Effect of two kinds of injected biomaterial combined with BMP on tendon-to-bone healing after anterior cruciate ligament reconstruction in rabbits / 西安交通大学学报(医学版)

ABSTRACT

Objective To investigate the effect of two kinds of injected biomaterial combined with bone morphological protein (BMP) on tendon-to-bone healing after anterior cruciate ligament reconstruction (ACL) in rabbits. Methods ACL reconstruction was performed bilaterally in 50 skeletally mature rabbits using long digital extensor tendon grafts. Injected fibrin glue (FG) or injected calcium phosphate cements (CPC) combined with BMP were implanted into the treated knee of each rabbit,with the contralateral knees as controls. Every three rabbits were killed at 2,6 and 12 weeks postoperatively for routine histological studies. The samples were processed through Micro CT and subsequent HE and toludine blue staining. The remaining 16 rabbits were sacrificed at 6 and 12 weeks. Their femur-tendon graft-tibia complexes were harvested for subsequent mechanical testing. Results Imageological results showed that 6 weeks after operation,bone mineral density (BMD) values in FG-bBMP group were higher than those in CPC-bBMP group. However,12 weeks after operation,BMD values in CPC-bBMP group were the highest in the three groups. Histological findings of the interface between the tendon and bone differed in the three groups. Two weeks after operation,more chondrocyte-like cells that were fairly disorganized were noted between the tendon and bone in FG-bBMP group. Six weeks after operation,mature bone formation around the tendon was observed in FG-bBMP group while more immature bone ingrew toward implanted tendon in CPC-bBMP group; at 12 weeks,more chondrocyte cells and new bone formation were seen in CPC-bBMP group while a small quantity of mature bone was around tendon in FG-bBMP group. In biomechanical evaluation,the maximum pull-out load of the tendon from the bone tunnel was significantly higher in the two treatment groups than in the control group 6 and 12 weeks after operation (P