Ottawa Ankle / Knee / Foot Rules

The Ottawa Ankle and Foot Rules (Stiell et al.) and Ottawa Knee Rule are highly sensitive tools developed to safely reduce unnecessary radiographs after blunt trauma. Ankle series is indicated when there is malleolar-zone pain plus bone tenderness at the posterior distal 6 cm or tip of either malleolus, or inability to take four steps both immediately and in the ED. Foot series is indicated with midfoot-zone pain plus tenderness at the navicular or base of the fifth metatarsal, or the same weight-bearing failure. Knee radiographs are indicated if any of: age ≥55 years, isolated patellar tenderness, fibular-head tenderness, inability to flex to 90°, or inability to bear weight (four steps) immediately and in the ED. Rules apply to blunt trauma; use caution at extremes of age and with altered mental status or distracting injury. Negative rules make clinically significant fracture very unlikely but do not exclude all soft-tissue injury.