1992 Fiscal Year Final Research Report Summary
Basic and Clinical Study on Mechanical Control of Bone and Soft Tissue Formation
| Project/Area Number |
01440060
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthopaedic surgery
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| Research Institution | University of Tokyo |
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Principal Investigator |
KUROKAWA Takahide University of Tokyo, Orthopaedic Surgery, Professor, 医学部(病), 教授 (90010298)
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| Co-Investigator(Kenkyū-buntansha) |
MURASHIMA Ryutarou University of Tokyo, Orthopaedic Surgery, Assistant, 医学部(病), 助手 (90239517)
NAGANO Akira University of Tokyo, Orthopaedic Surgery, Associate Professor, 医学部(分), 助教授 (30111537)
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| Project Period (FY) |
1989 – 1992
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| Keywords | External Fixator / Twisting Load / Remodeling / Bone Healing / Compression / Destruction / Sarcomere Length / Bone Mineral Density |
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| Research Abstract |
As a result of basic study, we found the following.
(1) Long bones in lower legs of adult rabbits can be torsionally deformed without osteotomy, by continuously twisting them with external fixators. As a result of twisting, periosteal and endosteal lamellar bones decreased, while osteonal bones increased. Osteonal remodeling was activated by such twisting.
(2) In lower legs of adult rabbits, both compression and distraction by Imm on the osteotomy site activate bone healing. Compression and distraction revealled the same effectiveness.
(3) We studied changes in sarcomere lengrh in situ, stretching the extensor digitorum longus (EDL) of mouses maximally and immobilizing them by a plaster cast. Sarcomere length shortened gradually for seven days. The length after seven days was the same as the that of EDL that has not been stretched. It is because sarcomeres recover their original length that skeletal muscles adapt to the new leg length in leg lengthening.
Result of our clinical study are as
… More
follows.
(1) We succeeded in, producing an external fixator that realizes precise movements and made it suitable for practical use.
(2) The bone mineral density of callus in lengthened site was measured periodically with a dual energy X-ray absorptiometry (DXA). The bone mineral density of callus of femur was higher than that of tibia.
(3) As for relationship between leg lengthening speed and ankle contracture, ankle contracture is often observed when leg lengthening is conducted at a high speed. Contracture cannot be prevented by merely slowing the lengthening speed.
(4) As for relationship between leg lengthening speed and nerve conduction velocity, nerve conduction blocks are hardly observed when the lengthening speed is lower than 0.5mm/days. Conduction blocks are far less frequently observed when leg lengthening is conducted 1440 times a day for the lengthening speed of 0.5mm/day or more, compared with cases where lengthening is conducted only twice a day to achieve the same lengthening speed. Less
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