functional anatomy of the ankle joint complex

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Functional Anatomy of the Ankle Joint Complex

Professor Emeritus Moira O’Brien

FRCPI, FFSEM, FFSEM (UK), FTCD

Trinity College

Dublin

The Ankle Joint

• The ankle joint is one of the most common joints to be injured.

• The foot is usually in the plantar flexed and inverted position when the ankle is most commonly injured.

Bröstrom, 1966

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Tennis

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• Dorsiflexion and plantar flexion take place at the ankle joint

• In plantar flexion there is some side-to-side movement

Last, 1963

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The Ankle Joint MOB TCD

Inversion and Eversion

• Initiated at the transverse tarsal joint

• A radiological term• Calcaneo-cuboid• Anterior portion of the

talocalcaneonavicular• Amputation at this joint,

no bones are cutLast, 1963

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• Main movement take place at the clinical sub-talar joint i.e.:• Talocalcaneal

• Inferior portion of the talocalcaneonavicular

• The pivot is the ligament of the neck of the talus

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Inversion and Eversion

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• A uniaxial, modified synovial hinge joint

• Proximally the articulation depends on the integrity of the inferior tibiofibular joint

• Close pack• DorsiflexionWilliams & Warwick, 1980

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• In the anatomical position the axis of the ankle joint is horizontal

• But is set at 20-25º obliquely to the frontal plane

• Running posteriorly as it passes laterally

Plastanga et al., 1990

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• In dorsiflexion the foot moves upwards and medially

• Downwards and laterally in plantar flexion

Plastanga et al., 1990

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Proximal Articular Surface

• The distal surface of the tibia • which is concave antero-

posteriorly and convex from side to side

• Medial malleolus (comma- shaped facet)

• Lateral malleolus (triangular facet is convex from above downwards apex inferiorly

Williams & Warwick, 1980

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Proximal Articulation

• The inferior transverse tibiofibular ligament

• Deepens it posteriorly• Passes from the lower margin of

the tibia• To the malleolar fossa of the fibulaWilliams & Warwick, 1980

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• Proximally the articulation depends on the integrity of the inferior tibiofibular joint

• A syndesmosis• Lateral malleolus is larger,

lies posteriorly• Extends more inferiorly

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Proximal Articular Surface MOB TCD

Distal Articular Surface

• The superior surface of the body of the talus is wider anteriorly

• Convex from before backwards • Concave from side to side • Medial comma-shaped facet• Lateral triangular facetFrazer, 1965

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• The talus has no muscles attached to it

• Has a very extensive articular surface

• As a result fractures of the talus may result in avascular necrosis of either the body or the head

O’Brien et al., 2002

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Distal Articular Surface

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Posterior Aspect of Talus

• Two tubercles• Groove contains flexor

hallucis longus• Medial tubercle is smaller• Lateral is larger, posterior

talofibular ligament attached• 7% separate ossification called os

trigonum• There is a triangular facet on the

posterior surface which articulates with the inferior transverse tibiofibular ligament

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Congenital Abnormalities

• Congenital abnormalities include os trigonum and tarsal coalition

• Os trigonum in 7% of normal population but in 32% of soccer players

• It is a problem in soccer players, ballet dancers and javelin

• Forced hyperplantar flexion compresses the posterior portion of the ankle and may fracture the lateral tubercle or an os trigonum

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Articular Surfaces

• Articular surfaces are covered with hyaline or articular cartilage

• Synovial fold which may contain fat

• Fills the interval between tibia, fibula and inferior transverse tibiofibular ligament

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Capsule

• Is attached just beyond the articular margin

• Except anterior-inferiorly• Attached to the neck of the

talusWilliams & Warwick, 1980

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• The capsule is thin and weak in front and behind

• The anterior and posterior ligaments are thickenings of the joint capsule

• The anterior runs obliquely from the tibia to the neck of the talus

Williams & Warwick,1980

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The Posterior Ligament

• The posterior ligament fibres pass from: the tibia and fibula and converge to be attached to the medial tubercle of the talus

• Transverse ligament fibres form the lower part of the posterior part of the capsule, blend with the inferior transverse ligament

• The posterior ligament is thicker laterally

• Capsule is strengthened on either side by the collateral ligaments

Williams & Warwick,1980

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The Medial (Deltoid) Ligament

• A strong triangular ligament

• Superiorly attached • The medial malleolus of

the tibiaWilliams & Warwick, 1980

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Medial Ligament

• Inferiorly, ant-post• The tuberosity of the

navicular• Neck of talus• The free edge of the

spring ligament• The sustentaculum tali • The body of the talusLast, 1963

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Medial or Deltoid Ligament (Superficial)

Crosses two joints• Anterior tibionavicular

pass to the tuberosity of the navicular

• The free edge of the spring ligament

• The middle fibres, the tibiocalcaneal are attached to the sustentaculum tali


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Medial or Deltoid Ligament (Deep)

• The anterior tibio-talar to the nonarticular part of the medial surface of the talus

• The posterior tibiotalar to the medial side of the talus

• The medial tubercle of the talus

• Tibialis posterior and flexor digitorum longus cross ligament


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Lateral Ligaments of Ankle

• The anterior talofibular ligament (ATFL)

• The calcaneofibular (CFL)

• The posterior talofibular (PTF)

• They radiate like the spokes of a wheel

Liu & Jason, 1994

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The ATFL

• Is part of the capsule • An upper and lower bands• It is cylindrical, 6-10 mm

long and 2 mm thick• The anterior inferior

border of the fibula runs parallel to the long axis of the talus when the ankle is neutral or dorsiflexion

• More perpendicular to the talus when the foot is equinus

Liu & Jason, 1994

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• It is the weakest ligament• Strain increases with

increasing plantar flexion and inversion

• The AFTL is a primary stabiliser against inversion and internal rotation for all angles of plantar flexion

Liu & Jason, 1994

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The ATFL MOB TCD

• The anterior draw tests the ATFL

• Test should be done with the ankle in 10o-20o

plantar flexion• Low loads

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Test for the ATFL MOB TCD

• A long rounded 20-25 mm long, 6-8 mm in diameter

• It contains the most elastic tissue

• It is attached in front of the apex of the fibular malleolus

• Passes downwards and backwards

• To a tubercle on the lateral aspect of the calcaneusWilliams & Warwick, 1980

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The CFL MOB TCD

• It is separated from the capsule by fibro-fatty tissue

• Part of the medial wall of the peroneal tendon sheath

• Crosses both the ankle and subtalar joints

• The CFL has the highest linear elastic modulus of the three ligaments

Siegler et al., 1988

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The CFL MOB TCD

• When the ankle is in the neutral or dorsiflexion, the CFL is perpendicular to the long axis of the talus

• Dorsiflexion and inversion result in an increased strain

• Talar tilt tests the CFL

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The CFL MOB TCD

The Lateral Ligament

• The angle between the ATFL and CFL varies between 100o and 135o

• Increasing the potential instability of the lateral ligament

• The ATFL is the main talar stabiliser and the CFL acts as a secondary restraint

Hamilton, 1994; Peters, 1991

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ATFL and CFL

• A difference of 10o between the two ankles is significant.

• A talar tilt of more than 10o is a lateral ligament injury in 99% of cases

• The AFTL is injured in 65% and combined injuries of the AFTL and CFL occur in 20%

• The CFL is a major stabiliser of the subtalar joint

Liu & Jason, 1994

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The Posterior Talar Fibular (PTL)

• The PTL is the strongest part of the lateral ligament

• It runs almost horizontally from malleolar fossa to lateral tubercle of talus

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• During plantar flexion the posterior talofibular and the posterior tibio fibular ligament are edge to edge

• They separate during dorsiflexion• The greatest strain on the

ligament is when the foot is plantar flexed and everted

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The PTL MOB TCD

• In 7% of normal population the lateral tubercle has a separate ossification and is called an os trigonum

• It occurs in 32% of soccer players

• Tarsal coalition is another congenital abnormality

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Synovial Membrane

• Lines the capsule and the non articular areas

• It is reflected on to the neck• Extends upwards between

the tibia and fibula to the interosseous ligament of the inferior tibiofibular joint

• Covers the fatty pads that lie in relation to the anterior and posterior parts of the capsule

Plastanga et al.,1980

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Ankle Stability

• The ankle is most stable in dorsiflexion, with increasing plantar flexion there is more anterior talar translation (drawer) and talar inversion (tilt)

• The ATFL is the main talar stabiliser and the CFL acts as a secondary restraint

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• The tibiocalcaneal and the tibionavicular control abduction of the talus

• The calcaneofibular controls adduction• The anterior tibiotalar and the anterior talofibular

ligament control plantar flexion• Posterior tibiotalar and the posterior talar fibular

ligament resist dorsiflexion• Both the anterior tibiotalar and the tibionavicular

control external rotation and with the anterior talofibular internal rotation of the talus

• The anterior talofibular is the primary stabilizer of the ankle joint

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Ankle Stability MOB TCD

Blood Supply of the Ankle

• Malleolar branches of the anterior tibial

• Perforating peroneal and posterior tibial arteries

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Nerve Supply of the Ankle

• Nerve supply is via articular branches of the deep peroneal

• Tibial nerve from L4 - S2

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Anterior Aspect

• Dorsi-flexors• Tibialis anterior• Extensor hallucis longus• Anterior tibial becomes the

Dorsalis pedis artery• Deep peroneal nerve • Extensor digitorum longus• Peroneus tertius

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• The medial branch of the superficial peroneal nerve is superficial to the retinaculum

• The long saphenous vein and the saphenous nerve lie anterior to the medial malleolus

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Anterior Aspect MOB TCD

Postero-Medial Aspect of the Ankle

• Tibialis posterior• Flexor digitorum longus• Posterior tibial vessels• Posterior tibial nerve • Flexor hallucis longus

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• The tibial nerve gives off the medial calcaneal nerve then divides into the medial and lateral plantar nerves

• The medial calcaneal vessels and nerve pierce the flexor retinaculum to supply the skin of the heel

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Postero-Medial Aspect of the Ankle MOB TCD

Posterior Aspect

• Achilles tendon separated by a bursa and pad of fat

• Posterolateral portal is lateral to achilles tendon, sural nerve and short saphenous vein at risk

• Postero-medial not used; flexor retinaculum structures at risk

Jaivin & Ferkel, 1994

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Lateral Aspect of the Ankle

• The inferior extensor retinaculum

• Extensor digitorum brevis• Peroneus longus and

brevis• Peroneal retinaculum• Ligament of the neck of

talus• Bifurcate ligament• Sural nerve• Short saphenous vein

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• Plantar flexion and eversion• Peroneus longus• Peroneus brevis

• Dorsi-flexion and eversion• Peroneus tertius

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Lateral Aspect of the Ankle MOB TCD

Nerves Related to Ankle Joint

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Tibialis Posterior Superficial Peroneal Nerve

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Movements of Ankle joint

• Dorsiflexion is close packed or stable position

• Wider portion of body of talus between malleoli

• Range of 30 o

• Need 10 o dorsiflexion to run

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Dorsiflexion

• Dorsiflexion is produced by the tibialis anterior

• Extensor hallucis longus• Extensor digitorum longus • The peroneus tertius• Deep peroneal nerve

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Movements of Ankle joint

• Plantar flexion• Some side to side

movement• Narrow portion of body

between malleoli, 50-60 o

• Least pack, unstable position

• Wide variation

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Plantar Flexion

• During plantar flexion• The dorsal capsule• The anterior fibres of the

deltoid• The anterior talofibular

ligaments are under maximum tension

• Plantar flexion is caused mainly by the action of the achilles tendon

• Assisted by the tibialis posterior

• Flexor digitorum longus• Flexor hallucis longus• Peroneus longus and

brevis

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• The ankle is most stable in dorsiflexion, with increasing plantar flexion there is more anterior talar translation (drawer) and talar inversion (tilt)

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Examination of Ankle

• ATFL• CFL• Distal tibiofibular• Syndesmosis• Deltoid ligament• Lateral malleolus• Medial malleolus• Base 5th metatarsal

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• Achilles tendon• Peroneal tendons• Posterior tibial tendon• Anterior process of calcaneus• Talar dome• Sinus tarsi• Bifurcate ligament

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Examination of Ankle MOB TCD

Ankle Examination

• Anterior drawer• Talar tilt• Inversion stress• Squeeze test• External rotation test

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Tests for Ankle Ligament Injury

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Ottawa Ankle Rules

• Anteroposterior• Oblique• Lateral views

• Bone tenderness• Medial or lateral malleolus

• Unable to weight bear• Four steps post injury

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A Few Statistics

• Basketball 5.5 ankle injuries/1000 player hours• Netball 3.3 ankle injuries/1000 player hours• Volleyball 2.6 ankle injuries/1000 player hours• Soccer 2.0 ankle injuries/1000 player hoursHopper et al., 1999

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Basketball Statistics

• 53% of basketball injuries are ankle injuries

• 30.4 ankle injuries/1000 games

• 10.0 ankle injuries/season for a squad of twelve

Garrick, 1977

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Risk Factors

Extrinsic• Training error• Type of sport• Playing time• Level of competition• Equipment• Environmental

Intrinsic

• Malalignment• Strength deficit• Reduced ROM• Joint instability• Joint laxity• Foot type• Height/weight

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• Previous ankle injury Ekstrand & Gillquist, 1983; Milgrom et al., 1991

• Competition Ekstrand & Gillquist, 1983

• Muscle Imbalance Baumhauer et al., 1995

• Mass moment of inertia Milgrom et al., 1991

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Risk Factors MOB TCD

Ankle Injuries

• Lateral ligament sprain• Medial ligament sprain• Peroneal dislocation• Fractures• Dislocations

• Tendon rupture• Tibialis posterior• Peroneal tendons• Ruptured syndesmosis• Superficial peroneal

nerve lesion• Reflex sympathetic

dystrophy

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Ankle Sprains

• Grade oneStretch of ATFL; mild swelling; no instability

• Grade twoPartial macroscopic tear; pain; swelling; mild-moderate instability

• Grade threeComplete tear; severe swelling; unable to weight bear; limited function; and instability

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Proprioception Theory

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Reducing Injury

• Proprioceptive • Agility and Flexibility training Ekstrand & Gillquist, 1983

• Taping • Loosens in 10 minutes Garrick, 1977

• Nil effect in 30 minutes? Tropp et al., 1985; Rovere et al., 1988; Sitler et al., 1994

• Bracing

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functional anatomy of the ankle joint complex

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