Ankle & Foot Diagnostic Imaging Arthritis & Trauma I

10% of all fractures. 2nd m/c following femoral neck Fx. Demographics: active young males and older osteoporotic females
Stable Fx: overall prognosis is good
Unstable Fx: require ORIF. 15%-20% chances of 2nd OA.
Role of imaging is to determine the complexity, stability and care planning (i.e., operative vs. conservative)
Weber classification considers tearing of distal tibial-fibular syndesmosis and potential instability
Weber A - below syndesmosis. Stable, typically avulsion of the distal fibular malleolus
Weber B - at the level of syndesmosis: may be outside syndesmosis and stable or tearing syndesmosis and unstable
Weber C - above syndesmosis. Always unstable d/t tearing of syndesmosis
Variations of fractures may involve the position/role of the talus bone during Fx (e.g., abduction, adduction, rotation, etc.) this is known as Lauge-Hanson classification

Reveal infrasyndesmotic Fx of fibular malleolus (Weber A)
Stable Injury
Conservative care in the form of short-leg walking cast/boot can be used. Good recovery. If no evidence of osteochondral injury, relatively low chances of post-traumatic OA
No further imaging required. MRI may help to reveal bone contusion and osteochondral injury

Can be stable or unstable. On occasions, the decision is made during operative exploration.
CT scanning may help with further evaluation
Management: depends on stability. Additional stabilization required if syndesmosis is ruptured

AP, medial oblique and lateral views reveal Weber C - suprasyndesmotic injury with abnormal joint widening d/t disruption of the tib-fib syndesmosis. Very unstable injury.
Occasionally, when Weber C Fx positioned 6-cm from the tip of the lateral malleolus, it may be termed as Pott's ankle Fx (name after Percival Pott's who has proposed the original classification of ankle fractures based on their stability and degree of rotation). The term is somewhat outdated.
Management: operative with additional stabilization of the syndesmosis

Often spiral fracture of the proximal fibula combined with an unstable ankle injury
No immediate ankle fracture is noted radiographically, thus can be missed on ankle views and require tibia and fibula views
Rad features: widening of the ankle d/t syndesmosis tear and sometimes deltoid ligament disruption. Interosseous membrane is torn with proximal fibular Fx caused by pronation with external-rotation force
Management: operative

Above top images Bimalleolar Fx v. unstable, the result of pronation and abduction/external rotation. Rx: ORIF.
Trimalleolar Fx: 3-parts ankle Fx. Medial and lateral malleolus and avulsion of the posterior aspect of tibial plafond. More unstable. Rx: operative

Pediatric Fx affecting older child when the medial side of the physis is closed or about to close with lateral side till open. Avulsion by the anterior tibi-fibular ligament. Complications: 2nd dry/premature OA. Rx: can be conservative if stable by boot cast immobilization.

Salter-Harris classification helps to diagnose and prognosticate physeal injuries.
Helpful mnemonic: SALTR
S: type 1-slip through the growth plate
A: type 2-above, Fx extends into the metaphysis
L: type 3-lower, intra-articular Fx extends through the epiphysis
T: type4, "through" Fx extends through all: physis, metaphysis and epiphysis.
R: type 5, "ruined." Crush injury to physis leading to complete death of the growth plate
Type 1 and 5: present with no fracture
Type 2: has the best prognosis and considered the most common.
Management: referral to a pediatric orthopedic surgeon
Complications: early physis closure, limb shortening, premature OA and others.

Most frequent tarsal Fx. 17% open Fx
Mechanisms: axial loading (intra-articular Fx into sub-talar and calcaneal-cuboid joints in 75% cases). Avulsion by Achilles tendon (m/c in osteoporotic bone). Stress (fatigue) Fx.
Intra-articular Fx carries a poor prognosis. Typically comminuted. Rx: operative.
B/I calcaneal intra-articular fx with associated vertebra compression Fx with associated vertebral compression Fx (T10-L2) often termed Casanova aka Don Juan (Lover's) fx.
Imaging: x-radiography with added "heel view" 1st step. CT scanning is best for Dx and pre-op planning.
Radiography: Bohler's angle (<20-degrees) Gissane angle >130-degrees. Indicate Calcan, Fx.

M/C fractured tarsal bone is the Talus. M/C region: talar neck (30-50%). Mechanism: Axial loading in dorsiflexion. Complications: Ischemic osteonecrosis (AVN) of the talus. Premature (2nd OA). Imaging: 1st step: radiographs, CT can be helpful with further delineation
Hawkins classification helps with Dx, prognosis & treatment. "Hawkins sign' on plain film/CT scan may help with AVN Dx. (above blue arrows indicate good prognosis d/t radiolucent line indicating no AVN because the bone is vascularized and hence resorbed)
Rx: Type 1: conservative with short leg cast or boot (risk of AVN-0-15%), Type 2-4-ORIF (risk of AVN 50%-100%)