The incidence of arterial occlusive lesions in the lower extremities has been increasing year by year, and the treatment methods have been constantly innovated, from the earliest forgaty catheter to the later artificial vascular bypass, until the emergence of endoluminal technology, the style of surgery has undergone great changes. The arterial distortion and shortening phenomenon is obvious, which has become a difficult point of clinical treatment at present. 1, the classification of trans-knee arterial lesions First of all, I personally believe that there are many causes of trans-knee arterial occlusive lesions, and the treatment options are different for different causes, so it can be broadly divided into primary arterial occlusion and secondary arterial occlusion. Primary arterial occlusive disease mainly refers to the narrowing of the arterial lumen caused by the lesion of the arterial intima itself, which then develops into an occlusive lesion, mainly caused by arteriosclerosis and secondary thrombosis on the basis of sclerosis, and rarely caused by thrombo-occlusive vasculitis; secondary arterial occlusive disease, mainly embolism of the artery (caused by proximal emboli), thrombosis secondary to N artery aneurysm and N artery trapping and other factors. Among them, atherosclerosis-type lesions occupy about 70% or more, so they are also the focus of our attention. 2, arteriosclerosis-induced trans-knee artery occlusion 2.1 Characteristics of atherosclerosis-like diseases Atherosclerosis-like diseases are mostly chronic onset with a long course, and there are also acute onset patients with an acute history of chronic disease, and atherosclerosis-induced arterial occlusion is often not all caused by intimal hyperplasia and plaque, which are mostly interspersed with old mechanized thrombus, and in patients with acute onset, most of them are due to The majority of patients with acute onset of arterial occlusion are due to arterial occlusion caused by secondary thrombosis on the basis of severe stenosis of arteriosclerosis. Therefore, it can be assumed that arterial occlusive lesions caused by atherosclerosis are more or less likely to have mechanized or fresh thrombi. 2.2 Anatomical characteristics of the trans-knee artery-N artery The N artery is the most complex artery in the human body subjected to forces, and is mainly characterized by many lateral branches, twisting, tortuosity, extension and shortening with activity. The knee joint is also the most common joint in the body with the greatest variation in motion and position. The N artery is often divided into three regions, P1, P2, and P3, from near to far, and the nature of the force and the changes after the force are different in different regions. Therefore, when using endoluminal therapy, attention should be paid to the segment where the lesion is located. 2.3 Feasibility and common problems of endoluminal treatment At present, endoluminal treatment is still our first choice for this type of disease, excluding the problem of surgical tolerance, endoluminal treatment has obvious advantages in terms of surgical trauma and postoperative recovery, and when endoluminal treatment cannot solve the problem, we can also perform surgical open surgery. Because of the anatomical peculiarities of the N artery, intracavitary treatment is destined to be different from other sites. Firstly, when arteriogram shows more thrombus and the intraoperative thrombolysis effect is unsatisfactory, it is recommended to leave the catheter for thrombolysis, which will correspondingly reduce the possibility of applying balloon and stent and reduce the number of applications, and also pay attention to the protection of the puncture site and apply small puncture sheath as much as possible, and pay attention to the postoperative braking, and closely observe the puncture site for any abnormal blood leakage and hematoma. Second, on the basis of clear atherosclerotic stenosis or occlusion, the next step of treatment is carried out. Balloon dilation is the most common and the main means of treatment, which can not only determine the effect of surgery, but also decide whether stents need to be placed. Balloon dilation is currently recommended as incremental balloon dilation, from small to large, from low to high pressure, while short balloons are recommended to minimize endothelial damage. If the balloon can solve the problem without leaving the graft, that is the result we all want to see; however, it is often against the wish, for example, soft plaque can easily fall off during balloon dilation leading to embolization of the distal artery, and very hard sclerotic plaque, simple balloon dilation cannot achieve satisfactory results. Domestic colleagues have also proposed that balloon expansion should expand the plaque until it is open but not broken, so as to avoid the appearance of entrapment, but this is related to many factors, such as the strength should be uniform, the plaque should have a certain elasticity, and the density and hardness of the plaque should be more consistent. Therefore stenting of arteries is sometimes a choice we have no choice. Thirdly, the previous generation and second generation arterial stents do not have transarticular characteristics. The third generation stents currently applied, such as viabahn, have achieved more satisfactory results in clinical trials, but a successful product still needs the test of time. This means that we should consider carefully whether to place a stent in the N artery luminal treatment; however, if stenting is unavoidable, we should apply a more subtle treatment to reduce the complications of stent placement. It is recommended that DSA imaging in the flexed knee position be performed prior to stent placement to not only detect occult stenoses but also to help define the inflection point of the artery, which is more accurate than simple orthopantomogram with the articular surface as the marker. For lesions in the P1 segment alone, it is recommended that the distal end does not enter the P2 region, and if it cannot be controlled above the P2 region, then it is recommended that the inflection point of the artery be crossed with a relatively long stent; for lesions in the P2 segment alone, it is recommended that the long stent cover the entire P1 and P2 segments and that the distal end does not enter the P3 segment; for lesions in the P3 segment alone, it is recommended that the short stent, with both ends Try to control within the P3 segment; if it is a multi-stage combined lesion, then there is no other choice, either no release or full coverage, and long stents are recommended in the coverage instead of choosing multiple short stent articulation. After the completion of stent release be sure to perform another DSA imaging in the flexed knee position, or even 360 degrees if necessary, to observe the degree of stent compliance and local post-balloon expansion if necessary. At present, the technology of endoluminal treatment is changing day by day, and the latest plaque removal system, in clinical application, has also achieved good results, but due to the relative complexity of the technology, the cost and other related issues, the large-scale development is still in need of time. 3. Don’t forget the open surgery In today’s dominance of endoluminal treatment, please don’t forget that surgical open surgery used to be the main way to solve our problems. Until today, not all cases can be solved by endoluminal treatment, such as complete CTO lesions in N arteries, where guidewires cannot pass and endoluminal treatment fails. For embolization of arteries, incision for embolization is more concise and effective; in addition, for arterial occlusion caused by anomalous factors such as N artery entrapment and aneurysm, open surgery is a more effective route. Currently, there are mainly artificial vessel replacement and autologous saphenous vein grafting, both of which are clinically equivalent, but in cases where there is a risk of infection, autologous saphenous vein is recommended to be safer. Overall, the management of N artery occlusion is relatively complex, and there is no clear guidance or consensus on the choice of surgical approach and surgical details, such as stent and balloon selection, so extensive attempts should be made to find better treatment options for N artery trans-knee lesions. In addition, a more appropriate treatment strategy should be chosen based on the patient’s specific situation.