Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review.
OBJECTIVE
To summarise the evidence on accuracy of the Ottawa ankle rules, a decision aid for excluding fractures of the ankle and mid-foot.


METHODS
Systematic review.


METHODS
Electronic databases, reference lists of included studies, and experts.


METHODS
Data were extracted on the study population, the type of Ottawa ankle rules used, and methods. Sensitivities, but not specificities, were pooled using the bootstrap after inspection of the receiver operating characteristics plot. Negative likelihood ratios were pooled for several subgroups, correcting for four main methodological threats to validity.


RESULTS
32 studies met the inclusion criteria and 27 studies reporting on 15 581 patients were used for meta-analysis. The pooled negative likelihood ratios for the ankle and mid-foot were 0.08 (95% confidence interval 0.03 to 0.18) and 0.08 (0.03 to 0.20), respectively. The pooled negative likelihood ratio for both regions in children was 0.07 (0.03 to 0.18). Applying these ratios to a 15% prevalence of fracture gave a less than 1.4% probability of actual fracture in these subgroups.


CONCLUSIONS
Evidence supports the Ottawa ankle rules as an accurate instrument for excluding fractures of the ankle and mid-foot. The instrument has a sensitivity of almost 100% and a modest specificity, and its use should reduce the number of unnecessary radiographs by 30-40%.
Bachmann
Lucas M
LM
Horten Centre, Zurich University, Postfach Nord, CH-8091 Zurich, Switzerland. lucas.bachmann@evimed.ch
Kolb
Esther
E
Koller
Michael T
MT
Steurer
Johann
J
ter Riet
Gerben
G
D016512:Ankle Injuries / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D018409:Foot Injuries / Q000175:diagnosis* / Q000000981:diagnostic imaging; D050723:Fractures, Bone / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D012372:ROC Curve; D011859:Radiography; D012680:Sensitivity and Specificity