2015 ISAKOS Biennial Congress ePoster #412
Study of Coating With Biomimetic Mineralization to Biocompatibility of PET Ligament Material In Vitro and Graft to Bone Healing In Vivo
Shiyi Chen, MD, PhD, Prof., Shanghai CHINA
Fudan University Sports Medicine Center, Huashan Hospital, Shanghai 200040, CHINA
FDA Status Not Applicable
Summary: silk fibrin (SF) implemented on HAp to biomimetic regulate the coating on PET ligament surface (SF+HAp group) in order to achieve a more stable graft-bone healing effect through the new mineralization method to evaluate the tendon-bone healing effects of silk/HAp mineralization coating in vivo, exploring the mechanism of osteogenesis differentiation.
The graft selection in knee anterior cruciate ligament reconstruction is one of the most controversy topics. At present, a number of clinical studies have shown the efficacy and safety of PET artificial ligament in 4-6 years with reasonable failure rate at about 5-7%. The failure reason has imputed to the poor graft-bone healing with scar tissue formation in the interface of bone-screw-PET graft. Purpose This study is to use silk fibrin (SF) implemented on HAp to biomimetic regulate the coating on PET ligament surface (SF+HAp group) in order to achieve a more stable graft-bone healing effect through the new mineralization method to evaluate the tendon-bone healing effects of silk/HAp mineralization coating in vivo, exploring the mechanism of osteogenesis differentiation.
36 adult male beagles underwent ACL reconstruction on their right knee. 18 of them were implanted with non-coating PET graft as control while the other 18 received SF+HAp mineralization coated PET graft as experimental group. The beagles were randomly sacrificed at 4th and 8th week after surgical procedure for biomechanical test, histological examination, histomorphometric and real-time polymerase chain reaction analysis.
At 4th week after implant, there was no statistically significant difference in the load to failure between the PET group and the SF+HAp group (P>0.05). At 8th week after surgery, the stiffness and the mean load to failure of the SF+HAp group was higher than the control group (P<0.01). HE staining shown that thick fibrous scar tissue was formed in the control group at the graft-bone interface at 4th and 8th week after surgery. While at 8th week after surgery, the interface width became much narrower and less scar tissue noticed in the SF+HAp group. Some penetrating new bone tissue was found at the interface and within the PET graft. Masson staining shown that the collagen fibers moderately formed and infiltrated into the PET graft respectively at 4th and 8th week after surgery in the control group. While in the SF+HAp group at 8th week after surgery, there were more collagen fibers formed and the PET fibers were almost completely encircled by collagen. Histomorphometric analysis showed that the width of graft-bone interface in the SF+HAp group was narrower than those in the control group (P<0.05) at 4th week after surgery. The mRNA expression level of BMP-7 in SF+HAp group was significantly higher than those in the control group (P<0.01) at 4th week after surgery. At 8th week, the mRNA expression level of BMP-7 in SF+HAp group was also higher than those in the control group (P<0.01).
CONCLUSION(S): The study shown that the SF+HAp coating on the surface of PET artificial ligament graft could induce the artificial ligament graft osseointegration in the bone tunnel, providing theoretical and experimental foundation to develop new type of artificial ligaments to meet the clinical demanding.