Real time ultrasonic scanning with a Duplex scanner (A.T.L.) was used to study Dacron arterial grafts crossing the hip and knee joints in 27 patients (25 males, 2 females), mean age 61 years. Ultrasonic imaging of the grafts was rapid and demonstrated kinking during knee flexion in 83 percent of grafts anastomosed to the distal popliteal artery. Only 7 percent of grafts crossing the inguinal ligament kinked during 60° of hip flexion.
Graft kinking during knee flexion may be a factor in acute thrombosis associated with long periods of immobility, such as during air travel.