An approach An approach to to

ankle x-raysankle x-raysAric Storck PGY2

(acknowledgement to Dr. Dave Dyck for several slides)

September 11, 2003

ObjectivesObjectives• Review basic ankle fracture classification

• Review x-rays of common ankle fractures

• Discuss management of common ankle fractures

Case 1:Case 1:• 25 year old female

o Jumped off roofo Right ankle paino 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:Ottawa Ankle Rules:• Order ankle x-rays if acute trauma to ankle

and one or more ofo Age 55 or oldero Inability to weight bear both immediately and in ER

(4 steps)o Bony tenderness over posterior distal 6 cm of

lateral or medial malleoli

• Sensitivity ~100%• Specificity ~40%

You have decided to You have decided to order an “ankle x-ray.” order an “ankle x-ray.”

The nurse entering The nurse entering your orders asks your orders asks

which views you want which views you want ……

Ankle X-rays: 3 viewsAnkle X-rays: 3 views• AP

o Identifies fractures of malleoli, distal tibia/fibula, plafond, talar dome, body and lateral process of talus, calcaneous

• Mortiseo Ankle 15-25 degrees internal rotationo Evaluate articular surface between talar dome and

mortise

• Lateral o Identifies fractures of anterior/posterior tibial

margins, talar neck, displacement of talus

AP x-ray:AP x-ray:• Identifies fractures

of o malleolio distal tibia/fibulao plafondo talar domeo body and lateral

process of taluso calcaneous

Tib/fib clear space Tib/fib overlap

AP xrayAP xray

Now apply Now apply what what

you’ve you’ve learned …learned …

• Lateral malleolar fracture

• Tib/fib clear space <5mm

• Tib/fib overlap >10 mm

• No evidence of syndesmotic injury

Mortise X-RayMortise X-Ray• Taken with ankle

in 15-25 degrees of internal rotation

• Useful in evaluation of articular surface between talar dome and mortise

Mortise x-ray:Mortise x-ray:• Medial clear space

o Between lateral border of medial malleous and medial talus

o <4mm is normalo >4mm suggests lateral

shift of talus

Mortise x-ray:Mortise x-ray:• Talar tilt

o Normal = -1.5 to +1.5 degrees (ie. Parallel)

o Can go up to 5 degrees in stress views

o <2mm difference between medial and lateral talar/plafond distances

Lateral x-ray:Lateral x-ray:• Identifies fractures

of o Anterior/posterior

tibial marginso Taluso Displacement of

taluso Os trigonum

Stable vs UnstableStable vs Unstable• The ankle is a ring

o Tibial plafondo Medial malleoluso Deltoid ligamentso calcaneouso Lateral collateral ligamentso Lateral malleoluso Syndesmosis

• Fracture of single part usually stable

• Fracture > 1 part = unstable

Source: Rosen

Walking the Walking the walk ….walk ….Talking the Talking the

talktalk

Ortho is on the phone. They ask you to describe the fracture….

Lauge-Hansen:Lauge-Hansen:• 15 basic types of injury in 5 major

categorieso Described by two words

1.Position of foot at time of injury2.Direction of talus within mortise

causing fractureo Eg: supination-external rotationo Further subdivided into worsening

areas of injury

Danis-WeberDanis-Webero Defines injury based on level of fibular

fracture• A=below tibiotalar joint

o No disruption of syndesmosiso Usually stable

• B=at level of tibiotalar jointo Partial disruption of syndesmosis

• C=above tibiotalar jointo Disrupts syndesmosis to level of fractureo unstable

o THE MORE PROXIMAL THE FIBULAR # THE MORE SEVERE THE INJURY

AO classification:AO classification:• Similar to Danis-Weber scheme

• Takes into account damage to other structures (usually medial malleolous)

• ~2 pages of classificationso Remember them all for your exam!

AO AO classificationclassification

Pott’s classification:Pott’s classification:• Easy to remember

• First degreeo unimalleolar

• Second degreeo bimalleolar

• Third degreeo trimalleolar

Case 2Case 2

Lateral Malleolar Lateral Malleolar FractureFracture

Danis-Weber ADanis-Weber A• Mechanism

o Suppination/adduction (inversion)

• Mortise intact• Stable fracture• Treatment

o Below knee cast

Case 3Case 3

Bimalleolar (lat & Bimalleolar (lat & post malleoli)post malleoli)

• Mechanismo Inversiono Avulsion of

posterior malleolus (post tibiofibular ligament)

• Medial mortise wideo Suggests instability

• Managemento Posterior slabo Orthopedic consult

Source: McRae’s Practical Fracture Treatment

Case 4Case 4

Trimalleolar FracturesTrimalleolar Fractures• Unstable

o Multiple ligamentous injurieso Usually involves syndesmosis

• Treatmento Posterior slabo Urgent orthopedic consultationo ORIF

Source:Rosen

CASE 5

Pilon (tibial plafond) fracturesPilon (tibial plafond) fractures

• Fracture of distal tibial metaphysiso Often comminutedo Often significant other injuries

• Mechanismo Axial loado Position of foot determines

injury

• Treatmento Unstableo X-ray tib/fib & ankleo Orthopedic consultation

Source:Rosen

Case 6Case 6

Tillaux FractureTillaux Fracture• Occurs in 12-14 year olds

o 18 month period when epiphysis is closing

• Salter-Harris 3 injuryo Runs through anterolateral physis until reaches fused

part, then extends inferiorly through epiphysis into jointo Visible if x-ray parallel to plane of fracture (may require

oblique)

• Mechanismo External rotationo Strenth of tibiofibular ligament > unfused epiphysis

Tillaux FractureTillaux Fracture• Management

o Inadequate reduction of articular surface can lead to early OA

o Gap >2mm in articular surface is unacceptableo Advanced imaging techniques may be

necessaryo Early orthopedic consultationo Non-displaced

• NWB below knee casto Displaced

• surgery

Case 7Case 7

Source: Rosen

Maisonneuve FractureMaisonneuve Fracture• Mechanism

o Eversion + lateral rotationo May cause medial malleolar fracture or deltoid ligament disruptiono Injury proceeds along syndesmosis and involves proximal fibula

• Always rule out Maisonneuve fracture in medial malleolar/ligamentous injury

Maisonneuve Maisonneuve FractureFracture

• Mechanismo Eversion + lateral rotationo 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 rotateo Posterior tib-fib ligament

ruptureso Interosseous membrane ripso Gross diastasis

o Dupuytren fracture – dislocation of the ankle

Case 8Case 8

the endthe end