1993 Fiscal Year Final Research Report Summary
STUDY ON MEASUREMENTS OF MECHANICAL PROPERTIES OF THE LONG BONE IN VIVO
| Project/Area Number |
04670886
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthopaedic surgery
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| Research Institution | SHINSHU UNIVERSITY |
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Principal Investigator |
NAKATSUCHI Yukio SHINSHU UNIVERSITY, SHOOL OF MEDICINE, UNIVERSITY HOSPITAL, LECTURER, 医学部・附属病院, 講師 (80115360)
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| Co-Investigator(Kenkyū-buntansha) |
NOMURA Akio SHINSHU UNIVERSITY, FACULTY OF ENGINEERING, DEPARTMEPNT OF INFORMATION ENGINEERI, 工学部・情報工学科, 教授 (00115362)
TSUCHIKANE Akira SHINSHU UNIVERSITY, SCHOOL OF MEDICINE, ASSISTANT, 医学部, 助手
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| Project Period (FY) |
1992 – 1993
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| Keywords | Long bone / Mechanical properties / Impulse response method / Fracture healing / Resonant frequency / Modal analysis |
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| Research Abstract |
The vibration of long bones could be approximately compared to the free vibration of a beam with both ends unattached. The healing course of tibial fractures was assessed with sequential changes of resonance frequency measured through the impulse response method (IRM). Fifty-six tibial fractures were consecutively examined with IRM during the treatment. The fracture site was distributed from a proximal metaphysis to a distal one. Vibrations were generated by the impact of an impulse-hammer on the medial malleolus of the tibia. The vibrational response was detected on the medial tibial condyle with an accelerometer. Each signal was transmitted to a 2 channel waveform-analyzer. Most cases showed a steady increase of resonance frequency in fracture site without reaching the level of intact side. A decline of the frequency during treatment suggested a risky condition of the healing. An acute increase of the frequency was found in an initial stage fracture healing. The use of various materials such as a plate, Ender's nails, a Kuentcher's intramedullary nail and an external fixator for fracture fixation did not disturb the measurement of resonance frequency of the bone in vivo. It was useful in clinical practice to measure the primary mode in lateral direction of the tibia because of its higher amplitude than in antero-posterior direction. However, it is very important to distinguish the two separate bending modes by varying the direction of hammmering, because there is a discrepancy between their frequencies ; the former frequency was usually lower than the latter one. IRM has a possibility of wider application to the fractures treated by various methods of fixation and it will give orthopoaedic surgeons useful mechanical information on bone healing, especially when he considers the necessity of additional treatment in difficult cases.
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