5) Lateral Ankle (Inversion) Injury

Question 1

Lateral ankle (inversion) sprains incidence

Answer 1

• 40 % of all sports injuries (most common injury in all of sports)
• 25 % of all time lost in sports
• Lateral: 85 %
• Medial: 5 %
• Syndesmosis: 10 %

Question 2

Sprain

Answer 2

• Stretching injury which may involve partial or complete tearing of the lateral ankle ligaments

Question 3

Lateral ankle inversion injury anatomy

Answer 3

• Shape of the talar dome: Wide anterior and narrow posterior
• Results in decreased frontal plane stability of the ankle when plantarflexed
• Increased stability with ankle dorsiflexion

Question 4

STJ and ankle joint biomechanics

Answer 4

• Subtalar joint: 2:1 inversion to eversion ratio

- “Ankle” inversion is generated at the subtalar joint

Question 5

Biomechanics: contributing factors

Answer 5

• Ankle equinus
• Gastrocnemius / soleus weakness
• Forefoot / rearfoot deformity
• Transverse plane abnormality

Question 6

Lateral ankle injury history

Answer 6

• Mechanism ?
• Could bear weight initially ?
• History of previous injury, treatment and outcome ?
• Audible “pop” ?
• Immediate treatment ?
• Inappropriate shoe gear
• Excessive cushioning; shoe or surface
• Irregular surface (ie some ones’ shoe !)
• Any contributory neurological history

Question 7

Palpation on physical examination

Answer 7

• Lateral malleolus
• Anterior talo – fibular ligament (ATF)
• Calcaneofibular ligament
• Posterior talofibular ligament
• Anterior – inferior syndesmosis
• Medial malleolus
• Deltoid ligament
• Achilles tendon
• Fifth metatarsal base
• Calcaneal anterior process

Question 8

Physical tests

Answer 8

• Squeeze test: anterior – inferior syndesmosis
  Anterior drawer test (push – pull test; “dimple sign”)
• Muscle testing (esp. peroneals and flexors)
• Dorsi / plantarflexion of the MTPJ: shepards fracture / flexor tendon injury

Question 9

Lateral ankle sprain physical examination order

Answer 9

• Vitals
• Begin proximal
• Begin at least painful areas

Question 10

Syndesmotic injury tests

Answer 10

• Squeeze test
• Tibio–talar shuck test
• External rotation test

Question 11

Lateral ligaments palpation

Answer 11

• Anterior talo – fibular
• Calcaneofibular
• Posterior malleolus

Question 12

Lateral ankle sprain grading

Answer 12

• Grade 1: Partial tear of the anterior talo – fibular ligament (“anterior sprain”)
• Grade 2: Complete tear of the ATF and partial tear to the calcaneofibular ligament
• Grade 3: Complete tear of the ATF and CF
• Grade 4: (some authors) posterior talo fibular ligament injury

Question 13

Lateral ankle sprain radiographic evaluation

Answer 13

• The Ottawa ankle rules: who gets an x – ray ?
• Can not bear weight initially and / or
• Pain over syndesmosis or posterior malleolus
• AP, MO, Lat ankle and MO foot
• In the USA: everyone gets an x – ray !

Question 14

Lateral ankle sprain associated injuries

Answer 14

• Ankle fracture
• Syndesmotic (“high”) ankle injury
• Shepard’s (Steida’s) fracture: posterior -lateral process of the talus
• Talar dome fracture
• Calcaneal anterior process fracture
• Fifth metatarsal base avulsion fracture
• Sinus tarsi syndrome

Question 15

Rare associated injuries

Answer 15

• Pseudo aneurism of the lateral malleolar artery
• Neoplasm
• Compartment syndrome
• Reflex sympathetic dystrophy
• Achilles rupture

Question 16

Calcaneal anterior process lateral injuries

Answer 16

• Avulsion injury via bifurcate ligament

Question 17

Fifth met base avulsion fracture

Answer 17

• Avulsion from a lateral slip of the plantar fascia and to a lesser extent, the peroneus brevis
• Jones fracture uncommon

Question 18

Talar dome fractures

Answer 18

• A common latent complaint

Question 19

Lateral ankle sprain initial management

Answer 19

• Protection
• Rest
• Ice
• Compression
• Elevation
• NSAID’s ?

Question 20

Lateral ankle sprains management (general/continuous)

Answer 20

• Jones compression for 0- 5 days
• Syndesmotic injury: wb immobilization 6 -8 weeks
• Limit the period of non – weight bearing
• CAM walker for early weight - bearing
• Consider bone scan / MRI / CT
• Begin rehabilitation ASAP

Question 21

CAM walker

Answer 21

• Allows for early weight – bearing and maintains (ankle dorsiflexed) ATF in close approximation (less pain !)

Question 22

Rehabilitation

Answer 22

• Acute phase
• Rehabilitative phase
• Functional phase
• Return to activity phase

Question 23

Functional phase: improve strength and proprioception

Answer 23

• BAPS (biomechanical ankle platform system) board
• Plyometrics
• Toe raises / other balancing exercises
• Side – to – side lateral movement (slide board, shuttle machine)
• Cybex / Biodex

Question 24

Return to activity phase

Answer 24

• Sport – specific movements
• Preventative strategies
• Equipment modifications

Question 25

Requirements for the athlete to return to full activity

Answer 25

- Minimal / no edema - No limp with normal gait - Be able to perform one – legged toe raise - Ability to descend stairs (without using the hand rail) - One – legged lateral hop test - Ankle dorsiflexion test

Question 26

Ankle braces and tape

Answer 26

- Both reduce the incidence of ankle inversion sprains by increasing peroneal reactivity (reaction time) and strength through direct contact with the skin (propricoeptors) - Braces >>> tape - Tape lasts 10 min (40% reduction) - Both do not alter athletic performance if applied correctly - Both >>> orthoses and high – top shoes - Athletes should be braced for up to 6 months following an injury

Question 27

Peroneal muscular strengthening and proprioceptive exercise

Answer 27

- Out-perform bracing, taping, orthoses and high tops in the prevention of lateral ankle inversion sprains - Cross – over effect of rehabilitation

Question 28

1 complication of inversion ankle sprains

Answer 28

- Chronic ankle instability and pain

Question 29

Stress radiography

Answer 29

- Must have a negative contralateral history - Common peroneal nerve block + inversion stress (talar tilt) = > 5 degrees compared with contralateral ankle + anterior drawer (push – pull) = > 10 mm of anterior talar displacement or > 4 mm compared with the contralateral ankle

Question 30

Anterior drawer (push-pull)

Answer 30

- Specific for the ATF

Question 31

Inversion stress

Answer 31

- Specific for CFL

Question 32

Radiographic finding inversion stress testing (by grading)

Answer 32

- Grade 1: + push – pull, -/+ inversion stress (>5 degrees) - Grade 2: + push – pull, + inversion stress (>10 degrees) - Grade 3: + push – pull, + inversion stress (>15 degrees) - Grade 4: + push – pull, + inversion stress ( > 15 degrees)

Question 33

Lateral ankle instability surgical intervantion

Answer 33

- Delayed primary ligamentous repair (Brostrom procedure) - Chrisman – Snook - Watson – Jones - Split peroneus brevis - Evans - Etc.

Question 34

Surgical management outcome studies

Answer 34

- Indicate that delayed primary ligamentous repair yields improved results when compared with stabilization procedures - Stabilization procedures are more disruptive to normal anatomy, more technically difficult and are more likely to result in over-tightening of the ankle

Question 35

Brostrom procedure

Answer 35

- Anterior talo-fibular ligament imbricated and repaired with non – absorbable suture (eg 00 – 2.0 ethibond) - Anterior – inferior extensor retinaculum over – sewn to anterior boarder of the fibula (Gould modification) - Repair of calcaneo – fibular ligament unnecessary

Question 36

Other treatment options for lateral ankle instability

Answer 36

- Prioltherapy: Thermal “shrinking” of the lateral ligaments with the “wand” - Prolotherapy: injectable sugar solution to enhance proprioception