Determines need for knee radiographs
Total Score
Low risk of fracture. Knee X-ray series is NOT indicated.
Disclaimer: The clinical scoring and algorithms on this platform are intended strictly for professional informational purposes. They do not constitute a definitive medical diagnosis, treatment, or clinical decision. The final judgment and responsibility lie with the treating physician.
Yasal Uyarı: Bu platformdaki klinik skorlamalar ve algoritmalar yalnızca sağlık profesyonellerini bilgilendirme amaçlıdır. Herhangi bir kesin tıbbi teşhis, tedavi veya klinik karar yerine geçemez. Nihai karar ve sorumluluk hastayı yatak başında değerlendiren hekime aittir.
The Ottawa Knee Rules are designed to rule out fractures (patella, femoral condyles, proximal tibia/fibula) in patients with acute knee injuries. By systematically assessing age, point tenderness, and range of motion, it drastically reduces unnecessary knee X-rays without missing clinically significant fractures.
If a patient cannot flex their knee to 90 degrees, it is hard to distinguish in the acute ED setting whether the restriction is due to pain or a mechanical block (e.g., tense hemarthrosis or meniscus tear). The rule safely dictates obtaining an X-ray in either scenario.
Stiell IG, Greenberg GH, Wells GA, et al. Prospective validation of a decision rule for the use of radiography in acute knee injuries. JAMA. 1996;275(8):611-615.
Disclaimer: The clinical scoring and algorithms on this platform are intended strictly for professional informational purposes. They do not constitute a definitive medical diagnosis, treatment, or clinical decision. The final judgment and responsibility lie with the treating physician.
Apply the Ottawa Knee Rules to adults with acute knee injury (pain, swelling, or limited range of motion following trauma). A knee X-ray series is required if ANY one of the 5 criteria is present (score ≥ 1). If no criteria are met, the negative predictive value for clinically significant fracture approaches 100% and imaging can be safely deferred. The rules are validated for adults; use caution in children under 18, where Salter-Harris physeal injuries may not be captured by this rule. Also exclude: isolated skin injuries, patients presenting more than 7 days post-injury, and those with prior knee surgery at the same site.
The Ottawa Knee Rules were prospectively validated in a large multi-center trial and showed a sensitivity of ~100% with a specificity of ~49%, meaning about half of patients who fail the rule do NOT have a fracture on X-ray. This is intentional — the rule prioritises sensitivity to avoid missing fractures. In practice, the rule is most useful to EXCLUDE imaging in patients who clearly meet zero criteria (e.g., a young athlete with an isolated ligamentous sprain and full weight-bearing capacity). The 'isolated patellar tenderness' criterion requires that only the patella is tender — if there is any additional bony tenderness, other criteria may apply.
The 'inability to bear weight' criterion requires evaluation in the ED — not just the history of inability at the time of injury. Ask the patient to attempt 4 steps in the department; a limp does NOT count as inability to bear weight. Fibula head tenderness is a separate criterion and should not be confused with ankle or distal fibula tenderness (which falls under the Ottawa Ankle Rules). The Ottawa Knee Rules do not assess for ligamentous injuries, meniscal tears, or osteochondral lesions — a negative rule with ongoing symptoms should prompt MRI referral.