AdultPediatric
True ankle sprains are uncommon in skeletally immature children — physes fail before ligaments. Salter-Harris injuries of the distal fibula (SH I) and distal tibia (Tillaux, triplane) are classic. Apply Ottawa rules cautiously in young children.
🚩 Red-flag clues (must not miss)
- •Inability to bear weight + bony tenderness over malleolus = fracture
- •Tense compartment, severe pain, paresthesias = compartment syndrome
- •Open fracture, neurovascular compromise = emergent ortho
- •Fever + atraumatic swelling = septic ankle / osteomyelitis
History
- Mechanism (inversion, eversion, axial load), pop, swelling timing
- Weight-bearing status, prior ankle injury
- Age — adolescents (closing physis) get Tillaux/triplane
Exam
- Inspection — swelling, ecchymosis, deformity
- Palpation — distal fibula (entire length), distal tibia, base of 5th metatarsal, navicular, Achilles
- Anterior drawer, talar tilt; squeeze test (syndesmosis)
- Neurovascular distal to injury
Labs
- Not needed for typical trauma
- If atraumatic / febrile: CBC, CRP, ESR, blood cx
Imaging
- Ottawa Ankle Rules (validated ≥ 5 y) — XR if bony tenderness at malleoli (within 6 cm), navicular, or 5th MT base, or NWB
- AP, lateral, mortise views
- CT for Tillaux/triplane (intra-articular adolescent fx)
- MRI for occult SH I, OCD talus, osteomyelitis
Differential & next step
| Diagnosis | Clue | Next step |
|---|---|---|
| Salter-Harris I distal fibula | Tenderness over physis, normal XR | Walking boot/splint, ortho follow-up |
| Salter-Harris II distal tibia | Physeal widening + metaphyseal fragment | Reduction PRN, short-leg cast, ortho |
| Tillaux fracture (SH III) | Adolescent (12–15 y), closing physis, lateral tibial epiphysis | CT, ortho — ORIF if > 2 mm displacement |
| Triplane fracture (SH IV) | Adolescent, complex 3-plane fracture | CT mandatory, ortho |
| Lateral ligament sprain (ATFL) | Inversion injury in older child, anterolateral tenderness | RICE, brace/boot, weight-bearing as tolerated |
| 5th metatarsal base fracture | Inversion, lateral foot pain — avulsion vs Jones | Boot if avulsion; Jones (zone 2/3) → cast NWB, ortho |
| Talar dome OCD | Persistent pain after sprain, locking | MRI, ortho |
| Achilles rupture (rare in peds) | Sudden pop, + Thompson | Splint plantarflexion, ortho |
| Sever disease (calcaneal apophysitis) | 8–12 y/o athlete, posterior heel pain | Rest, heel cup, stretching |
| Septic ankle / osteomyelitis | Fever, atraumatic swelling, ↑ CRP | Aspiration, IV abx, MRI |
| Tarsal coalition | Recurrent 'sprains', stiff hindfoot, adolescent | CT/MRI, ortho referral |
Medications & dosing
| Drug | Dose | Notes |
|---|---|---|
| Ibuprofen | 10 mg/kg PO q6–8h (max 600 mg) | |
| Acetaminophen | 15 mg/kg PO q4–6h (max 1 g) |
Management / next steps
- Tenderness over distal fibula physis with normal XR → treat as SH I (boot/splint, ortho)
- Boot > air-cast > tape for moderate sprains
- Adolescent ankle injury with intra-articular concern → CT before discharge
Pearls
- 'Ankle sprain' in a child with open physes is usually a SH I until proven otherwise.
- Tillaux occurs as the lateral physis is the last to close.
- Always palpate the proximal fibula (Maisonneuve) in eversion injuries.