LE: Ankle + Foot
talar tilt
AP Inversion + Eversion Stress Views of the Ankle: = refers to displacement of the talus, and it is measured as an angle determined by the intersection of the lines drawn across the tibial plafond and talar dome ontralateral ankle is measured to compare to a baseline. -Normal values: 5°-15° during tilt with forced inversion. -Normal values for talar tilt during eversion are up to 10° -Values significantly greater than this are pathological. -If there is more than a 5° difference compared to the uninjured side ("normal side"), then the tilt is considered significant.
STIR
Coronal Plane _____ MRI:
up
Foot radiographs are examined with the digits pointing ____.
CT scan
Indications for ______ of the Foot and Ankle: Severe trauma Complex fractures and dislocations of the ankle and hindfoot Loose bodies in the joints Osteochondral lesions Tarsal coalition Pre-operative planning Evaluation of any condition seen by MRI if MRI is contraindicated, including use of intraarticular contrast.
T2
Sagittal Plane ______ Weighted MRI
fractures, ligamentous
The difficulty of ankle injuries is the distinction between subtle ankle and foot _____ compared to ______ injuries -clinical presentations very similar -fractures can be missed on initial exam -appropriate imaging studies can minimize delays in appropriate treatment
MRI
______ Indications for Ankle + Foot: -Achilles tendon disorders -Posterior tibial tendon disorders -Peroneal tendon disorders -Anterior talofibular ligament (ATFL), calcaneofibular ligament, deltoid ligament, spring ligament, and syndesmotic ligament tears -Impingement syndromes -Osteochondral and articular cartilage abnormalities -Neurologic conditions -Loose bodies -Plantar fasciitis -Sinus tarsi syndrome -Synovial-based disorders -Marrow abnormalities -Infections or neoplasms of bone, joint, or soft tissue -Congenital and developmental conditions, including dysplasia and normal variants
1. AP 2. AP oblique (sometimes called the mortise view) 3. lateral view
3 Ankle recommended projections
AP, lateral, and oblique views
3 Foot recommended projections
Medial Collateral Ligament (MCL)
= AKA deltoid ligament -fan-shape from medial malleolus to navicular + sustentaculum tali -If injured, likely other injuries due to tensile strength of the ligament.
Trimalleolar fracture
= Fracture of the posterior portion of the tibia + the medial and lateral malleoli -best seen in lateral projection radiograph
Magic Angle Effect
= MRI phenomenon that causes an artificial increase in signal in tissues with ordered collagen (tendons, fibrocartilage, and hyaline cartilage). -when collagen is oriented at 55° to the main magnetic field, the T2 relaxation time is prolonged, resulting in higher signal intensity without any edema. -ankle placed in PF to decrease this effect
Calcaneal inclination
= angle described by the intersection of a line drawn along the plantar surface of the foot and a line drawn tangentially to the inferior surface of the calcaneus. -Normal values: 20°-30° -Higher values (>50°) indicate pes cavus -Lower values indicate pes planus
distal tibiofibular syndesmotic complex
= considered to be crucial in maintaining the width + stability of the ankle mortise -composed of the anterior tibiofibular ligament, the posterior tibiofibular ligament, + interosseous membrane.
ankle
= considered to be the most commonly injured, major weight-bearing joint in the body.
Lateral Collateral Ligament (LCL)
= has three distinct bands named for their origination and insertion: 1. anterior talofibular ligament 2. posterior talofibular ligament 3. calcaneofibular ligament -> injured much more frequently than the deltoid ligament.
Boehler angle
= used to evaluate the angular representation of the talus + calcaneus in the presence of trauma -determined by intersection of lines drawn from the posterior aspect of the subtalar joint to the anterior process of the calcaneus and across the posterior superior margin of the calcaneus. -Normal values: 25°-40° -Lesser values seen with impacted calcaneal fractures
syndesmosis
AP Ankle: This image shows the result of a high ankle sprain, where the ______ is disrupted. -can be assessed by measuring the gap between the distal fibula + tibia in either the AP view or the Ankle Mortise view. -AP Projection because there is still a litle bit of superimposition of the distal fibula over the posterior aspect of the tibia. -Ankle mortise view: no overlapping. -If the distance measures more than 5 mm, there is a high likelihood of disruption.
1. medially, laterally 2. inversion + eversion 3. widen
AP Inversion + Eversion Stress Views of the Ankle: 1. The plantar surface of the foot is turned _____ for the inversion view + ______ for the eversion view 2. If the ankle is stable and ligaments are intact, the ankle mortise will remain relatively constant during the ____ + _____ maneuvers. 3. If an ankle is unstable and the ligaments are disrupted, the mortise will _____: indicates disruption of deltoid ligament (medial talus + medial malleolus) or lateral collateral ligament (lateral talus + lateral malleolus)
1. calcaneous 2. first metatarsal 3. axial oblique + coronal oblique
Advanced Imaging of Foot: 1. An axial imaging plane for the hindfoot may be parallel to the long axis of the _______. 2. An axial imaging plane for the forefoot may be aligned with the shaft of the _____. 3. We refer to these planes as _____ + ______
T2
Axial Plane ______ Weighted MRI
True
T/F: The ankle and foot have separate imaging series
7, 5, 14
The foot consists of 26 bones: ____ tarsals, _____ metatarsals, and _____ phalanges.
1. hindfoot 2. midfoot 3. forefoot
The foot is divided into 3 anatomical segments: 1: talus + calcaneous 2. Navicular, cuboid, + cuneiforms 3. metatarsals + phalanges
standard three orthogonal planes of the body
The planes for MR or CT imaging of the ankle are _____
foot
The three planes of the _____ are more complicated: -sagittal = same -modifications to axial + coronal planes have to be made to align with clinically relevant anatomy to gain visual continuity of major structures
Coronal
______ Plane Proton Density MRI: Structures seen best -Deltoid ligaments -Calcaneofibular ligament -Tarsal tunnel -Talar dome -Subtalar joint -Plantar fascia in cross section
Axial
______ Plane Proton Density MRI: Structures to see -Ankle tendons -Sinus tarsi -Tibiofibular ligaments -Osseous structures tibia, fibula, talus
Sagittal
______ Plane T1 MRI: Structures to see -Achilles tendon -Tibiotalar joint -Subtalar joint -Transverse tarsal joint -Plantar fascia -Sinus tarsi
MR arthrography
______ has been used to help evaluate lateral collateral, ATFL, and calcaneofibular ligamentous injuries, impingement syndromes, cartilage lesions, osteochondral lesions, loose bodies, and synovial joint disorders.
Coronal
_______ Plane CT of Ankle: Structures to see depending on the slice -Ankle mortise -Talus -Subtalar joint -Calcaneus -Talocalcaneal coalition, if present -Sustentaculum tali
Axial
_______ Plane CT of Ankle: Structures to see depending on the slice -The tibiofibular joint space -Medial and lateral malleoli -Calcaneus and talus hindfoot -Sustentaculum tali of calcaneus -Transverse tarsal joint space -Navicular + cuboid -1st, 2nd, and 3rd cuneiform
Sagittal
_______ Plane CT of Ankle: Structures to see depending on the slice: -Anterior and posterior rims of the tibia -Talocrural joint space -Bodies of the talus and calcaneus -Subtalar joint space -Transverse tarsal joint space -Bodies of navicular and cuboid -Three cuneiform bones -Tarsometatarsal joint space -Shafts of metatarsals -Sesamoid bones
conventional radiographs
_______ will usually suffice for detecting bone + soft tissue abnormalities of the foot and ankle. -allow for the diagnosis of the problem, initiation of treatment, or exclude an abnormality + direct further imaging -limited in their ability to show bone density changes + usually show the changes after a significant loss of density. -unable to differentiate the soft tissues with specificity
AP oblique (mortise view)
________ Projection of Ankle: = shows the entire ankle mortise. The patient's leg and foot is internally rotated 15°-20° to place both of the malleoli in the same plane.. Identify: -Distal tibia -Distal fibula -Talar dome -Entire ankle mortise
Lateral
________ Projection of Ankle: Identify: -Anterior tubercle and posterior malleolus of distal tibia -Distal fibula superimposed behind the tibia and talus -Tarsal bones -Joints
AP
________ Projection of Ankle: Identify: -Distal tibia -Distal fibula extending below the medial malleolus -Proximal talus or talar dome -Ankle mortise
AP
________ Projection of Ankle: Things to check for: 1. The lateral malleolus is at least partially superimposed behind the lateral aspect of the talus. 2. Only the upper and medial portion of the ankle mortise are visible. 3. The talar dome is visible as it articulates in the ankle mortise. 4. The medial or lateral shift or displacement of the talus within the mortise may indicate laxity, instability, or fracture. 5. Check for abnormally wide joint spaces between the distal tibia and distal fibula, as this may indicate disruption of the distal tibiofibular syndesmotic complex.
AP oblique (mortise view)
________ Projection of Ankle: Things to check for: 1. The mortise width should be able 3-4 mm over the entire surface of the talus. An extra 2 mm in widening is considered abnormal, which may indicate ligamentous laxity, injury, or fracture. 2. Displacement of the talus to one side of the mortise may indicate ligamentous laxity, injury, or fracture. 3. Although the tibiofibular joint articulation is not well demonstrated in this plane, an abnormally side space between the distal tibia and fibula suggests disruption of the distal tibiofibular syndesmotic complex (>6mm).
lateral
________ Projection of Ankle: Things to check for: 1. The posterior rim (often called the posterior malleolus) + anterior tubercule of the tibia are well seen without fracture. 2. The subtalar joint should be well demonstrated. 3. The talus + calcaneous should be seen in their entirety, as well as their articulations with the navicular and cuboid.
oblique
________ Projection of Foot:
oblique
________ Projection of Foot: = patient's foot + leg are medially rotated as a unit 45° from the AP dorsoplanar view. Identify: -First through fifth digits -First through fifth metatarsals -Cuboid + third cuneiform -Talus, calcaneus, and navicular -Joint spaces at the intermetatarsal and midtarsal joints
AP
________ Projection of Foot: = sole of the foot is placed on top of the image receptor, and the central beam is projected through the top of the foot in a dorsal to plantar direction. -All bones of the forefoot + midfoot are well demonstrated.
AP
________ Projection of Foot: Identify: -Phalanges and their joint spaces -Metatarsals -The first intermetatarsal angle -Sesamoid bones at the first metatarsal head -Tarsals of the midfoot -Transverse tarsal joints
Lateral
________ Projection of Foot: Identify: -Tibia and fibula -Transverse tarsal and tarsometatarsal joints -Talus and calcaneus -Tarsal sinus and subtalar joint
Lateral
________ Projection of Foot: Things you should be able to measure: 1. Boehler angle 2. Calcaneal inclination
Anterior Talar Drawer
________ Stress View = The leg and ankle are in a lateral position. A stress is applied on the posterior aspect of the heel, resulting in anterior transposition of the talus on the tibia -measurement is taken from the posterior aspect of the tibia to the posterior aspect of the talus. -Separation of 5 mm: normal -Separation of up to 10 mm: may or may not be normal. -You have to compare the measurement to the contralateral, unaffected side. -A measurement of greater than 10 mm indicates disruption of the anterior talofibular ligament.
MRIs
_____may be useful to evaluate: -Acute trauma -Prolonged, refractory, or unexplained ankle or heel pain -Ankle or subtalar instability -Ankle and hindfoot injuries in athletes and dancers -Limited or painful ROM -Unexplained swelling, mass, or atrophy, nerve entrapment, tarsal tunnel syndrome -Patients for whom diagnostic or therapeutic arthroscopy is planned -Patients with recurrent, residual, or new symptoms following ankle/foot surgery
Vertebral compression fracture
what injury often occurs in conjunction with calcaneal fracture?
