[The Ottawa ankle guidelines: analysis of their validity as clinical decision guidelines in the indication of X-rays for ankle and/or middle-foot injuries].

Objective: To analyse the validity of the Ottawa ankle guidelines (OAG) as clinical decision guidelines in the indications of X-rays for ankle and/or middle-foot traumas in primary care.

Design: Observational, with application of the OAG and prospective measurement of the results.Setting. Hospital casualty.

Patients: Adults who attended casualty for ankle or middle-foot traumas between 1st June 1999 and 31th March 2000. Criteria for exclusion were: under 18, pregnancy, grave sensory and/or awareness disturbances, multi-trauma or multi-contusion patients, traumas over a week old, skin lesions as side-effects of the trauma, X-ray in other department, high inflammation or oedema hindering palpation of bone protuberances.

Measurements: Application of the OAG and X-ray on all patients, regardless of the result of the OAG. Calculation of sensitivity, negative predictive value, specificity and positive predictive value.

Results: 56 of a sample of 494 patients had a fracture (11.34%), 34 in the malleolus area (6.9%) and 22 in the middle-foot area (4.44%). OAG sensitivity was 96.43% (95% CI, 94.8-98). Negative predictive value was 97.22% (95.77-98.67). Specificity was 15.98% (12.75-19.21), and positive predictive value was 12.8% (9.86-15.74).

Conclusions: The OAG are valid in primary care as guidelines to decide whether to request X-rays for patients with ankle or middle-foot traumas.