The Accuracy of the Ottawa Knee Rule To Rule Out Knee Fractures

A Systematic Review

20 January 2004 | Volume 140 Issue 2 | Pages 121-124

Background: The Ottawa knee rule is a clinical decision aid that helps rule out fractures and avoid unnecessary radiography.

Purpose: To summarize evidence about the accuracy of the Ottawa knee rule.

Data Sources: Relevant English- and non–English-language articles were identified from PreMEDLINE and MEDLINE (1966–2003), EMBASE (1980–2003), CINAHL (1982–2003), BIOSIS (1990–2003), the Cochrane Library (2002, Issue 3), the Science Citation Index database, reference lists of included studies, and experts.

Study Selection: Articles were included if they reported enough information to determine the sensitivity and specificity of the Ottawa knee rule for detecting fractures confirmed either radiologically or in combination with follow-up.

Data Extraction: Two reviewers independently extracted data on study samples, the ways that the Ottawa knee rule was used, and methodologic characteristics of studies.

Data Synthesis: Of 11 identified studies, 6 involving 4249 adult patients were considered appropriate for pooled analysis. The pooled negative likelihood ratio was 0.05 (95% CI, 0.02 to 0.23), the pooled sensitivity was 98.5% (CI, 93.2% to 100%), and the pooled specificity was 48.6% (CI, 43.4% to 51.0%).

Conclusion: A negative result on an Ottawa knee rule test accurately excluded knee fractures after acute knee injury. However, because the rule is calibrated toward 100% sensitivity and actual fracture prevalences are usually low, large-scale, multicentered studies are still needed to establish the cost-effectiveness of routinely implementing the rule.

Author and Article Information

From Zurich University, Zurich, Switzerland, and Academic Medical Center, Amsterdam, the Netherlands.

Acknowledgments: The authors thank Dr. Pius Estermann, information specialist at the hospital library, University Hospital, Zurich, Switzerland, for performing the literature searches.

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Lucas M. Bachmann, MD, PhD, Horten Centre, Zurich University, Postfach Nord, CH-8091 Zurich, Switzerland; e-mail, lucas.bachmann{at}evimed.ch.

Current Author Addresses: Drs. Bachmann, Haberzeth, and Steurer: Horten Centre, Zurich University, Postfach Nord, CH-8091 Zurich, Switzerland.

Dr. ter Riet: Department of General Practice, Academic Medical Center, Meibergdreef 15, 1105 AZ Amsterdam, the Netherlands.