[Experimental study on fixed angle adjustment in simultaneous reconstruction of anterior and posterior cruciate...

To explore the best flexion angle of the transplantation tendon for fixing joint in simultaneously reconstructing of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) using semitendinosus tendon as autologous graft.

Twenty-four clean level New Zealand White rabbits [(aged 6-8 months, male or female, and weighing (2.5 +/- 0.2) kg] were selected and divided randomly into 3 groups (n = 8) according to fixation angle of the reconstructed ligaments. The bilateral semitendinosus tendons of hind legs were used to reconstruct the PCL and ACL of right hind leg, and the reconstructed ligaments were fixed at knee flexion angles of 90 degrees (group A), 60 degrees (group B), and 30 degrees (group A). The rabbit general situation was observed after operation, and the specimens of the knee joints (including 10 cm distal end and 10 cm proximal end) were harvested for testing extension and flexion, displacement, and internal and external rotation at 3 months after operation.

All the rabbits survived to the end of experiment. There was no significant difference in maximal displacements of ACL and PCL among 3 groups (P > 0.05). The anterior and posterior displacements of shift in 3 groups were less than 1 mm, suggesting good stability. The anterior displacement and the posterior displacement at 30 degrees flexion and 90 degrees flexion in group A were significantly larger than those in group C (P < 0.05). There were significant differences in internal rotation angle and external rotation angle between group A and group C (P < 0.05), and there was no significant difference among other groups (P > 0.05).

When simultaneously reconstructing ACL and PCL, the knee flexion angle of 60 degrees for fixing the reconstructed ligaments can achieve the best effect.