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Editor,—Further to previous correspondence I think the use of the Ottawa Ankle Rule needs some clarification.1 Firstly, the Ottawa group2, 3 themselves acknowledge that clinical judgement should take precedence over sticking to rigid rules. They are also careful to point out several groups in whom they do not feel the rules should be applied, such as the intoxicated, the multiply injured, or those with communication problems either because of language or mental disorder. They are very specific in stating that the entire posterior 6 cm of the maleoli should be palpated (a common error from my observation is just to palpate the tip), and that in the presence of gross swelling this may be impossible to do accurately and therefore a radiograph may be required. I do not believe they recommend radiography for all patients over 55 years old, but that this is the case for the knee4 rather than ankle rules.
Perry et al5 do not clearly apply the entire rule in their study, and therefore it is difficult to be sure that the four “missed” fractures would definitely not have been picked up if applying it carefully. Nevertheless I think they make a valid point in their conclusions—rules and protocols will not always be right, and experience and clinical judgement are invaluable tools in medicine. The problem we now face is incorporating this notion safely into our evidence-based practice.
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The authors reply
We thank Dr Rae for her interest in our paper on the Ottawa Ankle Rules. The Ottawa Group do acknowledge that clinical judgement should take precedence over adhering to rigid rules. However, they claim a sensitivity of 1:0 if the rules are used and that any missed fractures would not be of clinical significance1—that is, bone fragments greater than 3 mm in breadth. All four of the missed fractures in our study were significant.2 As discussed in the original article, no reason could be found to explain why these cases fulfilled none of the Ottawa Ankle Rules.
We do accept that it was not clearly stated that the entire posterior 6 cm of the malleoli were examined and this may have influenced the study's outcome. However, after retrospective review of the case notes of the four missed fractures we felt that this was not the case.
The Ottawa Ankle Rules were initially devised to include age greater than 55 years as a criterion for radiography.3 Subsequent refinement and validation found age not to be a significant factor.1 It was included in our study as the aim was to determine if the Ottawa Ankle Rules were valid in a setting of an urban teaching hospital in the United Kingdom.
We accept that there were limitations in our study but feel that it does illustrate the need to be cautious when applying decision rules and that these should not replace clinical judgement and experience.