Analysis on correlation between each bone layer volume of femur and mechanical properties of osteoarthritis model rabbits

Objective To investigate the changes of each bone layer volume and mechanical properties of osteoarthritis(OA)rabbit femur and to clarify the correlation between the each bone layer volume and mechanical properties.Methods 0.3mL.kg-1 3% papain were injected into the joint space of right knee of 10rabbits on the 1st,5th and 12th days,respectively,to establish OA models(model group);the left legs of the rabbits were used as normal control group.Four times of CT scanning were performed 3dbefore modeling and 7,27,37dafter modeling,then the CT data was imported into MIMICS software,the femur model was extracted in the MIMICS software and the total volume of each femur bone layer was acquired.After CT scanning for 4times,the left and right rabbit femurs were taken as specimen.The tree-point bending test was performed and the load-deflection curves were obtained.The elastic load and the elastic deflection were contrasted and the maximum bending stress was calculated.Results Compared with normal control group,the deflection and cross-sectional moment of inertia of the right leg of the rabbits in model group had on significant changes in the rabbit bone growth process(P 0.05);but the growth rate and maximum flexural strength and maximum bending normal stress and cortical bone growth rate and compact bone growth rate were greatly decreased(P0.05),and the soft bone reduce rate was basically consistent(P0.05).Conclusion The increasing rates of each bone layer and the mechanical properties of the femur in the rabbits with OA are significantly decreased and the mechanical properties have correlation with each bone layer.