Direct bone-to-bone integration between recombinant human bone morphogenetic protein-2-injected tendon graft and tunnel wall in an anterior cruciate ligament reconstruction model.
OBJECTIVE
This study was performed to evaluate one-stage anterior cruciate ligament (ACL) reconstruction using a semitendinosus tendon graft injected with bone morphogenetic protein 2 (BMP-2) in a rabbit model.


METHODS
We injected recombinant human BMP-2 (rhBMP-2) in the experimental group and phosphate-buffered saline in the control group at two sites of the semitendinosus tendon (15 μg in each site) to replace tendon with bone in the bone tunnel. Twenty minutes later, the injected tendon graft was transplanted for ACL reconstruction by passing the graft through the bone tunnel. The animals were harvested at four, eight, or 12 weeks postoperatively and examined by histological and biomechanical methods.


RESULTS
Histological analysis revealed that the tendon graft was replaced with new bone in the tunnel of the experimental group. Characteristic features identical to the regenerated direct insertion morphology at the bone-tendon junction were acquired at eight or 12 weeks in the experimental group. Biomechanical pull-out testing revealed greater stiffness in the experimental than control group at 12 weeks, although the maximum load to failure showed no significant difference between the two groups at four, eight, or 12 weeks.


CONCLUSIONS
These results indicate the potential for ACL reconstruction with regenerated direct insertion morphology.
Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
Junsei
J
Takigami
Yusuke
Y
Hashimoto
Shinya
S
Yamasaki
Shozaburo
S
Terai
Hiroaki
H
Nakamura
D000818:Animals; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D055396:Bone Morphogenetic Protein 2; D016025:Bone Transplantation / Q000379:methods; D005260:Female; D023421:Models, Animal; D011817:Rabbits; D011994:Recombinant Proteins; D013710:Tendons / Q000637:transplantation*; D023822:Tissue Engineering / Q000379:methods*; D016212:Transforming Growth Factor beta
D055396:Bone Morphogenetic Protein 2; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2