Need for Knee X-Ray Films

A series of knee x-ray films is required only for
patients with knee injury and any of the following findings:

• Age 55 years or older
• Isolated tenderness of the patella (no bone tenderness
  elsewhere in the knee)
• Tenderness at the head of the fibula
• Inability to flex the knee 90 degrees
• Inability to bear weight both immediately and in examination
  room or emergency department—that is, the patient is unable
  to take four steps or to transfer weight twice onto each limb