Onlay Reconstruction of the Posterior Cruciate Ligament: Biomechanical Comparison of Unicortical and Bicortical Tibial Fixation

The objective of this study was to compare immediate postimplantation biomechanics of unicortical versus bicortical tibial fixation of onlay PCL grafts. Eight knees were randomly assigned to one of two onlay PCL techniques (n = 4 knees/technique), performed by a single experienced surgeon. Testing consisted of a posterior-directed force at four knee flexion angles, 10, 30, 60, and 90 degrees, to measure load to 5 mm of posterior displacement, maximum displacement (at 100 N load), and stiffness. For statistical analyses, data for each knee were normalized to the native PCL-intact knee and were then grouped into unicortical or bicortical groups accordingly. Data for load to 5 mm (strength), displacement at 100 N, and stiffness were compared among PCL-intact, PCL-deficient, unicortical fixation, and bicortical fixation categories using one-way analysis of variance to assess for statistically significant (p < 0.05) differences. When compared with PCL-deficient knees, both fixation techniques had less laxity. When compared with PCL-intact knees, unicortical had more laxity at all angles, and bicortical had more laxity only at 90 degrees (p < 0.001). For relative graft strength, intact knees required significantly higher loads than both treatment groups. Bicortical, however, outperformed unicortical at all angles (p < 0.001) for relative strength. Regarding stiffness, there were no significant differences between unicortical and bicortical, and both...
Source: Journal of Knee Surgery - Category: Orthopaedics Authors: Tags: Original Article Source Type: research