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Objective:To measure and analyze the distribution characteristics of the micro-hardness of the middle-upper thoracic vertebrae (T 1-T 10) in the human body. Methods:T 1-T 10 vertebrae from three fresh cadavers were divided into vertebral body area and attachment area. 3 mm specimens were cut by a high-precision slow saw and 11 regions were selected and measured on each vertebrae by a Vickers microhardness tester (cortical bone: 1-9, cancellous bone: 10-11). The micro-hardness distribution of T 1-T 10 vertebrae was recorded and analyzed. Results:A total of 330 measurement areas from 30 vertebrae were measured, and 1 650 hardness values were collected. The average hardness values of the overall cortical bone of the middle-upper thoracic vertebrae of the 3 cadavers were 30.55±5.44 HV, 29.94±4.86 HV, and 29.55±4.36 HV, respectively. The difference among the groups was statistically significant ( F=4.680, P=0.009). The average hardness values of the overall cancellous bone were 27.93±5.61 HV, 28.21±4.96 HV, 27.98±3.94 HV, respectively. There was no significant difference among the groups ( F=0.091, P=0.913). There were statistically significant differences between the hardness values in the attachment area and vertebral body area of each cadaver ( t=7.467, 4.750, 6.621, P<0.001); the hardness of the cancellous bone in the attachment area of each cadaver was higher than that of the cancellous bone in the vertebral body ( t=1.785, 3.159, 3.103, P=0.077, 0.002, 0.003). The distribution of microhardness in 11 measurement areas of 3 cadavers were similar: the hardness of the cortical bone of pedicle, lamina and inferior endplate cortex (1, 2, 7) were higher; the hardness of the cortical bone of upper endplate and peripheral cortex (6, 8, 9) were lower. The distribution patterns of the microhardness in different vertebral segments of the 3 cadavers were similar: The hardness values gradually increased from T 1 to T 10. The vertebra with the largest hardness of the cortical bone was T 8; and the vertebra with the largest hardness of the cancellous bone were T 7, T 7 and T 6, respectively. Conclusion:The hardness of the upper endplate and peripheral cortex was low, which could disperse the load to protect the fragile cancellous bone. The hardness of the pedicle was the highest. The hardness of the cortical bone was higher than that of the cancellous bone, and the values of different segments gradually increased from top to bottom, which may be related to the physiological and anatomical morphology, and the gradual increase of the load of muscle force and body weight.
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Objective@#To investigate the microhardness distribution of cancellous bone in the proximal tibia and its clinical significance.@*Methods@#Three fresh tibias were obtained and examined by X-ray and CT to exclude skeletal pathologies, such as osteoporosis, osteoarthritis. According to the Heim's square, the proximal tibias were cut off. Each of the proximal tibias was divided into three parts, the medial condyle, the intercondylar area and the lateral condyle. Each part was divided into three sections, proximal, middle and distal sections. Each of the proximal tibias was divided into 9 regions. Bone specimens with a thickness of 3 mm were taken from each region using a high precision low-speed saw and fixed on flat sheets. The microhardness of the bone tissue was measured using a Vickers microhardness tester after polish. Ten effective micro-indentation tests were conducted in each region. After measurement the diagonal length of the indentations, the microhardness values were calculated via software provided by the hardness tester. Analysis of variance and Tukey method were used to compare the microhardness values of different parts, sections and regions of cancellous bone. The microhardness distribution of the proximal tibia was analyzed.@*Results@#A total of 270 effective indentations were made in the specimens, and the microhardness values were obtained. The average microhardness of the three proximal tibias was 40.98±3.44, 34.92±4.64 and 39.49±3.86 HV, respectively. There was a significant difference among the groups (F=55.87, P=0.000). The microhardness distribution of bone tissue in the three proximal tibias was similar. In the comparison of different parts, the microhardness of medial condyle was greater than that of the lateral condyle, which was larger than that of the intercondylar area. The difference between the parts was statistically significant (F=18.42, 8.236, 10.877; P=0.000, 0.001, 0.000). In the comparison of different sections, the microhardness of the distal section was greater than that of the proximal section, which was larger than that of the middle section. The difference between the sections was statistically significant (F=8.720, 17.140, 6.142; P=0.000, 0.000, 0.003). The microhardness distribution was similar among different regions. The region with the highest microhardness is the medial condyle of the distal section with microhardness of 44.87±3.25 HV (range 39.2-49.7 HV). The lowest microhardness was in the intercondylar area of the middle section with hardness of 29.41±4.53 HV (range 24.8-36.2 HV).@*Conclusion@#The microhardness value of cancellous bone near the articular surface at the proximal tibia was smaller, which could disperse the load and protect the fragile of articular cartilage. Furthermore, the microhardness of the transition zone is larger. The microhardness value of the cancellous bone in medial tibia condyle is the greatest, which is related to load-bearing.
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Objective@#To investigate the distribution characteristics and significance of bone hardness in different segments and layers of clavicle.@*Methods@#The right clavicles of three fresh Chinese corpses were taken and then divided into proximal, middle and distal segments according to Allman's classification. The clavicles were cut with diamond saw in the vertical of long axis equidistant exactly into 15 layers (proximal: 3 layers; midshaft: 7 layers; distal: 5 layers), and each layer was divided into four directions: superior, inferior, anterior, and posterior. The bone hardness were measured by Vickers microindentation, HV(kgf/mm2). The distribution of bone hardness was recorded and analyzed.@*Results@#A total of 180 parts of cortical bone were measured, generating 900 measurements. Meanwhile, a total of 45 parts of cancellous bone were measured, generating 225 measurements. We found that: (1)The average hardness of cortical bone was (35.9±8.1)HV, and the midshaft segment [(41.3±6.8)HV] was harder than the proximal segment [(33.8±6.1)HV] and the distal segment [(29.7±5.4)HV](P<0.05); (2)The average hardness of cancellous bone was (30.7±6.2)HV, and there were significant differences among the midshaft segment [(34.5±5.5)HV], the proximal segment [(29.2±2.9)HV] and the distal segment [(26.3±5.1)HV](P<0.05); (3)for cortical bone, the hardest segment was the fifth layer of the midshaft segment [(44.8±8.6)HV] while the most soft segment was the fourth layer of the distal segment [(28.0±3.5)HV](P<0.05); (4)for cancellous bone, the hardest segment was the fifth layer of the midshaft segmnet [(36.8±5.1)HV] while the most soft was the fifth layer of the distal segment [(23.0±4.4)HV](P<0.05); (5)There were no statistically significant differences among four directions of segments(P>0.05).@*Conclusion@#The microindentation hardness varies greatly among different segments and layers of the clavicles. The cortical bone and cancellous bone have consistent hardness changes, which shows that the middle segment is obviously harder than the proximal and distal segments with a gradually gradient decreasing trend from the middle to both ends. The data can be used to guide the design of 3D printing implants that conform to the stress conduction characteristics of the clavicle under physiological conditions, and provide good data support for the modeling and finite element analysis of the clavicle under simulated physiological conditions.
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Objective To investigate the distribution characteristics and significance of bone hardness in different segments and layers of clavicle. Methods The right clavicles of three fresh Chinese corpses were taken and then divided into proximal, middle and distal segments according to Allman's classification. The clavicles were cut with diamond saw in the vertical of long axis equidistant exactly into 15 layers ( proximal:3 layers; midshaft:7 layers; distal:5 layers ) , and each layer was divided into four directions:superior, inferior, anterior, and posterior. The bone hardness were measured by Vickers microindentation, HV ( kgf/mm2 ) . The distribution of bone hardness was recorded and analyzed. Results A total of 180 parts of cortical bone were measured, generating 900 measurements. Meanwhile, a total of 45 parts of cancellous bone were measured, generating 225 measurements. We found that:(1)The average hardness of cortical bone was (35.9 ±8.1)HV, and the midshaft segment[(41.3 ±6.8)HV] was harder than the proximal segment [(33.8 ±6.1)HV] and the distal segment [(29.7±5.4)HV](P<0.05);(2)Theaveragehardnessofcancellousbonewas(30.7±6.2)HV, and there were significant differences among the midshaft segment [(34. 5 ± 5. 5)HV], the proximal segment [(29.2±2.9)HV] and the distal segment [(26.3 ±5.1)HV](P<0.05);(3)for cortical bone, the hardest segment was the fifth layer of the midshaft segment [(44. 8 ± 8. 6)HV] while the most soft segment was the fourth layer of the distal segment [(28. 0 ± 3. 5)HV](P<0. 05);(4)for cancellous bone, the hardest segment was the fifth layer of the midshaft segmnet [(36. 8 ± 5. 1)HV] while the most soft was the fifth layer of the distal segment [(23. 0 ± 4. 4) HV] (P<0. 05);(5) There were no statistically significant differences among four directions of segments(P >0. 05). Conclusion The microindentation hardness varies greatly among different segments and layers of the clavicles. The cortical bone and cancellous bone have consistent hardness changes, which shows that the middle segment is obviously harder than the proximal and distal segments with a gradually gradient decreasing trend from the middle to both ends. The data can be used to guide the design of 3D printing implants that conform to the stress conduction characteristics of the clavicle under physiological conditions, and provide good data support for the modeling and finite element analysis of the clavicle under simulated physiological conditions.
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Objective To investigate the clinical application of epinephrine hydrochloride in the prevention of bone cement implantation syndrome in the cemented hip replacement. Methods The clinical data of 48 patients treated with cemented hip replacement from July 2008 to April 2009 were retrospectively analyzed. All the patients were divided into control group and intervention group. The bone marrow cavities of 24 patients in the control group were not pretreated with saline epinephrine hydrochloride before implantation of bone cement; the bone marrow cavities of 24 patients in the intervention group were pretreated with saline epinephrine hydrochloride before implantation of bone cement. Systolic blood pressure (SBP), diastolic blood pressure (DBP), the mean arterial pressure (MAP), heart rate (HR)and pulse oxygen saturation ( SPO2 ) were compared between the two groups before bone cement implantation and 1,2, 3, 4, 5, 6, 7, 8, 9, 10 minutes after bone cement implantation. The data were analyzed with variance analysis and Q test. Results (1) In the control group: the blood pressure was decreased in control group one minute after bone cement implantation and a significant decrease of the blood pressure was observed at 2-6 minutes after the implantation ( P ＜ 0. 01 ). The blood pressure was increased seven minutes after the implantation, with the most significant increase of DBP ( P ＜ 0.05 ).The blood pressure recovered to normal 10 minutes later. The SPO2 was decreased significantly ( P ＜0.05 ) but no significant change was observed in HR ( P ＞ 0.05). (2) In the intervention group: the bone marrow cavity was pretreated with saline epinephrine hydrochloride before implantation of bone cement.ity. No significant difference was found in SBP, DBP, MAP, HR and SPO2 at different time points before and after bone cement implantation (P ＞0.05 ). Significant decrease of blood pressure and SPO2 was observed in control group and a significant hemodynamic change was detected at 2-6 minutes after the bone cement implantation. In the intervention group, no hemodynamic change was found in all the patients except that one patient was found with decrease of blood pressure and another one with the occasional premature ventricular contractions. Conclusion Pretreatment of bone marrow cavity with saline epinephrine hydrochloride can effectively prevent bone cement implantation syndrome.