North America

ACR Appropriateness Criteria® acute trauma to the knee

Summary

Consensus guidelines recommend the clinical parameters that do not require radiographs following knee trauma are i) the patient is able to walk without a limp, and ii) the patient had a twisting injury and there is no effusion. The clinical parameters for ordering radiographs following knee trauma are i) joint effusion within 24 hours of direct blow or fall, ii) palpable tenderness over the fibular head or patella, iii) inability to walk (4 steps) or bear weight immediately, or in the emergency department, or within a week of the trauma, iv) inability to flex knee to 90 degrees, and v) altered mental status. Following a fracture, a normal single lateral view of the knee eliminates the need for additional radiographic views. Soft-tissue injuries such as meniscal injuries, chondral surface injuries, and ligamentous disruption are best evaluated by MRI. For knee dislocations, workup should include an MRI and angiography to detect for vascular injury that may require surgery.