Ottawa rules
Imaging after acute trauma: ankle, midfoot or knee.
Ottawa — Ankle
Principle
Clinical decision rule from the cited reference; categorical output, no numeric score or fracture diagnosis.
Scope
Adult ≥18 years, isolated acute trauma and reliable examination. Outside pilot: pregnancy, multiple trauma, impaired consciousness/sensation or inability to perform a reliable examination. A negative rule does not replace examination or reassessment for persistent pain; it does not diagnose the absence of fracture.
Interpretation limits
Adult ≥18 years, isolated acute trauma and reliable examination. Outside pilot: pregnancy, multiple trauma, impaired consciousness/sensation or inability to perform a reliable examination. A negative rule does not replace examination or reassessment for persistent pain; it does not diagnose the absence of fracture.
Formula and logic
If zone pain: radiography if targeted bone tenderness is present OR four steps are impossible immediately AND at assessment. Without zone pain: rule not applicable.
Interpretation
- Radiography not indicated by the rule
- Zone pain present, without an identified imaging criterion. The decision remains clinical.
- Radiography criterion present
- Zone pain with targeted bone tenderness or inability to take four steps at both time points.
- No zone pain — rule not applicable
- Absence of pain in this zone does not allow this rule to assess another injury site.
Definition version : 0.1.0
Sources
- NSW Agency for Clinical Innovation — Ottawa ankle rules (adult) — ECAT appendix
2023-12 · Full ankle/foot scoring, zone pain and four steps at both time points. Read on 6 October 2026; institutional adaptation of Stiell 1994. No diagram reproduced.
Ottawa — Foot
Principle
Clinical decision rule from the cited reference; categorical output, no numeric score or fracture diagnosis.
Scope
Adult ≥18 years, isolated acute trauma and reliable examination. Outside pilot: pregnancy, multiple trauma, impaired consciousness/sensation or inability to perform a reliable examination. A negative rule does not replace examination or reassessment for persistent pain; it does not diagnose the absence of fracture.
Interpretation limits
Adult ≥18 years, isolated acute trauma and reliable examination. Outside pilot: pregnancy, multiple trauma, impaired consciousness/sensation or inability to perform a reliable examination. A negative rule does not replace examination or reassessment for persistent pain; it does not diagnose the absence of fracture.
Formula and logic
If zone pain: radiography if targeted bone tenderness is present OR four steps are impossible immediately AND at assessment. Without zone pain: rule not applicable.
Interpretation
- Radiography not indicated by the rule
- Zone pain present, without an identified imaging criterion. The decision remains clinical.
- Radiography criterion present
- Zone pain with targeted bone tenderness or inability to take four steps at both time points.
- No zone pain — rule not applicable
- Absence of pain in this zone does not allow this rule to assess another injury site.
Definition version : 0.1.0
Sources
- NSW Agency for Clinical Innovation — Ottawa ankle rules (adult) — ECAT appendix
2023-12 · Full ankle/foot scoring, zone pain and four steps at both time points. Read on 6 October 2026; institutional adaptation of Stiell 1994. No diagram reproduced.
Ottawa — Knee
Principle
Clinical decision rule from the cited reference; categorical output, no numeric score or fracture diagnosis.
Scope
Adult pilot ≥18 years, isolated acute knee trauma, reliable examination. Outside pilot: pregnancy, multiple trauma, impaired consciousness or sensation, reassessment of the same injury and old injury. Does not diagnose fracture or ligament injury; reassess if symptoms persist.
Interpretation limits
Adult pilot ≥18 years, isolated acute knee trauma, reliable examination. Outside pilot: pregnancy, multiple trauma, impaired consciousness or sensation, reassessment of the same injury and old injury. Does not diagnose fracture or ligament injury; reassess if symptoms persist.
Formula and logic
Radiography if age ≥55 years OR isolated patellar tenderness OR fibular head tenderness OR flexion90° impossible OR four steps impossible immediately AND at assessment.
Interpretation
- Radiography not indicated by the rule
- None of the five criteria identified; still subject to clinical judgement.
- Radiography criterion present
- At least one Ottawa knee criterion is present.
Definition version : 0.1.0
Sources
- Royal College of Radiologists — Radiography for knee trauma — Ottawa Knee Rule
Revu 2022-07-24 · The standard section: five knee criteria, ≥55 years and inability to take four steps at both time points. Full scoring system read on 6 October2026; original1995/1996 identified, not read in full.