OBJECTIVESTo provide the data on the shape, sizes, and locations of the attachments of the anterolateral bundle (ALB) and posteromedial bundle (PMB) of the posterior cruciate ligament (PCL) to the tibia, and to determine the reference landmarks and the methods for tibial tunnel positioning in double-bundle PCL reconstruction using double-double tunnel.

METHODSThirty cadaveric knees were used as specimens. PCLs were separated into bundles according to the PCL tension pattern during knee flexion-extension, and the functional bundle in each bundle was determined. Data were obtained to describe the size, shape, position, and center of the attachments of PCL bundles. The reference landmarks and methods for tibial tunnels positioning in double-bundle PCL reconstruction using double-double tunnel were determined.

RESULTSThe PCL insertion site was situated in the posterior intercondylar fossa. The longitudinal axis of the tibial attachment of PCL proceeded from proximal medial to distal lateral, and the mean angle between them and the tibial shaft was (16.5 +/- 1.4) degrees . The tibial insertion site of ALB and PMB were arranged in the proximal and distal on the whole, the tibial attachment of ALB could generally be described as rhomb in shape, and the mean area of it was (90 +/- 20) mm(2); the tibial attachment of PMB was rectangle in shape, the mean area of it was (96 +/- 32) mm(2), there was no statistic difference between the area of them (P > 0.05). There were functional bundles in both ALB and PMB persistently, which attached to the distal-lateral portion of the tibial attachment of ALB and the distal-medial portion of the tibial attachment of PMB respectively, they were both oval in shape, the mean area of them were (35 +/- 12) mm(2) and (36 +/- 6) mm(2) respectively, the difference between them was no statistic significant (P > 0.05). The mean distance between the centres of the tibial attachments of the functional bundles of ALB and that of PMB was (12.7 +/- 1.9) mm. The medial tibial spine, lateral tibial spine and the bony ridge on the posterior-proximal tibia were the key anatomic landmarks that could be used to aid in placement of independent tibial tunnels for a 2-bundle PCL reconstruction.

CONCLUSIONSThe tibial attachment of the PCL is sufficiently large to allow for placement of 2 independent tunnels. There are functional bundles in both ALB and PMB persistently and the optimum position for the tibial tunnel in double-bundle PCL reconstruction using double-double tunnel should be located in the attachment sites of the functional bundles of ALB and PMB.