Subtalar dislocation

Background

• Usually high-energy trauma
• 80% medial dislocations
• 25% open, with lateral more likely
• Associated with fractures ~50%

Differential Diagnosis

Foot diagnoses

Acute

• Foot and toe fractures
• Subtalar dislocation
• Metatarsophalangeal joint sprain (turf toe)
• Acute arterial ischemia
• Calcaneal bursitis

Subacute/Chronic

• Diabetic foot infection
• Peripheral artery disease
• Plantar fasciitis
• Trench foot
• Ingrown toenail
• Paronychia
• Tinea pedis
• Morton's neuroma
• Diabetic neuropathy

Diagnosis

Talus and subtalar joint

Medial

• Foot displaced to supination
• Talar head superior to navicular on lateral XR

Lateral

• Foot displaced to pronation
• Talar head inferior to navicular on lateral XR

Treatment

• Closed reduction and short leg NWB cast first-line, with ortho c/s
• Reduce with ankle plantarflexed, then hindfoot inversion/eversion
• Requires CT after reduction for associated fractures

See Also

• Talus fracture

References

• Weatherford B. Talar neck fractures. Orthobullets, last updated 12/19/14. http://www.orthobullets.com/trauma/1048/talar-neck-fractures.
• Judd DB, Kim DH. Foot Fractures Frequently Misdiagnosed as Ankle Sprains. Am Fam Physician. 2002 Sep 1;66(5):785-795.