Tibial deformities and failures of anterior cruciate ligament reconstruction in immature rabbits.

We evaluated the effects of anterior cruciate ligament (ACL) reconstruction on growth and development of the knee in immature New Zealand white rabbits (8 weeks old). In 25 rabbits, the ACL was reconstructed with an autogenous iliotibial band (ITB), and in 31 rabbits an autogenous patellar tendon bone (PTB) graft was used. Reconstructed ACLs failed in 20 of the 25 animals in the ITB group and in 26 of 31 in the PTB group. Gross and histological examinations in the animals with successfully reconstructed ACLs (5 in the ITB group and 5 in the PTB group) showed significant tibial deformity and tibial shortening, with progressive thinning of the epiphyseal plate and disorders of the cartilage column on the medial side of the tibia. These abnormalities were not observed in rabbits whose ACLs were torn. This experiment showed that successful ACL reconstruction in young animals with an open physis may result in deformities and/or shortening of the leg. Accordingly, we believe that special care should be taken when surgically reconstructing an ACL in a young patient whose physes are still open.