Ankle Foot Radiology

-Birth: calcaneus and talus are ossified (cuboid sometimes)
-Centers of ossification appear between 1 and 4 y/o
-Fully ossified at 20 y/o
-Width of foot will change with age

-AP
-AP mortise
-Lateral
-Oblique
-In addition inversion and eversion stress projections may be done

-Distal tibia and fibula
-Medial and lateral malleoli (lat should be lower)
-Head of talus
-Bones of foot superimposed

-Leg is rotated to position the malleoli in the same plane (~15 degrees internal)
-View of the entire ankle mortise (talocrural joint)
-Again the structures of the foot are superimposed and difficult to distinguish
-Note the tibiofibular syndesmosis

-Medial to lateral beam direction
-Lateral aspect is closest to film
-Relationship of the tibia to talus
-Subtalar articulation
-Talus and calcaneus (should see joint space b/t)
-Shows predominantly tri-malleolar fracture
-Can see fat pad

-AP: medial 2 rays, phalanges, stress films
-Oblique: 45 degrees from AP, 1st metatarsal against film; 3rd through 5th rays including phalanges
-Lateral: lateral portion of foot closest to film; talar/calcaneal relationship

note sesamoid bones on 1st ray, maybe 2nd

-Line along the midshaft of the metatarsal
-Line bisecting the talus
-Normal is a straight line
-Weightbearing versus nonWB
-Looking at degree of pes cavus or planus (osteophytes common with high arch)

-Pic is flat foot

-Ankle mortise joint space is viewed
-Normal: inversion 5-15 degrees, eversion 10 degrees

-Inability to bear weight and walk 4 steps immediately after the injury, or on presentation to the emergency department
OR
-Bony tenderness localized to the posterior edge or inferior tip of the lateral malleolus
-Bony tenderness up to 6cm above either malleolus

-Inability to bear weight and walk 4 steps immediately after the injury or on presentation to the emergency department
OR
-Bony tenderness over the navicular
OR
-Bony tenderness over the based of the 5th met

fracture of the 5th met

-Inability to bear weight immediately after the injury
OR
-Point tenderness over the medial malleolus, the posterior edge or inferior tip of the lateral malleolus, talus, or calcaneus
OR
-Inability to ambulate 4 steps in ER
–> Indicate xray ankle (AP, lateral, mortise views)

-Do not meet Ottawa rules and neuro intact (nothing)

-Do not meet Ottawa but neuro not intact (xray ankle)

-Persistent pain, radiographs not obtained at time of injury (xray ankle)

-Persistent pain >1 week, initial radiographs negative (MRI without contrast, xray ankle)

-Radiographs demonstrate talus fracture (CT ankle without contrast)

-Radiographs suggest osteochondral injury (MRI ankle without contrast)

-Radiographs and/or physical exam suggesting syndesmotic injury (xray tib/fib, MRI ankle without contrast)

-Acute injury to the foot
-Positive Ottawa Rules
-Suspicious for fracture
–> These three indicate xray of foot

-Do not meet Ottawa with neuro intact (nothing)

-Do not meet Ottawa but nonintact neuro (xray foot)

-Do not meet Ottawa but have
polytrauma (xray foot)

-Do not meet Ottawa but physical exam indicating Lisfranc injury (xray foot)

-Do not meet Ottawa, physical exam Lisfranc injury, radiographs normal but not able to tolerate WB view (MRI foot without contrast, CT foot without contrast)

-Exam concerning for an acute tendinous rupture or dislocation in foot, radiographs negative (MRI foot without contrast)

-Metatarsal-phalangeal joint injury, suspect plantar plate injury (xray foot)

-Physical exam concerning for penetrating trauma with foreign body in soft tissues (xray foot; if negative, can do US foot)

-Chronic ankle pain of any origin (xray ankle)

-Multiple sites of DJD in hindfoot (image-guided anesthetic injection hindfoot/ankle)

-Suspected osteochondral injury (MRI ankle without contrast)

-Suspected tendon abnormality (MRI ankle without contrast, US ankle)

-Suspected ankle instability (MRI ankle without contrast, MR arthrography ankle)

-Suspected ankle impingement syndrome (MR arthrography, US ankle, CT arthrography ankle, MRI ankle without contrast)

-Pain of uncertain etiology (MRI ankle without contrast)

-Suspected inflammatory arthritis (MRI ankle without and with contrast, MRI ankle without contrast)

-Weakest of the 3 lateral ligaments and is the most commonly injured
-Tenderness in area
-Stress tests positive
-Hematoma, swelling

-Can occur with inversion trauma
-Sensory abnormalities

-Tenderness in area
-Unable to WB
-Swelling

-Typically popping or snapping is heard/felt at time of injury
-Pain and swelling is posterior to lateral malleolus
-Depending on degree, there will be some instability with inversion testing

-2% of all fractures are calcaneal
-75% of these are intra-articular
-Often bilateral
-Mechanism: typically fall from a height
-Associated injuries: spinal, head trauma, LE long bone fractures

-No evidence of acute fracture or malalignment
-Cortically based centrally radiolucent lesion with well-defined sclerotic rim and slightly scalloped contour in distal tibial metaphysis

-Foot positioning with plantar surface flat against receptor
-Beam is directed in a dorsal plantar direction centered in the base of the 3rd met

-Foot positioned at about a 45 degree angle with the medial portion against the receptor
-Beam directed straight down centered on the base of the 3rd met