Flexions of the popliteal artery: technical considerations of femoropopliteal stenting

Popliteal artery morphology changes while undergoing knee motion. A main flexion (i.e., the 'hinge point') and other flexions (termed 'accessory flexions') were described as a result of popliteal artery adaptation to knee flexion. Knee dynamics challenge the outcome of popliteal artery endovascular procedures. Complications such us stent fractures were reported despite rapidly improving technology. Understanding popliteal artery dynamics allows us to develop an endovascular technique that facilitates the avoidance of the difficulties of one of the most mobile arteries in the body. Here we report two cases with a novel stent implantation technique in the popliteal artery. The method includes diagnostic angiography, lesion angioplasty, and stenting using both extended and flexed knee in lateral view. The pressure gradients were measured with knee in extension and flexion before and after each step. A successful outcome was achieved in both cases. This method allows us: 1) to identify the flexions of the popliteal artery and its relationship with the lesions; 2) to detect those obstructions not visible with an extended knee; 3) to understand that the hinge point and accessory flexions can develop undesired and unexpected artery obstruction after a stent implantation only observed in knee flexion; and 4) to identify the morphological changes caused in the popliteal artery and its subsequent solution.