Ankle fractures and the Ottawa ankle rules

Ithan D. Peltan, MS IVGillian Lieberman, MDHarvard Medical School

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Agenda

Focused H&P for the injured ankleEpidemiology of ankle injuryOttawa ankle rulesGross and radiologic ankle anatomyApproach to injured ankle radiographsExamples of ankle fractures

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Patient #1: History

A 52-year-old man with no PMH presents to the emergency room 3 hours after tripping over his wife’s cat and “rolling” his left ankle. The pain is worst on the outside of his ankle, which is moderately swollen. When the pain didn’t improve, his wife helped him into a cab which brought him to BIDMC.

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Ankle injury: Focused history

MechanismTimingAudible injuryAssociated injuriesDistal sensation, tinglingAble to ambulate

Significant PMH– Diabetes– Peripheral sensory

impairment– Steroids– Immunosuppression

Previous injuries

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Ankle injury: Focused exam

VitalsGeneralMSK– Appearance / deformity– ROM– Point tenderness– Vascular: Pulses, capillary refill– Neuro: sensation, distal motor– Ambulate four steps

Don’t forget nearby and contralateral joints!

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Patient #1: Physical exam

T 98.2 HR 102 BP 152/92

Knee, hip and bones above ankle all OK.

Left ankle swollen and tender to palpation. Active/passive ROM limited by pain.

Neurovascularly intact: DP/PT pulses intact, capillary refill <2s, toes are warm with intact sensation to light touch. Able to wiggle toes.

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Patient #1: A&P

Resident: Great. What do you want to do next?

Attending: Do we really need one? Can you make an evidence-based decision?

Student: An ankle film?

http://dms.dartm

outh.edu/admissions

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Assessing the need for ankle radiographs

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Epidemiology: Ankle injuries

1.8 million ED visits per year nationally

Chief complaint for 4.3% of ED patients but as high as 10% at some centers

But just 15% of patients presenting with an ankle injury patients have a fracture

Heyworth, 2003McCraig, 2004

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Epidemiology: Ankle injuries at BIDMC

BIDMC —2007– 4,375 ankle films– 3.5% of all plain films– $85 per film

Can estimate 2,200 ED visits/year for ankle injuries at BIDMC

PACS, BIDMC

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medial

The Ottawa ankle rules

Bachmann et al. BMJ, 2003.

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OAR: Sensitivity and specificity

Sensitivity: 98-100%

Specificity: 20-40%

Bachmann et al. BMJ, 2003.

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OAR: Test characteristics

Bachmann et al. BMJ, 2003.

Sensitivity Excellent

Negative predictive value Excellent

Specificity Poor

Positive predictive value Poor

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OAR: Effects28% fewer ankle films

14% fewer foot films

ED stay shorter by 36 minutes

Patient satisfaction: no change

Stiell et al. JAMA, 1994.Annis et al. Ann Emerg Med, 1995

600 less ankle films/year at BIDMC

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OAR: Cost effects

Saves $85* per ankle patient

Nationally, up to $153 million** in annual savings for ED patients alone – Does not include PCP patients!

Annis et al. Ann Emerg Med, 1995.McCaig and Nawar. CDC, 2006.

* $70 technical, $15 professional** Based on data from 2004 CDC survey of

ED utilization and BIDMC reimbursement

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OAR: Caveats

May not apply if:– Impaired lower extremity sensation

• Diabetes• Nerve damage

– Impaired inflammation• Steroids• Immunosuppressed

– Under 18 years

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Patient #1: Additional physical exam

Left ankle tender to palpation over the lateral malleolus and possibly the fifth metatarsal.

OAR positive

Obtain ankle and foot radiographs

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Interpreting ankle radiographs

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Menu of radiologic tests for the acutely injured ankle

Plain filmCT: useful for assessment of complex fractures, detailed assessment of talus and calcaneus, and pre-operative planningMRI: assessment of ligamentous injury

Plain filmCT: useful for assessment of complex fractures, detailed assessment of talus and calcaneus, and pre-operative planningMRI: assessment of ligamentous injury

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Standard radiographic views of the ankle & foot

Ankle plain film: assess for fracture, joint assymetry, or effusion– Core: AP + lateral + mortise

• Mortise view (AP with 15-20˚ internal rotation) assesses joint widening and integrity of tibiotalar articulation

– Additional: Stress view (both ankles)

Foot plain film– AP– Lateral– Internal oblique (lateral foot elevated 30˚)

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Normal ankle plain film

Lateral AP Mortise

PACS, BIDMC

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Ankle and foot gross anatomy

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Bony ankle anatomy

“Interactive ankle.” http://anatomy.tv

TibiaFibula

Talus

Calcaneus

Navicular

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Ligamentous ankle anatomy: Lateral

Lateral collateral ligament

Anterior tibiofibular (syndesmotic) ligament

“Interactive ankle.” http://anatomy.tv

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Ligamentous ankle anatomy: Medial

“Interactive ankle.” http://anatomy.tv

Deltoid / medial collateral ligament

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Fifth metatarsal anatomy“Interactive ankle.” http://anatom

y.tv

Proximal fifth metatarsal

Peroneus brevis muscle/ tendon

Styloid process of 5th metatarsal

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Radiologic “living” anatomy of the ankle and foot

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Living anatomy: Lateral ankle

Calcaneus

Fibula

Tibia

Fifth metatarsal

Talus

Achillesfat triangle

Lateral view

PACS, BIDMC

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Living anatomy: Ankle mortise

Fibula

Tibia

Medialmalleolus

Talus

Mortise

Lateralmalleolus

Fifthmetatarasal PACS, BIDMC

Mortise view

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Living anatomy: Ankle mortise detail

Medial clear space

Mortise

Lateral clear space

Normaltibial-

fibular overlap

PACS, BIDMC

Mortise view detail

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Normal foot plain film

APLateral

APInternaloblique

PACS, BIDMC

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Living anatomy: Lateral foot

Talus

Calcaneus Achillesfat triangle

PACS, BIDMC

Lateral view

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Living anatomy: AP foot

Firstmetatarasal

SesamoidsNavicularMedial

cuneiformPACS, BIDMC

AP view

**

Fifthmetatarasal

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Approach to radiographs of the injured ankle I

QCSoft tissue: – Effusions (Achilles fat pad)– FB

Bone from far: – Density– Shape– Position

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Approach to radiographs of the injured ankle II

Bone from near: – Cortical or periosteal disruptions– Trabeculation

Joint (mortise view): – Congruent– Symmetric– No widening: Medial clear space < 4 mm

Lateral clear space < 5 mm

36What do you see?

Patient #1: Lateral malleolar fracture

Patient #1: 52M s/p L ankle inversion injury

PACS, BIDMC

Fracture Unimalleolar

Details Avulsion fracture affecting the tip of the lateral malleolus

Mech Ankle inversion

Weber A

Stable Yes

Patient #1: Lateral malleolar fracture

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Ankle motion and injury mechanism

Plantarflexion Dorsiflexion

Inversion Eversion

85% of ankle injuries

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Classifying ankle fractures

System Criteria Benefits Problems

Lauge- Hausen

1) Ankle position at time of injury

2) Direction of force

Predicts type of injury

Injury mechanism is rarely provided on requistion

Danis- Weber

Level of fracture of the fibula/lateral malleolus. Can be subdivided based on medial malleolar/tibial involvement.

Evaluation based on radiographic assessment

Poor prognostic usefulness, only predicts the minor determinant of need for ORIF

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Weber classifications IA

BC

Williamson and Schartz. Emergency Radiology, 1999.

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Weber classifications II

B

A

CWilliamson and Schartz. Emergency Radiology, 1999.

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Companion patient #1: Medial malleolar fracture

Companion patient #1: 54F w/ TIDM s/p twisted ankle 1 week ago

PACS, BIDMCWhat do you see?

Fracture Unimalleolar

Details Oblique fracture of medial malleolus with widening of the lateral mortise and edema seen as opacification of the Achilles fat triangle

Mech Ankle eversion

Weber —

Stable No

Companion patient #1: Medial malleolar fracture

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Companion patient #1: Medial malleolar fracture (Lateral view)

54F w/ TIDM s/p twisted ankle 1 week ago

PACS, BIDMC

Fracture Unimalleolar

Details Oblique fracture of medial malleolus with widening of the lateral mortise and edema seen as opacification of the Achilles fat triangle

Mech Ankle eversion

Weber —

Stable No

Companion patient #1: Medial malleolar fracture (lateral view)

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Companion patient #2: 39F s/p fall on rollerblades, left ankle “popped”

Companion patient #2: Bimalleolar fracture

PACS, BIDMC What do you see?

Fracture Bimalleolar

Details Spiral fracture of lateral malleolus. Widened medial and lateral clear spaces and loss of tibiofibular overlap suggest another injury. A closer look …

Mech More forceful ankle inversion

Weber BStable No

Companion patient #2: Bimalleolar fracture

Fracture Bimalleolar

Details Spiral fracture of lateral malleolus. Widened medial and lateral clear spaces and loss of tibiofibular overlap suggest another injury. A closer look: oblique medial malleolus

Mech More forceful ankle inversion

Weber BStable No

Companion patient #2: Bimalleolar fracture s/p ORIF

44What do you see?

Comparison patient #3: 21M s/p inversion injury, tender in mid-foot

Companion patient #3: Fifth metatarsal avulsion fracture (ankle mortise view)

PACS, BIDMC

Comparison patient #3: 5th metatarsal avulsion fx (ankle)

Fracture 5th metatarsal

Details Avulsion fracture of styloid process of 5th metatarsal at the insertion site of the peroneus brevis ligament

Mech Ankle inversion tenses peroneus brevis ligament

Weber —

Stable Yes

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Companion patient #3: Fifth metatarsal avulsion fracture (lateral foot view)

Fracture 5th metatarsalDetails Avulsion fx 5th metatarsal styloid at

peroneus brevis ligament insertionMech Inversion tenses peroneus brevis ligamentWeber —Stable Yes

PACS, BIDMC

21M s/p inversion injury, tender in mid-footComparison patient #3: 5th metatarsal avulsion fx (lateral foot)

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Companion patient #4 58F s/p inversion injury p/w ankle and foot pain

Companion patient #4: Jones fracture

PACS, BIDMC

What doyou see?

Companion patient #4: Jones fracture

Fracture Fifth metatarsal

Details Jones fracture: Transverse fx of fifth metatarsal shaft

Weber —

Mech Ankle inversion with force on lateral foot

Stable Yes

High risk (up to 50%) of non-union without operative intervention

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Companion patient #5 27F s/p fall down stairs, left ankle inversion

Companion patient #5: Trimalleolar fracture

What doyou see?

Fracture Tri-malleolarDetails Spiral lateral malleolar fracture

Transverse medial mallelar avulsionOblique posterior malleolar fracture

Weber BStable No

Companion patient #5: Trimalleolar fracture

Barron and Branfoot, Imaging, 2003

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What doyou see?

Companion patient #6: 43M s/p ankle injury, pain over proximal fibula

Companion patient #6: Maisonneuve fracture

Courtesy Jean-Marc Gauget, MD

Companion patient #6 Maisonneuve fracture

Fracture Proximal fibula

Details Maisonneuve fx: spiral fx of proximal fibular shaft and disruption of tibiofibular syndesmosis

Mech External rotation at ankle transmits through interosseous membrane

Weber CStable No

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SummaryApplication of Ottawa ankle rules safely avoids unneeded radiographs

Reviewed anatomy and developed approach to interpretation of ankle plain film

Reviewed classic malleolar and fifth metatarsal fractures

Joint stability (widening, subluxation) decides need for ORIF in non-displaced fractures

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AcknowledgementsGillian Lieberman, MD

Adam Jeffers, MD

Jean-Marc Gauget, MD

Maria Levantakis

Larry Barbaras

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Bibliography I

Alsobrook J, Hatch RL. (2008) “Proximal fifth metatarsal fractures.” Up-To-Date v. 16.2. Accessed Oct 12, 2008.Annis AH, Stiell IG, Stewart DG, Laupacis A. (1995) Cost effectiveness analysis of the Ottawa ankle rules. Ann Emerg Med 26: 422-428.Bachmann LM, Kolb E, Koller MT, Steurer J, ter Riet G. (2003) Accuracy of Ottawa ankle rules to exclude fractures of ankle and mid-foot: systematic review. BMJ 326: 417-419.Barron D, Branfoot T. (2003) Imaging trauma of the appendicular skeleton. Imaging 15 324-340.Gray, Henry. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918. Available online at: www.bartleby.com/107. Accessed Oct. 7, 2008.Heyworth J. (2003) Ottawa ankle rules for the injured ankle. BMJ 326 405-406.McCraig LF, Nawar EW. (2006) National hospital ambulatory medical care survey: 2004 emergency department summary. CDC Adv Data Vital Health Stats (372). Available at: http://www.cdc.gov/nchs/data/ad/ad372.pdf. Accessed Oct. 14. 2008.

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Bibliography II

Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Worthington JR. (1992) A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med 21: 384-90.Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Reardon M, Stewart JP, Maloney J. (1993) Decision rules for the use of radiography in acute ankle injuries. Refinement and prospective validation. JAMA 269: 1127-1132.Stiell IG, McKnight RD, Greenberg GH, McDowell I, Nair RC, Wells GA, Johns C, Worthington JR. (1994) Implementation of the Ottawa ankle rules. JAMA 271: 827-832.Stiell IG, Wells G, Laupacis A, Brison R, Verbeek R, Vandemheen K, Naylor CD. (1995) Multicentre trial to introduce the Ottawa ankle rules for use of radiography in acute ankle injuries. BMJ 311: 594-597. Wartella J, Cohen R, Schwartz DT. “The foot.” In Emergency Radiology. Schwartz DT, Reisdorf EJ, eds. New York: McGraw-Hill, 1999.Wheeless 3rd CR. Wheeless’ Textbook of Orthpaedics. Williamson B, Schwartz DT. “The ankle and leg.” In Emergency Radiology. Schwartz DT, Reisdorf EJ, eds. New York: McGraw-Hill, 1999.“Interactive Ankle.” Anatomy.tv