アキレス腱付着部症に対しアキレス腱モーメントアーム長が及ぼす影響

Insertional Achilles tendinopathy (IAT) is caused by traction force of the tendon. The effectiveness of the suture bridge technique in correcting it is unknown. We examined the moment arm in patients with IAT before and after surgery using the suture bridge technique, in comparison to that of healthy individuals. We hypothesized that the suture bridge method influences the moment arm length. An IAT group comprising 10 feet belonging to 8 patients requiring surgical treatment for IAT were followed up postoperatively and compared with a control group comprising 15 feet of 15 healthy individuals with no ankle complaints or history of trauma or surgery. The ratio of the moment arm (MA) length/foot length was found to be statistically significant between the control group, the IAT group preoperatively and the IAT group postoperatively (p < 0.01). Despite no significant difference in the force between the control and preoperative IAT groups, a significantly higher force to the Achilles tendon was observed in the IAT group postoperatively compared to the other groups (p < 0.05). This study demonstrates that a long moment arm may be one of the causes of IAT, and the suture bridge technique may reduce the Achilles tendon moment arm.博士（医学）・甲第845号・令和4年9月28日© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

大腿骨頭靭帯の組織学的および分子学的特性に関する研究

The ligamentum capitis femoris (LCF) has increased in clinical significance through the development of hip arthroscopy. The histological pathologies and molecular composition of the femoral attachment of the LCF and the degeneration caused by LCF disruption were investigated in the human hip joint. Twenty-four LCFs were retrieved at surgery for femoral neck fracture (age range: 63–87 years). In the “intact” (i.e., intact throughout its length, n = 12) group, the attachment consisted of rich fibrocartilage. Fibrocartilage cells were present in the midsubstance. In contrast, the construction of the attachment in the “disrupted” (i.e., ligament no longer attached to the femoral head, n = 12) group had disappeared. The attachment in the disrupted group was not labeled for type II collagen or aggrecan, while that in the intact group was labeled for types I, II and III collagen, chondroitin 4-sulfate, chondroitin 6-sulfate, aggrecan, and versican. The percentage of single-stranded DNA-positive chondrocytes was significantly higher in the disrupted group than in the intact group. We conclude that the femoral attachment of the LCF has a characteristic fibrocartilaginous structure that is likely to adjust to the mechanical load, and suggest that its degeneration is advanced by disruption and should be regarded as a clinical pathology.博士（医学）・乙第1353号・平成27年3月16日© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Sensitivity study for N-NB-driven modes in JT-60U: boundary, diffusion, gyroaverage, compressibility

The sensitivity of the growth and nonlinear evolution of fast-ion-driven modes is examined with respect to the choice of particle boundary conditions, diffusion coefficients, fast ion gyroradii and bulk compressibility. The primary purpose of this work is to justify the choice of parameters to be used in the self-consistent long-time simulations of fast ion dynamics using global MHD-kinetic hybrid codes that include fast ion sources and collisions. The present study is conducted for a scenario based on the N-NB-driven JT-60U shot E039672, which is subject to abrupt large events (ALE). We use realistic geometry, a realistic fast ion distribution, and focus on experimentally observed harmonics with low toroidal mode numbers n  =  1, 2, 3. The use of realistic boundary conditions and finite Larmor radii for the fast ions is shown to be essential. The usual values μ0η＝υ＝χ～10-6υΑ０R0 used for resistivity, viscosity and thermal diffusivity, and Τ=5/3used for the specific heat ratio (controlling the effect of compressibility) are shown to be reasonable choices. Our method for performing the parameter scans around the threshold for the onset of convective amplification is proposed as a strategy for nonlinear benchmark studies

足関節運動とアキレス腱の緊張がアキレス腱と踵骨間の接触圧に与える影響

Impingement between the Achilles tendon and the posterosuperior prominence of the calcaneus is considered to be a cause of insertional Achilles tendinopathy. The corresponding treatment intends to reduce tensile stress from calf muscles and avoid hyper-dorsiflexion of the ankle joint for decreasing the contact pressure; however, no study has reported on whether these treatments can decrease impingement. Thus, this study investigated the hypothesis that the tensile stress of the Achilles tendon and ankle motion affect the contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus. Six fresh-frozen cadaveric lower leg specimens were procured. Each specimen was set to a custom foot-loading frame and loaded with a ground reaction force of 40 N and a tensile load of 70 N along the Achilles tendon. The contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus was measured using a miniature pressure sensor under different tensile loadings of the Achilles tendon at the neutral ankle position. Similarly, the contact pressures during the ankle motion from a neutral position to maximum dorsiflexion were measured. The tensile load of the Achilles tendon and ankle motion affected the contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus. The contact pressure increased with tensile load or ankle dorsiflexion. Conditions with increasing the tensile load of the Achilles tendon or under ankle dorsiflexion increase the contact pressure between the Achilles tendon and the posterosuperior prominence of the calcaneus.博士（医学）・甲第806号・令和3年12月21日Copyright © 2021 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved