Injury to the popliteal artery during an orthopedic procedure is believed to be under reported6 but is considered a rare complication. The incidence of popliteal artery injury in TKA is thought to be 0.03% to 0.2%.1,2,5,7,8 Vessel injury in both high tibial osteotomy and arthroscopic surgeries (lateral meniscal repair) have also been reported.5,6,8,10 Despite the rare occurrence of this complication, it may have devastating outcomes. The injury can be repaired with vascular grafting depending on its severity; however, it could also lead to compartment syndrome, loss of function, chronic ulcers, and necrosis of the affected limb resulting in below the knee amputation. The current consensus is that the popliteal artery moves posteriorly away from the tibia when the knee is in 90° of flexion,5 which is the standard position for many orthopedic knee surgeries. This position limits the risk of injuring the vessel. However, Metzdorf and colleagues,4 Smith and colleagues,6 and Zaidi and colleagues8 suggested that the vessel not be displaced posteriorly with flexion. These studies reported that the behavior of the popliteal artery varied among individuals since in some cases it had moved closer to the tibia in flexion when compared with extension.
Regardless of the behavior of the artery, it is protected by the popliteus muscle in most orthopedic knee surgeries since the majority course posterior to the muscle. However, in cases of Lippert’s type IIA variation, it not only loses protection as it courses beneath the popliteus but also is extremely vulnerable from the close relationship to the posterior tibial cortex. Klecker and colleagues2 described the aberrant artery locations related to common orthopedic procedures, which demonstrated its close proximity to various surgical plane levels. The position of the aberrant artery is approximately 1 to 1.5 cm distal to the posterior tibial joint line, just posterior to the posterior capsule, and close to the posterior cruciate ligament insertion site where the transverse tibial cut is made during TKA. This location also corresponds to the position for an inlay block and the tibial tunnel for posterior cruciate ligament reconstruction. A transverse cut for a high tibial osteotomy is approximately 1.5 to 2.5 cm distal to the posterior tibial joint line; the aberrant artery appeared directly posterior to the tibial cortex. These relationships were equivalent findings in this case. Such relationships of the aberrant anterior tibial artery to both the posterior tibial cortex and the posterior capsule increase the risk of vessel (anterior tibial artery) injury intraoperatively. The risk further increases in a revision of total knee replacement. This is secondary to limited flexibility of the vessel from scar formation which requires a more distal incision.1,4
CONCLUSION
Vascular injuries in knee surgeries are rare and often overlooked. Despite their low occurrence rate, outcomes of these injuries have grave consequences not only regarding medical but also legal matters. Variations in the popliteal artery are not uncommon and could potentially contribute to risks of vessel injury. Of these variations, the high originating anterior tibial artery poses a special risk. However, due to the low occurrence rate of these injuries, screening the general population may not be cost-effective. Since many patients already have obtained necessary imaging (preferably MRI), a careful review of these images along with preoperative planning and special care during surgery is recommended to identify popliteal artery variants and avoid iatrogenic vascular injury.
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