Objective To investigate the correlations between the bone mineral densities and biomechanical properties on different layers of the cancellous bone in the proximal tibia.Methods Quantitative CT was conducted of the 15 specimens of adult male tibia Based on the artificial destruction levels at the trabecular bone on the tibial plateau,the 15 specimens were randomly divided into 3 groups(n=5):group A(cancellous bone on the 1.5 cm layer below the articular cartilage),group B(cancellous bone on the 3.0 cm layer under the articular cartilage)and group C(cancellous bone on the 0 to 3 cm range of the subchondral bone).After standing positions were simulated in the 3 sets of specimens,they were connected to a biomechanical testing machine.Twenty-four sites were selected and subjected to a vertical load of600 N.Strain values and overall displacement values of the specimens were recorded before and after trabecular bone destruction.The correlations were analyzed between bone density and displacement values in groups A and B.The strain values before and after trabecular bone destruction,as well as the overall deformation values of the specimens were compared between the 3 groups.Results The bone densities of specimens in groups A and B were negatively correlated with the displacement values before and after destruction(P＜0.05).Comparisons of strain values at the 24 sites before and after trabecular bone destruction within 3 groups:There were statistically significant differences in the strain values at 8 sites between before and after trabecular bone destruction in group A(P＜0.05).Of the 8 sites,6 showed increased strains which were mainly concentrated around the insertion point of the anterior cruciate ligament and the medial tibial plateau.There were statistically significant differences in the strain values between before and after trabecular bone destruction at 3 sites in group B(P＜0.05).The strains at all the 3 sites increased,mainly concentrated behind the surface below the level of destruction.There were statistically significant differences in the strain values at 10 sites in group C between before and after trabecular bone destruction(P＜0.05).Of the 10 sites,5 showed a decrease in the strain which was concentrated above the destruction plane,and 5 showed an increase in the strain which was concentrated below the destruction plane.The overall deformation values of the speci-mens in groups A,B,and C were(0.033±0.003)mm,(0.015±0.003)mm,and(0.066±0.007)mm,respectively,showing statistically significant differences between the 3 groups(P＜0.05)as well as between any 2 groups(P＜0.05).Conclusions Bone mineral density in the cancellous bone of the proximal tibia has some value in assessment of the bone strength.Destruction of the proximal tibial cancellous bone can signif-icantly change the strain distribution on the proximal tibia.The proximal cancellous bone of the tibia plays a key role in stress support and load conduction.
关键词
胫骨/生物力学/骨密度/胫骨近端/松质骨
Key words
Tibia/Biomechanics/Bone density/Proximal tibia/Cancellous bone
维普
万方数据