Bone Healing Capacity Of Alendronate/Caicium Phosphate Cement In A Rabbit Femoral Condylar Defects

ObjectiveAn active drug alendronate was introduced into calcium phosphate cement to prepare a new type of calcium phosphate cement composite carrying alendronate.To observe the effect of alendronate(ALN)/calcium phosphate cement(CPC)on the repair of femoral defects in rabbits.MethodThe bilateral femoral condylar defects models were created in 36 healthy adult New Zealand rabbits and randomly divided into the experimental group(n=18)and the control group(n=18).Then the pre-set ALN/CPC composite materials was implanted into femoral condyle.Calcium phosphate cement(CPC)without ALN was used as a control.The rabbits were reared in the same conditions after operation.The specimens were subjected at the 4,8 and 12 weeks after operation to general observation,X-ray examination,bone mineral density measurement,histological section and scanning electron microscopy to observe the formation of new bone.ResultsThere was no obvious inflammatory tissue reaction in the two groups,and the tissue compatibility was good.According to the imaging examination,histological observation and scanning electron microscope: After 4 weeks of operation,The cement showed no obvious degradation,and the boundaries between the new bone and the cement were obvious,no callus formation was observed.After 8 weeks of operation,Bone cement showed different degrees of degradation and the boundary between new bone and the cement decreased,the interface was fuzzy and a small amount of callus growth was observed..After 12 weeks of operation,The bone cement was obviously degraded and closely inosculated with surrounding bone tissue.the CPC column is surrounded by a large number of callus.An ongoing cement degradation and bone ingrowth were performed simultaneously.The degradation and osteogenesis of the experimental group were much rapider than that of the control group.The bone mineral density of the experimental group was higher than that of the control group at 4,8 and 12 weeks(P<0.05).Bone mineral density increased gradually with time in both groups and there was statistically significant difference(P<0.05).ConclusionThis study shows that ALN/CPC composites have both bone conductivity and osteogenic activity,as well as good biocompatibility and biodegradability.The new composite of ALN/CPC compared with simple calcium phosphate cement can accelerate the repair of bone defect in rabbit femur and strengthen the strength of femur.As an artificial bone substitute in bone defect repair,it has the value of further study and good prospect of application.It provides a theoretical basis for its preliminary clinical application and lays a foundation for the study.