Foot and Ankle Biomechanics in Athletic Injuries 2003 World Exercise Professionals Symposium KACEP 4 th Annual Meeting Daejeon, KOREA KyungMo Han, PhD., ATC California State University Dominguez Hills

Introduction Anatomy of the foot and ankle Anatomy of the foot and ankle Biomechanics of the foot and ankle Biomechanics of the foot and ankle Athletic injuries of the foot and ankle Athletic injuries of the foot and ankle

Bone of the Foot 28 bones (26 +2) 28 bones (26 +2) 14 phalanges 14 phalanges 5 metatarsals 5 metatarsals 7 tarsals 7 tarsals 2 sesamoids 2 sesamoids

Plantar Flexion Gastrocnemius Gastrocnemius Soleus Soleus Plantaris Plantaris Peroneus Longus & Brevis Peroneus Longus & Brevis Tibialis Posterior Tibialis Posterior Flexor Hallucis Longus Flexor Hallucis Longus Flexor Digitorum Longus Flexor Digitorum Longus

Dorsiflexion Tibialis Anterior Tibialis Anterior Extensor Digitorum Longus Extensor Digitorum Longus Extensor Hallucis Longus Extensor Hallucis Longus Peroneus Tertius Peroneus Tertius

Inversion, Adduction and Supination Tibialis Posterior Tibialis Posterior Tibialis Anterior Tibialis Anterior Flexor Digitorum Longus Flexor Digitorum Longus Flexor Hallucis Longus Flexor Hallucis Longus Extensor Hallucis Longus Extensor Hallucis Longus

Eversion, Abduction and Pronation Peroneus Longus Peroneus Longus Peroneus Brevis Peroneus Brevis Peroneus Tertius Peroneus Tertius Extensor Digitorum Longus Extensor Digitorum Longus

Arches of the Foot Anterior metatarsal arch Anterior metatarsal arch Transverse arch Transverse arch Medial longitudinal arch Medial longitudinal arch Lateral longitudinal arch Lateral longitudinal arch

Articulations Forefoot Forefoot Metatarsophalangeal (MTP) Joint Metatarsophalangeal (MTP) Joint Proximal interphalangeal (PIP) Joint Proximal interphalangeal (PIP) Joint Distal interphalangeal (DIP) Joint Distal interphalangeal (DIP) Joint Midfoot Midfoot Tarsometatarsal (Lisfranc) Joint Tarsometatarsal (Lisfranc) Joint Hindfoot Hindfoot Subtalar Joint Subtalar Joint Midtarsal Joint Midtarsal Joint

Single Plane Movements Inversion/Eversion Inversion/Eversion Frontal plane (X axis) Frontal plane (X axis) The foot twists inward and upward The foot twists inward and upward Abduction/Adduction Abduction/Adduction Transverse plane (Y axis) Transverse plane (Y axis) The foot rotates laterally and medially The foot rotates laterally and medially Plantar flexion/Dorsiflexion Plantar flexion/Dorsiflexion Sagittal plane (X axis) Sagittal plane (X axis) The foot moves upwards and downwards The foot moves upwards and downwards

Tri-Plane Movements Supination Supination Inversion Inversion Plantar flexion Plantar flexion Adduction Adduction Pronation Pronation Eversion Eversion Plantar flexion Plantar flexion Adduction Adduction

Supination of the Subtalar Joint (Open Chain: NWB) Talus Talus Neutral Neutral Calcaneus Calcaneus Inverts Inverts Adducts Adducts Plantar flexes Plantar flexes

Pronation of the Subtalar Joint (Open Chain: NWB) Talus Talus Neural Neural Calcaneus Calcaneus Everts Everts Abducts Abducts Dorsiflexes Dorsiflexes

Supination of the Subtalar Joint (Closed Chain: WB) Talus Talus Moves lateral Moves lateral Externally rotates Externally rotates Dorsiflexes Dorsiflexes Calcaneus Calcaneus Inverts Inverts

Pronation of the Subtalar Joint (Closed Chain: WB) Talus: Talus: Moves medially Moves medially Internally rotates Internally rotates Plantar flexes Plantar flexes Calcaneus Calcaneus Everts Everts

Subtalar 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 inversion Convex portion of calcaneus glides laterally with inversion Convex portion of calcaneus glides medially with eversion Convex portion of calcaneus glides medially with eversion Open pack position: subtalar joint neutral Open pack position: subtalar joint neutral Closed pack position: full supination Closed pack position: full supination

TRIPLANAR MOTION

Longitudinal Midtarsal Axis 9 degrees from 9 degrees from the sagittal plane (X axis) the sagittal plane (X axis) 15 degrees from the transverse plane (Y axis) 15 degrees from the transverse plane (Y axis) Primarily provides Z axis, Frontal plane motions Primarily provides Z axis, Frontal plane motions INVERSION/EVERSION INVERSION/EVERSION ABDuction/ADDuction ABDuction/ADDuction dorsiflesion/plantar flexion dorsiflesion/plantar flexion

Oblique Midtarsal Axis 57 degrees from the sagittal plane (X axis) 57 degrees from the sagittal plane (X axis) 52 degrees from the transverse plane (Y axis) 52 degrees from the transverse plane (Y axis) Therefore, primarily provide X & Y axes, sagittal & transverse plane motions Therefore, primarily provide X & Y axes, sagittal & transverse plane motions DORSI flexion/PLANTAR flexion DORSI flexion/PLANTAR flexion ABDuction/ADDuction ABDuction/ADDuction inversion/eversion inversion/eversion

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

Weight Distribution (Barefoot standing)

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

Deltoid Ligament Stress LS: talar lateral shift LS: talar lateral shift AS: anterior shift AS: anterior shift TT: valgus talar tilt TT: valgus talar tilt DD: deep deltoid DD: deep deltoid SD: superficial deltoid SD: superficial deltoid

Ankle Joint Stability The superficial and deep deltoid ligaments are responsible for resistance to eversion and external rotation stress The superficial and deep deltoid ligaments are responsible for resistance to eversion and external rotation stress

Mechanisms of Inversion Sprain The mechanism of lateral ankle sprains involves a combination of sudden uncontrolled plantar flexion and inversion at the beginning of the initial contact of the foot with even or uneven surfaces The mechanism of lateral ankle sprains involves a combination of sudden uncontrolled plantar flexion and inversion at the beginning of the initial contact of the foot with even or uneven surfaces This causes unexpected inversion torque to the ankle joint This causes unexpected inversion torque to the ankle joint An ankle sprain occurs when this torque is applied at a rate that exceeds the minimum time necessary for the neuromuscular system to respond An ankle sprain occurs when this torque is applied at a rate that exceeds the minimum time necessary for the neuromuscular system to respond

Ankle Joint Stability The ATF and CF ligaments forms a 105 degrees angle with one another The ATF and CF ligaments forms a 105 degrees angle with one another ATF ATF Resists ankle inversion and plantar flexion (resists to anterior talar displacement and internal rotation of the talus) Resists ankle inversion and plantar flexion (resists to anterior talar displacement and internal rotation of the talus) Greatest tension in PF Greatest tension in PF CF CF Resists ankle inversion and dorsiflexion (contributes the subtalar joint stability) Resists ankle inversion and dorsiflexion (contributes the subtalar joint stability) Greatest tension in DF Greatest tension in DF

Peroneus Longus Latency

Flat Feet/Fallen Arch (Pes Planus) Associated with excessive pronation, forefoot varus, wearing tight shoes (weakening supportive structures) being overweight, and excessive exercise placing under stress on arch Associated with excessive pronation, forefoot varus, wearing tight shoes (weakening supportive structures) being overweight, and excessive exercise placing under stress on arch Excess pronation causes the foot’s arch to collapse & elongate giving the appearance of a flat foot Excess pronation causes the foot’s arch to collapse & elongate giving the appearance of a flat foot

High Arch (Pes Cavus) Associated with excessive supination, accentuated high medial longitudinal arch Associated with excessive supination, accentuated high medial longitudinal arch Poor shock absorption resulting in metatarsalgia, foot pain, clawed or hammer toes Poor shock absorption resulting in metatarsalgia, foot pain, clawed or hammer toes Associated with forefoot valgus, shortening of Achilles and plantar fascia Associated with forefoot valgus, shortening of Achilles and plantar fascia

Achilles Tendonitis Inflammation of the achilles tendon Inflammation of the achilles tendon Commonly occurs from shearing and tractional placed on the achilles tendon at the back of the heel Commonly occurs from shearing and tractional placed on the achilles tendon at the back of the heel The foot accelerates into an excessively pronated position and the calcaneus is everted The foot accelerates into an excessively pronated position and the calcaneus is everted An increase in medial tendo-achiulles traction An increase in medial tendo-achiulles traction Results in transverse shearing of the tendon and sheath Results in transverse shearing of the tendon and sheath

Plantar Fasciitis Excess subtalar joint pronation lowers the arch Excess subtalar joint pronation lowers the arch Places a traction force on the plantar fascia Places a traction force on the plantar fascia Inflammation of the fascia and surrounding tissues  causing pain in the arch and heel Inflammation of the fascia and surrounding tissues  causing pain in the arch and heel Chronic traction  development of a bony growth on the calcaneal tuberosity  “heel spur” Chronic traction  development of a bony growth on the calcaneal tuberosity  “heel spur”

Jones Fracture Caused by inversion and plantar flexion, direct force (stepped on) or repetitive trauma Caused by inversion and plantar flexion, direct force (stepped on) or repetitive trauma Most common = the base of 5th metatarsal Most common = the base of 5th metatarsal

Hallux Valgus (Bunion) Exostosis of 1st metatarsal head; associated with forefoot varus; shoes that are too narrow, pointed or short Exostosis of 1st metatarsal head; associated with forefoot varus; shoes that are too narrow, pointed or short Bunionette (Tailor’s bunion) impacts 5th metatarsophalangeal joint - causes medial displacement of 5th toe Bunionette (Tailor’s bunion) impacts 5th metatarsophalangeal joint - causes medial displacement of 5th toe

Turf Toe (1 st metatarsophalangeal joint sprain) Hyperextension (or hyperflexion) injury resulting in sprain of 1st metatarsophalangeal joint Hyperextension (or hyperflexion) injury resulting in sprain of 1st metatarsophalangeal joint May be the result of single or repetitive trauma during push off in walking, running, and jumping May be the result of single or repetitive trauma during push off in walking, running, and jumping

Other Athletic Injuries Injuries to the tarsal region Injuries to the tarsal region Fracture of the talus or calcaneus Fracture 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 contusion Heel contusion Cuboid subluxation Cuboid subluxation Tarsal tunnel syndrome Tarsal tunnel syndrome Tarsometatarsal (fracture) dislocation Tarsometatarsal (fracture) dislocation

Other Athletic Injuries Injuries to the metatarsal region Injuries to the metatarsal region Longitudinal arch strain Longitudinal arch strain Metatarsal stress fractures Metatarsal stress fractures Sesamoiditis Sesamoiditis Metatarsalgia Metatarsalgia Morton’s Neuroma Morton’s Neuroma Injuries to the toes Injuries to the toes Sprained toes Sprained toes Fractures and dislocations of the phalanges Fractures and dislocations of the phalanges Morton’s toe Morton’s toe Hallux Rigidus Hallux Rigidus Hammer toe, Mallet toe or Claw toe Hammer toe, Mallet toe or Claw toe Overlapping toes Overlapping toes