A 35-year-old man involved in a motor vehicle accident presents with a knee dislocation that is easily reduced. Radiography of the knee shows no fracture. Which of the following statements about his treatment are true?

B. If he has normal pulses he requires either close observation or arteriography

DISCUSSION: Knee dislocations commonly cause popliteal vessel injury. Early after injury, flow may be sustained in the injured popliteal artery; therefore, these injuries require close observation or arteriography. When an occluded popliteal artery is evident clinically, immediate repair is indicated and arteriography is unnecessary. Repair should ideally utilize the contralateral saphenous vein, to maintain optimal venous return in the injured leg. Injured popliteal veins should be repaired if at all possible. Ligation may jeopardize the arterial repair and increase the likelihood of chronic venous insufficiency and the risk of pulmonary embolism.