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What is the diagnosis?

Open subtalar dislocation with ipsilateral intertrochanteric and femoral shaft fractures (rare combination)

• Pearl: Emergently acting on subtalar dislocations is paramount given the risk of avascular necrosis and they’re easily missed for “ankle dislocation,” which we typically think of as a tibiotalar joint.

Subtalar dislocation statistics [1,2]:

· 68% - 85% reported as medial dislocations

· 28% open, with lateral having a higher proportion than medial of open to closed

· Associated with fractures ~50%

What is the mechanism of injury?

Usually, high-energy trauma with extensive soft tissue injury as seen in this case. 28% of these result in open injuries [1].

What physical exam findings are expected?

Obvious physical exam findings are deformity. If the dislocation is medial, the foot will be displaced to supination. If the dislocation is lateral, the foot will be displaced to pronation.

Which imaging modalities can be used?

In the ED multiple imaging studies can be utilized. X-ray will show dislocation of talocalcaneal and talonavicular joints. In rare occasions, there may also be dislocation of the tibiotalar joint, making it a pantalar dislocation (like our case, all 3 joints were disrupted). If it is a medial subtalar dislocation, the talar head will likely appear superior to the navicular on lateral x-ray. If it is a lateral subtalar dislocation, the talar head will often appear to be inferior to the navicular on lateral x-ray. After reduction, all cases need CT scan to evaluate for occult fractures of the foot [3].

 Image 2. Plain radiographs of the injured lower extremity. Arrow indicating where the talus is. Author’s own images and annotations.

What is the management in the ED?

In the ED, emergent reduction is indicated. Closed reduction and short leg NWB splint first-line, with emergent ortho consult. Reduce with ankle plantar flexed, using axial traction, then hindfoot inversion/eversion. Oftentimes there will be soft tissue interposed that needs to be swept out of the way, such as the peroneal tendons for medial dislocation or posterior tibialis and flexor hallucis longus tendons in lateral dislocations. Note: closed reduction is found to be successful in only 2 out of 3 cases [1]. CT is required after reduction to evaluate for associated fractures.

• Pearl: This is an open fracture so be sure to start antibiotics as quickly as possible. Follow your institutional antibiotic guidelines for open fractures as they can vary slightly from institution to institution. 

When do you consult Orthopedics?

Orthopedic surgery, if available, should be consulted immediately for all subtalar dislocations given these need emergent reduction. Additionally, reduction is frequently difficult and operative management is almost unanimously indicated for either temporary or definitive treatment.