An approach to ankle x-rays Aric Storck PGY2 (acknowledgement to Dr. Dave Dyck for several slides) September 11, 2003

Objectives Review basic ankle fracture classification Review x-rays of common ankle fractures Discuss management of common ankle fractures

Case 1: 25 year old female Jumped off roof Right ankle pain Inability to weight bear on right foot What else do you want to know on history and physical examination? Does she need x-rays ?

Ottawa Ankle Rules: Order ankle x-rays if acute trauma to ankle and one or more of Age 55 or older Inability to weight bear both immediately and in ER (4 steps) Bony tenderness over posterior distal 6 cm of lateral or medial malleoli Sensitivity ~100% Specificity ~40%

You have decided to order an “ankle x-ray.” The nurse entering your orders asks which views you want …

Ankle X-rays: 3 views AP Identifies fractures of malleoli, distal tibia/fibula, plafond, talar dome, body and lateral process of talus, calcaneous Mortise Ankle degrees internal rotation Evaluate articular surface between talar dome and mortise Lateral Identifies fractures of anterior/posterior tibial margins, talar neck, displacement of talus

AP x-ray: Identifies fractures of malleoli distal tibia/fibula plafond talar dome body and lateral process of talus calcaneous

Tib/fib clear spaceTib/fib overlap

AP xray

Now apply what you’ve learned … Lateral malleolar fracture Tib/fib clear space <5mm Tib/fib overlap >10 mm No evidence of syndesmotic injury

Mortise X-Ray Taken with ankle in degrees of internal rotation Useful in evaluation of articular surface between talar dome and mortise

Mortise x-ray: Medial clear space Between lateral border of medial malleous and medial talus <4mm is normal >4mm suggests lateral shift of talus

Mortise x-ray: Talar tilt Normal = -1.5 to +1.5 degrees (ie. Parallel) Can go up to 5 degrees in stress views <2mm difference between medial and lateral talar/plafond distances

Lateral x-ray: Identifies fractures of Anterior/posterior tibial margins Talus Displacement of talus Os trigonum

Stable vs Unstable The ankle is a ring Tibial plafond Medial malleolus Deltoid ligaments calcaneous Lateral collateral ligaments Lateral malleolus Syndesmosis Fracture of single part usually stable Fracture > 1 part = unstable Source: Rosen

Walking the walk …. Talking the talk Ortho is on the phone. They ask you to describe the fracture….

Lauge-Hansen: 15 basic types of injury in 5 major categories Described by two words 1. Position of foot at time of injury 2. Direction of talus within mortise causing fracture Eg: supination-external rotation Further subdivided into worsening areas of injury Impossible to remember and clinically useless in the ED

Danis-Weber Defines injury based on level of fibular fracture A=below tibiotalar joint No disruption of syndesmosis Usually stable B=at level of tibiotalar joint Partial disruption of syndesmosis C=above tibiotalar joint Disrupts syndesmosis to level of fracture unstable THE MORE PROXIMAL THE FIBULAR # THE MORE SEVERE THE INJURY

AO classification: Similar to Danis-Weber scheme Takes into account damage to other structures (usually medial malleolous) ~2 pages of classifications Remember them all for your exam!

AO classification

Pott’s classification: Easy to remember First degree unimalleolar Second degree bimalleolar Third degree trimalleolar

Case 2

Lateral Malleolar Fracture Danis-Weber A Mechanism Suppination/adduction (inversion) Mortise intact Stable fracture Treatment Below knee cast

Case 3

Bimalleolar (lat & post malleoli) Mechanism Inversion Avulsion of posterior malleolus (post tibiofibular ligament) Medial mortise wide Suggests instability Management Posterior slab Orthopedic consult Source: McRae’s Practical Fracture Treatment

Case 4

Unstable Multiple ligamentous injuries Usually involves syndesmosis Treatment Posterior slab Urgent orthopedic consultation ORIF Trimalleolar Fractures

Source:Rosen CASE 5

Fracture of distal tibial metaphysis Often comminuted Often significant other injuries Mechanism Axial load Position of foot determines injury Treatment Unstable X-ray tib/fib & ankle Orthopedic consultation Pilon (tibial plafond) fractures Source:Rosen

Case 6

Tillaux Fracture Occurs in year olds 18 month period when epiphysis is closing Salter-Harris 3 injury Runs through anterolateral physis until reaches fused part, then extends inferiorly through epiphysis into joint Visible if x-ray parallel to plane of fracture (may require oblique) Mechanism External rotation Strenth of tibiofibular ligament > unfused epiphysis

Tillaux Fracture Management Inadequate reduction of articular surface can lead to early OA Gap >2mm in articular surface is unacceptable Advanced imaging techniques may be necessary Early orthopedic consultation Non-displaced NWB below knee cast Displaced surgery

Case 7 Source: Rosen

Maisonneuve Fracture Mechanism Eversion + lateral rotation May cause medial malleolar fracture or deltoid ligament disruption Injury proceeds along syndesmosis and involves proximal fibula Always rule out Maisonneuve fracture in medial malleolar/ligamentous injury

Maisonneuve Fracture Mechanism Eversion + lateral rotation Causes medial malleolar fracture or deltoid ligament disruption

If injury proceeds along syndesmosis it involves proximal fibula = Maisonneuve Fracture Always rule out Maisonneuve fracture in medial malleolar/ligamentous injury

As talus continues to rotate Posterior tib-fib ligament ruptures Interosseous membrane rips Gross diastasis Dupuytren fracture – dislocation of the ankle

Case 8

the end