The risk of sacrificing the PCL in cruciate retaining total knee arthroplasty and the relationship to the sagittal inclination of the tibial plateau

Background: In cruciate retaining total knee arthroplasty (TKA), a partial avulsion of PCL may occur when en-bloc tibial osteotomy is performed. We evaluated the effects of a tibial cut performed with different degrees of posterior slope on PCL insertion and whether the results are affected by the sagittal slope of patients’ tibial plateaus. Methods: We selected 83 MRI of the knees showing mild or no degenerative changes. The effects of a simulated tibial cut performed with a posterior slope of 0°,3°, 5° and parallel to the patient’s slope of tibial plateaus on PCL insertion in the proximal tibia were investigated. The results were correlated with the degree of posterior slope of tibial plateaus. Results: Every angle we used for the tibial cut caused a PCL avulsion greater than 50%. The percentage of PCL avulsion significantly increased with increasing the posterior slope of the tibial cut. Patients with sagittal slope of tibial plateaus < 5° showed greater PCL avulsion than those