DPT 642: Radiology of the Foot & Ankle

Medial Collateral Ligament

AKA Deltoid Ligament

Fan shape from medial malleolus to the talus, navicular and sustentaculum tali of the calcaneus

Very strong; seldom injured in isolation.

Lateral Collateral Ligament

3 distinct bands extending from lateral malleolus to the talus and calcaneus

Anterior Talofibular (ATFL)

Posterior Talofibular

Calcaneofibular

Tibiofibular Syndesmotic Complex

Considered one of the most important stabilizing structures of the ankle

Consists of 3 structures:

Anterior Tibiofibular ligament

Posterior Tibiofibular ligament

Interosseous Membrane

It's the shortest and weakest of the three lateral ankle ligaments, making it the first to fail during a sprain

why is the anterior talofibular ligamentmost commonly injured ligament

Anteroposterior (AP)

Lateral

Oblique

Basic Recommended Projections for the Foot

Anteroposterior (AP)

AP oblique (mortise)

Lateral

Basic Recommended Projections for the Ankle

Trauma

Osseous changes due to metabolic disease, systemic disease or nutritional deficiency

Neoplasms

Bone pathologies

Infections

Arthopathies (pre-op. post-op, or follow up)

Congenital syndromes or developmental disorders

Vascular lesions

Evaluation of soft tissue

Pain

indication for radiographs of the foot/ankle

Anteroposterior of Ankle (AP)

Demonstrates distal tibia and fibula including the medial and lateral malleoli and dome of talus

AP Oblique (mortise view) of Ankle

Demonstrates the entire ankle mortise.

Achieved by internally rotating the leg 15-20 degrees to place both malleoli in the same plane

Lateral view of the Ankle

Demonstrates the anterior and posterior aspects of the distal tibia, lateral relationship of the tibiotalar and subtalar articulations, the talus and the calcaneus

Lateral view of the Ankle

Observe:

Fibula is superimposed behind the posterior tibia and talus

Anterior tubercle and posterior rim of the tibia are well demonstrated

Subtalar joint

Talus & Calcaneus seen clearly and their articulations with the navicular and cuboid bones.

Stress views of ankle

consists of AP inversion and eversion and anterior talar drawer

Anteriorposterior view of foot

Demonstrates:

Phalanges

Metatarsals

Cuneiforms

Cuboid

Navicular

Sesamoid Bones?

Possible at Met heads 1-3

First Intermetatarsal Angle

Transverse Tarsal Joint (Chopart)

Tarsometatarsal Joint (Lisfranc)

Lateral view of foot

Demonstrates:

Calcaneus

Talus

Subtalar Joint

Chopart

Lisfranc

Tarsal Sinus

Boehler angle AKA tuberosity or Salient angle

Calcaneal Inclination Angle

Oblique view of foot

Foot and leg are medially rotated as a unit approximately 45 degrees from AP view

Severe Trauma

Complex Fractures & Dislocations

Loose Bodies

OCD lesion

Tarsal Coalition

Pre-op Planning

indications for CT of foot/ankle

Alignment of Anatomy

Bone Density

Cartilage and Joint Spaces

Soft Tissues

ABCDS of CT of foot/ankle

Alignment, bone signal, cartilage or joint spaces, edema, soft tissue

ABCDS of MRI

Achilles tendon disorders

Posterior tibial tendon disorders

Ligamentous tears

Osteochondral or articular cartilage abnormalities

Loose bodies

Plantar fasciitis, rupture or fibromatosis

Sinus tarsi syndrome

Synovial based disorders

Marrow abnormalities

Neoplasms

Infections

Arthritides

Tumors

Fractures

Trauma

Instability

Prolonged or refractory ankle pain

indications for MRI of foot/ankle

Ottawa Ankle and Foot Clinical Prediction Rule

States that x-rays should be ordered after ankle or foot trauma IF:

The patient is unable to weight bear AND

The patient has point tenderness in either the malleolar zone midfoot zone, base of fifth metatarsal or navicular

Is 100% sensitive for detecting fractures

inversion sprains

85% of all ankle sprains

Stress the Lateral Collateral ligaments

Anterior talofibular & Calcaneofibular are most commonly injured components

Typically do not result in bony involvement

eversion sprains

Stress the Medial Collateral Ligaments

Generally associated with bony damage

Avulsion fractures

Instability

Tearing of the distal tibiofibular syndesmotic complex

Sinus tarsi syndrome

Impingement syndrome

Associated Injuries with Severe Sprains may include:

Tendinitis or tendinopathy

partial tears in the tendon

tendinosis

micro tearing within the tendon with subsequent healing by disorganized collagen, which has less tensile strength than a normal tendon.

Fractures at the Ankle

MOI: generally axial or rotational loading

Classification:

Unimalleolar

Bimalleolar

Trimalleolar

Other:

Shaft fractures of fibula and tibia

Comminuted fracture of the distal tibia

Intra-articular fractures of the tibial plafond or talar dome

trimalleolar fracture

indication of fracture of BOTH malleoli and the posterior rim of the tibia, sometimes called the third malleolus

bimalleolar fracture

indication of fracture of BOTH the medial and lateral malleolus

unimalleolar fracture

indication of fracture of EITHER the medial or lateral malleolus

hindfoot

most common locations for a fracture in the foot

hindfoot fracture

Calcaneal

MOI: Fall from height

*most fractured tarsal

Classified as intra-articular (three times more common) or extra-articular

Talar

MOI: large force through DF foot

midfoot fracture

Navicular

Most stress fractured tarsal

4 Types:

Dorsal avulsion at deltoid attachment

Tuberosity fractures

Body fractures

Stress fractures

forefoot fracture

MOI: direct trauma like dropping heavy object on them

Classification usually by location

First metatarsal

Second, third or fourth metatarsals

Fifth metatarsal

hallux valgus

Deformity of forefoot in which the first metatarsal is deviated medially and great toe is deviated laterally (greater than 10 degrees)

More common in females

pes cavus

claw foot"

Medial longitudinal arch is abnormally high

Etiology unknown

pes planus

"flat foot"

Classified as:

Rigid (Pathological)

Flexible (Physiological)

Low arch in weight bearing that returns to normal in NWB