Ankle Fractures: syndesmosis

Arash Aminian MD

June 7, 2013

I have no conflicts of interest

20% of all ankle sprains

10% of all ankle fractures

•A deltoid tear can be seen with medial malleolar fracture? T•Medial tenderness is predictive of deep deltoid tear? F•Intra-operative post reduction stress views should be performed after lateral malleolus fixation? T

Bone qualityPre-reduction films: energy of injuryPatient factors: BMICommonly mal-reduced: IR or anterior translation

Not every fracture is the sameDon’t be in a hurry

AITF

PITF

Transverse TF

IOS

Deltoid Ligament:

Superficial

Deep: prevents lateral shift and resists ER

Contribution from peroneal/AT

Peroneal artery perforates IO membrane 3 cm proximal to ankle

JBJS 2012

Fibula migrates 2.4 mm and ER with DF

Deltoid cut 2 mm shift/15 degrees valgus – Harper 1987

• Can have a high fibula fx without complete rupture of the IO, deep deltoid

• 39% Weber B – Tornetta JOT 2007

Boden JBJS 1989

Maintain talus in mortise

1 mm shift-42% loss of contact surface RH 1976, 40% Lloyd FAI 2006

2 mm – 49% pressure Zindrick 1985

• Medial Tenderness• Anterior tenderness – nonspecific• ER test• Squeeze test• Check proximal fibula tenderness

• AP WB x-rays• Mortise: Medial clear space• “Shenton’s line”• Talocural angle 83 +/- 4 degrees on

mortise• Tib fib overlap/clear space

Stable vs Unstable

Acute vs Chronic

Latent vs Frank

• Hook test sensitivity/specificity 0.25/0.98• ER test sensitivity/specificity 0.58/0.96

• 3 vs 4 cortices? • 3.5 vs 4.5 mm? Biomechanically similar (FAI

2000)• Location of the screw?

• Postero-lateral to anteromedial

• TSS fixation level above • plafond? 2-5 cm

• Use a clamp? Prevents motion, shifting of the drill hole

• Position of the ankle? DF (JBJS 2001) • HWR?• Fix a high fibula fracture vs only screws?• Fixing the posterior malleolus?

Displacement/stability

• 2 wks in splint, then CAM• NWB 6 wks• WBAT with boot for 6 wks• Counsel about hardware breakage

Thank you