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Paper text:
a 23-year - old male with no significant prior medical history underwent arthroscopic surgery due to a cruciate ligament injury five months before being referred to the department of thoracic & cardiovascular surgery in busan paik hospital .
after surgery , a pulsatile mass was palpable around the previous surgical wound in the superomedial part of the right knee , and was observed to be growing continuously .
he was therefore referred to our department . on physical examination , a 64-cm pulsatile oval - shaped mass was detected .
the mass was clinically suspected to be an aneurysm , and computed tomography ( ct ) angiogram of the lower extremities was therefore performed .
the angiogram revealed a 2.2-cm pseudoaneurysm of the descending genicular artery and a fistula with the superficial vein of the right vastus medialis ( figs . 1 , 2 ) .
we did not consider endovascular treatment because the patient was young and the mass was near the knee joint , leading to the possibility of stent - related and coil - related complications during his lifetime .
we performed pseudoaneurysmectomy and ligation of the arteriovenous fistula ( avf ) . during the operation
3 ) . after surgery , we confirmed the flow of the right popliteal artery using doppler imaging .
the patient s postoperative course was unremarkable , and he was discharged on the seventh postoperative day .
pseudoaneurysm has been reported as a complication after arthroscopy , arthroplasty , ligament repair , synovectomy , penetrating knee trauma , and intramedullary nailing of the tibia .
the most common cause of pseudoaneurysm has been found to be total knee replacement , and the most common site of pseudoaneurysm has been found to be the popliteal artery .
however , pseudoaneurysms of the descending genicular artery , sural artery , and arterial branches to the vastus medialis muscle and the medial head of the gastrocnemius muscle have also been reported .
wilson et al .   found that the incidence of vascular lesions among patients undergoing elective orthopedic surgery was 0.005% . in 1986 , committee on complications of the arthroscopy association of north america   reported that nine patients out of 375,000 cases developed pseudoaneurysms after knee arthroscopy . nonetheless ,
no case of pseudoaneurysm combined with an avf of the descending genicular artery has yet been reported .
pseudoaneurysm generally occurs after acute trauma , which may or may not be surgical , or after chronic repeated trauma .
theoretically , an injury to the arterial wall appears to be necessary for a pseudoaneurysm to develop . in some cases ,
pseudoaneurysms have been observed to form after knee arthroscopy without penetration of the knee capsule or direct injury to the vessel wall .
one possible explanation for this is the shear stress on the knee structures and arteries during surgery .
pseudoaneurysm can be diagnosed by physical examination , ultrasonography ( usg ) with vascular doppler imaging , ct , magnetic resonance imaging , and angiography .
symptoms and signs may include a range of pain from no discomfort to aggravated pain , the presence of a pulsating mass or a large hematoma with audible bruit or thrill , and space - occupying effects such as nerve compression , neuralgia , venous compression , and thrombosis .
if a pseudoaneurysm presents subcutaneously or grows to the point of being palpable , as occurred in our case , it can be suspected clinically .
usg with doppler imaging is a non - invasive technique that can confirm the abnormal anatomical relationship of the artery .
moreover , small pseudoaneurysms can be treated by usg - guided compression or usg - guided thrombin injection .
ct angiography with three - dimensional reconstruction is now relatively easy to perform in korea .
it is helpful for confirming the anatomic structures around the pseudoaneurysm , and it takes less time than other methods such sonogram , conventional angiography , magnetic resonanse imaging .
mri has similar characteristics to ct , but has the advantage of avoiding radiation exposure .
angiography was historically considered the gold standard , but it was also considered to be more invasive than other imaging modalities .
some researchers have reported successful results by observing small aneurysms until spontaneous thrombosis , as well as the use of thrombin injection or usg - guided compression therapy .
open surgical repair with excision , ligation of the pseudoaneurysm , inverted saphenous interposition grafting or bypass , and primary repair of the defect have been reported .
some studies have reported the use of endovascular repair with embolization and stent insertion to treat popliteal pseudoaneurysms or avf .
the studies that reported the endovascular repair of popliteal pseudoaneurysms showed that stent implantation has the advantage of avoiding the complications of open repair , such as wound infection , the need for general anesthesia , and a hospital stay .
endovascular repair can lead to complications such as displacement , fracture , occlusion of the stent , or endoleak ; however , the above studies did not report stent - related complications over the course of 24 months of follow - up .
reported that thrombosis can occur spontaneously or be induced by compression from the echography probe in aneurysms smaller than 2 cm . for aneurysms less than 5 cm , it may be sufficient to ligate the defect in the arterial wall or to administer a percutaneous injection of thrombin into the aneurysmal sac along with therapeutic embolization by means of coils or thrombin injection . for bigger lesions , surgical exclusion of the aneurysm
should be performed and blood flow should be restored via bypass surgery . in our case ,
the pseudoaneurysm was too close to the knee joint and was accompanied by an avf ; therefore , we chose surgical treatment in order to avoid the possible complications of endovascular treatment . in conclusion , pseudoaneurysm is a rare complication after arthroscopy that may lead to serious complications .
if a pseudoaneurysm is suspected clinically , usg , ct , or magnetic resonance imaging are helpful imaging modalities for arriving at a diagnosis .
once the diagnosis of pseudoaneurysm is confirmed , a choice must be made between endovascular repair and surgical repair .
pseudoaneurysm with arteriovenous fistula is a rare complication of arthroscopy , and can be diagnosed by ultrasonography , computed tomography , magnetic resonance imaging , or angiography . 
 this condition can be treated with open surgical repair or endovascular repair . 
 we report our experience with the open surgical repair of a pseudoaneurysm with an arteriovenous fistula in a young male patient who underwent arthroscopy five months previously .