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The Journal of Foot & Ankle Surgery 50 (2011) 612–615

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The Journal of Foot & Ankle Surgery

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Lateral Subtalar Dislocation Associated with Bimalleolar Fracture:Case Report and Literature Review

Xavier Conesa, MD 1, V�ıctor Barro, MD 2, David Barastegui, MD 2, Lled�o Batalla, MD3, Jordi Tom�as, MD 3,Vicente Molero, PhD 4

1Orthopedics and Traumatology Surgeon, Department of Orthopedics and Traumatology, Hospital Municipal de Badalona, Barcelona, Spain2Resident in Orthopedics and Traumatology, Department of Traumatology, Hospital Vall d'Hebr�on, Barcelona, Spain3Orthopedics and Traumatology Surgeon, Department of Traumatology, Hospital Vall d'Hebr�on, Barcelona, Spain4Orthopedics and Traumatology Surgeon, Chief of Clinic, Department of Traumatology, Hospital Vall d'Hebr�on, Barcelona, Spain

a r t i c l e i n f o

Level of Clinical Evidence: 4Keywords:anklefibulainjurysurgerytalustibiatrauma

Financial Disclosure: None reported.Conflict of Interest: None reported.Address correspondence to: Xavier Conesa, MD,

Surgeon, Hospital Municipal de Badalona, C/ Eivissa,08186 Spain.

E-mail address: xaviconesa@hotmail.com (X. Cone

1067-2516/$ - see front matter � 2011 by the Americdoi:10.1053/j.jfas.2011.04.034

a b s t r a c t

Subtalar dislocation is an uncommon injury that affects the talocalcaneal and talonavicular joints, with thetibiotalar and calcaneocuboid joints remaining intact. The 4 types of subtalar dislocation are medial, lateral,anterior, and posterior, although the latter 2 are rare. These injuriesdespecially lateral dislocationdoccur asa result of high-energy trauma. Medial dislocation is the most common type, and lateral dislocation is asso-ciated with osteochondral fractures of the talus and calcaneus, as well as with open injuries; hence, its worseprognosis. We report the case of a 62-year-old woman diagnosed with lateral subtalar dislocation accompa-nied by an ipsilateral bimalleolar fracture after a fall downstairs. She underwent emergency reduction of thedislocation under sedation. Surgical treatment of the bimalleolar fracture was delayed 9 days to avoid cuta-neous complications. This is the first report of a subtalar dislocation accompanied by a bimalleolar fracture.

� 2011 by the American college of Foot and Ankle Surgeons. All rights reserved.

Subtalar dislocation was first described in 1811 by Judcy andDufaurest as a displacement of the talonavicular and talocalcanealjoints in which the tibiotalar and calcaneocuboid joints remainedintact. This uncommon injury accounts for less than 1% of all dislo-cations and mainly affects males (6:1 ratio). It presents morecommonly in young adults and generally occurs as a result of high-energy trauma (1–3), falls from height, and traffic accidents,although it can also occur as a sports injury (“basketball foot”) (4). The4 types of subtalar dislocation are medial (accounting for 80% of thetotal), lateral (17%), and 2 rarer types, anterior and posterior (2,5,6).However, some investigators do not consider anterior and posteriordislocations as separate entities, because both usually occur withsome type of mediolateral displacement (7). The mechanism of injuryin medial dislocation is an inversion force applied in the forefoot,during which the neck of the talus pivots with the sustentaculum tali,acts as a fulcrum, and causes first the dislocation of the talonavicularjoint and then the dislocation of the subtalar joint. Lateral dislocationresults from forceful eversion of the foot with the anterior calcaneal

Orthopedics and Traumatologyno. 3 Llic�a d’Amunt, Barcelona,

sa).

an college of Foot and Ankle Surgeon

process acting as a fulcrum where the anterolateral talus pivots. Thecalcaneonavicular ligament is stronger than the talonavicular andtalocalcaneal ligaments; thus, these 2 disrupt and the first remainsintact. In medial dislocations, the navicular bone and calcaneus aredisplaced medially and the head of the talus protrudes dorsolaterally.In contrast, in lateral dislocations, the navicular bone and calcaneusare displaced laterally and the head of the talar bone protrudesmedially (1,6,8). Subtalar dislocation is accompanied by fracture in50% to 100% of cases; fracture is more common in lateral dislocations.The most commonly reported fractures are osteochondral injuries ofthe subtalar and talonavicular joints. Fractures of the ankle andforefoot are uncommon. Deep deltoid and calcaneofibular ligamentinjuries have also been described (6–9).

Case Report

A 62-year-old woman was assessed in the emergency room forpain, deformity, and functional impotence in the left ankle after a falldownstairs. The physical examination revealed marked swelling withdeformity in pronation and abduction, as well as medial protrusion ofthe head of the talus (Fig. 1). The posterior tibial and pedal pulseswere present, and no neurologic deficit was found. A plain radiographrevealed a lateral subtalar dislocation and associated ipsilateralcomminuted fracture of the lateral malleolus and fracture of themedial malleolus (Fig. 2).

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Fig. 1. Clinical deformity of ankle with medial protrusion of head of talus.

X. Conesa et al. / The Journal of Foot & Ankle Surgery 50 (2011) 612–615 613

She underwent immediate closed reduction under sedation.Traction and adduction were applied, and the foot was everted whilepressure was applied to the head of the talus with the knee in flexion.A radiograph revealed correct reduction of the talocalcaneal andtalonavicular joints, with a possible osteochondral fracture of thelateral region of the talus and a bimalleolar fracture by abduction(Fig. 3). Because the reduction was stable, it was immobilized witha dorsal plaster splint for imaging study and definitive treatment.Computed tomography confirmed the presence of an osteochondralfracture on the posterior-external edge of the talus and several smallfragments in the posterior subtalar joint. Both anterior and posteriortalocalcaneal joints were correctly aligned (Fig. 4).

The patient underwent surgery for the bimalleolar fracture 9 daysafter the fall to avoid cutaneous complications owing to the appear-ance of skin blisters on the medial malleolus and swelling. Surgeryinvolved open reduction and internal fixation with a preshaped distalfibular plate and cannulated screws on the medial malleolus (Fig. 5).

Fig. 2. Plain radiograph of lateral subtalar dislocationwith associated bimalleolar fracture.(A) Anteroposterior view; (B) lateral view.

The posterior plaster splint remained in place for 6 weeks, and partialweight bearing was begun at 10 weeks.

At 12 months after surgery, the patient was walking withoutcrutches and reported no pain or instability. The ankle joint range ofmotion was 20� of dorsiflexion and 30� of active plantar flexion, withcomplete subtalar motion limited to 40�.

Discussion

Subtalar dislocations result from high-energy trauma, with theamount of energy greater in lateral lesions. Consequently, associatedchondral injuries, osteochondral fractures, and open subtalar dislo-cations are more frequently associated with lateral dislocations thanwith medial dislocations (2,10–12).

A subtalar dislocation must be reduced as soon as possible toprevent the skin developing blisters, soft tissue necrosis, or neuro-vascular lesions from pressure of the underlying dislocated bone. The

Fig. 3. Plain radiograph after reduction of subtalar dislocation. Note, marked comminu-tion of fibula in bimalleolar fracture. (A) Anteroposterior view; (B) lateral view.

Fig. 4. Computed tomography images of subtalar dislocation showing osteochondralfragments at level of posterior subtalar joint, with intact articular relationship.

X. Conesa et al. / The Journal of Foot & Ankle Surgery 50 (2011) 612–615614

reduction is performed with the patient under sedation or spinalanesthesia. The technique involves flexing the knee at 90� to relax thecalf muscle and enable longitudinal traction to be applied from theheel by countertraction of the leg. The foot is directed into

Fig. 5. Simple postoperative radiographs after osteosynthesis of fibula and medial mal-leolus. (A) Anteroposterior view; (B) lateral view.

plantarflexion to open the subtalar joint with pressure on the head ofthe talus. Next, if the dislocation is medial, pronation or abduction ofthe foot is applied; if it is lateral, counter movements of inversion oradduction of the forefoot are applied (1,6–10). If closed reductioncannot be achieved after a few attempts, open reduction should beused to avoid iatrogenic injury related to excessive manipulation. Thereduction of lateral dislocations is most frequently hampered byinterposition of the posterior tibial tendon and the flexor digitorumlongus. Irreducibility of medial dislocations is associated with inter-position of the short extensor muscle or the extensor retinaculumand, more uncommonly, with bone fragments or the peronealtendons. Open reduction has been reported to be necessary in up to32% of cases in some series (3,6,9,10,13,14).

Peritalar fractures occur in 50% to 100% of dislocations and aremoreprevalent in lateral dislocations; therefore, routine computed tomog-raphy is recommended in all subtalar dislocations (12,15,16). Associa-tion with other fractures of the foot and ankledmetatarsals (6,9),medial malleolus, and lateral malleolus (9)dhas received very littleattention in published studies. Simultaneous occurrence of a bimal-leolar fracture and a subtalar dislocation has not been reported to date.The casewepresent involvedan injurycausedbypronation-abduction,with a transverse fracture of the tibial malleolus and marked commi-nution of the fracture of the fibula at the level of the syndesmosis.

The treatment of choice is immediate reduction and immobiliza-tion with a plaster splint, followed by physiotherapy and progressiveweight bearing. Prolonged cast immobilization increases the residualpain and rigidity (11,17), but short immobilization periods can lead tosubtalar instability (2,9). No agreement has been reached regardingthe length of an adequate immobilization period. DeLee and Curtis (9)described adequate joint stability and normal range of motion after 3weeks immobilization, and Garofalo et al (6) had excellent resultsafter a 4-week cast period in patients with subtalar dislocationwithout associated fractures. Other investigators such as Jungbluthet al (18) and de Palma (17) have recently supported the idea of castimmobilizations for 5- to 6-week periods as the treatment of choice,even in patients without associated bone fractures.

Long-term studies have reported a poorer prognosis for lateralsubtalar dislocations, owing to the greater association with osteo-chondral lesions (1,3,5–8,18). Studies comparing medial and lateraldislocation with no associated fractures have revealed a similarfunctional outcomewith no differences in the onset of arthrosis in themedium term (19). However, other investigators have detecteda greater prevalence of arthrosis in lateral lesions, which theyattributed to the presence of cartilage injuries after high-energytrauma (6).

Lateral subtalar dislocation is an uncommon injury resulting fromhigh-energy trauma. Most cases are associated with peritalar frac-tures and other injuries of the foot and ankle; therefore, computedtomography and specific treatment are recommended. The high-energy nature of these lesions, together with the associated frac-tures, explains their poor prognosis and commonly observed arthriticdegeneration.

References

1. Freund KG. Subtalar dislocations: A review of the literature. J Foot Surg 28:429–432, 1989.

2. Zimmer TJ, Johnson KA. Subtalar dislocations. Clin Orthop Relat Res 238:190–194,1989.

3. Bibbo C, Anderson RB, Davis WH. Injury characteristics and the clinical outcome ofsubtalar dislocations: A clinical and radiographic analysis of 25 cases. Foot AnkleInt 24:158–163, 2003.

4. Grantham SA. Medical subtalar dislocation: Five cases with a common etiology.J Trauma 4:845–849, 1964.

5. Saltzman C, Marsh JL. Hindfoot dislocations: When are they not benign? J Am AcadOrthop Surg 5:192–198, 1997.

X. Conesa et al. / The Journal of Foot & Ankle Surgery 50 (2011) 612–615 615

6. Garofalo R, Moretti B, Ortolano V, et al. Peritalar dislocations: A retrospective studyof 18 cases. J Foot Ankle Surg 43:166–172, 2004.

7. Buckingham WW Jr, LeFlore I. Subtalar dislocation of the foot. J Trauma 13:753–765, 1973.

8. Monson ST, Ryan JR. Subtalar dislocation. J Bone Joint Surg Am 63:1156–1158, 1981.9. DeLee JC, Curtis R. Subtalar dislocation of the foot. J Bone Joint Surg Am 64:433–

437, 1982.10. Merchan EC. Subtalar dislocations: Long-term follow-up of 39 cases. Injury 23:97–

100, 1992.11. Ruiz VT, Miguel-Vielba JA, Hernandez GC, et al. Subtalar dislocation: A study of

nineteen cases. Int Orthop 20:83–86, 1996.12. Sands CL, Daly N, Karlin JM, Scurran BL. Lateral subtalar dislocation: A liter-

ature review and unusual case report. J Am Podiatr Med Assoc 82:162–166,1992.

13. Leitner B. Obstacles to reduction in subtalar dislocations. J Bone Joint Surg Am36:299–306, 1954.

14. Rodriguez-Merchan EC. Subtalar dislocations: A study of 19 cases. Int Orthop21:142–145, 1997.

15. Bibbo C, Lin SS, Abidi N, et al. Missed and associated injuries after subtalardislocation: The role of CT. Foot Ankle Int 22:324–328, 2001.

16. Kou JX, Fortin PT. Commonly missed peritalar injuries. J Am Acad Orthop Surg17:775–786, 2009.

17. de Palma L, Santucci A, Marinelli M, et al. Clinical outcome of closed isolatedsubtalar dislocations. Arch Orthop Trauma Surg 128:593–598, 2008.

18. Jungbluth P, Wild M, Hakimi M, et al. Isolated subtalar dislocation. J Bone JointSurg Am 92:890–894, 2010.

19. Merianos P, Papagiannakos K, Hatzis A, Tsafantakis E. Peritalar dislocation: Afollow-up report of 21 cases. Injury 19:439–442, 1988.