Syndesmotic injury high ankle sprain ICD-10 S93.43
Maisonneuve fracture
Peroneal tendon subluxation or tear
Achilles tendon rupture ICD-10 S86.01
Ankle dislocation ICD-10 S93.0
Non-traumatic mimics
Non-traumatic mimics
Gout flare
Septic arthritis
Cellulitis
Inflammatory arthritis flare
Deep vein thrombosis
Charcot neuroarthropathy
Laboratory Tests
Routine testing
Routine testing
No routine labs for isolated uncomplicated ankle sprain
Pregnancy test when imaging planned and pregnancy status uncertain
Urine hCG
If alternate diagnosis suspected
If alternate diagnosis suspected
Infection concern
White blood cell count for systemic infection
C reactive protein for inflammatory burden
Blood cultures if sepsis criteria
Crystal arthritis concern
Arthrocentesis fluid analysis
Gram stain
Culture
Cell count
Crystal analysis
Anticoagulant associated hemarthrosis concern
INR for warfarin use
Hemoglobin for significant bleeding concern
Diagnostic Tests
Scoring Systems
Scoring systems
Ottawa ankle rules
Pain in malleolar zone
Bone tenderness posterior edge or tip of lateral malleolus
Bone tenderness posterior edge or tip of medial malleolus
Inability to bear weight 4 steps immediately and in ED
Ottawa foot rules
Pain in midfoot zone
Bone tenderness at base of fifth metatarsal
Bone tenderness at navicular
Inability to bear weight 4 steps immediately and in ED
Reported sensitivity range 92 percent to 100 percent for fracture exclusion
Specificity range 16 percent to 51 percent
Not validated for gross intoxication or unreliable exam
Use caution in neuropathy and reduced pain perception
MRI
MRI
MRI indications
Persistent pain and swelling beyond expected recovery
Suspected osteochondral lesion
Suspected syndesmotic injury with normal radiographs
Suspected tendon tear
Suspected occult fracture
MRI limitations
Limited acute ED availability
Incidental findings not correlating with symptoms
MRI interpretation pearls
ATFL and CFL disruption grading
Bone marrow edema for occult fracture
Cartilage defect for talar dome lesion
CT
CT
CT indications
Complex fracture characterization
Suspected occult fracture with high clinical suspicion and equivocal radiographs
Preoperative planning request
CT limitations
Ionizing radiation
CT interpretation pearls
Subtle talar fractures
Posterior malleolus involvement
Ultrasound
Ultrasound
POCUS applications
Joint effusion identification
Tendon integrity assessment
Achilles tendon discontinuity
Peroneal tendon subluxation dynamic exam
Ultrasound limitations
Operator dependence
Limited ability to exclude fracture
Ultrasound adjunct role
Supportive evidence when radiographs negative and tendon injury suspected
Disposition
Discharge criteria
Discharge criteria
Pain controlled with oral medications
No open injury
No neurovascular compromise
No fracture or dislocation on imaging when obtained
Safe ambulation plan
Crutches or walker training
Clear follow up plan
Admission or urgent specialty evaluation
Admission or urgent specialty evaluation
Open fracture or open joint concern
Neurovascular deficit
Suspected compartment syndrome
Suspected septic arthritis
Unstable fracture pattern
Ankle dislocation
Suspected syndesmotic injury with instability
Suspected Achilles rupture
Inability to mobilize safely at home
Treatment
Immobilization and functional support
Immobilization and functional support
Early phase goals
Pain reduction
Swelling control
Protection of injured ligament
Support selection by severity
Mild sprain
Lace up brace or elastic support
Moderate sprain
Air stirrup brace or walking boot
Severe sprain
Short period immobilization in boot or cast
Weight bearing
Early weight bearing as tolerated when stable
Crutches for pain limited gait
Elevation and compression
Compression wrap for swelling reduction
Elevation above heart level for swelling
Analgesia and anti-inflammatory therapy
Analgesia and anti-inflammatory therapy
Acetaminophen
Adult dosing
1000 mg orally every 6 to 8 hours as needed
Maximum 4000 mg per day
Liver disease or heavy alcohol use
Maximum 2000 mg per day
Ibuprofen
Adult dosing
400 mg orally every 6 to 8 hours as needed
Maximum 2400 mg per day
Avoid or use caution
Chronic kidney disease
Peptic ulcer disease
Anticoagulant use
Third trimester pregnancy
Naproxen
Adult dosing
500 mg orally once then 250 mg orally every 6 to 8 hours as needed
Maximum 1250 mg per day on day 1
Maximum 1000 mg per day after day 1
Topical NSAID
Diclofenac gel
Apply to painful area up to 4 times daily
Avoid broken skin
Evidence summary
NSAIDs and acetaminophen similar short term pain relief in acute ankle sprain
Opioids not superior for pain relief
Rehabilitation and return to activity
Rehabilitation and return to activity
Early motion
Pain limited range of motion exercises
Ankle alphabet
Dorsiflexion stretching
Strengthening progression
Peroneal strengthening
Resistance band eversion
Calf strengthening
Heel raises progression
Proprioception and balance
Single leg stance progression
Eyes open
Eyes closed
Unstable surface
Return to sport criteria
Pain free full range of motion
Near symmetric strength
Functional hop or agility testing without pain
Recurrence prevention
Ankle brace during high risk sport participation
Consider 6 to 12 months for recurrent sprain risk reduction
Procedures and escalation
Procedures and escalation
If suspected septic arthritis
Arthrocentesis prior to antibiotics when feasible
If dislocation
Immediate reduction pathway
If suspected fracture with skin tenting
Urgent reduction or splinting and consult
If suspected syndesmotic instability
Ortho consultation for stress imaging or advanced imaging
Special Populations
Pregnancy
Pregnancy
Pregnancy considerations
Avoid NSAIDs in third trimester
Prefer acetaminophen for pain control
Imaging considerations
Radiographs acceptable when clinically indicated
Shielding when feasible
VTE risk context
Immobilization increases VTE risk
Early mobilization when safe
Geriatric
Geriatric
Higher fracture risk
Lower threshold for radiographs
Osteoporosis considerations
Occult fracture risk with low energy mechanism
Mobility and falls risk
Assistive device needs assessment
Home safety planning
Medication risk
NSAID renal and GI risk increased
Prefer topical NSAID when appropriate
Pediatrics
Pediatrics
Growth plate considerations
Salter Harris injury mimic sprain
Ottawa ankle rules age considerations
Use caution in younger children
Lower threshold for imaging when exam unreliable
Weight based analgesia
Acetaminophen 15 mg per kg per dose orally every 6 hours as needed
Maximum 60 mg per kg per day
Ibuprofen 10 mg per kg per dose orally every 6 to 8 hours as needed
Maximum 40 mg per kg per day
Background
Epidemiology
Epidemiology
Common sports related injury
Lateral ligament complex most frequently injured
High recurrence risk after first sprain
Chronic ankle instability subset
Pathophysiology
Pathophysiology
Lateral ligament complex injury sequence
ATFL most commonly injured
CFL next most commonly injured
PTFL less commonly injured
Injury mechanisms
Inversion with plantarflexion stressing ATFL
Inversion with dorsiflexion stressing CFL
Syndesmotic injury mechanism
External rotation and dorsiflexion
Therapeutic Considerations
Therapeutic considerations
Functional support preferred over prolonged immobilization for most sprains
Early progressive loading supports recovery
Balance and proprioception training reduces recurrence
NSAID benefit similar to acetaminophen for short term pain in many studies
Persistent pain triggers evaluation for occult fracture or osteochondral lesion
Patient Discharge Instructions
copy discharge instructions
copy discharge instructions
Diagnosis ankle sprain
Brace or boot use as directed
Remove for hygiene and exercises if allowed
Weight bearing as tolerated
Crutches until able to walk without limping
Swelling control
Elevation above heart level
Compression wrap snug not tight
Ice 10 to 15 minutes up to 3 to 5 times daily for pain
Pain medications
Use acetaminophen or NSAID as directed
Avoid NSAIDs if pregnant in third trimester or kidney disease
Exercises start within 24 to 72 hours if pain allows
Gentle range of motion
Balance drills when walking comfortable
Follow up
Primary care or sports medicine within 5 to 10 days
Physiotherapy referral if ongoing pain or instability
Return to ED now
Increasing pain not controlled with medications
New numbness or weakness
Foot becomes cold or pale
Inability to bear weight worsening
Fever
Spreading redness
Wound drainage
Urgent ortho or sports medicine
Persistent pain or swelling beyond 2 weeks
Recurrent giving way
Suspected Achilles rupture signs
References
Clinical guidelines and evidence
Clinical guidelines and evidence
JOSPT clinical practice guideline for lateral ankle ligament sprains revision 2021
Functional support and therapeutic exercise emphasis
AAOS OrthoInfo sprained ankle overview
Early weight bearing as tolerated
Short period immobilization for higher grade injuries
Umbrella review of acute ankle sprain management 2022
NSAIDs and acetaminophen similar short term pain relief
Meta analyses on Ottawa ankle rules diagnostic accuracy
High sensitivity for fracture exclusion
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.