Normal Anatomy Ossification Order of ossification of tibia: central to medial to lateral Osteology & Attachments Anterior view Anterolateral view Posterior view Medial view Lateral view Superior view Radiographic Views AP view Positioning patient supine knee extended + foot dorsiflexed beam aim at mid-tibiotalar joint Critique lateral malleolus closer to plate open medial joint space + tibiotalar joint closed lateral joint space slight superimposition of talus + fibula increased by ER + decreased by IR Mortise view Positioning patient supine knee extended + leg IR 15° + foot dorsiflexed beam aim at mid-tibiotalar joint Critique slight superimposition of fibula + tibia open lateral joint space + tibiotalar joint closed medial joint space no visualization of sinus tarsi too much IR if visible Lateral view Positioning patient supine knee extended + leg/ankle ER 90° + foot dorsiflexed beam aim at medial malleolus Critique superimposition of medial + lateral malleoli superimposition of talar domes superoinferior plane = lateral dome moves more proximal if proximal tibia higher than distal tibia AP plane = lateral dome moves posterior if too much ER superimposition of fibula + tibia fibula on posterior half of tibia but not superimposing posterior malleolus fibula moves anteriorly if too much IR open tibiotalar joint visualization of pre-talar fat pad requires foot dorsiflexion Oblique view Positioning patient supine knee extended + foot IR/ER 45° beam aim at mid-tibiotalar joint Critique medial/IR open lateral mortise + tibiotalar joint mortise closes with too much IR closed medial mortise slight superimposition of fibula + tibia no superimposition of talus + fibula no visualization of sinus tarsi too much IR if visible lateral/ER superimposition of fibula + tibia Stress view Positioning patient manual stress = supine + knee extended + ankle inverted/everted gravity stress = supine + hip ER + knee flexed + ankle placed on bump beam aim at tibiotalar joint Uses joint stability = < 5° difference between ipsilateral + contralateral ankles ER stress = evaluates syndesmotic/deep deltoid ligament injury IR stress = evaluates LCL injury Normal Radiographic Findings VIEW MEASUREMENT TECHNIQUE NORMAL FINDINGS Tib-fib clear space AP/mortise measure 1 cm above joint < 6mm Tib-fib overlap AP/mortise measure at maximum overlap > 6mm or 42% fibular width on AP view; > 1mm on mortise view Talar tilt AP/mortise difference in width of superior clear space < 2mm or < 2° on AP view, < 2mm or 0° on mortise view Talocrural angle mortise angle between intermalleolar line + line perpendicular to tibial articular surface < 83° ± 4° Medial clear space mortise distance between lateral medial malleolus + medial talus ≤ 4mm Shenton's line mortise line along lateral plafond continuous Dime test mortise line along lateral talus + lateral malleolus continuous Hawkin's sign mortise subchondral radiolucent band in talar dome seen 6-8 wks post-injury, results from revascularization of talar body present (absence indicates AVN) Heel-pad thickness lateral shortest distance between plantar calcaneus + skin 23mm in females, 25mm in males (increased in acromegaly) Achilles tendon thickness lateral measure 1-2cm above calcaneus 4-8mm Radiographic Clinical Pearls Ottawa Ankle Rules XRs are indicated if any of the following criteria are met TTP at medial malleolus TTP at lateral malleolus inability to bear weight, i.e. ambulate >4 steps Ankle Effusion Malleolar sign = asymmetrical thickness of soft tissue overlying medial + lateral malleolus Effusion teardrop sign = occurs at anterior/posterior juxta-capsular region Kager’s fat pad = located between FHL + achilles tendons Pediatric Ankle Fracture Classification = Dias-Tachdijian supination-inversion pronation-eversion ER supination-plantarflexion supination-ER Recommended views AP lateral mortise full-length tibia, or proximal tibia, to rule out Maisonneuve-type fracture Treatment criteria nonoperative treatment acceptable if < 2mm displacement + extra-articular CRPP vs. ORIF if > 2mm displacement intra-articular irreducible reduction by closed means Tillaux Fracture Recommended views AP lateral mortise Findings SH III avulsion of AITFL off anterolateral tibia Treatment criteria nonoperative treatment acceptable if < 2mm displacement ORIF if > 2mm displacement Triplane Fracture Recommended views AP lateral mortise Findings consists of 3 parts anterolateral quadrant of distal tibial epiphysis medial and posterior portions of epiphysis with posterior metaphyseal spike tibial metaphysis AP radiograph shows Salter-Harris III lateral radiograph shows Salter-Harris II Treatment criteria nonoperative treatment acceptable if < 2mm displacement CRPP vs. ORIF if > 2mm displacement