The effect of bone growth factor in the tendon to bone healing in anterior cruciate ligament reconstruction: An experimental study in rabbits

BACKGROUND: Reconstruction of the anterior cruciate ligament (ACL) involves use of semintendinosis and gracilis tendons graft that is transplanted into bone tunnels at the femoral and tibial insertion sites and the sites and the bone tendon interface is a weak link in the early healing period due to slow rate of healing. We hypothesized that an addition of bone growth factor like Sadat-Habdan mesenchymal stimulating peptide (SHMSP) could enhance bone tendon healing rate so that re-rupture of the tendon does not take place. METHODOLOGY: Twenty skeletally mature rabbits underwent ACL reconstruction of the right knee. In 10 of the rabbits at the site of the tendon-graft 5 mg/kg body weight of SHMSP was put in the bone tunnel. In 10 other animals, nothing was added. At eight and 12 weeks 5 animals from each group were sacrificed. The tendon-graft site was harvested and sent for histopathological examination to assess the healing at the tendon-bone graft to the tibial tunnel. RESULTS: There were no deaths in both the groups. One rabbit of the control group developed an infection. In all the animals of the study group from 4 weeks onward showed bone formation, wherein the control group only granulation tissue was observed. By 8 weeks in the study group, the canal was totally obliterated with the new bone formation which extended onto the periosteal area. In the control, there was minimal change in the formation of the new bone formation. CONCLUSION: Addition of a growth factor like SHMSP would enhance the osteo-integration of the tendon-graft in the bony tunnel after ACL reconstruction in vivo.