Preservation of the posterior septum and stump for anatomical posterior cruciate ligament reconstruction of the tibial tunnel reference position

Abstract

Abstract Background: The purpose was to explore the anatomic position relationship and locate the lowest tunnel within the the PCL tibial insertion while intactly preserved the PCL stump, posterior septum and capsule. Methods: Twelve fresh unpaired adult human cadaveric knees were used to observe the spatial anatomical position between the PCL tibial insertion, posterior septum and posterior capsule. Then, the distal reflexion of the posterior capsule and the posterior septum were intactly preserved and used as references to search for the center of the tibial insertion (CP) and lowest tibial tunnel (SP). And measured the distance of the SP and CP points and PCL tibial insertion by anatomical measurements and CT scan. Results: In twelve specimens, the PCL tibial insertions were fully located within the posterior medial compartment of the knee. The distance of the CP from the tibial plateau articular surface was (6.5±0.2) mm, and the horizontal and vertical distances from the posterior septum were (5.9±0.3) and (5.4±0.4) mm, while the SP from them were (9.5±0.4), (4.3±0.3) and (4.1±0.3) mm, respectively. All the tibial tunnels established centered around the SP retained the intact posterior wall, which was (1.6±0.3) mm to the distal reflexion of the posterior capsule. The SP/CP was (17.6±5.6) % and (49.9±0.3) % closer to the inferior boundary, while (49.3±13.2) % and (33.9±6.8) % relative to the lateral boundary of the insertion. Conclusion: The PCL tibial insertion was located in the posterior medial compartment of the knee, with the posterior septum and distal reflexion of the posterior capsule as its lateral and inferior boundaries. Using the posterior septum and posterior capsule as reference marks, a low tibial tunnel with high repeatability can be established in the PCL tibial insertion without damaging the posterior septum.