The position of the popliteal artery in the arthritic knee.

We studied the position of the popliteal artery in 32 patients with primary osteoarthritis of the knee. A total of 45 knees were studied using a noninvasive technique with color-flow duplex scanning. The distance between the popliteal artery and the posterior tibial cortex was measured in various positions of flexion. The distance separating them was found to be maximal between 60 degrees and 90 degrees. The study was repeated in a smaller series of 17 patients (20 knees) after knee replacement but with less conclusive results. We believe the safest position on which to operate in primary arthroplasty is with the knee in flexion, but the safety margins are not the same in revision surgery.