UCSD Musculoskeletal Radiology bonepit.com Ankle alignment

On AP radiograph

Tibiofibular overlap:  N >6mm.   <10mm implies syndesmotic injury

Tibiofibular clearspace:  1cm above ankle.  N<5-6mm.  >10mm  implies syndesmotic injury

Talar tilt:  >2mm difference side to side implies medial or lateral disruption.

On Mortise radiograph

Medial clear space:  >4mm indicates lateral talar shift.

Talocrural angle:  8-15 degrees.  Less indicates fibular shortening

Tibiofibular overlap:  <1mm implies syndesmotic injury

Tibiofibular clearspace:  1cm above ankle.  N <5-6mm.    >10mm implies syndesmotic injury

Talar tilt:  >2mm difference side to side implies medial or lateral disruption.