Ankle Sprains, Lateral

By admin On Nov 27, 2023

Ovid: 5-Minute Sports Medicine Consult, The

Christopher A. Gee

Basics

Description

Lateral ankle sprains are the most common injury sustained by athletes and comprise ∼14% of all sports-related injuries (1).
∼80% of sprains are due to an inversion type of mechanism that injures the lateral ankle restraints.
While the medial side of the ankle has the broad, strong deltoid ligament as a restraint, the lateral side of the ankle has 3 smaller ligaments that act as the static restraint system.
Primary static restraints to ankle inversion:
- Anterior talofibular ligament (ATFL): Passes from the tip of the fibula to the lateral talar neck; taut in plantar flexion; injured most commonly
- Calcaneofibular ligament (CFL): Passes inferior and posterior from the tip of the fibula to the lateral calcaneous; usually injured with the ATFL
- Posterior talofibular ligament (PTFL): Passes posteriorly from the fibula to the talus; injured less commonly
These ligaments are injured in a sequential pattern as extreme inversion and plantarflexion forces are placed on the ankle. The ATFL is injured 1st (isolated ATFL injuries occur in ∼2/3 of injuries). After the small ATFL is injured, the CFL then is stressed and injured, followed by the PTFL. The ankle joint capsule is also sprained during an inversion injury. Given this pattern, isolated CFL injuries are uncommon.
Bony support of the distal fibula assists the deltoid ligament in restricting eversion stress to the ankle. However, the medial malleolus is smaller than the lateral malleolus and, as such, more easily allows inversion stress to injure the lateral ankle ligaments.
Ankle sprain grading:
- Grade 1: Stretching to partial tearing of ligaments but with no gross laxity
- Grade 2: Partial tear of ligaments with increased laxity of ankle but still with firm endpoint
- Grade 3: Complete rupture of ligaments; gross laxity of ankle with no endpoint

Epidemiology

Incidence

Very common injury in athletes and the general population, with ∼23,000 cases every day (2)

Risk Factors

Athletes (especially those involved in sports with jumping near other players and quick “cutting” motions) (3)
Dancers
Congenital tarsal coalition
Prior ankle injury (4)

Etiology

Lateral ankle sprains occur when the ankle is stressed with extreme inversion and plantarflexion forces that overcome the static restraints (ligaments). Spraining and tearing of the ligaments lead to pain, swelling, and varying degrees of disability.

Diagnosis

History

Patients report history of inversion-type injury often with an audible pop. This is followed by rapid swelling, pain, and an inability to walk.

Physical Exam

Physical examination reveals ecchymosis and diffuse swelling about the ankle joint.
Tenderness to palpation is noted along the course of injured ligaments and can be diagnostic of which ligaments are injured.
Palpation of the anterior ankle joint and the talar dome with the foot in full plantarflexion can help to diagnose other forms of pathology.
It is important to palpate both the medial and lateral malleoli and the base of the 5th metatarsal to examine for possible fracture.
Occasionally, the ankle ligaments can be disrupted and the stress passed up the tibiofibular syndesmosis. This leads to syndesmotic injuries or the so-called high ankle sprain.
Assess neurovascular status by feeling distal pulses and manually testing appropriate muscle groups.
Grading of ankle injury can be accomplished by testing the integrity of various ligaments. Examiner also should take into account the fact that prior ankle sprains may have left residual laxity on either side.
Anterior drawer:
- Tests stability of ATFL; performed by holding the distal tibia and pulling the heel forward. Increased laxity relative to the opposite side indicates a tear of the ATFL.
- Inversion tilt: Tests stability of CFL; performed by holding the distal tibia and moving the foot from a neutral position to an inversion position. Increased laxity compared with opposite side indicates a tear of the CFL.

Diagnostic Tests & Interpretation

Imaging

Plain radiographs of affected ankle (including anteroposterior, lateral, and Mortise views) to rule out fracture
May not need to perform x-rays if patient doesn't have tenderness along posterior 6-cm edge of lateral and medial malleoli and can bear weight initially after injury (Ottawa ankle rules) (5).
CT scans may be performed to evaluate for occult fracture.
MRI is rarely useful in ankle sprains but may be useful in assessing integrity of various ligaments in patients with chronic ankle instability.

Differential Diagnosis

Tibia fracture
Pilon fracture
Fibula fracture
Osteochondral defect in talar dome
Anterior ankle impingement
Talus fracture
Calcaneal fracture

Treatment

Initial therapy focuses on RICE (rest, ice, compression, elevation) protocol to decrease pain and swelling.
Crutches can be used until patient is able to bear weight as tolerated.
Various kinds of braces, compression devices, stirrup splints, and walking boots can be used to provide protection and support and to encourage walking.
Severe sprains may be best treated with more motion restriction in devices such as casts or walking boots (6).
Progressive therapy through a 3-phase approach may best promote rapid recovery:
- Phase 1 consists of RICE protocols to improve pain and swelling (often wks 1–2).
- Phase 2 consists of progressive range-of-motion exercises to improve motion and decrease swelling. Patients should continue to use a protective brace when walking to prevent further injury. Patients should be working toward full weight bearing during this stage (wks 2–4).
- Phase 3 begins more aggressive strengthening and rehabilitation exercises. Specifically, patients should work on proprioception and endurance. This can be a formalized physical therapy program as needed (wks 4–6).

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Medication

NSAIDs can be used after initial injury for pain. They should be avoided in patients at risk for GI bleeding.

Additional Treatment

Physical therapy can be used to assist patients in strengthening and generally rehabilitating the injured ankle.
Electrical stimulation and iontophoresis may have a role in pain and swelling control.

Surgery/Other Procedures

Often general rehabilitation principles and conservative therapy are adequate to return athletes to their sport without more aggressive interventions. Patients rarely need primary repair of ligaments after an acute lateral ankle sprain.
Occasionally, severe laxity of lateral ankle restraints may lead to recurrent ankle injuries and chronic ankle instability. These patients may benefit from ligament repair or ankle reconstruction to improve stability.

Ongoing Care

Follow-Up Recommendations

Patient Monitoring

Patients may return to play once they have achieved a full range of motion and strength, as well as being able to perform their sport-specific activities without limitations. Some may be able to return to play with a supportive device to protect from further injury depending on the sport and the patient's position.
Depending on the sport, certain patients may need to go through a progression of sport-specific activities to return to play.

Prognosis

Prognosis depends on the extent of injury and any concurrent injuries, but for most patients, prognosis is excellent. More severe injuries may require more extensive rehabilitation for patients to return to full function and prevent recurrence.
Patients with recurrent instability and those in high-risk sports (eg, volleyball, basketball) may benefit from functional bracing or taping.
Patients who fail to undergo proper rehabilitation are often left with chronic instability and recurrent ankle injuries.

Complications

Stiffness from prolonged immobilization
Recurrent instability
Osteochondral defects

References

1. Fong DT, Chan YY, Mok KM, et al. Understanding acute ankle ligamentous sprain injury in sports. Sports Med Arthrosc Rehabil Ther Technol. 2009;1:14.

2. Kannus P, Renström P. Treatment for acute tears of the lateral ligaments of the ankle. Operation, cast, or early controlled mobilization. J Bone Joint Surg Am. 1991;73:305–312.

3. Nelson AJ, Collins CL, Yard EE, et al. Ankle injuries among United States high school sports athletes, 2005–2006. J Athl Train. 2007;42:381–387.

4. Malliaropoulos N, Ntessalen M, Papacostas E, et al. Reinjury after acute lateral ankle sprains in elite track and field athletes. Am J Sports Med. 2009;37:1755–1761.

5. Stiell IG, Greenberg GH, McKnight RD, et al. A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med. 1992;21:384–390.

6. Lamb SE, Marsh JL, Hutton JL, et al. Mechanical supports for acute, severe ankle sprain: a pragmatic, multicentre, randomised controlled trial. Lancet. 2009;373:575–581.

Codes

ICD9

845.02 Calcaneofibular (ligament) ankle sprain
845.09 Other ankle sprain