In vitro study of knee stability after two-band two-tunnel posterior cruciate ligament reconstruction.

Objective: To compare the ability of three different reconstruction procedures in restoring the posterior displacement of tibia and the posterior stability of the knee joint from 0 degree to 120 degrees flexion.

Methods: Three posterior cruciate ligaments (PCL) reconstruction procedures were performed, namely two-band two-tunnel reconstruction, one-band anterior tunnel reconstruction and one-band posterior tunnel reconstruction. The posterior displacement of the tibia in relation to the femur was measured when a 200N posterior force was applied.

Results: Within the flexion range of 0 degree to 30 degrees, the displacement in the one-band posterior tunnel reconstruction showed little difference from that of an intact knee (P>0.05). But when the flexion exceeded 30 degrees, especially when it exceeded 60 degrees, the displacement in one-band posterior tunnel reconstruction was much greater than that of an intact knee (P<0.01). In two-band two-tunnel reconstruction and one-band anterior tunnel reconstruction, the displacement was approximately the same as that of an intact knee ranging from 0 degree to 120 degrees (P>0.05), while a slight over-restriction might be found at some angles.

Conclusions: Two-band reconstruction could effectively restrict the posterior displacement of the tibia and restore anterior, posterior stability of the knee joint within its full range of flexion. One-band anterior tunnel reconstruction also could maintain the posterior stability of the knee, while the result of one-band posterior tunnel reconstruction is the most unsatisfactory.