- Discussion:
- femoral tunnel
- tibial tunnel:
- isometric placement of ACL refers to the concept that a full range of knee can be achieved w/o causing long-term ligament deformation;
- isometry can not exist because, during ROM, there is no one point on femur that maintains a fixed distance from a single point on tibia;
- elongation always will occur;
- placement of graft as closely as possible to centers of tibial & femoral attachments of anterior medial band results in least amount of strain (least
change in length of ACL during complete ROM of knee);
- many researchers have tried to determine which bundle regions of ACL are most isometric;
- bone patellar bone grafts attempted replacement of anteromedial band of ACL, which is most nearly isometric portion of the normal structure;
- of note, most surgeons feel that it is more important to replace the more non-isometric posterolateral band;
- ACL graft should pull up into the tibial tunnel by about 2-3 mm with extension when fixed on the femoral side;
- this represents the closest reconstitution of the ACL's "physiometry";
- a graft that tightens (pulls up into tibial tunnel) w/ flexion will have a much higher likelyhood of failure and usually indicates a femoral tunnel too far anterior in notch.
- Graft Fixation:
Testing for isometry during reconstruction of the anterior cruciate ligament. Anatomical and biomechanical considerations.
Tibial tunnel placement in anterior cruciate ligament reconstructions and graft impingement.
Strategies to Improve Anterior Cruciate Ligament Healing and Graft Placement
Anatomical single-bundle anterior cruciate ligament reconstruction with a transtibial technique.
Anatomic Graft Placement in ACL Surgery: Plain Radiographs Are All We Need