Your standard approach should be the medial approach with the patient positioned supine. The knee should be flexed and supported by pillows, and the thigh should be externally rotated as much as possible. Take the time to get the leg as secure as possible in this position so that all hands are free to operate and not having to hold the leg in position. Completely prep and drape both legs and the lower abdomen. Mark an incision starting 1 cm posterior to the medial femoral condyle at the knee, and extend it proximally along the anterior border of the sartorius muscle and distally parallel and 1 cm posterior to the tibia (see Fig. 67.1a). A good rule of thumb is to identify the location of the vascular injury and plan for at least 10 cm of exposure proximally and distally. Leaving a skin bridge across the knee joint may aid in closure and wound healing, but do not sacrifice adequate exposure if needed. The saphenous vein and nerve should be identified in the subcutaneous fat and kept with the posterior flap of the incision. For the above-knee popliteal vessel, divide the superficial fascia longitudinally, and then follow the plane between the sartorius and gracilis muscles which should lead directly to the distal superficial femoral artery and above-knee popliteal vessels. The vein will be lateral to the artery at this location so the first major vascular structure encountered will be the artery. Mobilize the vessels distally into the popliteal fossa (this may require division of the adductor tendon), and note that here, the vein changes to a posterior position relative to the artery. For exposure of the below-knee popliteal vessel, retract the medial gastrocnemius posteriorly, and then carefully open the deep fascia to expose the vessels. You must be aware that in this position, the vein will be the first structure encountered, with the artery lying lateral to the vein and the tibial nerve posterior to the artery. For more distal exposure of the popliteal and the first bifurcation, divide the soleus muscle from its attachment to the tibia and retract it posteriorly (see Fig. 67.1b).

Have vessel loops readily available to place around the artery and vein, and these can also be used to identify and retract the tibial nerve. Bulldog clamps are often adequate for arterial control, particularly for the distal end of the vessel. Have small and medium clips available as you can expect bleeding from multiple small venous branches. Two self-retaining retractors with deep blades provide excellent hands-free exposure and retraction and should be placed immediately above and below the knee joint. A dry lap sponge placed into the wound covering the tissue to be retracted can help keep the operative field dry and protect underlying structures from retractor injury.

This approach is much less commonly used in emergency situations for the reasons cited above. However, it does provide superior exposure to the entire popliteal fossa and contents and can be considered as an option for localized wounds in the center of the popliteal fossa. The patient should be placed prone with appropriate padding of the trunk and hips. The opposite leg should also be prepped as saphenous vein can easily be harvested below the knee. You should mark your incision in a “lazy S” pattern beginning 10 cm above the fossa and proceeding longitudinally down the posteromedial thigh. The incision should then cross the posterior knee crease transversely and proceed longitudinally 5–10 cm down the posterolateral calf (see Fig. 67.2a). Skin flaps are then raised superiorly and inferiorly, avoiding injury to the greater saphenous vein (medial) and lesser saphenous vein (lateral). The junction of the lateral and medial gastrocnemius is identified and marks the lower boundary of the popliteal fossa. Retraction of the gastrocs will expose the popliteal fossa, but remember that the most superficial structure will usually be the tibial nerve. The popliteal vein and artery are then easily identified, and division of several small vein branches is usually required to mobilize the artery away from the vein. This approach should allow access to the entire popliteal artery from the adductor canal to the bifurcation of the anterior tibial artery (see Fig. 67.2b).

After gaining adequate exposure and control of hemorrhage, a full exploration should be performed to identify the location and extent of injury. Whenever possible, proximal and distal control should be obtained by exposure of uninjured artery outside the zone of injury and hematoma. Proximal control can also be obtained by a direct cutdown to the femoral artery in the groin or with a pneumatic tourniquet. Similarly, distal control can also be rapidly obtained with a calf tourniquet or with manual compression of the calf by an assistant. Unlike blunt trauma which can result in a wide spectrum of vascular injury, penetrating mechanisms are usually associated with either vessel laceration or complete transection. Occasionally, there will be thrombosis of an intact vessel due to local blast effect, but this is uncommon. If the vessel has been completely transected, the ends will usually be retracted and have little to no bleeding due to contraction and clot formation. In contrast, partial lacerations often continue to bleed profusely and will require full proximal and distal control. If you cannot identify one or both ends of the transected artery, a useful trick is to make a small arteriotomy on normal proximal or distal artery and pass an embolectomy catheter until it can be seen protruding from the injured vessel.

The type of injury that is identified will determine your options for repair. For small lacerations, a simple running suture repair (lateral or transverse arteriorrhaphy) with 5-0 or 6-0 prolene may be adequate. Care must be taken not to narrow the lumen, and if your repair is going to result in significant stenosis (>25 %), then you should choose an alternative method. Most penetrating injuries will not be amenable to this simple method and will require a more complex repair.

Standard repair options at this point include patch angioplasty with vein or prosthetic, primary end-to-end anastomosis, and placement of a prosthetic or vein bypass graft. Patch angioplasty is an excellent option for a small injury or hole involving <50 % of the vessel wall after adequate debridement. All devitalized tissue should be sharply debrided, and make sure you inspect the intimal edges for any flaps or tears. A small piece of vein for the patch can usually be found within the incision rather than going to the opposite leg, and larger branches of the saphenous will often suffice. Alternatively, a section of prosthetic material such as a carotid endarterectomy patch can be used. The small patch will be difficult to handle until it is fixed in at least two places, so use two 6-0 prolene sutures to secure the patch to the proximal and distal margin of the arterial defect. The two fixation sutures can then each be run along opposite sides of the defect, taking bites from outside to inside on the patch and inside to outside on the vessel wall. You should intermittently flush the operative field and the vessel lumen with heparinized saline throughout the procedure to minimize clot formation. Prior to completing the repair, proximal and distal control should be alternately released to assess inflow and outflow and to flush clot out of the vessel lumen. If there is any question about the adequacy of flow, then one or two careful passes of a Fogarty embolectomy catheter proximally and distally should be performed.

In cases of complete or near-complete transection, the vessel ends should be debrided (complete the transection sharply) and mobilized for several centimeters in each direction. To avoid significant retraction when you are completing a near transection, you can place a fixation stitch from normal proximal vessel to normal distal vessel prior to dividing the remainder of the vessel wall. If the vessel ends can be brought together with minimal tension, then a primary end-to-end anastomosis can be performed. This is usually possible with stab wounds, while gunshot wounds most often result in enough vessel loss to require graft placement. The vessel ends should be spatulated with a fresh scalpel blade or fine scissors and a running end-to-end anastomosis performed with 6-0 prolene suture. Simple anterior and posterior fixation sutures between the two ends of the vessel can be placed first, which can then be used to manipulate and roll the anastomosis to maximize exposure and ease of suturing. The more difficult half of the anastomosis (usually the far side) should be done first, followed by the easier half. Alternatively, a three-suture triangulation technique for the anastomosis can be performed, equally dividing the anastomosis into three 120° segments. Inflow and outflow should again be assessed prior to completion of the anastomosis and Fogarty catheter embolectomy through the anastomosis performed as needed.

The final and most commonly required repair option is replacement or bypass of a segment of the popliteal artery with a vein or prosthetic graft (see Fig. 67.3). Saphenous vein is the preferred conduit, particularly for a repair that crosses the knee joint. Vein should be harvested from the uninjured leg using an anteromedial longitudinal thigh incision. Estimate the length of vein needed, and then add an additional 25–50 % to ensure adequate final length. Make sure you adequately prepare the vein by reversing the segment to allow flow through the valves, ligating any branches without narrowing the main vessel lumen, and then fully dilating the vein with heparinized saline flush. Stripping the vein of any remaining adventitial bands will allow for greater dilation and better size matching to the injured artery. If adequate length or caliber of vein is not available, then an adequate diameter (usually 6 mm) of prosthetic graft can be used. For prosthetic graft that will cross the popliteal fossa, a graft with ring reinforcement may be chosen to avoid kinking with knee flexion.

The bypass graft can most often be placed in the normal anatomic position of the popliteal artery (interposition graft) unless there has been significant tissue loss or contamination. In these situations, you should place the vein or prosthetic graft in a lateral or medial extra-anatomic tunnel to ensure adequate protection and soft tissue coverage. The length of the interposition graft should always be assessed with the leg near full extension to ensure adequate length, but excess length must be avoided to prevent kinking of redundant vein. There is no absolute rule for the order in which you should perform the anastomoses. The cut ends of the artery and the vein graft or prosthetic should be spatulated as previously described. Due to the usual size mismatch between artery and saphenous vein, the vein graft will often require an additional several millimeter incision at the heel of the spatulation to match the luminal diameter of the artery. The end-to-end anastomoses can be performed with 6-0 prolene as described previously, either using two opposite running sutures or a three-suture triangulation technique. When the final anastomosis is near complete, proximal and distal flushing of clot and debris should be performed as well as Fogarty catheter embolectomy if there is inadequate inflow or outflow.