Ankle Sprain - Foot & Ankle

Introduction

Overview
- ankle sprains involve an injury to the ATFL and CFL and are the most common reason for missed athletic participation
  - treatment usually includes a period of immobilization followed by physical therapy. Only when nonoperative treatment fails is surgical reconstruction indicated.
Ankle sprains consist of
- high ankle sprain
  - syndesmosis injury
  - 1-10% of all ankle sprains
- low ankle sprain (this topic)
  - ATFL and CFL injury
  - >90% of all ankle sprains
Epidemiology
- incidence
  - ankle sprains are the most common reason for missed athletic participation
- demographics
  - most common injury in dancers
- risk factors
  - patient-related
    - limited dorsiflexion, decreased proprioception, balance deficiency
  - environmental-related
    - indoor-court sports have the highest risk (basketball, volleyball)
Pathophysiology
- Mechanism of injury
  - Inversion type ankle injury on a plantarflexed foot
  - Recurrent ankle sprains can lead to functional instability
Associated injuries/conditions include
- osteochondral defects
- peroneal tendon injuries
- subtle cavovarus foot
- deltoid ligament injury (isolated deltoid ligament injuries are very rare)
  - superficial deltoid: limits talar abduction
  - deep deltoid: limits external rotation
    - initally treated conservatively, but may require reconstruction if patient continues to have instability
- complex regional pain syndrome
- fractures
  - 5th metatarsal base
  - anterior process of calcaneus
  - lateral or posterior process of the talus
Prognosis
- natural history
  - pain decreases rapidly during the first 2 weeks after injury
  - 5-33% reports some pain at 1 year
  - increased risk of a sprain to ipsilateral and contralateral ankle

Anatomy

Ligamentous anatomy of the ankle
ATFL
- most commonly involved ligament in low ankle sprains
- mechanism is plantar flexion and inversion
- physical exam shows drawer laxity in plantar flexion
CFL
- 2nd most common ligament injury in lateral ankle sprains
- mechanism is dorsiflexion and inversion
- physical exam shows drawer laxity in dorsiflexion
- subtalar instability can be difficult to differentiate from posterior ankle instability because the CFL contributes to both
PTFL
- less commonly involved

Classification

Classification of Low Ankle Sprains

Ligament disruption

Ecchymosis and swelling

Pain with weight bearing

Grade I
none

minimal

normal

Grade II
stretch without tear

moderate

mild

Grade III
complete tear

severe

severe

Presentation

Symptoms
- pain with weight bearing (may or may not be able to bear weight)
- swelling and ecchymosis
- recurrent instability
- catching or popping sensation may occur following recurrent sprains
Physical exam
- focal tenderness and swelling over-involved ligament(s)
- anterior drawer test
  - looks for excessive anterior displacement of talus relative to tibia
  - limited usefulness in acute setting
  - ATFL best tested in plantarflexion, CFL in dorsiflexion
- Talar tilt test
  - excessive ankle inversion (> 15 degrees) compared to contralateral side indicated injury to ATFL and CFL

Imaging

Radiographs
- indications for radiographs with an ankle injury include (Ottawa ankle rules)
  - inability to bear weight
  - medial or lateral malleolus point tenderness
  - 5MT base tenderness
  - navicular tenderness
  - 96-99% sensitive in ruling out ankle fracture
- radiographic views to obtain
  - standard ankle series (weight bearing)
    - AP
    - lateral
      - ATFL injury suggested with anterior talar translation
    - mortise
  - ER rotation stress view
    - useful to diagnosis syndesmosis injury in high ankle sprain
    - look for asymmetric mortise widening
    - medial clear space widening > 4mm
    - tibiofibular clear space widening of 6 mm
  - varus stress (talar tilt) view
    - used to diagnose injury to CFL
    - measures ankle instability by looking at talar tilt
MRI
- indications
  - consider MRI if pain persists for 6-8 weeks following sprain
- useful to evaluate
  - peroneal tendon pathology
  - osteochondral injury
  - syndesmotic injury

Treatment

Nonoperative
- RICE, elastic wrap to minimize swelling, followed by therapy
  - indications
    - Grade I, II, and III injuries
  - technique
    - initial immobilization
      - may require short period (approx. 1 week) of weight-bearing immobilization in a walking boot, aircast or walking cast, but early mobilization facilitates a better recovery
      - grade III sprains may benefit from 10 days of casting and nonweightbearing
    - therapy
      - early phase
        
        early functional rehabilitation begins with motion exercises and progresses to strengthening, proprioception, and activity-specific exercises
      - strengthening phase
        
        once swelling and pain have subsided and patient has full range of motion begin neuromuscular training with a focus on peroneal muscles strength and proprioception training
        
        a functional brace that controls inversion and eversion is typically used during the strengthening period and used as prophylactic treatment during high-risk activities thereafter
  - outcomes
    - early functional rehabilitation allows for the quickest return to physical activity
    - supervised physical therapy has shown a benefit in early follow-up but no difference in the long term
Operative
- anatomic reconstruction vs. tendon transfer with tenodesis
  - indications
    - Grade I-III that continue to have pain and instability despite extensive nonoperative management
    - Grade I-III with a bony avulsion
  - technique (see below)
- arthroscopy
  - indications
    - recurrent ankle sprains and chronic pain caused by impingement lesions
      - anteriorinferior tibiofibular ligament impingement
      - posteromedial impingement lesion of ankle
      - often used prior to reconstruction to evaluate for intra-articular pathology
  - procedure
    - debride impinging tissue

Surgical Techniques

Gould modification of Brostrom anatomic reconstruction
- procedure
  - an anatomic shortening and reinsertion of the ATFL and CFL
  - reinforced with inferior extensor retinaculum and distal fibular periosteum (Gould modification)
- results
  - good to excellent results in 90%
  - consider arthroscopic evaluation prior to reconstruction for intra-articular evaluation
Tendon transfer and tenodesis (Watson-Jones, Chrisman-Snook, Colville, Evans)
- procedure
  - a nonanatomic reconstruction using a tendon transfer
- technique
  - any malalignment must be corrected to achieve success during a lateral ligament reconstruction
  - Coleman block testing used to distinguish between fixed and flexible hindfoot varus
- results
  - subtalar stiffness is a common complication

Rehabilitation

Return to play
- depends on, grade of sprain, syndesmosis injury, associated injuries, and compliance with rehab
  
  Classification
  
  Time to RTP
  
  Grade I
  1-2 weeks
  
  Grade II
  1-2 weeks
  
  Grade III
  few weeks
  
  High ankle (immobilization)
  several weeks
  
  High ankle (screw fixation)
  season

Prevention
- prevention techniques in athletes with prior sprains includes
  - semirigid orthosis
    - patients who demonstrate cavovarus alignment benefit from a brace with lateral hindfoot/forefoot wedging and first metatarsal recess
  - evertor muscle (peroneals) strengthening
  - proprioception exercises
  - season long prevention program

Complications

Pain and instability
- Incidence
  - up to 30% continue to experience symptoms following and acute ankle sprain
- Risk factors
  - most common cause of chronic pain is a missed injury, including
    - missed fractures (anterior process of calcaneus, lateral or posterior process of the talus, 5th metatarsal)
    - osteochondral lesion
    - injuries to the peroneal tendons
    - injury to the syndesmosis
    - tarsal coalition
    - impingement syndromes
Stretch neurapraxia
- Neuropathic pain in the distribution of the affected nerve