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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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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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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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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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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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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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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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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