Ottawa knee rule
The Ottawa knee rules were derived to aid in the efficient use of radiography in acute knee injuries.
The rule should be used in patients >2 years of age with knee pain/tenderness following trauma < 7 days ago.
Research authors: Stiell IG, Greenberg GH, Wells GA, McKnight RD, Cwinn AA, Cacciotti T, McDowell I, Smith NA.
Details Formula Study characteristics Files & References
★★★★
Model author
Model ID
496
Version
1.12
Revision date
2016-04-26
MeSH terms
  • Injuries, Knee
  • Diagnostic X-Ray Radiology
  • Clinical Prediction Rule
  • Model type
    Linear model (Calculation)
    Status
    public
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    Formula
    No Formula defined yet
    Condition Formula

    Additional information

    Study objective:
    To derive a highly sensitive decision rule for the selective use of radiography in acute knee injuries.

    Design:
    Prospectively administered survey.

    Setting: Emergency departments of two university hospitals.

    Participants: Convenience sample of 1,047 adults with acute knee injuries.

    Inclusion criteria:
    Adult patients who presented with acute blunt injuries of the knee caused by any mechanism of injury. The "knee" was considered to include the patella, the head and neck of the fibula, the proximal 8 cm of the tibia, and the distal 8 cm of the femur.

    Exclusion criteria:
    Patients who were younger than 18 years, were pregnant, had isolated injuries of the skin without underlying soft-tissue or bone involvement (eg, superficial lacerations, abrasions, puncture wounds, burns), had been referred from outside the hospital with radiographs, had sustained knee injury more than 7 days previously, had returned for reassessment of the same injury, had an altered level of consciousness, were paraplegic, or had multiple trauma or other fractures.

    Source:
    Original research paper: Stiell IG, Greenberg GH, Wells GA, et al. Derivation of a decision rule for the use of radiography in acute knee injuries. Ann Emerg Med. 1995;26(4):405-13.

    Study Population

    Total population size: 1047
    Males: {{ model.numberOfMales }}
    Females: {{ model.numberOfFemales }}

    Continuous characteristics

    Name Mean SD Unit
    Age 36 25 years
    Time from injury to assessment 19 29 hours
    Time in ED for nonfracture cases with radiography 127 50 minutes
    Time in ED for nonfracture cases without radiography 83 42 minutes

    Categorical characteristics

    Name Subset / Group Nr. of patients
    Mechanism of injury Twisting 524
    Other direct injury 94
    Direct blow (fall or object) 429
    Activity at time of injury Work 132
    Sports 404
    Other 511
    Isolated knee injuries Yes 932
    No 115
    Fracture present Yes 68
    No 979
    Type of fracture Patella 29
    Proximal tibia 29
    Head of fibula 8
    Distal femur 3
    Tibial spine 2
    Tibial tuberosity 2
    Ottawa knee rule
    V-1.12-496.16.04.26
    Refer to Intended Use for instructions before use
    Evidencio B.V., Irenesingel 19, 7481 GJ, Haaksbergen, the Netherlands

    Number of Ottawa knee rule criteria met:
    ...
    criteria

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    Result
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    Number of Ottawa knee rule criteria met: criteria

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    Outcome stratification

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    Conditional information

    Result interpretation


    How the Ottawa knee rule should be used:
    The Ottawa knee rule was initially developed for patients >18 years of age with knee pain/tenderness following trauma < 7 days ago.1 The rule is sensitive (95-100%) to rule-out fractures, but not specific (19-50%) to suggest who may have a fracture. In a multicenter trial including 750 patients aged 2 to 16 years, Bulloch et al (2003) showed that the Ottawa ankle rule is also valid in children.2

    Model performance:
    In the derivation study (N=1,047) by Stiell et el (1995), the sensitivity of the Ottawa knee rule was 100% (95% confidence interval [CI], 95% to 100%) and specificity was 54% (95% CI, 51% to 57%).1 In a prospecitve validation (N=1096) by the same group, again a sensitivity of 100% (95% CI, 94% to 100%) was found.3 Upon external validation, independent research groups found sensitivities of 95-100% for clinically significant knee fractures using the Ottawa knee rule, with specificities ranging from 19-50%.4-7

    Clinical implications of use:
    According to the derivation study and several external validation studies, application of the rule would have led to a 17-49% relative reduction in the use of radiography.1-7 Successful use of the rule (e.g. by triage nurses) could improve patient flow, decrease waiting times, and allow for more efficient and cost-effective patient management.8

    References:
    1 Stiell IG, Greenberg GH, Wells GA, et al. Derivation of a decision rule for the use of radiography in acute knee injuries. Ann Emerg Med. 1995;26(4):405-13.
    2 Bulloch B, Neto G, Plint A, et al. Validation of the Ottawa Knee Rule in children: a multicenter study. Ann Emerg Med. 2003;42(1):48-55.
    3 Stiell IG, Greenberg GH, Wells GA, et al. Prospective validation of a decision rule for the use of radiography in acute knee injuries. JAMA. 1996;275(8):611-5.
    4 Emparanza JI & Aginaga JR. Validation of the Ottawa Knee Rules. Ann Emerg Med. 2001;38(4):364-8.
    5
    Seaberg DC, Yealy DM, Lukens T, et al. Multicenter comparison of two clinical decision rules for the use of radiography in acute, high-risk knee injuries. Ann Emerg Med. 1998;32(1):8-13.
    6 Jalili M & Gharebaghi H. Validation of the Ottawa Knee Rule in Iran: a prospective study. Emerg Med J. 2010;27(11):849-51.
    7 Tigges S, Pitts S, Mukundan S Jr, et al. External validation of the Ottawa knee rules in an urban trauma center in the United States. AJR Am J Roentgenol. 1999;172(4):1069-71.
    8 Nichol G, Stiell IG, Wells GA, et al. An economic analysis of the Ottawa knee rule. Ann Emerg Med. 1999;34:438-47.
     

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    Calculations alone should never dictate patient care, and are no substitute for professional judgement. See our full disclaimer.

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