Injury to the popliteal artery and its anatomic location in total knee arthroplasty.

Injury to the popliteal artery during total knee arthroplasty (TKA) is a devastating complication. Although infrequent, these injuries can result in the need for further surgery, including revascularization or possibly even amputation. Several mechanisms are capable of producing direct trauma to the popliteal artery, including the use of posterior ret ractors. We investigated the proximity of the popliteal artery to the tibial joint surface during TKA to identify crucial steps in the procedure at which the artery was at highest risk for injury. TKA was performed on cadaveric specimens, and serial intraoperative arteriograms were taken throughout the procedure, demonstrating the potential for arterial injury by the instrumentation. Additionally, 50 transverse magnetic resonance imaging scans of unrelated knees were analyzed for the position of the popliteal artery relative to the midline of the tibial plateau as well as at a level 5 to 10 mm below this, at the site of a typical resection during TKA. All of the arteriograms showed the artery to be a lateral structure at the joint line. Additionally a posterior retractor placed the artery at risk when it was placed in a position lateral to the posterior cruciate ligament or when it was injudiciously inserted more than 1 cm into the soft tissues. Hyperextension of the knee, which might occur during preparation of the patella, produced dramatic tenting of the artery over the posterior joint line. These results demonstrate that the popliteal artery is at significant risk during TKA, particularly if posterior retractors are placed in a position lateral to the midline of the joint. Both hyperflexion and especially hyperextension produced severe deformities and kinking of the artery and would particularly jeopardize an artery with atherosclerosis. Our findings suggest that the popliteal artery may be at least risk during TKA if posterior retractors are placed medial to the midline of the tibial plateau and if care is taken to avoid extremes of both flexion and extension.