Ankle injuries

Anatomy

• Medial deltoid ligament is strongest
• Lateral ligament complex
  • Anterior talofibular (weakest and represents 85% of all ankle sprains)
  • Posterior talofibular
  • Calcaneofibular
• Syndesmosis
  • Four distinct ligaments and carries 16% of axial load

Ottawa ankle and midfoot rules

• X-ray only required if any pain in malleolar zone or midfoot along with bony tenderness in one of four locations or inability to weight bear both immediately and in ED
  • Posterior edge or tip of medial malleolus
  • Posterior edge or tip of lateral malleolus
  • Base of 5^th
  • Navicular
• Originally derived in patients over 18, able to cooperate, not intoxicated with no distracting injury or sensory loss
• Validated in children >2yo now

Plain films

• 95% sensitive if 2 out of 3 views obtained
• On AP
  • Medial fibular cortex to posterior edge of lateral tibial groove <=5mm
  • Overlap should be >10mm
• On mortise
  • Equal joint space either side
  • Medial joint space <= 4mm
• On lateral view
  • May see joint effusion (suspect talar dome fracture)

Tendon injuries

• Peroneal/fibular tendon
  • Subluxation or dislocation from behind lateral malleolus to in front from posterior retinaculum rupture
  • Occurs with hyperdorsiflexion in eversion
  • Rupture evidenced by weakness on eversion
• Achilles tendon rupture
  • Confirmed and severity graded by USS
  • Can place in gravity equinus (natural position of foot when relaxed while standing) plaster cast or moonboot with heel risers in gravity equinus position and gradual return to flat foot over time
  • Benefit of moonboot with heel risers is can weight-bear as tolerated from day 1 and doesn’t require repeated plaster casting
  • Shown to be equal in terms of functional outcome and re-rupture rates (5-6%) at 9 months in UKSTAR paper

Lateral ankle sprain

• Typically inversion with plantarflexion
• Grade I – No tearing of ligaments, minimal functional loss, pain, swelling and ecchymosis
• Grade II – Partial tear with some loss of function
• Grade III – More painful, swollen, bruised and difficulty weight bearing
  • Result from complete tear with laxity on stress testing
• Joint stability is the key determinant of therapy
• If stable and can weight bear – PRICE, no sports and follow-up with LMO in one week
• If stable but unable to weight bear – Ankle brace, crutches and LMO in one week
• If grossly unstable, backslab and ortho consult
• No consensus whether surgery or conservative therapy yields better outcomes

Medial ankle sprain

• Isolated deltoid sprain is rare
• Usually associated with fibular fracture or tear of syndesmosis from eversion injury
  • Maissoneuve is spiral fracture of proximal third of fibula associated with medial ankle ligament disruption
  • Can do cross-leg test for distal syndesmosis injury
• Negative X-rays suggest syndesmotic injury
• Early referral to fracture clinic improves detection of underlying fractures or syndesmotic injuries

General treatment of ankle sprains

• Protect
• Rest for 48-72 hours
• Ice 20/20
• Compression bandage
• Elevation
• Motion and strength exercises can begin within 48-72 hours
• Endurance training focused towards specific sports and training to improve balance after this
• Return to activity between 4-7 days have better functional outcomes

Ankle dislocations

• Posterior most common from backward force on plantarflexed foot often with lateral malleolar fracture
• Anterior from force on dorsiflexed foot with anterior tibial fracture
• Lateral dislocation rare
• Treatment
  • Neurovascular compromise is common
  • Grasp heel, apply traction and rotation opposite to direction of MOI
  • Apply splint and get radiographs and ortho admission
  • Confirm and document neurovascular status before and after

Fractures

• Ankle is ring of bone and ligaments around talus
• Single ring disruption usually stable but 2 or more disruptions are unstable
• Trimalleolar involve posterior malleolus of tibia
• Medial malleolar fracture is rarely an isolated event – Check other malleoli and entire length of fibula
• Treat small fibular avulsion fractures as stable ankle sprains as long as minimally displaced (<3mm in diameter) and no signs of medial ligament injury
• Posterior splint and NWB until ortho f/u organised

Occult fractures

• Maissoneuve
• Peroneal tendon dislocation
• Osteochondral injuries 
• Syndesmosis tear
• Anterior calcaneal process fractures (seen on lateral view)
• Lateral talar process fractures (just inferior to distal fibula)
• Os trigonum (tenderness anterior to Achilles tendon)

Weber classification

• Type A – Below level of talar dome, tibiofibular syndesmosis intact, deltoid ligament intact, medial malleolus occasionally fractured, usually stable if medial malleolus intact
• Type B – At level of talar dome, tibiofibular syndesmosis usually intact, medial malleolus may be fractured, deltoid ligament may be torn, stability depends on medial structures
• Type C – Above level of talar dome, syndesmosis disrupted, medial malleolus/deltoid rupture usually present, can be as high as proximal fibula (Maissoneuve)

Management

• Non-operative
  • Avulsions <3mm off fibula without medial ankle injury
  • Non-displaced fractures wth intact mortise
• Operative
  • Displaced
  • Unstable
  • Incongruity of mortise
  • Bi- or tri-malleolar
  • Isolated posterior malleolar fractures >20% joint surface involvement
  • Contralateral ligamentous damage
  • Usually delayed until swelling subsides

Crossbat Protocol

• Equipoise exists regarding management of isolated Weber B fractures
• The Crossbat trial in Australia and New Zealand was a combination prospective randomised open-label control trial AND observational review of surgical vs. conservative management
• Inclusion criteria were adults 18 to 65 years old with isolated closed Weber B fracture without talar shift (significant talar shift defined as medial clear space >2mm wider than superior clear space on mortise view)
• Patients had no other concomitant fractures, were mobile pre-injury
• Patients were randomised 1:1 to either surgical (plate and screws then NWB in cast) or non-surgical intervention (WBAT in moon boot)
• The primary outcome was patient-reported ankle function and health-related quality of life at 3, 6 and 12 months
• Safety outcomes were adverse events at 6 weeks, 3, 6 and 12 months.
• 160 patients were randomised to either intervention and 276 participated in the observational cohort
• In the randomised cohort, 12 month follow-up showed surgical group not superior to conservative management in terms of function or QoL
• Adverse events were significantly more common in the surgical group

CAST Trial (Mechanical supports for acute, severe ankle sprain: a pragmatic, multicentre, randomised controlled trial. Lamb et al. Lancet)

• Randomised individuals in the UK with severe ankle sprains (defined as inability to weight bear at day 3) and no fracture on X-ray to either tubigrip, Aircast stirrup brace, moonboot or plaster cast for 10 days after an initial period of 3 days non-weight bearing
• All participants were provided with crutches
• Found the plaster cast and Aircast stirrup brace had similar benefit over the other two with respect to patient function at 3 months

Last Updated on June 1, 2023 by Andrew Crofton