Anatomic study of the middle genicular artery.

PURPOSE To study the anatomy of the middle genicular artery and thus mitigate the risk of vascular injury in knee surgery. METHODS The course, anatomic relations, and variations of the middle genicular artery in 8 cadavers (4 men and 4 women) were studied. RESULTS The middle genicular artery originated from the anterolateral surface of the popliteal artery in the popliteal fossa, 3 to 5 cm proximal to the joint line either alone or having a common origin with the lateral genicular artery. Its diameter varied from 2 to 4 mm and it was 3 to 5 cm long. It was accompanied by 2 venae comitantes. This vascular bundle, including the middle genicular artery, ran distally, anterior to the popliteal artery, and posterior to the joint capsule, sandwiched between them. Distally it pierced the posterior joint capsule and became intra-articular. The relation of the middle genicular artery to the popliteal artery altered with the position of the knee joint. This alteration was secondary to the distal gliding of the popliteal artery with knee flexion. The middle geniculate artery formed an angle of 15 to 30 degrees to the popliteal artery when the knee was extended, which became almost a right angle when the knee was flexed past 90 degrees. CONCLUSION Care must be taken when arthroscopic or open intra-articular surgery is performed in the posterior part of the knee joint using chondrotomes and saws, particularly with limited vision. Sharp dissection and diathermy under direct vision should be safer.