Anatomical dangerous triangle of popliteal vascular injury in total knee arthroplasty

Objective To investigate the anatomical dangerous region of popliteal vascular injury in total knee arthroplasty (TKA).Methods The retrospective data of 1 291 consecutive MRI of knees was collected,with 565 right knees and 726 left knees,727 women and 564 men.The patients's age ranged from 16 to 87 years with a median age of 37 years.The distances between the popliteal artery and lateral femoral condyle at the epicondylar level (PA-LFC),between the popliteal artery and the posterior capsule at the joint line level (PA-PC),between the popoliteal artery and posterior tibial cortex at the level of 10 mm below the joint line (PA-PTC) and the shortest distance between the poplitealartery and posterior tibial cortex in the sagital plane (PA-PTCs) were measured.The location of popliteal artery relative to posterior cruciate ligament was documented.Six fresh frozen cadaver knees were dissected to delineate the location of popliteal artery and measure the distances between popliteal artery and both knee capsule and popliteal muscle.Results Seventeen knees among 1 291 knees (1.32％,17/1 291) showed the aberrant high origin of anterior tibial artery.The values of PA-LFC,PA-PC,PA-PTC and PA-PTCs were 4.89± 1.80 mm,4.05± 1.43 mm,3.61±1.39 mm and 3.58±1.04 mm.The effusion of knees helped to increase PA-LFC and PA-PC but not PA-PTC or PA-PTCs.The popliteal artery laid anteriorly in the vessel bundle and it was located laterally to the medial border of posterior cruciate ligament at the joint line level.The cadaveric study showed a distance of 1.13±0.23 cm between joint line and superior border of popliteal muscle where the popliteal artery went very close to knee capsule and tibia cortex.There was an anatomical triangle accommodating popliteal artery,inferior lateral geniculate artery,middle geniculate artery and several unnamed small arteries.Conclusion When performing a total knee arthroplasty,we should pay attention to an anatomical triangle where the popliteal vessels including popliteal artery,inferior lateral geniculate artery,middle geniculate artery and several unnamed small arteries are significantly lack of protection of adequate soft tissues. Key words: Arthroplasty, replacement, knee;  Popliteal artery;  Anatomy, regional