Ankle fractures and the Ottawa ankle rules Ithan D. Peltan, MS IV Gillian Lieberman, MD Harvard Medical School
Agenda Focused H&P for the injured ankle Epidemiology of ankle injury Ottawa ankle rules Gross and radiologic ankle anatomy Approach to injured ankle radiographs Examples of ankle fractures 2
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. 3
Ankle injury: Focused history Mechanism Timing Audible injury Associated injuries Distal sensation, tingling Able to ambulate Significant PMH Diabetes Peripheral sensory impairment Steroids Immunosuppression Previous injuries 4
Ankle injury: Focused exam Vitals General MSK Appearance / deformity ROM Point tenderness Vascular: Pulses, capillary refill Neuro: sensation, distal motor Ambulate four steps Don t forget nearby and contralateral joints! 5
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. 6
Patient #1: A&P Resident: Great. What do you want to do next? Student: An ankle film? http://dms.dartmouth.edu/admissions Attending: Do we really need one? Can you make an evidence-based decision? 7
Assessing the need for ankle radiographs 8
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, 2003 McCraig, 2004 9
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 10
The Ottawa ankle rules medial Bachmann et al. BMJ, 2003. 11
OAR: Sensitivity and specificity Sensitivity: 98-100% Specificity: 20-40% Bachmann et al. BMJ, 2003. 12
OAR: Test characteristics Sensitivity Negative predictive value Specificity Positive predictive value Excellent Excellent Poor Poor Bachmann et al. BMJ, 2003. 13
OAR: Effects 28% fewer ankle films 600 less ankle films/year at BIDMC 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 14
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! * $70 technical, $15 professional ** Based on data from 2004 CDC survey of ED utilization and BIDMC reimbursement Annis et al. Ann Emerg Med, 1995. McCaig and Nawar. CDC, 2006. 15
OAR: Caveats May not apply if: Impaired lower extremity sensation Diabetes Nerve damage Impaired inflammation Steroids Immunosuppressed Under 18 years 16
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 17
Interpreting ankle radiographs 18
Menu of radiologic tests for the acutely injured ankle Plain film CT: useful for assessment of complex fractures, detailed assessment of talus and calcaneus, and pre-operative planning MRI: assessment of ligamentous injury 19
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 ) 20
Normal ankle plain film PACS, BIDMC Lateral AP Mortise 21
Ankle and foot gross anatomy 22
Bony ankle anatomy Fibula Tibia Talus Navicular Calcaneus Interactive ankle. http://anatomy.tv 23
Ligamentous ankle anatomy: Lateral Anterior tibiofibular (syndesmotic) ligament Lateral collateral ligament Interactive ankle. http://anatomy.tv 24
Ligamentous ankle anatomy: Medial Deltoid / medial collateral ligament Interactive ankle. http://anatomy.tv 25
Fifth metatarsal anatomy Peroneus brevis muscle/ tendon Interactive ankle. http://anatomy.tv Styloid process Proximal of 5th metatarsal fifth metatarsal 26
Radiologic living anatomy of the ankle and foot 27
Living anatomy: Lateral ankle Lateral view Talus Tibia Fibula Achilles fat triangle Fifth metatarsal Calcaneus PACS, BIDMC 28
Living anatomy: Ankle mortise Fibula Lateral malleolus Mortise view Tibia Mortise Medial malleolus Talus Fifth metatarasal PACS, BIDMC 29
Living anatomy: Ankle mortise detail Normal tibialfibular overlap Mortise Mortise view detail Medial clear space Lateral clear space PACS, BIDMC 30
Normal foot plain film Internal oblique AP PACS, BIDMC Lateral AP 31
Living anatomy: Lateral foot Lateral view Talus PACS, BIDMC Calcaneus Achilles fat triangle 32
Living anatomy: AP foot Fifth metatarasal AP view * * PACS, BIDMC Sesamoids First metatarasal Medial cuneiform Navicular 33
Approach to radiographs of the injured ankle I QC Soft tissue: Effusions (Achilles fat pad) FB Bone from far: Density Shape Position 34
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 35
Patient #1: 52M s/p L ankle inversion injury Patient #1: Lateral malleolar fracture Fracture Unimalleolar Patient #1: Lateral malleolar fracture Details Mech Weber Stable Avulsion fracture affecting the tip of the lateral malleolus Ankle inversion A Yes PACS, BIDMC What do you see? 36
Ankle motion and injury mechanism Plantarflexion Dorsiflexion 85% of ankle injuries Inversion Eversion 37
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 38
Weber classifications I A B C Williamson and Schartz. Emergency Radiology, 1999. 39
Weber classifications II A B Williamson and Schartz. Emergency Radiology, 1999. C 40
Companion patient #1: Companion patient #1: 54F w/ TIDM s/p twisted ankle 1 week ago Medial malleolar fracture Fracture Unimalleolar Companion patient #1: Medial malleolar fracture Details Mech Oblique fracture of medial malleolus with widening of the lateral mortise and edema seen as opacification of the Achilles fat triangle Ankle eversion Weber Stable No PACS, BIDMC What do you see? 41
Companion patient #1: 54F w/ TIDM s/p twisted ankle 1 week ago Medial malleolar fracture (lateral view) Fracture Unimalleolar Companion patient #1: Medial malleolar Details fracture (Lateral view) Mech Oblique fracture of medial malleolus with widening of the lateral mortise and edema seen as opacification of the Achilles fat triangle Ankle eversion Weber Stable No PACS, BIDMC 42
Companion patient #2: Companion patient #2: 39F s/p fall on rollerblades, left ankle popped Bimalleolar fracture s/p ORIF Fracture Bimalleolar Companion patient #2: Bimalleolar fracture Details Mech Weber Stable 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 More forceful ankle inversion B No PACS, BIDMC What do you see? 43
Comparison patient #3: Comparison patient #3: 21M s/p inversion injury, tender in mid-foot 5th metatarsal avulsion fx (ankle) Fracture 5th metatarsal Companion patient #3: Fifth metatarsal avulsion fracture (ankle mortise view) Details Mech Avulsion fracture of styloid process of 5th metatarsal at the insertion site of the peroneus brevis ligament Ankle inversion tenses peroneus brevis ligament Weber Stable Yes PACS, BIDMC What do you see? 44
21M s/p inversion injury, tender in mid-foot Comparison patient #3: 5th metatarsal avulsion fx (lateral foot) Companion patient #3: Fifth metatarsal avulsion fracture (lateral foot view) Fracture Details Mech Weber Stable Yes PACS, BIDMC 5th metatarsal Avulsion fx 5th metatarsal styloid at peroneus brevis ligament insertion Inversion tenses peroneus brevis ligament 45
Companion patient #4: Companion patient #4 58F s/p inversion injury p/w ankle and foot pain Jones fracture Fracture Fifth metatarsal Companion patient #4: Jones fracture Details Jones fracture: Transverse fx of fifth metatarsal shaft Weber Mech What do you see? Ankle inversion with force on lateral foot Stable Yes High risk (up to 50%) of non-union without operative intervention PACS, BIDMC 46
Companion patient patient #5 #5: 27F s/p fall down stairs, left ankle inversion Trimalleolar fracture Companion patient #5: Trimalleolar fracture Fracture Details Weber Stable Barron and Branfoot, Imaging, 2003 Tri-malleolar Spiral lateral malleolar fracture Transverse What medial domallelar avulsion Oblique posterior malleolar fracture you see? B No 47
Companion patient #6 Companion patient #6: 43M s/p ankle injury, pain over proximal fibula Maisonneuve fracture Companion patient #6: Maisonneuve fracture Fracture Proximal fibula Details Mech Maisonneuve fx: spiral fx of proximal fibular shaft and disruption of tibiofibular What do you see? syndesmosis External rotation at ankle transmits through interosseous membrane Weber Stable C No Courtesy Jean-Marc Gauget, MD 48
Summary Application 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 49
Acknowledgements Gillian Lieberman, MD Adam Jeffers, MD Jean-Marc Gauget, MD Maria Levantakis Larry Barbaras 50
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