| Project/Area Number |
09671461
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Orthopaedic surgery
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
MIYAGI Noboru Medical Hospital, Hokkaido Univ., Instructor, 医学部・附属病院, 助手 (90261297)
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| Co-Investigator(Kenkyū-buntansha) |
YASUDA Kazunori Fac.of Med., Hokkaido Univ., Professor, 医学部, 教授 (20166507)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1998: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1997: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | anterior cruciate ligament / freezing / initial tension / biomechanics / mechanical property / fibroblast / tensile strength / ultrastructure / 前十字靭帯 / 微細横造 |
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| Research Abstract |
1. We developed helical cryoprobe in which liquid nitrogen was circulated to perform in situ freezing of the canine anterior cruciate ligament (ACL). To know the ability of the cryoprobe we froze the ACLs of 4 adult dogs. After freezing, the ligaments were investigated with microscope and cell culture to detect living cell. No living cell was found in the frozen ACL.It was proved that the in situ freezing killed all fibroblasts of the AOL.
2. The ACLs of the 28mature beagle dogs were frozen in situ with the specially designed helical oryoprobe. After all fibroblasts died, the ACLs were thawed out with physiological saline. The tibial insertion of each AOL was made tree from the tibia with a cylindrical bone block by penetrating a hollow reamer. The dogs were divided in two groups. At the first group, the bone block was reduced anatomically (Sham group). At the second group, the AOL was completely relaxed by translocating the bone block to the proximal direction by 3 mm (Relax group). Th
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en, the each bone block was firmly fixed with an interference screw. The differences of the in situ frozen ACLs between the Sham and the Relax groups were investigated about the changes of mechanical properties and ultrastructure.
3. The cross sectional area of the AOL in Relax group was significantly greater than that in Sham group only at 12 weeks. The tensile strength and the tangent modulus in Relax group were significantly lower than that in Sham group at each period. There were no significant differences in the strain at failure between the two groups at each period.
4. The ACLs of four dogs were analyzed ultrastructurally. At 6 weeks after surgery, fibroblasts entered into the superficial substance of the in situ frozen ACL in the Sham group, although cells with oval nucleus entered into the *tersubstancial space in the Relax group. At 12 weeks, the fibroblasts were found at all the substance of the AOL in each group, although the shape of the nucleus of entered cell was spindle in the Sham group and oval in the Relax group. Less
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