Intercondylar roof impingement pressure after anterior cruciate ligament reconstruction in a porcine model

Abstract

Anterior cruciate ligament (ACL) graft impingement against the intercondylar roof has been postulated, but not thoroughly investigated. The roof impingement pressure changes with different tibial and femoral tunnel positions in ACL reconstruction. Anterior tibial translation is also affected by the tunnel positions of ACL reconstruction. The study design included a controlled laboratory study. In 15 pig knees, the impingement pressure between ACL and intercondylar roof was measured using pressure sensitive film before and after ACL single bundle reconstruction. ACL reconstructions were performed in each knee with two different tibial and femoral tunnel position combinations: (1) tibial antero-medial (AM) tunnel to femoral AM tunnel (AM to AM) and (2) tibial postero-lateral (PL) tunnel to femoral High-AM tunnel (PL to High-AM). Anterior tibial translation (ATT) was evaluated after each ACL reconstruction using robotic/universal force-moment sensor testing system. Neither the AM to AM nor the PL to High-AM ACL reconstruction groups showed significant difference when compared with intact ACL in roof impingement pressure. The AM to AM group had a significantly higher failure load than PL to High-AM group. This study showed how different tunnel placements affect the ACL-roof impingement pressure and anterior-posterior laxity in ACL reconstruction. Anatomical ACL reconstruction does not cause roof impingement and it has a biomechanical advantage in ATT when compared with non-anatomical ACL reconstructions in the pig knee. There is no intercondylar roof impingement after anatomical single bundle ACL reconstruction.

Effect of Femoral Socket Position on Graft Impingement After Anterior Cruciate Ligament Reconstruction

“…17,19 Prior data also suggest that a more anatomic femoral position may also mitigate impingement issues. 8 Data from the current study substantiate prior studies that suggest that moving the femoral tunnel position from an AM to a central or PL position can protect against graft impingement. Moreover, this study demonstrated that a central femoral position decreased impingement by approximately 40% as compared with an AM femoral position when an at-risk AM tibial tunnel position is used.…”

“…9 These data highlight the potential for impingement when graft placement extends beyond the native footprint, especially when the native footprint is narrow. Recent work by Iriuchishima et al, 8 however, found no difference in notch contact pressures in anteriorly placed compared with posteriorly placed tibial tunnels when combined with an anatomic femoral socket position. These data suggest that femoral socket position may influence notch impingement and that anatomic femoral socket position may be protective against the risk of graft impingement with increasingly anterior tibial tunnel position.…”

Anterior cruciate ligament biomechanics during robotic and mechanical simulations of physiologic and clinical motion tasks: A systematic review and meta-analysis

“…Variability in attributes such as anatomic versus non-anatomic tunnel placement, [94, 95] double versus single bundle grafts, [44] graft materials, [76] number of tunnels, [28] graft fixation method, [46] graft tension, [29] and graft length[96] has been shown to alter the mechanical response of an ACLR and could alter the ensemble mean. Potentially confounding factors within ACLR grafts were not accounted for in the exclusionary criteria because opinions on optimal surgical technique varies between orthopaedic surgeons, which leads to graft variability in ACLR populations that should not be artificially controlled in a meta-analysis.…”

In VivoThree-Dimensional Imaging Analysis of Femoral and Tibial Tunnel Locations in Single and Double Bundle Anterior Cruciate Ligament Reconstructions

“…Properly placed tibial and femoral tunnels are important because tunnel misplacement can cause graft impingement and changes in graft tension patterns, resulting in knee instability 2). Biomechanical tests on cadaveric reconstructions have demonstrated nearly normal knee kinematics when the tibial tunnel was located close to the center of the tibial footprint and the femoral tunnel was placed in the center of the femoral footprint of the ACL 2)…”