Intraoperative Analysis of Knee Kinematics During ACL Reconstruction - an Exploratory Study

Anterior cruciate ligament reconstruction is a common procedure in orthopaedic surgery, aimed at restoring knee stability following a ligament rupture. Despite technological advances and improvements in surgical techniques, failure rates remain a cause for concern.

There are many causes of ligament reconstruction failure, including biological factors (e.g. poor graft integration), repeated trauma and technical errors. Among the latter, poor tunnel positioning is the main cause, accounting for up to 29% of errors, the majority of which (75%) involve the femoral tunnel. Biomechanical studies have confirmed that inadequate positioning of the femoral tunnel alters knee kinematics, increasing stress on the graft and predisposing it to secondary rupture. In this context, a better understanding of intra-articular knee movements and the tension/relaxation profiles of the knee ligaments during flexion movements in surgery could improve the accuracy of reconstructions and reduce the long-term failure rate.

Using a surgical navigation system, it is possible to record data on the dynamic positioning of the femur and tibia during flexion and extension. MRI imaging also makes it possible to generate a digital twin of the patient's knee, including the patient's ligaments and their bony attachments. Aligning this digital twin with the positions of the femur and tibia recorded using intraoperative navigation makes it possible to determine, at different angles of flexion, the position of the digital twin and thus to measure the distance between the ligament insertions in the knee. This type of morpho-functional analysis of the 3D kinematics of the knee has not been published. This is why this research is initiated.

• Knee Cinematics (Procedure): The pins used for ACL reconstruction will serve as a mount for the optical markers used to record the position data of the femur and tibia during ACL reconstruction.

Primary outcomes

• Knee cinematics [Day 0]: The kinematic changes in the knee resulting from ACL reconstruction in flexion (at 90° and 45°) and in extension will be assessed intraoperatively, based on the following distances measured before and after placement of the ACL graft: * Femoro-tibial distance for the insertion of the LLE * Femoro-tibial distance for the insertion of the LLI * Femoro-tibial distance for the insertion of the ACL (before graft placement) * Distance between the centres of the intra-articular openings of the femoral and tibial tunnels (after graft placement) * Femoro-tibial distance for the insertion of the PCL

Sex: All, ages: 18 Years to 40 Years

Inclusion Criteria:

* Patient, male or female, aged between 18 and 40
* Patient eligible for ACL and LAL reconstruction
* Patient who is member of or covered by a social security scheme
* Patient who speaks French and has signed an informed consent form

Exclusion Criteria:

* Patient with a contraindication to MRI
* Patient with osteoarthritis of the joint
* Patient with a BMI > 30
* Patient with history of trauma or previous knee surgery
* Patient with knee trauma other than a sprain
* Patient under legal guardianship: an adult under guardianship, curatorship or other legal protection, or deprived of liberty by judicial or administrative order
* Pregnant or breastfeeding woman