The popliteal fossa is diamond-shaped and its borders are formed by the semimembranosus and semitendinosus muscles superiomedially, the biceps femoris muscle superiolaterally, the medial head of the gastrocnemius muscle inferiomedially, and the lateral head of the gastrocnemius muscle inferiolaterally. It contains the popliteal artery and vein, the tibial and common peroneal nerves, and is covered by subcutaneous tissue and skin.

The popliteal artery is the continuation of the superficial femoral artery after it passes through the adductor canal, an opening in the adductor magnus muscle, in the lower thirds of the thigh. It courses downward and laterally to the midline of the knee between the two condyles of the femur, into the popliteal fossa.

The popliteal artery has three segments: suprageniculate (above knee), midpopliteal (behind knee), and infrageniculate (below knee). Exposure to each segment of the popliteal artery is distinct.

The popliteal artery has superior and inferior genicular branches, which provide blood supply to the tissues surrounding the knee joint and provide important collaterals when there are occlusions of the superficial femoral or popliteal artery.

Below the knee, the popliteal artery branches into the anterior tibial artery, followed by the peroneal branch about 2–3 cm lower, which itself then branches into the peroneal and posterior tibial arteries.

The anterior tibial artery pierces the upper part of the interosseous membrane, courses in front of the membrane, under the extensor muscles of the anterior muscle compartment, and distally becomes the dorsalis pedis artery.

The tibioperoneal trunk is the direct continuation of the popliteal artery and, after approximately 3 cm, branches to form the peroneal artery laterally and the posterior tibial artery medially. The peroneal and posterior tibial arteries lie in the deep posterior compartment of the leg posteriorly of the fibula and tibia, respectively.

The posterior tibial artery continues directly to the ankle and lies superficially posterior to the medial malleolus, while the peroneal artery branches above the ankle to form collaterals to the dorsalis pedis and plantar branches of the posterior tibial artery in the foot.

The popliteal vein lies posterior to the artery (more laterally superiorly to more medially inferiorly). The tibial nerve is lateral and posterior to the artery.

Popliteal artery injury is the most limb threatening peripheral vascular injury and it is associated with a high incidence of lower extremity amputation.

Prognostic factors affecting limb salvage include: time interval between injury and treatment with a goal of less than 6 hours, mechanism, associated soft tissue, venous and nerve injuries, and chronic vascular disease.

Posterior dislocation of the knee is associated with an approximately 20% incidence of popliteal arterial injury. Reduce the dislocation without delay and always evaluate pulses and measure the ankle brachial index (ABI). An ABI <0.9 should be evaluated further with a CT angiogram because an arterial duplex is often impractical when the patient is in pain or has orthopedic hardware that limits the evaluation.

“Hard signs” of vascular injury include active hemorrhage, expanding or pulsatile hematoma, bruit or thrill, absent pulses, and distal ischemia as characterized by mottling or cyanosis, coolness, or decreased sensation or motor of the foot.

Most popliteal artery injuries, due to firearm injuries or blunt trauma, require reconstruction with interposition or bypass vein graft. In rare occasions after a stab wound, a primary repair may be possible.

In the presence of associated major orthopedic fractures, the blood flow can be restored with a temporary, intravascular shunt. Following orthopedic fixation, the definitive vascular reconstruction can be performed.

For patients requiring damage control or where the surgeon skillset is insufficient to perform definitive reconstruction, vascular shunting is the preferred method of restoring flow. Always use a Doppler probe to confirm flow through the shunt. Ligation should not be performed due to the high rate of limb loss.

Prior to placing the intravascular shunt, a thrombosed injury should be interrogated by gently passing a long 3 French Fogarty balloon catheter to extract thrombus. The Fogarty catheter should be passed both proximally and distally until there is no further thrombus removed. If systemic anticoagulation with unfractionated heparin is not feasible due to coagulopathy, the proximal and distal ends of the artery should be flushed with heparinized saline, or at least saline, prior to placement of the shunt.

On-table completion angiography should be performed if a palpable pulse is not restored following vascular reconstruction, as not all thrombus may have been removed.

The lower extremity should always be evaluated clinically and in the appropriate cases with pressure measurements. A four compartment fasciotomy should be performed in all cases of clinical compartment syndrome, and compartment pressures >30 mmHg. Routine prophylactic fasciotomy is not indicated. However, prophylactic fasciotomy should be considered liberally in patients where close observation is not possible, such as long transportation or austere environments.