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Fracture Fridays: A talus as old as time

The case

While taking the dog out our teenage patient slipped and fell awkwardly on an icy sidewalk, getting their foot caught in between the shrubbery and the cement after being pulled down several stairs. The foot was forcefully dorsiflexed upon impact. Their dog was unharmed. There was immediate pain in the anterior mid foot especially when trying to walk home. Bruising and swelling developed shortly thereafter. The patient’s mother noticed the patient hopping on one foot, and a near term visit to the Emergency Department resulted in the following X-Ray – which already has an “arrow sign” from the Radiologist.

From Ortho Bullets – https://www.orthobullets.com/trauma/1049/talus-fracture-other-than-neck

Diagnosis

This is a nondisplaced fracture of the lateral process of the talus. The talus is the second most common tarsal fracture after the calcaneous. Fractures of the head and neck occur with high energy trauma (falls from a height, MVCs). The body and lateral process can be injured in shorter mechanical falls an in sports like snowboarding. Talus fractures make up a small proportion of foot fractures overall, and in order of commonality you’ll see neck > body (includes the dome, lateral and posterior processes, and the body itself) > head.

Notably the talus has no muscular or tendon attachments and this irregularly shaped bone has five surfaces of articulation, most of which are covered by cartilage. It articulates with the fibula, tibia, calcaneous, and navicular bones – and as you’d surmise is important for weight bearing and gait. To get a true sense of how complicate the articulation surfaces are check out these 3D cartoons on Radiopedia (https://radiopaedia.org/cases/anatomy-of-the-talus).

courtesy HSS.edu – https://www.hss.edu/condition-list_osteochondral-lesion-talus.asp

Management

In a way, you can consider the talus to be the “scaphoid of the foot.” Especially for certain neck fractures a limited blood supply increases the risk of avascular necrosis. Let’s briefly take a look at neck, body, and head fractures. Management begins with dedicated foot X-Rays. Some nondisplaced fractures and complicated intraarticular fractures may be better elucidated by getting a CT or MRI. These decisions are best made in conjunction with Orthopedics. In general, you should probably call Ortho that day for most talus fractures. A non displaced stable injury can be splinted or placed in a boot – with crutches provided and non-weight bearing status recommended.

Talus neck fractures are classified according to the eponymous Hawkins nomenclature as seen below in this graphic from Life in the Fast Lane.

From Life in the Fast Lane – https://litfl.com/hawkins-classification/
  • Type I: Nondisplaced talar neck fracture
  • Type II: Talar neck fracture with subtalar dislocation
  • Type III: Talar neck fracture with subtalar and tibiotalar dislocation
  • Type IV: Talar neck fracture with subtalar and tibiotalar and talonavicular dislocation

Type I neck fractures are candidates for nonoperative treatment. Any displacement may necessitate open reduction and internal fixation. This is where CT is quite helpful. (ORIF), highlighting the role of CT in the evaluation of these fractures. Type II require surgical reduction and fixation. Type III and IV neck fractures might need closed reduction in the ED followed by definitive ORIF.

Talus head fractures that are nondisplaced can be managed non operatively with 6-8 weeks of casting. Displaced talar head fractures require surgery to reduce the chance of osteoarthrosis and osteonecrosis.

Talar body fractures can be managed conservatively if nondisplaced – this includes nondisplaced posterior and lateral body fractures in many cases. The case in this post is a great candidate for nonoperative management. Most body fractures end up needing surgery unfortunately. It’s a bit complicated but ORIF is necessary if fracture fragments are either displaced greater than 2 mm or are larger than 1 cm in size.

Take Home Points

  • The talus has a nuanced blood supply and muscular attachments which makes fractures prone to avascular necrosis. That’s why you can consider it the “scaphoid of the foot.”
  • Nondisplaced talus fractures are managed conservatively
  • Displaced talar fractures need surgical intervention
  • CT and MRI can better define the degree of displacement when X-Rays are inconclusive
  • You should contact Ortho on the day of diagnosis for most talus fractures

References

Russell. Talus Fractures. STAT Pearls, October, 2020.

Aiyer. Talus Fracture (other than neck). Ortho Bullets. Accessed December 10, 2020. https://www.orthobullets.com/trauma/1049/talus-fracture-other-than-neck

Cadogan, Hawkins Classification, Life in the Fast Lane. November, 2020. Accessed December 10, 2020. https://litfl.com/hawkins-classification/

Source: PEM Cincinnati

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