Subtalar dislocations: Mechanisms, clinical presentation and methods of reduction

Table 1 Classification of subtalar dislocation and associated mechanism of injury

Direction of dislocation	Percentage of all subtalar dislocations (%)	Position of foot at time of injury	Mechanism of injury
Medial (Calcaneus is medial to talus)	65-85[10]	Plantarflexion	“Acquired club foot”, forceful inversion of forefoot[10], foot locked in supination
Lateral (Calcaneus is lateral to talus)	15-35[18]	Plantarflexion	“Acquired flat foot”, forceful eversion of forefoot[10], foot locked in pronation
Posterior	0.8-2.5[7]	Hyper-plantarflexion	“Shortened foot”, force applied to dorsum of foot leading to hyperplantarflexion[10]
Anterior	1[19]	Hyper-dorsiflexion	“Elongated foot”, forceful foot supination and ankle dorsiflexion[20] or direct rear impact to posterior heel[21]

Table 2 Associated bony injuries with each type of dislocation

Bony involvement	Medial dislocation[28]	Lateral dislocation[28]	Posterior dislocation[29]	Anterior dislocation[30]
Talus	+	+	+	+
Navicular	+	-	-	+
Cuboid	-	+	-	-
Fibula	-	+	+	-
Calcaneum	-	+	-	+

Table 3 Reduction methods as per dislocation anatomy

Direction of Dislocation	Reduction manoeuvre (in addition to traction)	Structures that commonly obstruct reduction	Open reduction approach
Medial	Dorsiflexion and eversion of foot	Talar head, extensor digitorum brevis	Ollier’s approach or anterolateral approach
Lateral	Plantarflexion and inversion of foot	Flexor digitorum longus and tibialis posterior	Direct incision atop of talar head
Posterior	Plantarflexion of foot and once talar head disengages from navicular, the foot is dorsiflexed and tractioned distally
Anterior	Posterior translation of foot whilst under traction