The Ottawa knee rules are used to determine the need for radiographs after knee injury.

The Ottawa knee rules are used to determine the need for radiographs after knee injury.

• A. To assess ligament stability
• B. To determine the need for radiographs after acute knee injury
• C. To evaluate meniscal tears
• D. To guide MRI indications

Answer: (B)

The main idea behind the Ottawa knee rules is to decide when a knee X-ray is needed after an acute injury. They outline simple clinical signs that, if present, mean imaging is warranted to rule out fracture, while if none are present, radiographs are usually unnecessary. The key criteria include being 55 years or older, tenderness around the patella, tenderness at the head of the fibula, an inability to bend the knee to 90 degrees, and an inability to bear weight (immediately after injury and for four steps in the emergency department). If any of these are present, radiographs are indicated because a fracture could be missed without them. If none are present, the chance of fracture is sufficiently low that imaging can often be avoided. This approach differs from evaluating ligament stability, meniscal tears, or MRI indications, which focus more on soft tissue injury and other imaging decisions rather than fracture screening after acute knee injury.

The main idea behind the Ottawa knee rules is to decide when a knee X-ray is needed after an acute injury. They outline simple clinical signs that, if present, mean imaging is warranted to rule out fracture, while if none are present, radiographs are usually unnecessary. The key criteria include being 55 years or older, tenderness around the patella, tenderness at the head of the fibula, an inability to bend the knee to 90 degrees, and an inability to bear weight (immediately after injury and for four steps in the emergency department). If any of these are present, radiographs are indicated because a fracture could be missed without them. If none are present, the chance of fracture is sufficiently low that imaging can often be avoided. This approach differs from evaluating ligament stability, meniscal tears, or MRI indications, which focus more on soft tissue injury and other imaging decisions rather than fracture screening after acute knee injury.