Ottawa knee rules
Background
- 98.5% sensitive and 48.6% specific in determining knee fracture[1]
- Can be applied to pediatric population[2]
- Rule has been retrospectively and retrospectively validated[3][4][5]
Criteria
X-ray is only required in patients who have an acute injury with one or more of the following:
- Age >55
- Isolated tenderness of the patella (no other bony tenderness).
- Tenderness at the fibular head.
- Inability flex to 90 degrees
- Inability to walk 4 steps BOTH immediately after the injury and in the ED
Diagram
Radiographs
If radiographs are required, three views are usually sufficient: anteroposterior view, lateral view, and Merchant's view (for the patellofemoral joint). Teenage patients who report chronic knee pain and recurrent knee effusion require a notch or tunnel view (posteroanterior view with the knee flexed to 40 to 50 degrees). This view is necessary to detect radiolucencies of the femoral condyles (most commonly the medial femoral condyle), which indicate the presence of osteochondritis dissecans.
Radiographs should be closely inspected for signs of fracture, particularly involving the patella, tibial plateau, tibial spines, proximal fibula, and femoral condyles. If osteoarthritis is suspected, standing weight-bearing radiographs should be obtained.
Caveats
- 99% sensitive in children OVER age 5[6]
- Beware of the Tillaux Fracture in adolescents with anteromedial ankle pain, as they would not qualify for imaging according to this rule.
External Links
See Also
References
- ↑ Bachmann LM, Haberzeth S, Steurer J, et al. The accuracy of the Ottawa knee rule to rule out knee fractures: a systematic review. Ann Intern Med. 2004; 140(2):121-4.
- ↑ Bulloch B, Neto G, Plint A, et al. Validation of the Ottawa Knee Rule in children: a multicenter study. Ann Emerg Med. 2003; 42(1):48-55.
- ↑ Stiell IG, Greenberg GH, Wells GA, et al. Derivation of a decision rule for the use of radiography in acute knee injuries. Ann Emerg Med. 1995; 26(4):405-13.
- ↑ 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.
- ↑ Stiell IG, Wells GA, Hoag RH, et al. Implementation of the Ottawa Knee Rule for the use of radiography in acute knee injuries. JAMA. 1997; 278(23):2075-2079.
- ↑ Vijayasankar D, Boyle AA, Atkinson P. Can the Ottawa knee rule be applied to children? A systematic review and meta-analysis of observational studies. Emerg Med J. 2009; 26(4):250-3.