Ankle Sprain

Author(s): Jonathan Kirschner, MD

Originally published:11/04/2012

Last updated:08/23/2016

1. DISEASE/DISORDER:

Definition

Ankle sprain is the stretching or tearing of ankle ligaments. In grade 1 (mild) sprains, few fibers are torn and there is no laxity or residual instability. Grade 2 (moderate) sprains involve an incomplete tear of the ligament with mild laxity and instability. Grade 3 (severe) sprains are characterized by complete disruption of the ligament with gross instability and laxity.

Etiology

Lateral ligament sprains are most common (85% of sprains) and occur from foot supination/inversion and tibial external rotation. As the foot rotates, the anterotalofibular ligament (ATFL) is injured first, then the calcaneofibular ligament (CFL) and posterior talofibular ligaments (PTFL) tend to tear in that sequence, depending on severity. Eversion sprains are caused by extreme external foot rotation, injuring the deltoid ligament.

Epidemiology including risk factors and primary prevention

Lateral ankle sprains are the most common athletic injury, comprising 2%-25% of all sports injuries. Up to 25,000 occur in the United States daily, and up to 40% of ankle sprains become chronic. Grade 1 sprains typically heal in 12 days, grade 2 in 2 weeks, and grade 3 from 4.5 to 26 weeks. Risk factors and primary prevention strategies address poor ankle proprioception, weak ankle dorsiflexors and invertors, and poor flexibility. High ankle sprains (10% of sprains) are more severe eversion injuries affecting the tibiofibular syndesmosis and/or the anterior tibiofibular ligament. These sprains and 10%-20% of lateral sprains may ultimately require surgery for chronic ankle instability.

Patho-anatomy/physiology

As the ankle moves from dorsiflexion to plantar flexion, bony stability decreases and forces on the ankle ligaments increase. The ATFL is intracapsular, has the lowest failure resistance, and is the most important ligament in talofibular stability. The CFL is extracapsular, thicker and stronger than the ATFL, and the next to tear in a plantarflexion/inversion injury. The PTFL is the strongest of the three ligaments and, because it is only taut in severe dorsiflexion, the least likely to fail.

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

New onset/acute
There is swelling, hemorrhage and hematoma at the site of ligament disruption. The typical inflammatory cascade ensues with the release of painful inflammatory mediators, such as prostaglandins and interleukins. Capillary endothelial permeability increases and monocytes migrate to the area. There is pain, antalgic gait, and decreased range of motion (ROM).

Subacute
Ecchymosis, swelling and ROM may worsen before starting to improve. There is fibrinous exudation and scar tissue formation as early as 3 weeks if the ligament ends are well approximated. The scar is 75% as strong as native tissue but can support weight bearing.

Chronic/stable
Swelling may take several months to completely resolve. ROM deficits, muscular and ligamentous weakness may persist. Functional instability and loss of normal ankle kinematics may lead to chronic, recurrent injury and early degenerative changes.

Specific secondary or associated conditions and complications

Ankle dislocation, osteochondral defects, distal lateral malleolar avulsion or spiral fracture, medial malleolar fracture, avulsion of the 5th metatarsal head, or talar neck or medial compression fractures may occur. Sural or peroneal nerve neurapraxia may develop, particularly with Maissoneuve fractures (proximal fibular fracture and syndesmotic injury) sometimes seen concomitantly with high ankle sprains. Knee, hip, low back or contralateral lower limb pain may develop from altered gait kinematics. Patients who use axillary crutches are at risk for radial nerve injury.

2. ESSENTIALS OF ASSESSMENT

History

Patients typically report walking on an uneven surface (e.g., pothole) and quickly turning the ankle, or jumping and landing with the foot plantarflexed. In sport this often means landing on another player’s foot. Patients may complain of feeling a pop, swelling, limited range of motion, and ankle weakness or instability. Pain is typically worse with weight bearing.

Physical examination

There is typically an antalgic gait and focal tenderness over the specific ligaments involved. Swelling of the soft tissues and possibly the tibiotalar joint in grade 2 sprains occur due to the intracapsular location of the ATFL. Stability of the involved ligaments should be assessed. The anterior drawer test assesses the integrity of the ATFL by applying a force anteriorly displacing the talus from the tibia. The CFL can be assessed by the talar tilt test, which applies an inversion force to the foot relative to the leg. The bony anatomy should be fully examined for fracture. Sensorimotor examination should be performed to assess for sural or common peroneal nerve injury.

Functional assessment

A full gait and kinetic chain assessment should be performed because ankle pain and instability can place undue stress at more proximal joints. The unaffected ankle should be assessed because inherent laxity or poor strength or flexibility may be an underlying risk factor. Proprioception and balance should be assessed. Static and dynamic hip abduction strength, single leg stance assessment, single leg squat, and forward stepdown tests can be useful.

Laboratory studies

None typically indicated.

Imaging

Plain radiographs (AP, lateral, mortise views) may be indicated to rule out avulsion fractures, osteochondral defects of the talar dome, and fractures of the 5th metatarsal head. Ultrasound may be used to assess the integrity of the ATFL, CFL and PTFL, and to assess for tibiotalar effusion, occasionally loose bodies and defects of the talar dome. Ultrasound has the advantage of assessing ankle stability with real-time stress views. Magnetic resonance imaging (MRI) is typically the study of choice to assess both intra-articular and extra-articular manifestations of lateral ankle sprains, but is less cost effective, may have inferior resolution for partial tears compared to ultrasound, and is rarely indicated for acute sprains.

Supplemental assessment tools

The Ottawa ankle rules were developed and validated to clarify the indications for plain radiographs, and have been shown to reduce x-ray utilization 30% while missing no major fractures (Stiell et al. 1992). The rules state that ankle radiographs are indicated if tenderness exists at the posterior half of the lower 6 cm of the tibia or fibula and the patient is unable to bear weight both immediately post-injury and in the emergency department (within 10 days of injury). Foot radiographs are indicated if there is bony tenderness over the navicular and/or 5th metatarsal head and an inability to bear weight, as described above.

Early predictions of outcomes

Occupational injuries to the ankle can get a rating from the AMA impairment guides.

Environmental

Risk factors for ankle sprain should be assessed, including the types of surfaces the patient works on or an athlete competes on. Footwear should be assessed and high top sneakers or high work boots should be utilized to prevent injury, if necessary.

Social role and social support system

Highly competitive athletes and performing artists may require psychological support to cope with the stress of not being able to perform. Injured workers may have better outcomes if they are returned to work sooner with restrictions in place instead of being kept out altogether. A fully disabled worker can suffer from lost self-esteem and depression from being taken from his or her role as a household breadwinner.

Professional Issues

Professional athletes have contractual obligations to fulfill their team roles and physicians may feel pressure from coaches, athletic trainers, the public or the athlete to return to play prematurely, resulting in re-injury. For injured workers there may be pressure from the employer to return the patient or difficulty in accommodating work restrictions. Patients may have less incentive to improve if there is pending litigation.

3. REHABILITATION MANAGEMENT AND TREATMENTS

Available or current treatment guidelines

Although no specific guidelines exist, treatment approaches are fairly standardized but also diverge along two pathways. The first pathway is a more conservative one in which bracing and rest dominate the early parts of treatment, maybe even including casting. The other extreme is to allow for as much mobilization as quickly as possible which can occur with effective early edema control and motion. Studies have shown the early mobilization approach to be superior to “standard” care involving relative rest and PRICE protocol (Bleakley 2010) for improving pain and functional outcomes in the short term.

At different disease stages

New onset/acute

  1. Potential curative interventions:
    In high ankle sprains, the clinician needs to look for clinical and radiographic signs of instability or fractures that may require surgical intervention. Rarely, aggressive trauma can produce ankle dislocation and even possible neural or vascular compromise that could require urgent surgical intervention.
  2. Symptom relief:
    Most ankle sprains receive PRICE therapy as the mainstay of acute care. This consists of protection, relative rest, ice, compression and elevation to reduce swelling, minimize pain and loss of ROM. Rarely, a walking boot is indicated for severe sprains or if radiographs are not available to rule out fracture; casting should be avoided. Crutches may be needed for protected weight bearing but long-term use should be discouraged.
  3. Rehabilitation strategies intended to stabilize or optimize function or prepare for further interventions at later disease stages:
    In the MEAT approach (Movement, Exercise, Analgesics, Treatments) ankle strengthening is the goal.

Subacute

  1. Secondary prevention and disease management strategies:
    Functional rehabilitation should be stressed, with ROM exercises instituted immediately after injury to promote stronger collagen formation and more organized scar tissue. Patients are typically instructed in alphabet exercises to maintain ROM, and rubber band exercises for strengthening. Dorsiflexion and eversion strengthening should be stressed for lateral ankle sprains. Proprioceptive exercises are extremely important to prevent sprain recurrence and to facilitate return to sport.

Symptom relief

  1. Control pain and edema with oral or topical anti-inflammatories, and cryotherapy, includes rehabilitation strategies that intend to optimize function.
    Minimizing pain and swelling, using elastic bandages, tape, lace-up ankle supports, or semi-rigid ankle supports allows for functional rehabilitation. This approach has been shown to result in a quicker return to sports and work compared with immobilization. Semi-rigid ankle supports (stirrup braces) are often used to permit flexion and extension while minimizing inversion stress on injured ligaments and have been shown to be preferable to the use of elastic bandage or tape.

Chronic/stable

  1. Secondary prevention and disease management strategies:
    Surgery is not shown to be effective for third- degree ankle sprains. It is indicated for widening of the ankle mortise or for certain fractures. Chronic pain may result from incomplete rehabilitation, so at this stage an increased focus on eversion strengthening should occur.
  2. Palliative strategies:
    Bracing often helps improve function in cases of chronic pain.
  3. Symptom relief:
    Continue with analgesics, and perform icing after activity.
  4. Rehabilitation strategies intended to optimize function:
    Patients should be weaned off of ankle braces in order to facilitate complete balance training, weight bearing, and functional restoration. Adding proprioceptive training may improve outcome and prevent recurrence.

Pre-terminal or end of life care

  1. Symptom relief:
    For patients with dementia, a removable cast or walking boot may be needed to maintain functional mobility.

Coordination of care

Professional athletes have contractual obligations to fulfill their team roles and physicians may feel pressure from coaches, athletic trainers, the public or the athlete to return to play prematurely resulting in re-injury. It is the physician’s role to design and ensure completion of a proper ankle rehabilitation program. For injured workers there may be pressure from the employer to return to work so it is the physician’s job to ensure safe accommodations versus ordering good work directed rehabilitation.

  1. Parallel practice: Patients may be rehabilitating but still working, competing or performing.
  2. Coordinated: Employers, coaches and family may need to be involved to promote a successful outcome.
  3. Multidisciplinary: Athletic trainers, physical therapists, orthotists may be utilized.
  4. Interdisciplinary: Orthopedic surgeons or podiatrists can be consulted in refractory cases.
  5. Integrated: n/a

Patient & family education

It is important to encourage early mobility and to review the home exercise program and balance training. The patient should be well versed on the proprioceptive and sports-specific program. The family can help encourage exercises.

Emerging/unique Interventions

IMPAIRMENT-BASED MEASUREMENT

Time off from work, performance or athletics can be used to estimate severity or to chart treatment outcomes.

MEASUREMENT OF PATIENT OUTCOMES

Outcomes measures for research purposes include the Foot and Ankle Outcome Score (FAOS), Karlsson’s scale, return to work or sport, or the more generalized SF-36. VAS scores can help track pain.

Translation into practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills

Often disagreements exist among clinicians about how aggressively to treat or when to transition the patient from ice and rest only to the mobilization and rehabilitation phases of treatment.

4. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE

Cutting edge concepts and practice

Ultrasound is being used more for diagnosis and guided intervention such as prolotherapy, PRP and autologous stem cell treatments.

EMERGING/UNIQUE INTERVENTIONS

There may be a role for regenerative therapy for torn ligaments, such as prolotherapy, platelet-rich plasma, or bone marrow or fat aspirates, but the effectiveness of these treatments is not yet fully proven. One study was performed in the ED involving PRP injection for acute ankle sprains; there was no significant difference in outcome in the PRP group but the study had significant flaws limiting the ability to draw meaningful conclusions. (Rowden 2015)

5. GAPS IN THE EVIDENCE-BASED KNOWLEDGE

Gaps in the evidence-based knowledge

Evidence on the role of surgery for chronic ankle instability is conflicting, and evidence on regenerative therapies to improve ligament healing is incomplete.

REFERENCES

Bibliography

Kemler E, van de Port I, Backx F, van Dijk NC. A systematic review on the treatment of acute ankle sprain: brace versus other functional treatment types. Sports Med. 2011; 41(3):185-197.

Hubbard TJ, Hicks-Little CA. Ankle ligament healing after an acute ankle sprain: an evidence-based approach. J Athl Train. 2008;43(5):523-529.

Safran MR, Benedetti RS, Bartolozzi AR 3rd, Mandelbaum BR. Lateral ankle sprains: a comprehensive review. Part 1. Etiology, pathoanatomy, histopathogenesis, and diagnosis. Med Sci Sports Exerc. 1999;31(7 suppl):S429-437.

Safran MR, Zachazewski JE, Benedetti RS, Bartolozzi AR, Mandelbaum R. Lateral ankle sprains: a comprehensive review. Part 2. Treatment and rehabilitation with an emphasis on the athlete.[Miscellaneous Article]. Med Sci Sports Exer. 1999;31(7suppl):S438-S447.

Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Worthington JR. A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med. 1992;21(4):384-390.

Van Rijn R, van Ochten J, Luijsterburg P, van Middelkoop M, Koes B, Bierma-Zeinstra S. Effectiveness of additional supervised exercises compared with conventional treatment alone in patients with acute lateral ankle sprains: systematic review. BMJ. Oct 26, 2010; Oct 26:341,c5688.

Rowden A, Dominici P, D’Orazio J, Manur R, Deitch K, Simpson S, Kowalski M, Salzman M, Ngu D. Double-blind, randomized, placebo-controlled study evaluating the use of platelet-rich plasma therapy (PRP) for acute ankle sprains in the emergency department.  The Journal of Emergency Medicine. 2015; 49(4):546-51.

Bleakley CM, O’Connor SR, Tully MA, Rocke LG, Macauley DC, Bradbury I, Keegan S, McDonough SM. Effect of Accelerated Rehabilitation on Function After Ankle Sprain: Randomised Controlled Trial. BMJ. 2010;340:c1964.

Original Version of the Topic:

Jonathan Kirschner, MD. Ankle Sprain. Publication Date: 2012/11/04.

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