Ankle Sprain

Brandi Kimble D.P.M.

Basic Information

Definition

An ankle sprain is an injury to the ligamentous structures that support the ankle joint. Most (85%) involve the lateral ligament complex (Fig. E1). The anterior inferior tibiofibular (AITF) ligament, deltoid ligament, and interosseous membrane may also be injured. A severe form of ankle sprain involves disruption of the ankle syndesmosis, known as a high ankle sprain. Lateral ankle sprains are classically graded I, II, or III in respect to specific ligament involvement and their integrity. Table E1 describes a classification of ankle sprains. The anterior talofibular ligament (ATFL) is the most commonly affected lateral ligament.

FIG.E1

The lateral ankle ligaments, anterior and posterior talofibular *(ATF, PTF)* and calcaneofibular *(CF).* Also shown are the anterior inferior tibiofibular ligament *(AITF)* and the beginning of the interosseous membrane *(IM).*

From Mercier LR [ed]: *Practical orthopaedics,* ed 4, St Louis, 1995, Mosby.

TABLEE1 Classifications of Ankle Sprains

Grade	Extent of Injury	Physical Findings	Treatments
I	Sprain of ATFL (midstretching of lateral ligament complex)	Mild swelling and tenderness; no joint instability	Weight bear as tolerated; free ROM exercises
II	ATFL tear CFL strain	Moderate swelling and tenderness; laxity with positive anterior drawer test	Immobilization (air splint, CAM boot), physical therapy
III	ATFL tear CFL tear	Severe swelling and tenderness; instability with anterior drawer test and talar tilt; inability to bear weight	Immobilization, physical therapy (longer duration than grade II); surgery if symptoms unresolved
ATFL, Anterior talofibular ligament; CAM, controlled ankle movement; CFL, calcaneofibular ligament; ROM, range of motion.

ICD-10CM CODES
S93.409A	Sprain of unspecified ligament of unspecified ankle, initial encounter
S93.411A	Sprain of calcaneofibular ligament of right ankle, initial encounter
S93.411D	Sprain of calcaneofibular ligament of right ankle, subsequent encounter
S93.411S	Sprain of calcaneofibular ligament of right ankle, sequela
S93.412A	Sprain of calcaneofibular ligament of left ankle, initial encounter
S93.412D	Sprain of calcaneofibular ligament of left ankle, subsequent encounter
S93.412S	Sprain of calcaneofibular ligament of left ankle, sequela
S93.419A	Sprain of calcaneofibular ligament of unspecified ankle, initial encounter
S93.419D	Sprain of calcaneofibular ligament of unspecified ankle, subsequent encounter
S93.419S	Sprain of calcaneofibular ligament of unspecified ankle, sequela
S93.421A	Sprain of deltoid ligament of right ankle, initial encounter
S93.421D	Sprain of deltoid ligament of right ankle, subsequent encounter
S93.421S	Sprain of deltoid ligament of right ankle, sequela
S93.422A	Sprain of deltoid ligament of left ankle, initial encounter
S93.422D	Sprain of deltoid ligament of left ankle, subsequent encounter
S93.422S	Sprain of deltoid ligament of left ankle, sequela
S93.429A	Sprain of deltoid ligament of unspecified ankle, initial encounter
S93.429D	Sprain of deltoid ligament of unspecified ankle, subsequent encounter
S93.429S	Sprain of deltoid ligament of unspecified ankle, sequela
S93.431A	Sprain of tibiofibular ligament of right ankle, initial encounter
S93.431D	Sprain of tibiofibular ligament of right ankle, subsequent encounter
S93.431S	Sprain of tibiofibular ligament of right ankle, sequela
S93.432A	Sprain of tibiofibular ligament of left ankle, initial encounter
S93.432D	Sprain of tibiofibular ligament of left ankle, subsequent encounter
S93.432S	Sprain of tibiofibular ligament of left ankle, sequela
S93.439A	Sprain of tibiofibular ligament of unspecified ankle, initial encounter
S93.439D	Sprain of tibiofibular ligament of unspecified ankle, subsequent encounter
S93.439S	Sprain of tibiofibular ligament of unspecified ankle, sequela

Epidemiology & Demographics

Prevalence

One case/10,000 people each day

Especially prevalent in rigorous sports and training such as for basketball, football, and soccer

Predominant Sex

Varies according to age and level of physical activity

Physical Findings & Clinical Presentation

•

Often a history of a “pop”
•

Variable amounts of tenderness and hemorrhage (inversion sprains: tender laterally; syndesmotic injury: tender anterior leg about middle third of the leg).
•

Anterior talofibular ligament (ATFL) evaluation: anterior drawer test. (With the patient in the sitting position and knee flexed allow the ankle to plantar-flex slightly and apply an anterolateral rotatory force to the heel. Positive if abnormal increase in forward movement of the talus on the tibia; Fig. E2.)

FIG.E2

Anterior drawer test of the ankle (tests the integrity of the anterior talofibular ligament).

From Brinker MR, Miller MD: *Fundamentals of orthopaedics,* Philadelphia, 1999, Saunders.

•

Syndesmotic evaluation: manual squeeze test. (Compress the tibia and fibula toward each other at the middle third of the anterior leg. Splaying and pain are indicative of injury.)
•

Talar tilt test or inversion stress test (Fig. E3).

FIG.E3

Talar tilt test (inversion stress) of the ankle (tests the integrity of the anterior talofibular ligament and the calcaneofibular ligament).

From Brinker MR, Miller MD: *Fundamentals of orthopaedics,* Philadelphia, 1999, Saunders.

•

Severe tenderness to direct palpation of ligamentous structure.

Etiology

•

Lateral injuries usually result from inversion and plantar flexion injuries.
•

Eversion and rotational forces may injure the deltoid or AITF ligament or the interosseous membrane.

Diagnosis

Differential Diagnosis

•

Fracture of the ankle or foot, particularly involving the distal fibular growth plate in the immature patient (e.g., calcaneal fracture, lateral and/or medial malleoli fracture, talar dome fracture, Lisfranc injury)
•

Avulsion fracture of the fifth metatarsal base
•

Achilles tendon rupture
•

Peroneal tendon rupture

Workup

•

History and clinical examination are usually sufficient to establish the diagnosis.
•

Plain radiographs are not always needed.

Imaging Studies

Radiographic evaluation (Figs. E4 and E5): According to the Ottawa ankle rules (Table E2), radiography is indicated if there is pain in the malleolar or midfoot zone and either bone tenderness over an area of potential fracture or an inability to bear weight immediately after the injury and in the physician’s office. These rules can reduce radiographic evaluation by 30% to 40%. Pearls: palpate entire distal 6 cm of the fibula and tibia; do not use rule if the patient is younger than 18 years of age.

FIG.E4

Tibiotalar dislocation.

This 17-year-old male landed on his left ankle after dunking a basketball, sustaining a deformity. His tibiotalar joint is dislocated, with the talus dislocated posteriorly (visible on the lateral view, A) and medially (visible on the anterior-posterior view, B). No fractures are present in this case, although fractures are commonly associated with this injury because of the amount of force required to dislocate the ankle. This was an open injury, and the patient underwent exploration, irrigation, and debridement with primary closure.

From Broder JS: *Diagnostic imaging for the emergency physician,* Philadelphia, 2011, Saunders.

FIG.E5

Acute lateral ankle sprain with multiple ligamentous injuries. Axial fat-suppressed, T2-weighted MR image shows a tear of the anterior talofibular (ATFL) ligament *(arrow)*. Other ligamentous injuries include sprain to both the posterior talofibular (PTFL) and the deltoid *(D)* ligaments, characterized by loss of normal striation and increased signal on T2-weighted images in these ligaments. Bone bruise of the medial talar dome *(arrowhead)* is present.

From Pope TL, Bloem HL, Beltran J, Morrison WB, Wilson DJ: *Musculoskeletal imaging*, ed 2, Philadelphia, 2014, Saunders.

TABLEE2 Ottawa Ankle Rules

Accepted Indications: Ankle Radiographs	Accepted Indications: Midfoot Radiographs
Point tenderness about the inferior or posterior aspect of either malleolus (to include the distal 6 cm of the lateral malleolus)	Point tenderness about the navicular or the base of the fifth metatarsal
Inability to bear weight at the time of injury or clinical evaluation (four independent steps)	Inability to bear weight at the time of injury or clinical evaluation (four independent steps)

Treatment

Acute General Rx

•
The first line of treatment is described by the mnemonic PRICE:
1. 1.
  
  Protection (CAM boot, etc.)
2. 2.
  
  Rest
3. 3.
  
  Ice (3 to 7 days)
4. 4.
  
  Compression
5. 5.
  
  Elevation
•

Pain control with NSAIDs, acetaminophen, mild opioids.
•

In 48 hours, early controlled motion in a functional ankle brace.
•

Compression, support, and bracing is best achieved with an Air-Stirrup brace combined with an elastic compression wrap, or lace-up support alone (functional bracing for active patients).
•

In 4 to 5 days, exercise against resistance added.
•

Short period of immobilization (up to 10 days) in a below-knee cast or Aircast may shorten the recovery period.
•

Physical therapy may be indicated to improve proprioception, strengthen the soft tissue structures about the ankle (ligaments, peroneal tendons), and restore ROM.
•

Surgery is typically recommended for grade III sprains, which consist of a complete torn ligament and significant ligament laxity/instability in young, healthy, athletic patients.
•

If there is syndesmotic or deltoid ligament involvement, surgery is also the primary treatment of choice in athletes.

Chronic Rx

•

Lateral heel and sole wedge to prevent inversion
•

Protective taping or bracing during vigorous activities (Fig. E6)

FIG.E6

A, The most effective method of supporting most acute ankle sprains is by using an ACE wrap (BD, Franklin Lakes, NJ) reinforced with 1-inch medial and lateral tape strips. The anterior and posterior aspects of the ankle are left free to allow the patient to flex and extend the ankle. The patient is encouraged to bear weight with crutches. B, Diagram of an air splint. Straps are adjusted to heel size, the lower straps are wrapped about the ankle, and the side extensions are centered. The splint is then pressurized and straps adjusted until comfortable support and pressure are attained. C, As the ankle pain subsides, about the third to fifth day, balancing exercises can begin to allow the patient to regain ankle proprioception and avoid recurrent instability problems.

From Jardon OM, Mathews MS: Orthopedics. In Rakel RE [ed]: *Textbook of family practice,* ed 5, Philadelphia, 1995, Saunders.

•

Strengthening exercises
•

Protective bracing or taping indicated for 6 months in patients with symptomatic grade II and III injuries

Disposition

•
Lateral sprains of any severity may cause lingering symptoms for weeks and months.
1. 1.
  
  Some syndesmotic sprains take even longer to heal.
2. 2.
  
  Heterotopic ossification may even develop in the interosseous membrane, but long-term results do not seem to be affected by such ossification.
•

Continuing lateral symptoms may require surgical reconstruction, although late traumatic arthritis or long-term instability is rare regardless of treatment.
•

Approximately 15%-20% of patients require surgical intervention after continued lateral ankle instability after 6-8 months of rigorous physical rehabilitation.

Referral

Podiatric and orthopedic consultation for patients who do not respond to conservative treatment. Most ankle sprains resolve in 2 to 6 wk.

Pearls & Considerations

Comments

If healing seems delayed (more than 6 weeks), the following conditions should be considered:

1.

Talar dome fracture
2.

Reflex sympathetic dystrophy
3.

Chronic tendinitis
4.

Peroneal tendon subluxation
5.

Other occult fracture
6.

Peroneal weakness (poor rehabilitation)
7.

A “high” (syndesmotic) sprain

Repeat plain roentgenograms, bone scan, or MRI may be indicated.

Ferri – Ankle Sprain