From Wall Graft to Roof Graft: Reassessment of Femoral Posterior Cruciate Ligament Positioning

In many technique guides for poste­rior cruciate ligament (PCL) recon­struction, the PCL is depicted on the wall of the medial femoral condyle (MFC). We hypothesized that most of the anterolateral (AL) bundle orig­inates on the roof of the intercondy­lar notch (ICN), not on the wall.

Using a surgical navigation sys­tem, we delineated and morphed in the computer the entire PCL foot­print—the AL bundle, the posterome­dial (PM) bundle, and the Humphrey ligament (HL)—of 7 fresh-frozen cadaveric specimens. A clock face was defined in the en face view, with the 12-o’clock axis pointing anteriorly through the top of the notch and the roof being the region between 10 o’clock and 2 o’clock. The AL-bundle, PM-bundle, and HL positions were calculated in terms of this clock-face definition.

Mean centroids (o’clock position) over all specimens of AL bundle, PM bundle, and HL were, respectively, 10:49, 9:43, and 9:00 on the left knee and 1:11, 2:17, and 3:00 on the right knee. Mean areas were 63 mm2 (AL bundle), 63 mm2 (PM bundle), and 45 mm2 (HL). In 5 of the 7 speci­mens tested, 100% of the AL bundle originated on the roof of the ICN. Conversely, 66% of the PM bundle and 100% of the HL inserted on the wall of the MFC rather than on the intercondylar roof.

Using computer navigation soft­ware, we determined that most of the AL bundle originates on the roof of the ICN and that the PM bundle is centered near the tran­sition between the roof and the wall of the MFC. These findings contradict the depiction in most technique guides for PCL recon­struction. Implant companies and surgeons should modify their tech­niques to shift PCL graft tunnels from the wall of the MFC to the roof of the ICN.