Figure 1. Anteroposterior radiograph of the left knee.
Figure 2. Lateral radiograph of the left knee.
A 63-year-old man presents to the emergency department with left knee pain and deformity after he fell off a deck approximately 6 hours earlier. He was intoxicated when he fell approximately 10 feet and landed on his left leg. Anteroposterior and lateral radiographs of the left knee (Figures 1 and 2) show a posterior knee dislocation. The knee is reduced in the emergency department, and the patient continues to have absent pulses in the foot. The patient is then taken to the operating room and the popliteal artery is repaired.
What is the next best step in treatment after vascular repair?
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A knee dislocation is rarely seen in the emergency department. Approximately 16% of knee dislocations result in injury to the popliteal artery, which can be transected by a posteriorly displaced tibia. Vascular repair should be performed as soon as possible in the event of a popliteal artery injury in the lower extremity. Delay in lower extremity reperfusion lasting longer than 8 hours results has been associated with an amputation rate of 85%. The popliteal artery is most often reconstructed with a contralateral saphenous vein graft. An external fixator is usually placed to immobilize the extremity and to protect the vascular repair. The advantage of an external fixator over an immobilizer brace is the ability to monitor the soft tissue and conduct frequent neurovascular examinations while immobilizing the extremity. Patients who undergo vascular repair more than 6 hours after popliteal injury require fasciotomy of the lower extremity compartments. Traumatic vascular injuries have a high risk of compartment syndrome as a result of bleeding and swelling into the lower extremity compartments.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
Read our Legal Advisor column that describes outcomes from a vascular injury following knee dislocation.
- Farber A, Tan TW, Hamburg NM, et al. Early fasciotomy in patients with extremity vascular injury is associated with decreased risk of adverse limb outcomes: a review of the National Trauma Data Bank. Injury. 2012;43(9):1486-1491.
- Medina O, Arom G, Yeranosian MG, Petrigliano FA, McAllister DR. Vascular and nerve injury after knee dislocation: a systematic review. Clin Orthop Relat Res. 2014;472(9):2621-2629.