Subtalar Dislocations

Author: Brian Weatherford

Topic updated on 12/31/12 2:37pm

Introduction

Typically from a high-energy mechanism
- 25% may be open
- 65% to 80% are medial dislocations
- remaining are lateral dislocations
- case reports of anterior or posterior dislocations
Associated injuries
- associated dislocations
  - talonavicular
  - talocalcaneal
- associated fractures (up to 44%)
  - with medial dislocation
    - dorsomedial talar head
    - posterior tubercle of talus
    - navicular
  - with lateral dislocation
    - cuboid
    - anterior calcaneus
    - lateral process of talus
    - fibula

Presentation

Physical exam
- foot will be locked in supination with medial dislocation
- foot will be locked in pronation with lateral dislocation

Imaging

Radiographs
- medial subtalar dislocation
  - talar head will be superior to navicular on lateral image
- lateral subtalar dislocation
  - talar head will be colinear or inferior to navicular on lateral image
CT scan
- perform following reduction
- look for associated injuries or subtalar debris

Treatment

Nonoperative
- closed reduction and short leg non-weight bearing cast for 4-6 weeks
  - indications
    - first line of treatment
    - 60-70% can be reduced by closed methods
  - technique
    - requires adequate sedation
    - typical maneuvers include knee flexion and ankle plantar flexion
    - followed by distraction and hindfoot inversion or eversion depending on direction of dislocation
    - perform a post-reduction CT to look for associated injuries
Operative
- open reduction
  - indications
    - failure of closed reduction
      - up to 32% require open reduction
      - medial dislocation reduction blocked by lateral structures including
        
        peroneal tendons
        
        extensor digitorum brevis
        
        talonavicular joint capsule
      - lateral dislocation reduction blocked by medial structures including
        
        posterior tibialis tendon
        
        flexor hallucis longus
        
        flexor digitorum longus
      - place temporary transarticular pins as needed if joint remains unstable

Complications

Post-traumatic Arthritis
- long-term follow up of these injuries show degenerative changes
  - Subtalar joint most commonly affected with up to 89% of patients demonstrating radiographic arthrosis (63% symptomatic)

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Qbank (5 Questions)

TAG

(OBQ09.76) A 34-year-old male falls 10 feet from a balcony and is brought to the emergency room with the deformity seen in Figure A. Radiographs shown are shown in Figure B and C. Which of the following structures can block closed reduction of this injury pattern? Topic

Review Topic

FIGURES: A

1. Flexor hallucis longus tendon
2. Extensor digitorum brevis muscle
3. Posterior tibial tendon
4. Tibialis anterior tendon
5. Plantar fascia

PREFERRED RESPONSE ▶

DISCUSSION: Figures A through C show a medial subtalar dislocation. Irreducible dislocations are typically the result of either inadequate sedation or interposed soft tissue structures. In medial dislocations, the extensor digitorum brevis, the deep peroneal neurovascular bundle, or the joint capsule may block a closed reduction.

Bibbo et al found that subtalar dislocations were irreducible 32% of the time and that 88% had ipsilateral foot and ankle injuries. At follow up, 89% of patients demonstrated radiographic changes of the subtalar joint, and had worse function on the side of the subtalar dislocation as demonstrated by lower AOFAS scores.

Incorrect Answers:
Answer 1. The flexor hallucis longus tendon may be a block to closed reduction for lateral subtalar dislocations
Answer 3. The posterior tibial tendon may be a block to reduction for lateral subtalar dislocations
Answer 4. The tibialis anterior tendon does not commonly preclude closed reduction of a subtalar dislocation
Answer 5. The plantar fascia does not block closed reduction of the subtalar joint

REFERENCES:

1. Fischgrund JS (ed): Orthopaedic Knowledge Update 9. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2008, pp 493-509

2. Bibbo C, Anderson RB, Davis WH. Injury characteristics and the clinical outcome of subtalar dislocations: a clinical and radiographic analysis of 25 cases. Foot Ankle Int. 2003 Feb;24(2):158-63. PMID:12627624 (Link to Abstract)

Question Authors:

Brian Weatherford MD, John Badylak MD,

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TAG

(OBQ09.123) A 37-year-old female sustains the injury seen in Figures A and B. At long-term follow up, degeneration of which of the following joints has been shown to have the highest rate of patient symptoms? Topic

Review Topic

FIGURES: A

1. Tibiotalar joint
2. Talonavicular joint
3. Calcaneocuboid joint
4. Lisfranc joint
5. Subtalar joint

PREFERRED RESPONSE ▶

DISCUSSION: Figures A and B show a medial subtalar dislocation, which is more common than a lateral dislocation (65% vs. 35%). The referenced article by Bibbo et al looked at long-term follow up of these patients, and noted that radiographic degeneration of the ankle and subtalar joints were 89%, although 31% of ankle joints were symptomatic and 68% of subtalar joints were symptomatic. Midfoot degeneration was seen radiographically in 72% (15% symptomatic).

REFERENCES:

1. Fischgrund JS (ed): Orthopaedic Knowledge Update 9. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2008, pp 493-509

2. Bibbo C, Anderson RB, Davis WH: Injury characteristics and the clinical outcome of subtalar dislocations: A clinical and radiographic analysis of 25 cases. Foot Ankle Int 2003;24:158-163 PMID:12627624 (Link to Abstract)

Question Authors:

Ben Taylor MD,

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TAG

(OBQ08.175) What is the most common fracture associated with a lateral subtalar dislocation? Topic

Review Topic

1. Distal fibular fracture
2. Cuboid fracture
3. Calcaneus fracture
4. Talus fracture
5. Navicular fracture

PREFERRED RESPONSE ▶

DISCUSSION: The most common tarsal fracture associated with lateral dislocations is the cuboid, although the anterior process of the calcaneus and the lateral process of the talus can also be affected. In medial dislocations, the dorsomedial talar head, the posterior tubercles of the talus, and the lateral navicular are most often fractured.

Post-reduction x-rays need to be scrutinized carefully for fractures of the tarsal bones as this is the most common injury associated with subtalar dislocations. Occult fractures of the lateral process of the talus are also associated with these injuries.

The referenced study by Wagner et al noted radiographic subtalar DJD in 2/3 of their patients, but noted no correlation between radiographic and clinical outcomes. The referenced study by Bibbo et al noted an 88% incidence of other concurrent injuries and an 89% rate of radiographic DJD at 5 year follow-up. The referenced article by Saltzman et al is a review of hindfoot dislocations.

REFERENCES:

1. Wagner R, Battert TR, Weckback A: Talar dislocations, Injury 2004; 35: SB36-SB45 PMID:15315877 (Link to Abstract)

2. Bibbo C, Anderson RB, Davis WH: Injury Characteristics and the clinical outcomes of subtalar dislocations: A clinical and radiographic analysis of 25 cases. Foot Ankle Int 2003; 24: 158-163 PMID:12627624 (Link to Abstract)

3. Saltzman C, Marsh JL: Hindfoot dislocations: When are they not benign? J Am Acad Orthop Surg 1997; 5: 192-198 PMID:10797221 (Link to Abstract)

Question Authors:

Ben Taylor MD,

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TAG

(OBQ08.216) A 30-year-old male falls off the roof and sustains the injury seen in Figure A. Multiple attempts at a closed reduction are attempted, but are unsuccessful. Entrapment of which of the following structures is the most likely reason? Topic

Review Topic

FIGURES: A

1. Peroneal tendons
2. Posterior tibial tendon
3. Extensor retinaculum
4. Anterior tibial tendon
5. Flexor hallucis longus

PREFERRED RESPONSE ▶

DISCUSSION: The radiograph shows a lateral subtalar dislocation with an associated talonavicular dislocation as well. Dislocations of the talonavicular and talocalcaneal joints are often seen with subtalar dislocations and one needs a high index of suspicion in order not to miss this associated injury . Subtalar dislocations are associated with high energy, open(25%), and irreducible (33%) fractures. Lateral subtalar dislocations are thought to result from forceful eversion of a plantar-flexed foot, with the anterior process of the calcaneus acting as a fulcrum around which the anterolateral corner of the talus pivots. The reduction maneuver involves initial traction and foot hyperpronation, followed by supination for lateral dislocations. Lateral dislocations that are irreducible are blocked most commonly by the posterior tibialis tendon. The tendons of the FHL and FDL less commonly block reduction. These dislocations often require emergent open reductions, tendon relocation, and stabilization. Medial dislocations account for 65%, and reduction is often blocked by the extensor digitorum brevis. They are thought to be more common due to the strong buttress of the lateral malleolus. Saltzman and Marsh present a review article about acute hindfoot dislocations and discuss their management and long term follow up. Patients with lateral dislocations, high energy injuries, and open wounds had poor outcomes.

REFERENCES:

1. Saltzman C, Marsh JL: Hindfoot dislocations: When are they not benign? J Am Acad Orthop Surg 1997;5:192-198 PMID:10797221 (Link to Abstract)

2. Bray TJ: Fractures of the hindfoot, in Chapman MW (ed): Chapman's Orthopaedic Surgery, ed 3. Philadelphia, PA, Lippincott, 2001, pp 2953-2981.

3. Heckman JD: Fractures of the talus, in Bucholz RW, Heckman JD (eds): Fracture in Adults, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 2091-2132.

Question Authors:

Jan Szatkowski MD,

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TAG

(OBQ04.153) A 40-year-old male suffers the isolated injury shown in figure A with no associated fractures. What joint is dislocated in this radiograph? Topic

Review Topic

FIGURES: A

1. Tibiotalar
2. Talonavicular
3. Calcaneocuboid
4. First metatarsophalangeal
5. First tarsometatarsal

PREFERRED RESPONSE ▶

DISCUSSION: The radiograph shows a subtalar (talocalcaneal) dislocation with a talonavicular dislocation as well. If subtalar dislocations also involve dislocation of the articulations at both the talonavicular and ankle (tibiotalar) joint, a talar extrusion is seen. Subtalar dislocations are associated with high energy, open (25%), and irreducible (33%) fractures. Medial dislocations account for 65%, and reduction is blocked by the extensor digitorum brevis (EDB). Lateral dislocations that are irreducible are blocked by the posterior tibialis, FHL, and FDL tendons. These dislocations often require emergent open reductions, tendon relocation, and stabilization.

Bibbo et al reported clinical and radiographic outcome on 25 patients and the majority of these patients had radiographic degenerative changes at 5 years follow up.

The review reference by Bohay and Manoli covers subtalar joint dislocations and notes the importance of anatomic reduction to achieve optimal outcomes.

REFERENCES:

1. Bibbo C, Anderson RB, Davis WH. Injury characteristics and the clinical outcome of subtalar dislocations: a clinical and radiographic analysis of 25 cases. Foot Ankle Int. 2003 Feb;24(2):158-63. PMID:12627624 (Link to Abstract)

2. Bohay DR, Manoli A 2nd. Subtalar joint dislocations. Foot Ankle Int. 1995 Dec;16(12):803-8. PMID:8749354 (Link to Abstract)

Question Authors:

Ben Taylor MD, Patrick McCulloch MD, John Badylak MD,

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Evidence & References Show References

Level of Evidence 2 (Prospective Cohort Study)

Wagner R, Battert TR, Weckback A: Talar dislocations, Injury 2004; 35: SB36-SB45 PMID:15315877 (Link to Abstract)

Level of Evidence 3 (Retrospective Cohort Study or Case-Control Study)

Bibbo C, Anderson RB, Davis WH: Injury Characteristics and the clinical outcomes of subtalar dislocations: A clinical and radiographic analysis of 25 cases. Foot Ankle Int 2003; 24: 158-163 PMID:12627624 (Link to Abstract)

Level of Evidence 4 (Case Series)

Bibbo C, Anderson RB, Davis WH. Injury characteristics and the clinical outcome of subtalar dislocations: a clinical and radiographic analysis of 25 cases. Foot Ankle Int. 2003 Feb;24(2):158-63. PMID:12627624 (Link to Abstract)
Bibbo C, Anderson RB, Davis WH. Injury characteristics and the clinical outcome of subtalar dislocations: a clinical and radiographic analysis of 25 cases. Foot Ankle Int. 2003 Feb;24(2):158-63. PMID:12627624 (Link to Abstract)

Level of Evidence 5 and Other Journal Articles (includes Case Reports, Expert Opinions, Personal Observations, and Biomechanic Studies)

Fischgrund JS (ed): Orthopaedic Knowledge Update 9. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2008, pp 493-509
Saltzman C, Marsh JL: Hindfoot dislocations: When are they not benign? J Am Acad Orthop Surg 1997; 5: 192-198 PMID:10797221 (Link to Abstract)
Bohay DR, Manoli A 2nd. Subtalar joint dislocations. Foot Ankle Int. 1995 Dec;16(12):803-8. PMID:8749354 (Link to Abstract)

Textbooks

Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012
AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009
Orthopaedic Knowledge Update 10, John M Flyn. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2011
Hoppenfeld SP. Surgical Exposures in Orthopaedics: The Anatomic Approach. Lipponcott, Williams, and Wilkins, Philadelphia, PA, Copyright 2009
Orthopaedic In-training Examination (OITE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Self-Assessment Examination (SAE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Bray TJ: Fractures of the hindfoot, in Chapman MW (ed): Chapman's Orthopaedic Surgery, ed 3. Philadelphia, PA, Lippincott, 2001, pp 2953-2981.
Heckman JD: Fractures of the talus, in Bucholz RW, Heckman JD (eds): Fracture in Adults, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 2091-2132.

Undefined

Fischgrund JS (ed): Orthopaedic Knowledge Update 9. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2008, pp 493-509
Bibbo C, Anderson RB, Davis WH: Injury characteristics and the clinical outcome of subtalar dislocations: A clinical and radiographic analysis of 25 cases. Foot Ankle Int 2003;24:158-163 PMID:12627624 (Link to Abstract)
Saltzman C, Marsh JL: Hindfoot dislocations: When are they not benign? J Am Acad Orthop Surg 1997;5:192-198 PMID:10797221 (Link to Abstract)

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