ACL Tunnel Placement
Move the femoral tunnel on the notch and the tibial tunnel on the plateau, then flex the knee: graft length, tension and roof impingement update live, with the classic technical errors one click away.
What you can do
- Set the femoral tunnel by depth and height on a sagittal knee and follow graft length from 0° to 130°.
- Load classic errors: too anterior (resident's ridge), posterior fixed in flexion, low on the wall, high and posterior.
- Open the notch view from the anterior portal with a clock face and see why a 12 o'clock tunnel makes a vertical graft.
- Move the tibial tunnel toward the notch roof and see impingement in extension.
- Change the tibial guide angle and the knee angle at fixation.
- Work through board-style cases and pearls for each error.
Key concepts
An anatomic femoral tunnel keeps graft length close to constant through motion. A tunnel that is too anterior tightens the graft in flexion; a posterior tunnel fixed in flexion costs extension.
A vertical graft high in the notch, often from a transtibial guide, restores anteroposterior stability but not rotational control: normal Lachman, positive pivot shift.
An anterior tibial tunnel makes the graft hit the notch roof in extension, with loss of extension, anterior pain and a possible cyclops lesion.
Further reading
- Campbell's Operative Orthopaedics, 15th edition (2026): Knee Injuries, ch 50 (ACL anatomy, tunnel placement and technical errors).
- Campbell's Operative Orthopaedics, 15th edition (2026): ch 56 (arthroscopic landmarks of the notch).
Designed for Orthoverse by Dr. M. M. Bakhshaei. Built to make orthopedic concepts visible, measurable and easy to explore.
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