(Fig 2-C.10) Amis and Jacob’s method, ACL tibial tunnel

https://youtu.be/SgpiUyyzRlY

https://youtu.be/uDgqFi3itg0

1️⃣ Importance in Tibial Tunnel Placement

• The entire opening of the tibial tunnel must be located dorsally to the line drawn along the Blumensaat’s line.

2️⃣ Amis and Jakob's Line

• The Amis and Jakob line is one of the most commonly used methods to evaluate the anterior-posterior direction of the tibial tunnel.
• The Amis and Jakob’s line is defined as a line passing through the most posterior edge of the tibial plateau and parallel to the medial tibial plateau surface.
• This method involves a percentage-term measurement generated from the Amis and Jakob’s line intersecting the anterior border (0%) and posterior border (100%) of the tibia plateau.
• The measurement is reported at around 43%. (Normal values range between 27 and 60%.)

3️⃣ Risks Associated with Incorrect Tunnel Placement

• If the tunnel is too forward, there is an increased risk of impingement of the graft with the intercondylar notch, possibly causing an extension deficit or a Cyclops lesion.
• Conversely, a tunnel positioned too posterior could lead to a vertical graft, responsible for an incomplete control of knee antero-posterior and rotatory stability.

 

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