easily missed foot and ankle fractures nordic trauma course 2016

EASILY MISSED FOOT AND ANKLE

FRACTURES

NORDIC TRAUMA COURSE 2016, AARHUS

Ken F. Linnau, MD, MS

Emergency Radiology

Harborview Medical Center – University of Washington

Seattle, WA

Thanks to

Claire K Sandstrom

Harborview Medical Center

Seattle, WA

TARSAL STRESS FX

How many of these radiographs are normal?

Metatarsal stress fractures

• Metatarsals are most common site of stress fracture

• Occur with activity done in excess: hiking, running, marching

• May occur after foot surgery

• Often not evident on initial radiographs

Metatarsal stress fractures: options

• Re-image with radiographs in 7-10

days: cheap

• Bone scan: sensitive

• MRI: fancy, not cheap, sensitive

45 YOF W FOOT PAIN AFTER RUNNING

Sag STIR

Ax T1

Ax T2 FS

Sag T1

34 yom calcaneus fx pinned 2 wks ago,

continued pain

Stress fractures in the foot:

• Any bone except phalanges.

• Metatarsal (2nd and 3rd ): fluffy periosteal reaction.

• Calcaneus: narrow bands of sclerosis @ tuberosity.

• Talus: notoriously missed: consider MRI.

• Navicular: fracture is typically sagittal in orientation:

• External oblique view or CT or MRI.

22 yo bicyclist who crashed

How many fractures do you see?

22 yo bicyclist who crashed

22 yo bicyclist who crashed

The same bicyclist 10 days later

The same bicyclist 10 months later

Tarso-metatarsal (TMT) fracture -

dislocation (Lisfranc)

• Due to forced plantar flexion, twist or

crush.

• Transverse metatarsal ligaments II – V.

• Skip MT I-II (arrow).

• Oblique Lisfranc ligament (yellow).

• Base of MT II locked in mortise

between medial and lateral cuneiform

25 yof car vs. bulldozer

Lisfranc fracture-dislocation:

Unique osseous and ligamentous anatomy

• Predisposition for MT I- II separation

• More disruption with high-energy

• Divergent

• Homolateral

• Radiographic clues

22 yof jumped from 9ft

Click to add text

Stress views!

Every year in July…..

22 yof jumped from 9ft

Stress views:

• Warranted if tender or swollen

• Early diagnosis improves

outcomes of Lisfranc fx

• Ankle block or anesthetic

• Forefoot abduction with fulcrum

at calcaneo-cuboid joint

• Operative indication if TMT joint

displacement > 2 mm

22 yof jumped from 9ft

Lisfranc injury?

Click to add text

45 yof fall from standing height

No Lisfranc on CT!

Metadiaphyseal fracture of the 5th MT

(Jones)

• 1.5 - 2 cm from base of MT V

• Extra-articular

• Propensity for non-union

• Distinguish from avulsion

• Os vesalianum

• Sesamoid of peroneus

tendon

• Common in running athletes

• Inversion or stress-related

46 yo man

persistent

pain

6 weeks

after fall

What o’clock is the important abnormality?

46 yom, ankle pain 6 weeks post fall

46 yom, ankle pain 6 weeks post fall

46 yom, ankle pain, post op

Lateral process of the talus

• Always inspect carefully, if swelling inferior to lat. malleolus

• Fractures usually only seen on AP view

• Contains the lateral portion of posterior facet

• If untreated: premature subtalar osteoarthritis

• Snowboarder fracture

24 yom, basketball injury

Fibula Fx

High Fibula Fx 6 cm above malleolus tip

Post mal Fx

Pron-Ext Rotation Stage IV

NO post mal Fx

Pron-Ext Rotation Stage III

Low Fibula Fx at or below

tibial plafond

Spiral (Low ant/High

post)

Med mal Fx or deltoid lig tear

Sup-Ext Rotation Stage IV

NO med mal fx or deltoid lig tear

Post mal Fx

Sup-Ext Rotation Stage III

NO post mal Fx

Sup-Ext Rotation Stage II

Oblique (Low med/High

lat)

Pron-Abduction

Stage III

Transverse

Med mal Fx (vertical)

Sup-Adduction Stage II

NO med mal Fx

Sup-Adduction Stage I

Modified from

Arimoto HK and Forrester DM. Classification of Ankle

Fractures: An Algorithm. AJR 135:1057-1063 (1980)

http://www.ajronline.org/cgi/reprint/135/5/1057.pdf

Weber B Weber A

Weber C

Joseph Yu’s checklist for low-energy ankle

trauma:

Medial malleolus (1)

Lateral malleolus (2)

Anterior tibial tubercle (3)

Posterior tibial malleolus (4)

Talar dome (5)

Lateral talar process (6)

Posterior talar process (7)

Dorsal to talonavicular joint (8)

Anterior calcaneus process (9)

Calcaneal insertion of ext dig

brev (10)

Base of 5th MT (11)

Emergency Radiology (2009) 16: 309-318

24 yof rock climber: fall

Click to add text

Which side is abnormal?

Click to add text

24 yof rock climber: fall

Joseph Yu’s checklist for low-energy ankle

trauma:

Medial malleolus (1)

Lateral malleolus (2)

Anterior tibial tubercle (3)

Posterior tibial malleolus (4)

Talar dome (5)

Lateral talar process (6)

Posterior talar process (7)

Dorsal to talonavicular joint (8)

Anterior calcaneus process (9)

Calcaneal insertion of ext dig

brev (10)

Base of 5th MT (11)

Emergency Radiology (2009) 16: 309-318

24 yof rock climber: fall

Osteochondral defects:

• Talar dome (5)

• Most common talus fracture

• ¼ lateral, ¾ medial

• MRI can be helpful to assess

stage of injury

24 yof rock climber: fall

Posterior process of the talus (7):

• Medial and lateral tubercles form groove

for flexor hallucis tendon.

• Injury presents with posteromedial pain.

• Os trigonum = unfused lat tubercle.

• Completely corticated

• Synchondrosis anteriorly

• Differentiating os from fracture: CT, MR.

27 yof rolled her ankle

How many fractures do you see?

27 yof rolled her ankle

Anterior process of the calcaneus

(9):

• Insertion of the bifurcate ligament

• Stabilizer of plantar and dorsal

flexion.

• Avulsion fractures uncommon

• Often initially missed.

• Oblique views, CT, MR may help.

• DDX: os calcaneus secundarius

Joseph Yu’s checklist for low-energy ankle

trauma:

Medial malleolus (1)

Lateral malleolus (2)

Anterior tibial tubercle (3)

Posterior tibial malleolus (4)

Talar dome (5)

Lateral talar process (6)

Posterior talar process (7)

Dorsal to talonavicular joint (8)

Anterior calcaneus process (9)

Calcaneal insertion of ext dig

brev (10)

Base of 5th MT (11)

Emergency Radiology (2009) 16: 309-318

Summary:

Stress fractures are often initially radiographically inapparent

Lisfranc fracture dislocations can be subtle, but require

surgery

Talar fractures: lateral process fractures are often subtle,

scrutinize the AP view.

Joe’s ankle check list: try it, you may like it.

klinnau@uw.edu

Selected references:

1. Digiovanni CW, Benirschke SK, Hansen ST. Foot Injuries. In:

Browner BD, Jupiter JB, Levine AM, editors. Skeletal Trauma: WB

Saunders; 2003. p. 2466.

2. Nathan R, Ingraham C. Lower Extremity Trauma. In: Bittle MM,

Gunn ML, Gross JA, Stern EJ, editors. Trauma Radiology Companion.

2nd ed: Lippincott Williams & Wilkins; 2012. p. 376-410.

3. Rogers LF. The Foot. Radiology of Skeletal Trauma: Churchill

Livingston; 2002. p. 1319.

4. Yu JS, Cody ME. A template approach for detecting fractures

in adults sustaining low-energy ankle trauma. Emerg Radiol.

2009;16(4):309-18. Epub 2009/02/19.