Fig. 1.

a) and b) To create a rat model of anterior cruciate ligament (ACL) reconstruction, the rat was placed in the supine position and the flexor digitorum longus tendon was freed under aseptic conditions. c) A medial patellar incision was made to expose the knee joint and the intrinsic ACL was removed. d) A femoral tunnel was created with a drill (1 mm diameter). e) After femoral and tibial tunnels were established, both ends of the transplanted tendon were fixed and pulled into the bone tunnels. f) The incisions were sutured after injection of fibrin gel with or without recombinant secretory leucocyte protease inhibitor around the graft tendon, and the operation was completed.