The Ottawa ankle rules for the use of diagnostic X-ray in after hours medical centres in New Zealand.
OBJECTIVE
The aims of this study were to measure baseline use of Ottawa ankle rules (OAR), validate the OAR and, if appropriate, explore the impact of implementing the Rules on X-ray rates in a primary care, after hours medical centre setting.


METHODS
General practitioners (GPs) were surveyed to find their awareness of ankle injury guidelines. Data concerning diagnosis and X-ray utilisation were collected prospectively for patients presenting with ankle injuries to two after hours medical centres. The OAR were applied retrospectively, and the sensitivity and specificity of the OAR were compared with GPs  clinical judgement in ordering X-rays. The outcome measures were X-ray utilisation and diagnosis of fracture.


RESULTS
Awareness of the OAR was low. The sensitivity of the OAR for diagnosis of fractures was 100% (95% CI: 75.3 - 100) and the specificity was 47% (95% CI: 40.5 - 54.5). The sensitivity of GPs  clinical judgement was 100% (95% CI: 75.3 - 100) and the specificity was 37% (95% CI: 30.2 - 44.2). Implementing the OAR would reduce X-ray utilisation by 16% (95% CI: approx 10.8 - 21.3).


CONCLUSIONS
The OAR are valid in a New Zealand primary care setting. Further implementation of the rules would result in some reduction of X-rays ordered for ankle injuries, but less than the reduction found in previous studies.
Wynn-Thomas
Simon
S
Department of General Practice, Wellington School of Medicine and Health Sciences.
Love
Tom
T
McLeod
Deborah
D
Vernall
Sue
S
Kljakovic
Marjan
M
Dowell
Antony
A
Durham
John
J
D000328:Adult; D016512:Ankle Injuries / Q000000981:diagnostic imaging*; D005194:Family Practice / Q000706:statistics & numerical data; D050723:Fractures, Bone / Q000000981:diagnostic imaging*; D017408:Guidelines as Topic; D006801:Humans; D009520:New Zealand; D010044:Outpatient Clinics, Hospital / Q000706:statistics & numerical data; D011320:Primary Health Care / Q000706:statistics & numerical data*; D011446:Prospective Studies; D011859:Radiography / Q000706:statistics & numerical data*; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires