A Novel Animal Model for Anterior Cruciate Ligament Reconstruction Using Oval Tunnels / 中国运动医学杂志

ABSTRACT

Objective To study the general shape of anterior cruciate ligament (ACL) insertion in rabbits and establish an animal model of ACL reconstruction using oval tunnels.Methods Eighteen mature white New Zealand rabbits were used in this study.Eight of them were used for anatomy study and the other 10 were for building an animal model.After removal of the medial femoral condyle and other soft tissues around ACL,the morphology of the ACL insertion was examined and the diameter of ACL insertions was measured using a caliper.An oval-tunnel dilator (1.6 mm×2.5 mm) was designed to make an oval-tunnel in the right knee of the rabbits while a round tunnel was drilled using a 2 mm diameter Kirschner wire in the left knee of the rabbits.Their hamstring tendon grafts were harvested as grafts for both sides and the compatibility between the bone tunnel and graft was examined for both groups.Right after the surgery,the knees of both sides were given the three-dimensional CT scan.Results The shape of ACL insertion of rabbits was oval.In the femur side,the average major and minor diameter of the ACL insertion was 5.28 ± 0.83 mm and 2.61 ± 0.33 mm respectively.In the tibial side,the major and the minor diameter of the ACL insertion was 5.33 ± 0.40 mm and 2.68 ±0.11 mm.The bone tunnel was compatible with the graft in both groups.In the oval tunnel ACL reconstruction group,the cross sectional area of the femoral bone tunnel was 3.18 ± 0.09 mm2 and the cross sectional area of the tibial bone tunnel was 3.26 ± 0.15 mm2.In the round tunnel ACL reconstruction group,the corresponding measurements were 3.13 ± 0.10 mm2 and 3.11 ± 0.11 mm2 respectively.There was no significant difference between the two groups.Conclusion The shape of ACL insertion in rabbits is oval.Using the self-made oval tunnel dilator we have successfully built an oval tunnel ACL reconstruction animal model with a good compatibility between the bone tunnel and graft.This lays the foundation for further research in the future.