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Ankle Fracture Treatment Calculator
Ottawa ankle rules, Weber classification, and stability assessment for ankle fractures. Evaluates medial clear space, syndesmosis, talar tilt, and treatment decisions.
⚠️ Medical Disclaimer: This is a clinical decision support tool. All ankle injuries should be evaluated by a qualified healthcare provider. Imaging and treatment decisions require physical examination.
Ottawa Ankle Rules
✓ Ottawa Rules NEGATIVE — X-ray likely not needed (sens ~98%)
Fracture Classification & Stability
mm
mm
°
years
Likely Stable
Conservative management likely appropriate
Ottawa Rules⧉
Negative
0/5 criteria met. Sensitivity ~98% for fracture.
Weber Type⧉
Type B
At syndesmosis level — stability variable
Medial Clear Space⧉
4 mm
✓ Normal (<4 mm)
Tibiofibular Clear Space⧉
5 mm
✓ Normal (<6 mm)
Talar Tilt⧉
3°
✓ Normal (≤5°)
Recommendation⧉
Conservative
Conservative management likely appropriate
Weber Classification
| Type | Description | Stability | Treatment |
|---|---|---|---|
| A (Below syndesmosis) | Lateral malleolus fracture below tibiotalar joint line | Usually stable | Conservative (boot/cast) if stable |
| B (At syndesmosis) | Fracture at level of syndesmosis (most common) | Variable | Stress test needed; ORIF if unstable |
| C (Above syndesmosis) | Fracture above syndesmosis with ligament disruption | Unstable | Surgical fixation (ORIF) recommended |
Lauge-Hansen Classification
| Mechanism | Frequency | Pattern |
|---|---|---|
| Supination-External Rotation | 40-75% | Stage I-IV with progressive injury |
| Pronation-External Rotation | 7-19% | Medial structures first, then lateral |
| Supination-Adduction | 10-20% | Lateral then medial structures |
| Pronation-Abduction | 5-21% | Medial, posterior, then lateral |
Planning notes, formulas, and examples
About the Ankle Fracture Treatment Calculator
The Ankle Fracture Treatment Calculator combines the Ottawa Ankle Rules for imaging decisions, Weber classification for fracture categorization, and stability metrics (medial clear space, tibiofibular clear space, talar tilt) to frame review context around conservative versus operative pathways.
Ankle fractures are among the most common fractures in adults, with approximately 180 per 100,000 person-years. Treatment decisions hinge on two key factors: fracture pattern (Weber classification) and ankle mortise stability. Stable fractures can be managed conservatively with immobilization, while unstable fractures require open reduction and internal fixation (ORIF) to restore articular congruity and prevent post-traumatic arthritis.
This calculator implements the Ottawa Ankle Rules to determine imaging necessity (sensitivity ~98% for clinically significant fractures), classifies fractures by the Weber system (A/B/C relative to the syndesmosis), and evaluates stability using radiographic parameters. The tool integrates these assessments to provide a treatment recommendation backed by current orthopedic evidence.
When This Page Helps
Ankle fracture management requires integrating clinical examination, radiographic measurements, and classification systems. This calculator streamlines the decision process, reducing the risk of missed instability or unnecessary surgery by keeping the imaging rule, fracture pattern, and stability measures in one place.
How to Use the Inputs
- Check applicable Ottawa Ankle Rule criteria from the physical examination.
- If X-ray is obtained, select the Weber classification of the fracture.
- Select the injury mechanism.
- Enter medial clear space measurement from the AP mortise view.
- Enter tibiofibular clear space and talar tilt angle.
- Enter patient age for context.
- Review the stability assessment and treatment recommendation.
Formula used
Ottawa Ankle Rules: X-ray if bone tenderness at malleoli/midfoot OR inability to weight-bear
Stability criteria: Medial clear space ≤4 mm, Tibiofibular clear space ≤6 mm, Talar tilt ≤5°
Weber A = stable, B = variable stability, C = unstableExample Calculation
Result: Unstable — Medial widened (5.5 mm), syndesmosis widened (7 mm). ORIF likely needed.
Weber B fracture with widened medial clear space (>4 mm) and tibiofibular overlap (>6 mm) indicates an unstable injury with deltoid and syndesmotic disruption requiring surgical stabilization.
Tips & Best Practices
- A true mortise view (15° internal rotation) is essential for accurate medial clear space measurement.
- Gravity stress views can substitute for manual stress testing and are less painful for the patient.
- Weber B fractures should always get stress testing — 40% have occult instability.
- In elderly patients with osteoporosis, consider lower thresholds for surgical fixation.
- Posterior malleolus fragments >25-33% of the articular surface may need separate fixation.
The Ottawa Ankle Rules: Evidence and Application
Developed by Stiell et al. in 1992, the Ottawa Ankle Rules have been validated in over 40,000 patients across multiple emergency departments worldwide. Their near-perfect sensitivity (97.6%) for significant fractures means a negative Ottawa screen virtually excludes fracture, safely reducing unnecessary X-rays by 30-40% and saving significant healthcare costs.
Weber Classification and Clinical Implications
Weber A fractures (below the syndesmosis) are typically stable and respond to conservative treatment. Weber B fractures (at the syndesmosis level) have variable stability — the key decision point is whether the medial structures (deltoid ligament) are intact. Weber C fractures (above the syndesmosis) imply syndesmotic disruption and are presumed unstable requiring surgical fixation.
Postoperative Rehabilitation Protocols
Modern evidence supports early mobilization after stable fixation. Current protocols often allow early range-of-motion exercises within 1-2 weeks, protected weight-bearing at 2-4 weeks (based on fixation stability), and progressive strengthening starting at 6 weeks. Return to sport typically occurs at 12-16 weeks with full rehabilitation completion.
Sources & Methodology
Last updated:
Methodology
This worksheet combines three layers of review: the Ottawa Ankle Rules for whether imaging is indicated after acute injury, the Danis-Weber fracture level relative to the syndesmosis, and common radiographic markers of mortise instability such as medial clear space, tibiofibular clear space, and talar tilt. It is meant to summarize the usual orthopedic decision points in one place so the injury pattern and stability features can be reviewed together.
The result is not a stand-alone surgical decision. Final treatment depends on the actual radiographs, stress views when indicated, neurovascular status, skin condition, displacement, posterior malleolus involvement, and orthopedic examination.
Sources
- Implementation of the Ottawa ankle rules (PubMed / JAMA) — Foundational validation reference for the Ottawa Ankle Rules.
- Ankle Fractures (Orthobullets) — Reference summary for Weber classification and radiographic stability markers.
Frequently Asked Questions
Clinical decision rules that identify which ankle injury patients need X-rays. They have ~98% sensitivity for significant fractures and can safely reduce imaging by 30-40%.
Medial clear space >4 mm on a mortise view suggests deltoid ligament disruption, making the ankle mortise unstable even in isolated lateral malleolus fractures.
Yes, if the ankle is stable (normal medial clear space, no syndesmosis widening, minimal talar tilt). Gravity stress or external rotation stress films help determine stability.
Weber C fractures, bimalleolar or trimalleolar fractures, fractures with >2 mm displacement, open fractures, and any fracture with mortise incongruity or instability on stress testing.
Measured 1 cm above the tibial plafond, it should be <6 mm. Widening suggests tibiofibular syndesmosis disruption, which increases ankle instability.
Non-operative: 6-8 weeks in boot/cast. Post-ORIF: 6-12 weeks non-weight-bearing, then gradual return. Full recovery including sports may take 4-6 months.
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