Blunt Ankle Trauma

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Jack Casey, HMS III

Gillian Lieberman, MD

Page 1

Jack Casey, HMS IVGillian Lieberman, MD

Radiographic Evaluation of

Blunt Ankle Trauma



Jack Casey, HMS III


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Overview

• Importance of ankle injuries• Imaging– when, how, and what to look for

• Anatomy review• Common ankle injuries

– Patient cases to illustrate mechanisms of injury and

radiologic classification

Focus on radiology



Jack Casey, HMS III


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Historical Context



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Blunt Ankle Trauma– Still A Major Problem

• Most common MSK injury• Less that 15% of patients have clinicallysignificant fractures

• Ankle films are 3rd

most common radiologic studyordered in many hospitals

• > $500 million spent annually on ankle

radiographs in North America• Clinical guidelines can help guide management

Steill et al. JAMA, 1993.



Jack Casey, HMS III


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Indications for ImagingThe Ottawa Ankle Rules

• Set of clinical guidelines, designed to have

sensitivity of 100% for detecting fractures s/pblunt ankle trauma.

– willing to accept trade-off of lower specificity

• Expected benefits: Limit radiation exposure,

health care costs, ED waiting time.

• Designed to be easy to use



Jack Casey, HMS III


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Ottawa Ankle Rules- The basics

Ankle x-ray series is only

necessary if there is painnear the malleoli and anyof these findings:

1. Inability to bear weightboth immediately and inthe ED (four steps)

2. Bone tenderness atposterior edge or tip of medial or lateral

malleoli.

www.aafp.org/afp/20020901/785.html



Jack Casey, HMS III


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Ottawa Ankle Rules- The basics

Foot x-ray series is only

necessary if there is painin the mid-foot and any of

these findings:

• Inability to bear weight

both immediately and in

the ED (four steps)2. Bone tenderness at base of

fifth metatarsal or the

navicular.

www.aafp.org/afp/20020901/785.html



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Ottawa Ankle Rules- How good are they?

• Systemic review of 27 studies (15,581 patients)

– Sensitivity 96.4 - 99.6 %– Specificity varied widely (10-79%)

– Less than 2% of patients who were negative for fx according to

ankle rules actually had a fracture.

– Missed fractures were almost always minor, did not affect longterm outcomes.

• 28% reduction in use of ankle radiography

• No decrease in patient satisfaction

Bachmann et al. BMJ, 2003.

Steill et al. JAMA, 1993.



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Ottawa Ankle Rules

- A few limitations

• Not applicable to:– <18 y/o

– Altered mental status

– Multi-system trauma

– Chronic/ subacute injuries

• Always trust clinical judgment



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Implementing the OAR

• Thorough (but brief) H+PEvaluate skin/ soft tissue. Assess for open fx.

Check and document neurovascular status

Palpate entire distal 6 cm of both malleoli before askingpatient to bear weight

Palpate over 5th metatarsal and navicular for tenderness

Palpate for tenderness over proximal fibula to exclude

potential Maisonneuve fracture

• Think about underlying anatomy and mechanismof injury



Jack Casey, HMS III


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Basic Anatomy 1- Bones

Interactive

Foot andAnkle. PrimalPictures, Ltc.

Anterior Process

of Calcaneus



Jack Casey, HMS III


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Basic Anatomy 2- Ligaments

Greenspan, Orthopedic Radiology

THREE principal sets of

ligaments support the

ankle, all of which areessential to its stability.



Jack Casey, HMS III


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Basic Anatomy 3- Tendons

Greenspan,

Orthopedic

Radiology



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Anatomy- Putting it All TogetherBones and

connectivetissue give

rise to ring-like

structure

surroundingthe talus.

Rosen’s Emergency Medicine: Concepts and Clinical

Practice.



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Ankle Injuries-Inversion


Remember Ring-

Like Structure in

ConceptualizingInjury.

www.emedicinehealth.com



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Ankle Injuries- Eversion


Remember Ring-

Like Structure in

ConceptualizingInjury.www.x-strap.com



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Appropriate Views

• Must always include:1) AP

2) Mortise (ankle in 10 - 25 degrees of internal rotation)

3) Lateral

• May add additional views in questionablecases (i.e. stress views, comparison views

with uninjured ankle)



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Regions of Interest

• Bones of ankle joint• The fifth metatarsal tuberosity should be

seen in at least one projection.

• Important to visualize anterior process of

the calcaneus.



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Normal AP Radiograph

www.rad.washington.edu



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Normal Mortise Radiograph


Foot internally rotated 10-

35 degrees to allow forimproved visualization of

the mortise.



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AP vs. Mortise Views

AP Mortise

Images from Greenspan, Orthopedic Radiology



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Normal Lateral RadiographNote: ROI not

fully included (5th

metatarsal absent)




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Classifying Fractures

• Anatomic• Weber (AO)

• Other



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Anatomic Classification of Fx

Identifying additional sites of

fracture is not just anacademic exercise– as bi/tri

malleolar fx usually require

othopedics eval, surgical

management.

Greenspan,

OrthopedicRadiology



Jack Casey, HMS III


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Unimalleolar FxPatient 1–

s/p eversion

injury, fall

from 10 feet

Small fx,medial

malleolus

Also note

dislocation

talus

Image from BIDMC PACS



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Bimalleolar FxPatient 2-

“Fall with ankleinversion. Please

r/o fracture”

Images from BIDMC PACS

Mortise View AP view



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Trimalleolar Fx

Patient 3-“Eversion

injury. r/o fx”(ED films)




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Trimalleolar Fx ORIF


Patient 3

(Intra-op)



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Weber Classification of Fx

• Based on the level of fibular fracture

• Used to determine extent of syndesmotic

injury. A<B<C



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Weber APatient 4- s/p

fall with ankleinversion. r/o fx.

BIDMC PACS.

Avulsion fx

below joint line

J k C HMS III



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Weber B

www.wheelessonline.com

Spiral fibular fx:

assoc. with partial

disruption of tibiofibular ligament

J k C HMS III



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Weber C

How would you classify anatomically?

Patient 6—

“s/p ankle

trauma r/o fx”

Bimalleolar (comminuted)

BIDMC PACS.

J k C HMS III



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Recap of Classifications

• Anatomic- Uni/ Bi/ Tri Malleolar

• Weber- A/ B/ C

Jack Casey HMS III



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Fracture 5

th

Metatarsal

BIDMC PACS

Patient 7—

“s/p ankle

inversion injury.

r/o fx”

Jack Casey HMS III



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Fracture 5

th

Metatarsal

Mechanism of Injury

Jack Casey HMS III



Jack Casey, HMS III


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Beyond Simple Radiographs

If pain persists in 6-8 weeks, consider otherimaging modalities:

- MRI (for evaluation of ligaments/ tendons)

- CT

Jack Casey HMS III



Jack Casey, HMS III


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Summary

• Indications for RadiographsOttawa Ankle Rules:

o 4 sites for bony tenderness, 4 steps

o Save time, money, and avoid radiation exposure, withoutsacrificing quality

• Appropriate views, ROI

• Think about anatomy

• Always look for additional fx

Jack Casey HMS III



Jack Casey, HMS III


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Acknowledgements

• Gillian Lieberman, MD• Pamela Lepkowski

• Mary Hochman, MD• Larry Barbaras

Jack Casey, HMS III



Jack Casey, HMS III


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References• American College of Radiology. ACR appropriateness criteria. Imaging evaluation of suspected ankle fractures. www.acr.org

• Anis AH et al. Cost-effectiveness analysis of the Ottawa Ankle Rules. Annals of emergency medicine. 1995.; 26:422-428.

• Bachmann, LM et al. Accuracy of Ottawa ankle rules to exlude fractures of the ankleand the mid-foot: systematic review. BMJ 2003; 326: 417.

• Greenspan, A. Orthopedic radiology. A practical approach. Lipincott, Williams andWilliams. Philadelphia, PA. 2000.

• Marx: Rosen’s Emergency Medicine. Concepts and clinical practice. Fifth ed. 2002,Mosby, Inc.

• Steill IG et al. Implementation of the Ottawa ankle rules. JAMA 1994; 271: 827-832.

• Steill IG et al. Decision rules for the use of radiography in acute ankle injuries.Refinement and prospective validation. JAMA 1993; 269:1127.

• www.aafp.org/afp/20020901/785.html• www.rad.washington.edu

• www.x-strap.com/pix/eversion.jpg

Blunt Ankle Trauma

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