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Ottawa Knee Rule

Identifies adults with acute knee trauma needing radiographs: any one of five criteria indicates imaging.

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Check the population, units and version. The result shows the formula or classification; it does not make an automatic treatment decision.

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Method · Limits of application

Ottawa Knee/Stiell 1996 validation: 5 criteria, any positive; radiography in original scope

This Ottawa validation was conducted in adults with acute knee trauma. The observed 100% sensitivity has statistical uncertainty and is not a universal guarantee. The version’s eligibility and exclusions must be checked; a negative rule does not replace reassessment of persistent symptoms or automatically apply to children.

Conditions of use

Check the population, units, inclusion and exclusion criteria, and version in the original source. A result alone does not establish a diagnosis, discharge decision or prescription.

Documented parameters

Age 55 years or older
Isolated patellar tenderness (no other bony tenderness in the knee)
Tenderness at the fibular head
Unable to flex the knee to 90°
Unable to take 4 steps immediately after injury and at assessment

3/3 reference cases checked. Numerical tests are not clinical validation.

Sources and documentation

Documented formula

Transcribed from the source or a recorded revision; this is not a clinical recommendation.

Radiography is indicated with any one of five criteria: age ≥ 55 years; isolated patellar tenderness; fibular head tenderness; inability to flex to 90°; inability to bear weight (4 steps) immediately after injury and at assessment.

References

Stiell IG et al. Prospective validation of a decision rule for the use of radiography in acute knee injuries. JAMA, 1996.

Identifier: regra-de-ottawa-joelho

Original clinical content: Brazilian Portuguese.

Method version

Ottawa Knee/Stiell 1996 validation: 5 criteria, any positive; radiography in original scope

regra-de-ottawa-joelho@native-2026-10-05+852df998f6dd

Source for the active edition

The bibliographic edition identifies the source. By itself, it proves neither full conformity of the formula nor clinical approval.

Synthetic cases checked (3)

Synthetic cases for checking the implementation, with no patient data.

Case 1

reference-001

Inputs

Age 55 years or older: No
Isolated patellar tenderness (no other bony tenderness in the knee): No
Tenderness at the fibular head: No
Unable to flex the knee to 90°: No
Unable to take 4 steps immediately after injury and at assessment: No

{
  "idade55": false,
  "patela": false,
  "fibula": false,
  "flexao": false,
  "carga": false
}

Expected result

{
  "score": 0,
  "level": "low"
}

Actual result

{
  "score": 0,
  "positive": false
}

Case 2

reference-002

Inputs

Age 55 years or older: Yes
Tenderness at the fibular head: Yes
Isolated patellar tenderness (no other bony tenderness in the knee): No
Unable to flex the knee to 90°: No
Unable to take 4 steps immediately after injury and at assessment: No

{
  "idade55": true,
  "fibula": true,
  "patela": false,
  "flexao": false,
  "carga": false
}

Expected result

{
  "score": 2,
  "level": "mid"
}

Actual result

{
  "score": 2,
  "positive": true
}

Case 3

reference-003

Inputs

Unable to flex the knee to 90°: Yes
Age 55 years or older: No
Isolated patellar tenderness (no other bony tenderness in the knee): No
Tenderness at the fibular head: No
Unable to take 4 steps immediately after injury and at assessment: No

{
  "flexao": true,
  "idade55": false,
  "patela": false,
  "fibula": false,
  "carga": false
}

Expected result

{
  "score": 1,
  "level": "mid"
}

Actual result

{
  "score": 1,
  "positive": true
}

Code and reproducibility

This tool’s code on GitHub

Download code and tests

Sources, version and reproduction instructions

README

Local installation

Code license: Apache-2.0

Guidelines and conditions

This repository’s license applies to the code. Third-party instruments, questionnaires, data and models remain subject to their owners’ conditions.

The code tests are technical checks. Clinical approval and professional translation review are recorded separately.

Relationship with cancer research

General context — relationship to be defined

A resource for general clinical contexts. This edition does not assign a specific oncological relationship; selecting it for a study requires a justified question, population and purpose.