Tibial insertion of the posterior cruciate ligament: a sagittal plane analysis using gross, histologic, and radiographic methods.

Purpose: The literature is imprecise regarding the ideal tibial site for the posterior cruciate ligament (PCL) placement. We detail anatomic and radiographic landmarks for consistent placement of graft fixation in PCL reconstruction.

Methods: Fourteen fresh-frozen cadaver knees were sectioned in the sagittal plane. The distance from the posterior cortex of the tibia to the anterior edge of the PCL was measured. Three specimens were fixed in 10% formalin and stained using hematoxylin-eosin and trichrome to determine ligament fiber distribution and insertion. Two knees were used for radiographic analysis of pin placement.

Results: The mean distance across the PCL facet from the posterior cortex to the anterior edge of the PCL was 15.6 mm (+/-1.1 mm). Histologic analysis in three knees showed that the PCL fibers inserting along the PCL facet comprise the bulk of the ligament, while the fibers that insert along the posterior cortex are less than 0.5 mm thick.

Conclusions: The bulk of the PCL inserts in the posterior half of the PCL facet. We show that, in the sagittal plane, the center of the working fibers of the PCL lies 7 mm anterior to the posterior cortex of the tibia, measured along the PCL facet. Tunnel placement at the center of the original ligament can be measured along the PCL facet as seen in a true lateral radiographic view.

Clinical Relevance: This study provides anatomic and radiographic criteria helpful for guide-pin placement in arthroscopic PCL reconstruction.