TaloTarsal DislocationClinical Signs

What are the clues that the talus is not anatomically positioned on the

tarsal mechanism?

Clinical presentation can vary depending on the type of dislocation

(incomplete or complete).

There are external hints indicating internal deformity.

Sometime these clues are subtle, other times they are very obvious.

Complete TaloTarsal Dislocation

• Traumatic injury• Patient is not able to

bear weight on the foot.• Obvious deformity

Not the biggest bunion, but there is an external observation that

something internally is not right.

Have you developed your x-ray vision?

Let’s get started.

Radiographic Evidence of TaloTarsal Dislocation

Michael E. Graham, DPM, FACFAS, FASPS, FAENS

TaloTarsal Joint is Aligned

• This is a “normal” example.• Talotarsal mechanism (TTM) is

neither supinated, nor pronated.

• Articular facets of the TTM are stable.

• Weightbearing forces from above are being transferred though the articular facets in an optimum functioning system.

Is this normal?

• Yes • TTM is balanced, neither

supinated nor pronated.• TTM will function

effortlessly.

What do you think?

• Appears that the talus is no longer aligned on the tarsal mechanism.

• TTM is no longer balanced.• Weightbearing forces are

not being transmitted through the articular facets in a optimal manner.

Does this appear to be normal? What is wrong with this foot?

• Simply that the talus is no longer aligned on the tarsal mechanism.

• This is a pathologic condition.

• This will not resolve on its own.

• It requires physical, physician correction.

What is the difference between these feet?

Talus is not aligned on the

tarsal mechanism.

Talus is aligned on the

tarsal mechanism.

What is the difference between these feet?

Talus is not aligned on the

tarsal mechanism.

Talus is aligned on the

tarsal mechanism.

Talotarsal dislocation (TTD) can lead to a lowering of the arch.

This is due to navicular drop and/or hypermobile/elevated first

ray/metatarsal.

Is this hind-foot normal?

• No• Don’t always see an associated heel

valgus (depends on dominate plane of deformity).

• Transverse plane deformity = forefoot abduction.

Example of Pes Cavus with TTD

• TTD has little to do with the calcaneal inclination angle.

• The talus can still displace on the tarsal mechanism leading to other deformity within the foot.

• This foot exhibits a forefoot valgus, hallux abductovalgus, hyperkeratotic lesion to the plantar medial aspect of the 1st MPJ.

TaloTarsal Dislocation can occur in high arched feet as well as lower

arched feet.

Calcaneal Inclination Angle

Don’t be fooled by limiting your observation to stance position alone. Talotarsal dislocation is a dynamic deformity

best visualized with the patient walking - gait analysis.

TaloTarsal Dislocation - Incomplete

• This is usually a dynamic deformity.• Pathologic condition occurs during the

walking cycle.• Maximum deformity is during walking so

when a patient is just standing, you are not “seeing” the maximum talar displacement.

Gait Analysis

• Abductory Twist• Prolonged period of

pronation• Calcaneal valgus• Pelvic tilt• Shoulder tilt

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TaloTarsal Mechanism

• Relationship of the articular facets of the talus on the calcaneus and navicular.

• 3 bones, 4 articulations• Triplane helicoidal motion• Function is to transfer

vertical forces from above into horizontal forces below.

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Normal

• Articular facets are in constant contact

• Forces are balanced on the articular facets

• “Normal” amount of joint mechanism motion is available (no more, no less)

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Abnormal – TaloTarsal Mechanism

• Articular facets are displaced, one on the other.

• Excessive amount of joint motion is present

• Excessive forces are placed on supporting tissues

• Pathologic condition

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Degrees of deformity

There are various grading levels of deformities from mild to severe. Regardless of its severity- this is still a pathologic condition that will not resolve on its own; it is progressive and will only get worse with time.

Wouldn’t it be better/easier to fix this “sooner than later”?

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TaloTarsal Dislocation

Following the same thought process, there are various stages of talotarsal dislocation from mild to severe. This is also a dynamic,

progressive deformity that if left undiagnosed or undertreated, will lead to many other secondary pathologic conditions within the foot

and also the proximal musculoskeletal chain.

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Normal to abnormal talotarsal alignment

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TaloTarsal Dislocation

• Incomplete – partial displacement– Most common type of TTD– Usually dynamic, recurrent– No associated fractures

• Complete – total displacement– Least common type of TTD– Traumatic etiology– Associated with concomitant fractures.

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Complete TaloTarsal Dislocation

• Total displacement of articular facets.

• Patients are unable to bear weight

• Associated fractures• Traumatically induced

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TaloTarsal Dislocation Partial

• This is not normal• If there is partial

displacement of 1 articular facet to its counter-facet, then the remaining facets will also be displaced.

• Pathologic condition• Results in excessive abnormal

motion and excessive abnormal forces acting on the supporting soft tissues

1. Sagittal plane deformity2. Plantarflexed talus3. Anterior deviation of Cyma4. Obliterated Sinus tarsi5. Increased Talar Declination Angle

Diagnosis- TaloTarsal Dislocation (718.37)

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Is this normal?

• Yes• Talus is fully articulated

with the tarsal mechanism

• Weight/force of the body is anatomically and biomechanically correct. 1. No talotarsal displacement

2. Open Sinus Tarsi3. Normal Cyma

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Is this normal?

• NO• Talus is displaced on the

tarsal mechanism.• Pathologic event.• Deformity is above the

bottom of the foot.

1. Sagittal plane deformity (Increased Talar Declination Angle) Plantarflexed Talus

2. Anterior deviation of Cyma3. Obliterated Sinus TarsiDiagnosis: Chronic TaloTarsal Dislocation (718.37)

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Is this normal?

• NO• Talus is displaced on the

tarsal mechanism• Not anatomically

aligned (triplane deformity)

• Pathologic biomechanical mechanism

1. Plantarflexed talus (sagittal plane deformity)2. Anterior Cyma deviation3. Fully obliterated sinus tarsiDiagnosis: Chronic TaloTarsal Dislocation (718.37)

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Is this normal?

• No• Pathologic alignment• Notice that this is not a

“flat foot.” Take a look at the calcaneal inclination angle. 1. Obliterated sinus tarsi

2. Sagittal plane deformity3. Anterior deviation of Cyma

ICD-9 TaloTarsal Dislocation (718.37)

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Is this normal?

• Yes• Articular facets of the

talus are anatomically aligned with their counterparts on the tarsal mechanism. 1. No sagittal plane deformity

2. Normal Cyma3. “Open” sinus tarsi

CPT: 28585 with HyProCure.

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Is this foot normal?

• Yes• Talus is properly aligned

on the tarsal mechanism.

• Articular facets are aligned and in constant contact. 1. Normal Cyma

2. Normal TaloNavicular facet alignment3. No transverse plane deformity4. Assumed open sinus tarsi on lateral

Normal TaloTarsal Alignment

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Is this normal?

• NO• Medial displacement of

the head of the talus on the navicular.

• Displacement of 1 of the 4 articular facets results in partial displacement of the remaining 3 facets.

1. Transverse plane deformity2. Anterior deviation Cyma3. TaloNavicular displacement4. Assumed obliterated sinus tarsi on lateral radiograph.

Diagnosis- TaloTarsal Dislocation (718.37)

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Is this Normal?

• Yes• No Transverse plane

deformity• No displacement of the

talus on the tarsal mechanism 1. Normal Cyma

2. Normal TaloNavicular Articulation3. No transverse plane deformity

S/p TaloTarsal Stabilization with Internal Fixation- HyProCure (CPT- 28585)

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Point of Observation-

Notice the displacement of the talus on the tarsal mechanism. This particular case has a sagittal and transverse plane deformity with minimal anterior displacement.

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Cardinal Planes of Deformity

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TaloTarsal Dislocation- Sagittal Plane

• Plantarflexion of the talus on the tarsal mechanism indicates a sagittal plane deformity.

• This leads to an anterior pelvic tilt.

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• Medial displacement of the head of the talus with the navicular.

• This leads to excessive strain on the knee and hip.

• Compare the bisection of the talus to the 2nd metatarsal (Talar Second Metatarsal Angle)

TaloTarsal Dislocation- Transverse Plane

What is the easiest way to see a frontal plane deformity on a lateral view?

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• Sustentaculum tali is a great indicator of frontal plane deformity.

• Normal TaloTarsal Mechanism sustentaculum is angled superiorly.

• In a frontal plane TTD deformity it drops plantarly.

TaloTarsal Dislocation- Frontal Plane

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TaloTarsal Dislocation

There can be a single dominant plane of deformity:

– Sagittal > Transverse/Frontal– Transverse > Sagittal/Frontal– Frontal > Transverse/Sagittal

Single Transverse Plane Deformity

Single Transverse Plane Deformity

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TaloTarsal Dislocation

Two dominate planes of deformity:

Sagittal & Transverse > FrontalSagittal & Frontal > TransverseFrontal & Transverse > Sagittal

Transverse & Sagittal

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TaloTarsal Dislocation

• All three planes are involved.

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TaloTarsal Dislocation before/after

“Broken” TaloTarsal Mechanism(718.37)

“Fixed” TaloTarsal Mechanism(28585 with HyProCure)

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