2023 ASM / C-164
Radiograph and Computed Tomography for Ankle Trauma: Making an Impactful Report for Surgical Planning
Type:
Educational Exhibit
Keywords:
Musculoskeletal bone, Musculoskeletal joint, CT, Plain radiographic studies, Education, Surgery, Education and training, Trauma
Authors:
W. Y. Leung, R. Sendanayake
DOI:
10.26044/ranzcr2023/C-164
Imaging findings OR Procedure details
Case 1:
- 53-year-old female, inversion injury to right ankle.
- Injury Classification: Weber A / Lauge-Hansen supination-adduction stage 1 / AO 44A1.3 fracture.
- Mechanism: This is an avulsion fracture resulted by adduction force on the supinated foot, which causes substantial tension to the lateral ligaments.
- Pitfall: medial malleolus can be fractured occasionally, upgrading the fracture to Weber A stage 2 i.e. unstable bimalleolar fracture, see companion case below.
- Management: Non-operative. This patient was managed in a moonboot with ongoing physiotherapy follow up.
Case 2:
- 57-year-old female tripped on right ankle.
- Injury Classification: Weber A / Lauge Hansen supination-adduction stage 2 / AO/OTA 44A2.2.
- Mechanism: Extreme supination-adduction force.
- Pitfall and management: This injury warrants surgical fixation. There is a need to carefully screen for an impaction fracture that can be located at the junction of the plafond and the medial malleolar joint surface, should there be a bony fragment wedged in the “medial corner” space of the tibia, the surgeon will need to reduce this fragment prior to proceeding with an open reduction and internal fixation (ORIF) [3].
Case 3:
- 73-year-old female, “rolled” ankle during step.
- Injury Classification: Weber B / Lauge Hansen supination-external rotation stage 2 / AO/OTA 44B1.1 or 44B1.2.
- Mechanism: This injury is resulted by external rotational force applied to the supinated foot.
- Pitfall: Although on the lateral view there is no clear fracture line seen to indicate a posterior malleolus fracture, it would be vigilant to suggest a CT if there are clinical concerns as this will upgrade the injury and affect management.
- Management: Non operative. This patient was managed in short leg cast, non-weight bearing for 6 weeks.
Case 4:
- 64-year-old female, trip on gravel and fell.
- Injury Classification: Weber B / Lauge Hansen supination-external rotation stage 4 / AO/OTA 44B3.2.
- Mechanism: external rotational force applied to the supinated foot.
- Pitfall: Posterior malleolus fracture can sometime be difficult to detect on radiograph especially if it is non-displaced, therefore, high clinical suspicion of high-level injury warrants supplementary CT to improve diagnostic accuracy.
- Management: This patient had an ORIF with posterolateral approach to reduce the fibula and posterior malleolus and fixed with anatomical plates and locking screws which provides more secure fixation to osteoporotic bone [4]. The displaced fragment of the distal fibula needs to be reduced to restore the fibula length and rotation, and to assess for anterior-posterior translation; this can be achieved with the use of image intensifier to ensure the congruity of the tibio-talar joint.
Case 5:
- 55-year-old female with "twisting" injury to the left ankle.
- Injury Classification: Weber B / Lauge Hansen supination-external rotation stage 4 / AO/OTA 44B3.2.
- Mechanism: external rotational force applied to the supinated foot.
- Pitfall: always consider underlying soft tissue injury associated with high level ankle injury and utilise MRI to guide further management.
- Management: Due to instability of the ankle (and fibula shortening in this case), anatomical reduction of the fracture and surgical fixation is warranted. For this patient, one syndesmotic screw was placed in consideration of osteoporosis for a more secure fixation.
Case 6:
- 67-year-old female, fall, “twisting” the left ankle.
- Injury classification: Weber C / Lauge Hansen pronation-external rotation stage 4 / AO/OTA 44C2.3.
- Mechanism: This fracture pattern is resulted by external rotation force onto the foot in pronation. The continuous force twisting the fibula causing its distal displacement, followed by the disruption of the IOM.
- Pitfall: It is important to image the whole fibula to exclude coexisting proximal fibula injury and shortening.
- Management: Bridging plates are commonly used for fixation of multifragmentary fibula fracture when the distal tibiofubular joint is reduced, the plate will serve as an extramedullary splint joining the two major fragment [5].
- It is recommended to have radiograph of the contralateral uninjured ankle and utilise it as a template to optimise the anatomical reduction and rotation.
Case 7:
- 38-year-old-female, tripped on wet grass.
- Injury Classification: Weber C / Lauge Hansen pronation-external rotation stage 4 / OT/OTA 44C1.3.
- Isolated proximal fibula fracture on radiograph is rare and it almost always associates with other fractures and soft tissue injury. Radiologists should be extra cautious when reporting this kind of injury and supplementary CT is warranted to rule out concurrent medial or posterior malleolus fracture.
- Mechanism: This injury pattern is resulted by external rotation force applied to the pronated foot. With the failure of the medial aspect of the ankle, this frees the talus to move anteriorly with exorotational force in which externally rotate the fibula. This often results in injury or tearing of the AITFL and interosseous ligaments.
- Management: For the ligaments to heal, the tibia and fibula must remain in anatomical position [6]. A technique that was used in this case was a suture-button fixation which can be used when there is a stable fibula length. K-wires are often used for preliminary fixation followed by the confirmation of reduction with image intensifier before fixation using suture-button implants [7].
- Pitfall: In some ankle fractures, a more proximal fibular fracture may not be visible on the initial ankle radiograph due to inadequate field of view. This case demonstrates a vital message that although radiographs of the ankle mortise may be unremarkable at first glance, there can still be an unstable ankle injury, further reinforcing the importance of maintaining high clinical suspicion, meticulous review of initial radiograph and adequate reporting.
Case 8:
- 63-year-old male, thrown over quad bike, impact to right ankle.
- Injury Classification: Weber B / Lauge-Hansen supination-external rotation stage 4.
- Mechanism: external rotational force applied to the supinated foot.
- The use of CT in this case is crucial, as it is difficult to exclude posterior malleolus involvement with the disrupted ankle mortise obscuring the lateral view.
- The AO open fracture classification accesses three components: injury to the skin, muscles and tendons and neurovascular structures. The application of AO classification on open fracture is often performed intraoperatively by surgeons at the time of initial wound debridement [8]. This case can be categorised as AO/OTA IO2 MT2 NV1.
- A more commonly utilised classification for open fractures is the Gustilo-Anderson classification. This patient had a high impact injury and extensive soft tissue damage, making it a Grade IIIA injury [9].
- Management: Timely and meticulous surgical debridement of the injured area and administration of intravenous antibiotics is critical due to high infection risk from an open, and often contaminated, wound [10, 11]. For this patient, the fibula was fixed with plate and screws, followed by insertion of 2 cortex syndesmosis screws as fixation.