ankle sprain and what can be done to help to prevent reoccurrence of the injury.

The ankle is one of the most common sites for acute musculoskeletal injuries, and sprains account for 75 percent of ankle injuries. 1 Acute ankle trauma is responsible for 10 to 30 percent of sports-related injuries in young athletes. 2 Each year, an estimated 1 million persons present to physicians with acute ankle injuries. 2 More than 40 percent of ankle sprains have the potential to cause chronic problems. 3,4

Without adequate care, acute ankle trauma can result in chronic joint instability. Use of a standardized protocol enhances the management of ankle sprains. In patients with grades I or II sprains, emphasis should be placed on accurate diagnosis, early use of RICE (rest, ice, compression and elevation), maintenance of range of motion and use of an ankle support. Sprains with complete ligament tears (grade III) may require surgical intervention.

Ankle sprains range in severity from grade I to grade III. Grade I-II ankle sprains are treated without surgery. Grade III(complete rupture) ankle sprains usually require surgical management. Of note, late instability is as common after surgical treatment as after nonoperative treatment of severe ankle ligament injury. Furthermore, late reconstruction is effective in patients initially treated nonoperatively. 5

Pathoanatomy and Mechanisms of Injury

The most common mechanism of injury is a combination of plantar flexion and inversion(i.e. rolling foot inward). This can occur in all sports as well as hiking and even from an awkward step off a curb. The lateral stabilizing ligaments, which include the anterior talofibular ligament, the calacaneofibular ligament and the posterior talofibular ligament, are most often damaged. The anterior talofibular ligament(ATF) is the most easily injured. A combination of injury to the ATF and the calcaneofibular(CF) ligament can result in severe ankle instability. The posterior talofibular(PTF) ligament is the strongest of the three and is rarely injured in an inversion sprain.


Acute ankle trauma is evaluated with a careful history(situation, mechanism of injury, previous injury to the joint, etc.) and a careful examination(i.e. inspection, palpation, weight bearing status, special tests) should be performed by your physician, physical therapist, or athletic trainer to determine the severity of the injury and what structures are involved.

Significant swelling may or may not occur along with bruising, which may present the day after the injury. There is usually no gross deformity of the ankle though significant swelling can give that impression. With a history of severe trauma along with lateral ankle/lower leg pain, the shaft of the fibula should be palpated to identify a possible fracture of the distal(lower) portion of the fibula.

Radiographs should be obtained to rule out fracture when a patient presents within the first 10 days of injury, with an inability to weight bear immediately after the injury and at physician’s office and there is palpable bone tenderness at the posterior half of the lower(2.5 in.) portion of the fibula or tibia.

If, after complete evaluation and radiographic findings, there is suspicion of fracture, dislocation, tendon rupture, or other findings that make the diagnosis uncertain, a referral to an Orthopedic specialist is warranted.

In the next month’s topic I will discuss immediate management along with the proper rehabilitation protocol.


1. Barker HB, Beynnon BD, Renstron PA. Ankle injury risk factors in sports. Sports Med 1997;23:69-74.

2. Perlman M, Leveille D, DeLeonibus J, Hartman R, Klein J, Handelman R, et al. Inversion lateral ankle trauma: differential diagnosis, review of the literature, and prospective study. J Foot Surg 1987;26: 95-135.

3. Bennett WF. Lateral ankle sprains. Part II: acute and chronic treatment. Orthop Rev 1994;23:504-10.

4. Safran MR, Benedetti RS, Bartolozzi AR 3d, Mandelbaum BR. Lateral ankle sprains: a comprehensive review. Part 1: etiology, pathoanatomy, histopathogenesis, and diagnosis. Med Sci Sports Exerc 1999;31(7 suppl):S429-37.

5. McCluskey LC, Black KP. Ankle injuries in sports. In: Gould JS, et al., eds. Operative foot surgery. Philadelphia: Saunders, 1994:901-36.