wilkerson subtalar joint[1]

8/16/2019 Wilkerson Subtalar Joint[1]

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The Subtalar Joint: An Overlooked Link to

Kinetic Chain Dysfunction

Gary Wilkerson, EdD, ATCUniversity of Tennessee at Chattanooga

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2 “Ankle” Joints

1. Upper Ankle Joint: Talocrural Joint2. Lower Ankle Joint: Subtalar Joint

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Subtalar JointLateral Medial

Superior

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Subtalar Joint

“Lower Ankle Joint”Talo-Calcaneo-Navicular (TCN) Joint

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Subtalar Joint Functional Axis

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Functional Axis of Subtalar JointFunctions like a “mitred hinge”

Rotation of segments in orthogonal planesFoot rotation within frontal planeLeg rotation within transverse plane



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Terminology Defining Motions

Inconsistently defined & extremelyconfusing!

Derived from 18 th Century French, German,and Scandanavian literature pertaining tofracture mechanisms

Eversion/Inversion – Pronation/Supination

Abduction/Adduction – Int Rotation/Ext Rotation

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Definition of Ankle/Foot MotionsUniplanar displacement i n Frontal plane

versusTriplanar Displacement

Combined Sagittal + Transverse + Frontal

SUPINATION = Inversion + PF + Adduct ionPRONATION = Eversion + DF + Abd uct ionORINVERSION = Supination + PF + Adduct ionEVERSION = Pronation + DF + Abduct ion

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Definition of Ankle MotionsInversion – Eversion

1) Commonly use to describeopen-chain motion of foot inrelation to leg.

2) Almost exclusively used todescribe acute ankle ligamentinjury mechanism.

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Definition of Ankle MotionsSupination – Pronation

1) Commonly used to describe footalignment under weightbearingcondition.

2) Commonly used to describe footposition during different phases ofgait cycle.

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Gait CycleHeelstrike → Mid-Stance → Toe-Off

Heelstrike to Mid-StanceSupination to Pronation

Joint mobilityShock absorption

Mid-Stance to Toe-Off Pronation to Supination

Joint surfaces lockedFoot becomes rigid lever Force transfer from achilles tendon to toes

SUPINATION

PRONATION

MAX



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Pronation-Related ConditionsDiminished propulsive capability

Prolonged & excessive loads on tissues

Plantar FaciitisMedial Tibial Stress SyndromePosterior Tibialis Tendinitis

Achilles TendinitisMetatarsal Stress FracturePatello-Femoral Syndrome

ACL Rupture

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Open vs. Closed Kinetic Chain

Open Kinetic ChainLeg stationaryFoot motion unrestrictedNo compressive load on joint surfaces

Closed Kinetic ChainSome degree of foot fixation to groundCompressive loading of joint surfacesTorque transfer between foot/ankle and leg

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Subtalar PronationDoes the tibia rotate internally or externally?

Answer: BOTHInternally in relation to the talusExternally in relation to the femur

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Subtalar Pronation Associated withValgus Displacement of the Knee

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Pronation Components

1) Calcaneal Eversion (Valgus)

2) Internal Rotation of Leg

3) Lateral Deviation Of Leg

4) Plantar Flexion + Internal Rotation Of Talar Head

5) Compensatory Forefoot Supination (Varus)Rearfoot Pronation(Subtalar Joint)Forefoot Supination (Transverse Tarsal Joint)

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Functional Axis of Subtalar JointFoot-to-Leg or Leg-to-Foottransmission of torque

Biomechanics of Gait for the Foot and Ankle;J.W. Thomas Byrd, MD



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Definition of Ankle Motions2) Motion of moving (usually distal) segment in relation to

stationary adjacent (usually proximal) segment

Foot motion in relation to fixed leg ?Open-Chain (Foot Inversion/Eversion OR Supination/Pronation?)

Leg motion in relation to fixed foot ?Closed-Chain (Inversion/Eversion OR Leg Abduction/Adduction?)

MEDIAL LATERAL

POSTERIORVIEW OF

RIGHTEXTREMITY

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Foot Anglevs .

Leg Angle

Leg segment does not remainstationary in a vertical orientationduring functional activities!!!

Pronation assessment tends tobe focused on position of foot inrelation to horizontal supportsurface.

45°SUBTALARINVERSION

SUBTALAREVERSION

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Subtalar Pronation – Pes Planus:Plantar Flexion + Internal Rotationof Head of Talus on Calcaneus

Associated with “Navicular Drop”

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Transverse Tarsal JointTransitional link

Rearfoot – ForefootS-shaped joint line

Navicular

Cuboid

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Transverse Tarsal Joint

Rearfoot-Forefoottwist

SubtalarJoint

TransverseTarsal Joint



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Forefoot-Hindfoot TwistForefoot relation to horizontal support surface : NeutralForefoot relation to hindfoot : Supinated (varus position)

Forefoot -HindfootNeutral

HindfootPronation

CompensatoryForefoot

Supination

Tendency forLateral Lift-Off

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Posterior Tibialis TendonPrimary insertion on navicular tuberosityDynamic stabilizer of medial longitudinal arch

Subjected to great mechanical stressEccentric action: Heel strike to mid-stance

Deceleration of pronation

Concentric action: Mid-stance to push-off Supination of foot (increased rigidity)

PathologyTenosynovitisLongitudinal tearsComplete rupture

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Posterior Tibialis Role inTransfer of Force fromRearfoot to Forefoot

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2

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Excessive Pronation

1) Tibia + talus internally rotated2) Navicular + forefoot externally rotated

Forefoot abduction in relation to rearfoot

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Isotonic Invertor Strengthening



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Baumhauer JF, et al: A prospective study of ankleinjury risk factors. Am J Sports Med 23(5):564-570, 1995.

145 college-aged athletes tested at 30

degrees/sec15 athletes subsequently incurred aninversion ankle sprain

mean eversion/inversion peak torque ratio foruninjured subjects = .80

67% of injured subjects had aneversion/inversion peak torque ratio >1.00

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EVR/INV Torque Curves:Chronic Ankle Instability

53 year-old female dance instructor

Uninvolved 60 deg/sec Uninvolved 120 deg/sec

Involved 60 deg/sec Involved 120 deg/sec

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EVR/INV Torque Curves:Chronic Ankle Instability

Last test before discharge – 5 wks after initial test

Uninvolved 120 deg/secUninvolved 60 deg/sec

Involved 60 deg/sec Involved 120 deg/sec34

MRI Studies: Ankle Pathology

Subtalar ligaments are oftendamaged by inversion injury

Togichi et al: FAI, 1998> 50% of lateral ankle sprain cases

Clinicians often underestimateseverity of ankle ligament damage

Frey: FAI, 1996Initial diagnosis vs. MRI results

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Lateral Ankle Sprain PathomechanicsVertical Ground Reaction Force (VGRF)induces rotation around ST joint axis

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Subtalar Inversion +External Leg Rotation



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Rotary Displacement of Talus

Tensile load ruptures ATFL

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Functional Axes

1. Subtalar 2. Talocrural3. Oblique Transverse Tarsal4. Lateral Tarsometatarsal5. Metatarsophalangeal

MTP

LTMT

ST

TC

OTT

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2-Stage Mechanism of ATFL + CFL Rupture

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2 1

2

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Subtalar Pathology

Lateral Talocalcaneal LigamentInferior Peroneal RetinaculumInferior Extensor Retinaculum - Lateral Root

LTCLInf. Per. Ret.

Inf. Ext. Ret.

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Subtalar PathologyLateral Talocalcaneal LigamentInterosseus Talocalcaneal LigamentCervical Ligament

LTCLSinus Tarsi

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Subtalar JointLigaments

Capsule of Posterior Subtalar

Articulation

PeronealTendons

Lateral Root -Inf. Ext. Ret.

Ext.Dig.Brevis

CervicalLigament

IntermediateRoot -

Inf. Ext. Ret.Ant. Articular Surface

Medial Root -Inf. Ext. Ret

InterosseusTalo-Calcaneal

Ligament

Posterior Articular Surface

Superior View

ST Axis



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Subtalar Joint Ligaments

Inf Ext Ret

ITCLAnt. Band

Cervical

Ligament

Plantar Calcaneo- Navicular Ligament

Ant.Band

Post Band

Ant.Band

Ant.Band

Post Band

Post Band

ITCL

Post Band = Capsule ofPost ST Articulation

Capsule ofPost ST Articulation

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Medial Subtalar Glide Test

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Lateral Subtalar Sling

High-strength semi-elastic tape

1 or 2 strips oriented at 45º insagittal plane & wrapped aroundleg

spans all joints between forefoot& leg

4 th & 5th TarsometatarsalJointsTransverse Tarsal JointSubtalarJointTalocrural Joint

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Lateral Subtalar Sling

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Lateral Ankle Sprain:Structures Often Damaged

Togichi et al., Foot Ankle Int, 199824 patients with inversion injury mechanismMRI evidence of ligament lesions

Anterior Talofibular Ligament: 23Calcaneofibular Ligament: 15Interosseus Talocalcaneal Ligament: 13Cervical Ligament: 12Deltoid Ligament: 8

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Antero-Lateral Rotary Instability ATFL critical role: restraint of transverseplane rotation

Cass & Settles: FA, 1994Colville et al: AJSM,1990Hintermann: MSSE, 1999Johnson & Markolf: JBJS(A), 1983McCullough & Burge: JBJS(B), 1980Parlasca et al: Clin Orthop, 1979Rasmussen & Tovborg: Acta Orthop Scand, 1981Renstrom et al: FA, 1988Stormont et al: AJSM, 1985



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Antero-Posterior Displacement (mm)125 N (28 lb) anterior-posterior forceSignificant Trial X Method interaction (p <.001)

TRIAL

321 E s

t i m a

t e d M a r g

i n a

l M e a n s

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METHOD

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UntapedPre-Ex

UntapedPost-Ex

TapedPost-Ex

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Lateral Subtalar SlingER of leg generates tension within

longitudinal fibers of taperestrains INV of lateral border of footrestrains IR of talus in relation to leg ER

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Measurement of InversionVelocity & Leg ER

3X greater restraintof Max ER

2X greater reductionof Avg Inv Velocity

2X greater reduction

of Peak Inv Velocity

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Medial Subtalar SlingRestraint of subtalar eversionSupport of medial longitudinal archDecreased load on Posterior Tibialis

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SummaryThe foot, ankle, and leg are mechanically linked

Joint displacements are interdependentForefoot-hindfoot, ST-TC joints, ankle-knee-hip joints

The subtalar joint heavily influences torquetransmission through the kinetic chain

Diminished propulsive capability (push-off)Prolonged & excessive loads on tissues

An inversion ankle sprain is often associated withdamage to subtalar joint structures

Often unrecognized as a contributor to ankle instability

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[email protected]

University of Tennessee at ChattanoogaGraduate Athletic Training Programwww.utc.edu/gatp

423-425-5394

wilkerson subtalar joint[1]

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