Method for Determining the Isometricity of the Location of the Femoral and Tibial Tunnels Before Their Formation in The Anterior Cruciate Ligament Plasty

Relevance. One of the key points in plasty of the anterior cruciate ligament (ACL) is the isometric position of the graft, in which its tension remains the same during flexion and extension of the knee joint. However, no method has been described today for the intraoperative determination of the isometricity of the location of the femoral and tibial tunnels (for placing the graft) before their formation.

Purpose of the study. To develop a method for intraoperative determination of the isometricity of the location of the femoral and tibial tunnels before their formation during ACL plasty and to study its effectiveness.

Material and methods. The study included 30 patients who underwent ACL repair. For a preliminary intraoperative assessment of the isometric areas of graft fixation on the femur and tibia, the proposed original method with the use of two knot pushers and a thread passing through them. Isometry was assessed by the degree of displacement of this thread. After determining the isometric areas of fixation, the femoral and tibial tunnels were formed, and the isometric position of the graft before its fixation in the tibia was checked by the degree of displacement of the threads with which the graft was sutured relative to the aperture of the tibial tunnel.

Results. The average displacement of the thread relative to the pusher of the knot in the preliminary determination of the isometric areas of fixation according to the proposed method corresponded to the displacement of the threads with which the distal end of the graft was sewn relative to the outer aperture of the tibial tunnel (this value did not exceed 2 mm on average) until the final fixation of the graft in the tibial tunnel.

Conclusion. The developed method makes it possible to determine the isometric location of the femoral and tibial tunnels during arthroscopic plasty of the anterior cruciate ligament before their formation. If the location of the fixation points on the femur and tibia is determined non-isometric, it is possible to correct their position.

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