Posterior cruciate ligament architecture: Evaluation under microsurgical dissection

Purpose: Our objective was to verify the fiber anatomy of the posterior cru ciate ligament (PCL) and to measure the main dimensions and the femoral and tibial attachment site distances of the ligament after microsurgical disse ction. We hypothesized that PCL anatomy is more complex than the 2 traditio nally characterized bands. Type of Study: This is a purely anatomic descrip tion of micro-dissections of the PCL, focused on the fine anatomy of the li gament. Materials and Methods: Twenty-four fresh-frozen cadaveric knees wer e dissected using magnifying loupes and an operative microscope, being care ful to avoid creating artificially separated bundles. The main dimensions o f the PCL were measured using a micrometer. Results: The anterior, central, posterior-longitudinal, and posterior-oblique were the 4 fiber regions ide ntified based on their orientation and the osseous sires of their insertion s. These were partially separable anatomically but were functionally distin ct. The anterior and central fiber regions made up the bulk of the ligament , while the remaining 15% consisted of the posterior fiber regions. During manual joint motion, the behavior of these fiber regions was observed. The anterior fiber region appeared to be the most nonisometric and remained in tension mainly between 30 degrees and 90 degrees of flexion. The posterior fiber regions appeared to be the most isometric (especially the posterior-o blique) and remained in tension mainly in extension and partially in deep f lexion. The central fiber region appeared to have an intermediate behavior and remained in tension mainly between 30 degrees and 120 degrees of flexio n. Additionally, it appeared to be the widest of all fiber regions. Conclus ions: These findings should be of interest and help in interpreting some of the anatomy encountered during arthroscopic examination of the PCL, both f rom the anterior and posterior lateral portals. Furthermore, this informati on should prove useful in selecting treatment for the PCL.