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KMID : 0613319950010010007
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Journal of the Korean Bone and Joint Tumor Soceity
1995 Volume.1 No. 1 p.7 ~ p.16
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Experimental Studies on Heat Conductivity of Human Bone and Torsional Strength of Pasteurized Porcine Tibia
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Park Il-Hyung
Kim Sin-Gun
Shin Dong-Kyu
Ihn Joo-Chul
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Abstract
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In countries where Confucianism is popular, it is extremely hard to get fresh cadaver bone for allograft. Therefore in Korea, the reimplantation of resected autoclaved autogenous bone segments has been increasingly performed for limb reconstruction of extremities with malignancies. To preserve the bone morphogenetic protein and mechanical strength of heated bone, many studies have reported that pasteurization of bone is far better than autoclaving over 100°C. Based on this assumption, replacement with a pasteurized autogenous bone graft after resection of a malignant bone tumor was deemed feasible for reconstruction. However, little is known about how high a temperature and how much time for pasteurization is needed to make tumors completely necrotic and to maintain the mechanical strength of bone. Consequently, experimental studies were carried out to test heat conductivity of human bone and torsional strength of porcine tibia after pasteurization. First, two pairs of human proximal tibia and distal femur were used. We used T-type thermocoples to check core temperature of the bone and a computerized data acquisition system to record results. Without reaming of the medullary cavity, in a 60°C-thermostatic saline tub, it took 32 minutes and 50 seconds to raise the core temperature of human proximal tibia from 20°C to 58°C, and 30 minutes for distal femur. In a 80°C saline tub, it took 12 minutes and 50 seconds for proximal tibia, and 11 minutes and 10 seconds for distal femur. In contrast, using porcine tibia whose cortical thickness is similar to that of human tibia, after reaming of the medullary canal, it took less than 3 minutes and 30 seconds in a 60°C saline tub, less than I minute and 45 seconds in a 70°C tub, and less than 1 minute in a 80°C tub to elevate core temperature from 20°C to 58°C. Second, based on data of the heat conductivity test, we compared the torsional strength before and after pasteurization. Twenty matched pairs of porcine tibia were used, The left one was used as a non-heated control group and the right one as a pasteurized experimental group. Wighout reaming of the medullary cavity, there was no statistical difference in torsional strength between the pasteurization of the 60°C-35minute and of 80°C-15minute. With reaming, we also found no statistical difference among pasteurization of 60°C-15 minute, of 70°C-15 minute, and of 80°C - 15 minute groups. In conclusion, reaming of the medullary canal is very helpful in saving pasteruization time. And, in a 60°C saline tub, no significant weakness in torsional strength occurs with pasteurization of the bone for up to 35 minutes. Also no significant weakness in torsional strength occurs with an exposure of 15 minutes to the 80°C saline tub.
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KEYWORD
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Heat conductivity, Torsional strength, Pasteurization
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Listed journal information
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