Foot and Ankle Biomechanics Foot and Ankle Biomechanics in Athletic Injuriesin Athletic Injuries

2003 World Exercise Professionals Symposium 2003 World Exercise Professionals Symposium

KACEP 4KACEP 4thth Annual Meeting Annual Meeting

Daejeon, KOREADaejeon, KOREA

KyungMo Han, PhD., ATCKyungMo Han, PhD., ATC

California State UniversityCalifornia State University

Dominguez HillsDominguez Hills

IntroductionIntroduction

Anatomy of the foot and ankleAnatomy of the foot and ankle Biomechanics of the foot and ankleBiomechanics of the foot and ankle Athletic injuries of the foot and ankleAthletic injuries of the foot and ankle

Bone of the Bone of the FootFoot

28 bones 28 bones (26 +2)(26 +2) 14 phalanges14 phalanges 5 metatarsals5 metatarsals 7 tarsals7 tarsals

2 sesamoids2 sesamoids

Plantar FlexionPlantar Flexion GastrocnemiusGastrocnemius SoleusSoleus PlantarisPlantaris Peroneus Longus & Brevis Peroneus Longus & Brevis Tibialis PosteriorTibialis Posterior Flexor Hallucis LongusFlexor Hallucis Longus Flexor Digitorum LongusFlexor Digitorum Longus

DorsiflexionDorsiflexion Tibialis AnteriorTibialis Anterior Extensor Digitorum LongusExtensor Digitorum Longus Extensor Hallucis LongusExtensor Hallucis Longus Peroneus TertiusPeroneus Tertius

Inversion, Adduction and SupinationInversion, Adduction and Supination

Tibialis PosteriorTibialis Posterior Tibialis AnteriorTibialis Anterior Flexor Digitorum LongusFlexor Digitorum Longus Flexor Hallucis LongusFlexor Hallucis Longus Extensor Hallucis LongusExtensor Hallucis Longus

Eversion, Abduction and PronationEversion, Abduction and Pronation

Peroneus LongusPeroneus Longus Peroneus Brevis Peroneus Brevis Peroneus TertiusPeroneus Tertius Extensor Digitorum LongusExtensor Digitorum Longus

Arches of the FootArches of the Foot Anterior metatarsal archAnterior metatarsal arch Transverse archTransverse arch Medial longitudinal archMedial longitudinal arch Lateral longitudinal archLateral longitudinal arch

ArticulationsArticulations

ForefootForefoot Metatarsophalangeal (MTP) JointMetatarsophalangeal (MTP) Joint Proximal interphalangeal (PIP) JointProximal interphalangeal (PIP) Joint Distal interphalangeal (DIP) JointDistal interphalangeal (DIP) Joint

MidfootMidfoot Tarsometatarsal (Lisfranc) JointTarsometatarsal (Lisfranc) Joint

HindfootHindfoot Subtalar JointSubtalar Joint

Midtarsal JointMidtarsal Joint

Single Plane MovementsSingle Plane Movements Inversion/EversionInversion/Eversion

Frontal plane (X axis)Frontal plane (X axis) The foot twists inward and upwardThe foot twists inward and upward

Abduction/AdductionAbduction/Adduction Transverse plane (Y axis)Transverse plane (Y axis) The foot rotates laterally and mediallyThe foot rotates laterally and medially

Plantar flexion/DorsiflexionPlantar flexion/Dorsiflexion Sagittal plane (X axis)Sagittal plane (X axis) The foot moves upwards and downwardsThe foot moves upwards and downwards

Tri-Plane MovementsTri-Plane Movements SupinationSupination

InversionInversion Plantar flexionPlantar flexion AdductionAdduction

PronationPronation EversionEversion Plantar flexionPlantar flexion AdductionAdduction

Supination of the Subtalar Joint (Open Chain: NWB)

TalusTalus NeutralNeutral

Calcaneus Calcaneus InvertsInverts Adducts Adducts Plantar flexesPlantar flexes

Pronation of the Subtalar Joint (Open Chain: NWB)

TalusTalus NeuralNeural

CalcaneusCalcaneus EvertsEverts AbductsAbducts DorsiflexesDorsiflexes

Supination of the Subtalar Joint (Closed Chain: WB)

TalusTalus Moves lateralMoves lateral Externally rotatesExternally rotates DorsiflexesDorsiflexes

CalcaneusCalcaneus InvertsInverts

Pronation of the Subtalar Joint Pronation of the Subtalar Joint (Closed Chain: WB)(Closed Chain: WB)

Talus: Talus: Moves mediallyMoves medially Internally rotatesInternally rotates Plantar flexesPlantar flexes

CalcaneusCalcaneus EvertsEverts

Subtalar JointSubtalar Joint ROM: 20 degrees (inversion) & 5 degrees (eversion)ROM: 20 degrees (inversion) & 5 degrees (eversion)

Accessory motions: Accessory motions: Convex portion of calcaneus glides laterally with Convex portion of calcaneus glides laterally with

inversioninversion Convex portion of calcaneus glides medially with Convex portion of calcaneus glides medially with

eversioneversion

Open pack position: subtalar joint neutralOpen pack position: subtalar joint neutral Closed pack position: full supinationClosed pack position: full supination

TRIPLANAR MOTIONTRIPLANAR MOTION

Longitudinal Midtarsal AxisLongitudinal Midtarsal Axis

9 degrees from 9 degrees from

the sagittal plane (X axis)the sagittal plane (X axis) 15 degrees from the 15 degrees from the

transverse plane (Y axis)transverse plane (Y axis)

Primarily provides Z axis, Frontal Primarily provides Z axis, Frontal plane motionsplane motions INVERSION/EVERSIONINVERSION/EVERSION ABDuction/ADDuctionABDuction/ADDuction dorsiflesion/plantar flexiondorsiflesion/plantar flexion

Oblique Midtarsal AxisOblique Midtarsal Axis 57 degrees from the sagittal plane (X 57 degrees from the sagittal plane (X

axis) axis) 52 degrees from the transverse plane (Y 52 degrees from the transverse plane (Y

axis)axis)

Therefore, primarily provide X & Y Therefore, primarily provide X & Y axes, sagittal & transverse plane motionsaxes, sagittal & transverse plane motions DORSI flexion/PLANTAR flexionDORSI flexion/PLANTAR flexion ABDuction/ADDuctionABDuction/ADDuction inversion/eversioninversion/eversion

Compressive Forces of the FootCompressive Forces of the Foot(60 lb of load applied to the talus)(60 lb of load applied to the talus)

Weight DistributionWeight Distribution(Barefoot standing)(Barefoot standing)

Deltoid Ligament StressDeltoid Ligament Stress(Average of 14 degrees of valgus talar tilt)(Average of 14 degrees of valgus talar tilt)

Deltoid Ligament Deltoid Ligament StressStress

LS: talar lateral shiftLS: talar lateral shift AS: anterior shiftAS: anterior shift TT: valgus talar tiltTT: valgus talar tilt

DD: deep deltoidDD: deep deltoid SD: superficial deltoidSD: superficial deltoid

Ankle Joint Ankle Joint StabilityStability

The superficial and deep The superficial and deep deltoid ligaments are deltoid ligaments are responsible for resistance responsible for resistance to eversion and external to eversion and external rotation stressrotation stress

Mechanisms of Inversion SprainMechanisms of Inversion Sprain

The mechanism of lateral ankle sprains involves a The mechanism of lateral ankle sprains involves a combination of sudden uncontrolled plantar flexion combination of sudden uncontrolled plantar flexion and inversion at the beginning of the initial contact of and inversion at the beginning of the initial contact of the foot with even or uneven surfacesthe foot with even or uneven surfaces

This causes unexpected inversion torque to the ankle This causes unexpected inversion torque to the ankle jointjoint

An ankle sprain occurs when this torque is applied at An ankle sprain occurs when this torque is applied at a rate that exceeds the minimum time necessary for a rate that exceeds the minimum time necessary for the neuromuscular system to respondthe neuromuscular system to respond

Ankle Joint StabilityAnkle Joint Stability The ATF and CF ligaments forms a The ATF and CF ligaments forms a

105 degrees angle with one another105 degrees angle with one another ATFATF

Resists ankle inversion and plantar Resists ankle inversion and plantar flexion (resists to anterior talar flexion (resists to anterior talar displacement and internal rotation of the displacement and internal rotation of the talus)talus)

Greatest tension in PFGreatest tension in PF CFCF

Resists ankle inversion and dorsiflexion Resists ankle inversion and dorsiflexion (contributes the subtalar joint stability)(contributes the subtalar joint stability)

Greatest tension in DFGreatest tension in DF

Peroneus Longus Latency

0 50 100 150 200 250

Time (ms)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Pe

ron

eu

s L

on

gu

s E

MG

(m

V)

-60

-40

-20

0

Peroneus LongusPlatformAnkle

Ankle

Inversion Platform

Compute Mean and SD

of 100 ms before

Platform Drop

10 SD

above Mean

PL EMG

An

gle

(D

eg

)

Flat Feet/Fallen ArchFlat Feet/Fallen Arch(Pes Planus)(Pes Planus)

Associated with excessive pronation, forefoot varus, Associated with excessive pronation, forefoot varus, wearing tight shoes (weakening supportive structures) wearing tight shoes (weakening supportive structures) being overweight, and excessive exercise placing being overweight, and excessive exercise placing under stress on archunder stress on arch

Excess pronation causes the foot’s arch to collapse & Excess pronation causes the foot’s arch to collapse & elongate giving the appearance of a flat footelongate giving the appearance of a flat foot

High ArchHigh Arch(Pes Cavus)(Pes Cavus)

Associated with excessive supination, accentuated Associated with excessive supination, accentuated high medial longitudinal archhigh medial longitudinal arch

Poor shock absorption resulting in metatarsalgia, Poor shock absorption resulting in metatarsalgia, foot pain, clawed or hammer toesfoot pain, clawed or hammer toes

Associated with forefoot valgus, shortening of Associated with forefoot valgus, shortening of Achilles and plantar fasciaAchilles and plantar fascia

Achilles TendonitisAchilles Tendonitis

Inflammation of the achilles tendonInflammation of the achilles tendon

Commonly occurs from shearing and tractional Commonly occurs from shearing and tractional placed on the achilles tendon at the back of the heelplaced on the achilles tendon at the back of the heel

The foot accelerates into an excessively pronated The foot accelerates into an excessively pronated position and the calcaneus is evertedposition and the calcaneus is everted

An increase in medial tendo-achiulles tractionAn increase in medial tendo-achiulles traction Results in transverse shearing of the tendon and Results in transverse shearing of the tendon and

sheathsheath

Plantar FasciitisPlantar Fasciitis

Excess subtalar joint pronation lowers the archExcess subtalar joint pronation lowers the arch Places a traction force on the plantar fasciaPlaces a traction force on the plantar fascia Inflammation of the fascia and surrounding tissues Inflammation of the fascia and surrounding tissues

causing pain in the arch and heel causing pain in the arch and heel

Chronic traction Chronic traction development of a bony growth development of a bony growth on the calcaneal tuberosity on the calcaneal tuberosity “heel spur” “heel spur”

Jones FractureJones Fracture

Caused by inversion and plantar flexion, direct Caused by inversion and plantar flexion, direct force (stepped on) or repetitive traumaforce (stepped on) or repetitive trauma

Most common = the base of 5th metatarsalMost common = the base of 5th metatarsal

Hallux ValgusHallux Valgus(Bunion)(Bunion)

Exostosis of 1st metatarsal head; Exostosis of 1st metatarsal head; associated with forefoot varus; shoes associated with forefoot varus; shoes that are too narrow, pointed or shortthat are too narrow, pointed or short

Bunionette (Tailor’s bunion) impacts Bunionette (Tailor’s bunion) impacts 5th metatarsophalangeal joint - 5th metatarsophalangeal joint - causes medial displacement of 5th causes medial displacement of 5th toetoe

Turf ToeTurf Toe (1(1stst metatarsophalangeal joint sprain) metatarsophalangeal joint sprain) HyperextensionHyperextension (or hyperflexion) injury resulting (or hyperflexion) injury resulting

in sprain of 1st metatarsophalangeal jointin sprain of 1st metatarsophalangeal joint May be the result of single or repetitive trauma May be the result of single or repetitive trauma

during push off in walking, running, and jumpingduring push off in walking, running, and jumping

Other Athletic InjuriesOther Athletic Injuries

Injuries to the tarsal regionInjuries to the tarsal region Fracture of the talus or calcaneusFracture of the talus or calcaneus Apophysitis of the calcaneus (Sever’s Disease)Apophysitis of the calcaneus (Sever’s Disease) Retrocalcaneal bursitis (Pump Bump)Retrocalcaneal bursitis (Pump Bump) Heel contusionHeel contusion Cuboid subluxationCuboid subluxation Tarsal tunnel syndromeTarsal tunnel syndrome Tarsometatarsal (fracture) dislocationTarsometatarsal (fracture) dislocation

Other Athletic InjuriesOther Athletic Injuries Injuries to the metatarsal regionInjuries to the metatarsal region

Longitudinal arch strainLongitudinal arch strain Metatarsal stress fracturesMetatarsal stress fractures SesamoiditisSesamoiditis MetatarsalgiaMetatarsalgia Morton’s NeuromaMorton’s Neuroma

Injuries to the toesInjuries to the toes Sprained toesSprained toes Fractures and dislocations of the phalangesFractures and dislocations of the phalanges Morton’s toeMorton’s toe Hallux RigidusHallux Rigidus Hammer toe, Mallet toe or Claw toeHammer toe, Mallet toe or Claw toe Overlapping toesOverlapping toes