In anterior cruciate ligament (ACL) reconstruction, navigation and robotic assistance now provide the possibility of precise positioning of the tunnels.

The challenge is therefore to carry out isometric preoperative planning which can be carried out with robotic or navigation assistance.

In the classic reconstruction technique this isometry is assumed by positioning the tunnels on the center of the native ACL footprints. However, studies cast doubt on this hypothesis.

In this work, the investigators will study the isometry of the center of the native footprints on a dynamic 4D scanner in order to obtain the variation in the distance between the centers of the native footprints during a knee flexion cycle.

This study is part of a larger project. the objective is, if the absence of isometry of the center of the native impressions is confirmed, to develop software assistance which will help the surgeon plan preoperatively an isometric reconstruction. The hypothesis is that the techniques based on the center of the native footprints does not allow isometric reconstruction.

Inclusion Criteria:

• Healthy volunteers aged 18 or older
• Signed informed consent
• Affiliation to a social security system
• Negative pregnancy test for women of childbearing age

Exclusion Criteria:

• Volunteer having already undergone knee ligament reconstruction or having peri- or intra-articular knee fractures
• Volunteers for whom ligamentoplasty would not have been the therapeutic option chosen in the event of an ACL rupture
• Pregnant woman
• Volunteer under guardianship or curators, under the protection of justice or deprived of public law.
• Minor volunteer
• Contraindication to MRI or scanner