How To Reduce The Risk Of Tibial Osseous Tunnel Intersection When Reconstructing Posterior Cruciate Ligament And Posterior Oblique Ligament Simultaneously: Using A 3-Dimensional Finite Element Model

Background: There is tibial tunnel intersection risk when we reconstruct the posterior cruciate ligament (PCL) and posterior oblique ligament (POL) simultaneously with tibial technique. This study is to determine when the PCL and POL tunnels at the tibial side will intersect during simultaneous reconstruction by evaluating different POL tunnel geometries and trajectories, with different PCL tunnel insertion points.Methods: Five 3-dimensional images from two pairs and a single cadaveric lower limb were created. A transtibial PCL reconstruction was simulated with two tibial tunnel entry points; one with the PCL tunnel centered directly within the native fovea, and the other with the tibial tunnel placed in the posterior half of the fovea. Both tunnels were set to be 10 mm in diameter and 50 degrees off the joint line in the sagittal plane. Two different POL tunnel geometries were then simulated within each of these PCL models; one utilizes a continuous cylindrical tunnel, and the other utilizes a differentially reamed grenade shaped tunnel. Utilizing a coronal plane along the posterior tibial condyles as a reference, we then noted the degree of angle(s) at which the POL tunnel would intersect the PCL tunnel. We also noted the POL tunnel relationship with respect to Gerdy's tubercle and the patellar tendon.Results: With the PCL tunnel centered directly in the fovea, PCL tunnel intersection occurred at angles <=(29.00 degrees +/- 5.79 degrees), and patellar tendon violation occurred at angles >=(30.75 degrees +/- 5.32 degrees) with a cylindrical shaped POL tunnel. With a grenade shaped tunnel, these values were <=(27.40 degrees +/- 6.35 degrees) and >=(29.60 degrees +/- 4.39 degrees), respectively. When the PCL tunnel was placed in the posterior half of the fovea, these values were <=(19.20 degrees +/- 3.56 degrees) and >=(27.40 degrees +/- 4.04 degrees) with a cylindrical shaped POL tunnel, and 5 (17.80 degrees +/- 4.09 degrees) and >=(30.75 degrees +/- 4.50 degrees) with a grenade shaped tunnel.Conclusions: Drilling the PCL tibial tunnel in the posterior half of the fovea and utilizing a POL tunnel starting from the medial edge of Gerdy's tubercle and exiting anteriorly just lateral to the tibial tubercle is the most effective reconstruction technique for minimizing the risk of tunnel intersection.Background: There is tibial tunnel intersection risk when we reconstruct the posterior cruciate ligament (PCL) and posterior oblique ligament (POL) simultaneously with tibial technique. This study is to determine when the PCL and POL tunnels at the tibial side will intersect during simultaneous reconstruction by evaluating different POL tunnel geometries and trajectories, with different PCL tunnel insertion points.Methods: Five 3-dimensional images from two pairs and a single cadaveric lower limb were created. A transtibial PCL reconstruction was simulated with two tibial tunnel entry points; one with the PCL tunnel centered directly within the native fovea, and the other with the tibial tunnel placed in the posterior half of the fovea. Both tunnels were set to be 10 mm in diameter and 50 degrees off the joint line in the sagittal plane. Two different POL tunnel geometries were then simulated within each of these PCL models; one utilizes a continuous cylindrical tunnel, and the other utilizes a differentially reamed grenade shaped tunnel. Utilizing a coronal plane along the posterior tibial condyles as a reference, we then noted the degree of angle(s) at which the POL tunnel would intersect the PCL tunnel. We also noted the POL tunnel relationship with respect to Gerdy's tubercle and the patellar tendon.Results: With the PCL tunnel centered directly in the fovea, PCL tunnel intersection occurred at angles <=(29.00 degrees +/- 5.79 degrees), and patellar tendon violation occurred at angles >=(30.75 degrees +/- 5.32 degrees) with a cylindrical shaped POL tunnel. With a grenade shaped tunnel, these values were <=(27.40 degrees +/- 6.35 degrees) and >=(29.60 degrees +/- 4.39 degrees), respectively. When the PCL tunnel was placed in the posterior half of the fovea, these values were <=(19.20 degrees +/- 3.56 degrees) and >=(27.40 degrees +/- 4.04 degrees) with a cylindrical shaped POL tunnel, and <=(17.80 degrees +/- 4.09 degrees) and >=(30.75 degrees +/- 4.50 degrees) with a grenade shaped tunnel.Conclusions: Drilling the PCL tibial tunnel in the posterior half of the fovea and utilizing a POL tunnel starting from the medial edge of Gerdy's tubercle and exiting anteriorly just lateral to the tibial tubercle is the most effective reconstruction technique for minimizing the risk of tunnel intersection.