Anterior bone tunnel position increases meniscus migration in medial meniscus posterior root repair: A cadaveric study of suture length changes.

Purpose: This study investigated differences in the migration of meniscus sutured with pull-out sutures for treating medial meniscus posterior root tears (MMPRTs) according to the bone tunnel position, using cadaveric knees. Methods: Six knees of three donors fixed using Thiel's method were included in this study. The MMPRTs were created, and a single suture was performed at the torn meniscus using an arthroscopic procedure. The suture was pulled out through the tibial bone tunnel, and the meniscus displacement was measured as the change in length during 0-120° of knee flexion. Three types of bone tunnels (anatomical, anterior and posterior) were created for each knee, and the sutures were pulled out of each tunnel three times. After completing all measurements, the proximal tibia was extracted and micro-computed tomography was performed to evaluate the tunnel position. Results: A significantly smaller change in suture length was observed in the posterior group compared to the other two groups (anatomical group, 5.17 ± 1.8 mm; anterior group, 7.50 ± 3.2 mm; posterior group, 1.17 ± 1.0 mm; Conclusions: When pull-out sutures were used to repair MMPRTs, the suture length change was approximately 5 mm during knee flexion and extension when the bone tunnel was located at the anatomical attachment site. This change was larger when the tunnel position was anterior, and smaller when the tunnel position was posterior. Level of Evidence: LEVEL Ⅲ case-control study.