手関節伸展荷重時の遠位橈尺関節の3次元動態解析

PURPOSE: To assess the wrist joints of healthy volunteers in extended and loaded states versus the unloaded state by using computed tomography (CT) to analyze the in vivo 3-dimensional movements in the distal radioulnar joint (DRUJ). METHODS: The dominant arms of 9 volunteers with healthy wrists were studied. We mounted a compression device onto the elbows in an inverted position. A 0-kg and 7-kg load each was applied during low-dose radiation CT imaging and a bone model was produced. We marked the insertion sites for the 4 radioulnar ligaments stabilizing the DRUJ: palmar superficial radioulnar ligament (PS-RUL), dorsal superficial radioulnar ligament (DS-RUL), dorsal deep radioulnar ligament (DD-RUL), and palmar deep radioulnar ligament (PD-RUL). Using Marai's method, each ligament was virtualized and the length of each simulated ligament was measured. We also computed the 3-dimensional displacement and corresponding rotation of the distal ulna where it comes into contact with the radius in the sigmoid notch. RESULTS: The lengths of palmar ligaments (PS-RUL and PD-RUL) increased significantly under loaded conditions, and although not significant, the length of dorsal ligaments (DS-RUL and DD-RUL) tended to increase. When the wrist was loaded, the ulna rotated toward the open palmar side. CONCLUSIONS: The length of simulated radioulnar ligaments increased when the wrist joint was loaded in an extended position. This kinematic movement of DRUJ separation under a loading condition is different from physiological active movement. CLINICAL RELEVANCE: The 3-dimensional kinematic analysis revealed that palmar radioulnar ligaments were stretched during axial loading, suggesting that a tear of the palmer ligament can result from a fall on an outstretched hand.博士（医学）・甲第704号・平成31年3月15日© 2019 by the American Society for Surgery of the Hand. All rights reserved

Notch-Fatigue Properties of Advanced TRIP-Aided Bainitic Ferrite Steels

To develop a transformation-induced plasticity (TRIP)-aided bainitic ferrite steel (TBF steel) with high hardenability for a common rail of the next generation diesel engine, 0.2 pct C-1.5 pct Si-1.5 pct Mn-0.05 pct Nb TBF steels with different contents of Cr, Mo, and Ni were produced. The notch-fatigue strength of the TBF steels was investigated and was related to the microstructural and retained austenite characteristics. If Cr, Mo, and/or Ni were added to the base steel, then the steels achieved extremely higher notch-fatigue limits and lower notch sensitivity than base TBF steel and the conventional structural steels. This was mainly associated with (1) carbide-free and fine bainitic ferrite lath structure matrix without proeutectoid ferrite, (2) a large amount of fine metastable retained austenite, and (3) blocky martensite phase including retained austenite, which may suppress a fatigue crack initiation and propagation.ArticleMETALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE. 43A(11):4129-4136 (2012)journal articl

Three-Dimensional Kinematic Analysis of the Distal Radioulnar Joint in the Axial-Loaded Extended Wrist Position.

PURPOSE: To assess the wrist joints of healthy volunteers in extended and loaded states versus the unloaded state by using computed tomography (CT) to analyze the in vivo 3-dimensional movements in the distal radioulnar joint (DRUJ). METHODS: The dominant arms of 9 volunteers with healthy wrists were studied. We mounted a compression device onto the elbows in an inverted position. A 0-kg and 7-kg load each was applied during low-dose radiation CT imaging and a bone model was produced. We marked the insertion sites for the 4 radioulnar ligaments stabilizing the DRUJ: palmar superficial radioulnar ligament (PS-RUL), dorsal superficial radioulnar ligament (DS-RUL), dorsal deep radioulnar ligament (DD-RUL), and palmar deep radioulnar ligament (PD-RUL). Using Marai's method, each ligament was virtualized and the length of each simulated ligament was measured. We also computed the 3-dimensional displacement and corresponding rotation of the distal ulna where it comes into contact with the radius in the sigmoid notch. RESULTS: The lengths of palmar ligaments (PS-RUL and PD-RUL) increased significantly under loaded conditions, and although not significant, the length of dorsal ligaments (DS-RUL and DD-RUL) tended to increase. When the wrist was loaded, the ulna rotated toward the open palmar side. CONCLUSIONS: The length of simulated radioulnar ligaments increased when the wrist joint was loaded in an extended position. This kinematic movement of DRUJ separation under a loading condition is different from physiological active movement. CLINICAL RELEVANCE: The 3-dimensional kinematic analysis revealed that palmar radioulnar ligaments were stretched during axial loading, suggesting that a tear of the palmer ligament can result from a fall on an outstretched hand.博士（医学）・甲第704号・平成31年3月15日© 2019 by the American Society for Surgery of the Hand. All rights reserved.identifier:The Journal of hand surgery Vol.44 No.4 p.336.e1-336.e6 (2019 Apr)identifier:03635023identifier:http://ginmu.naramed-u.ac.jp/dspace/handle/10564/3552identifier:The Journal of hand surgery, 44(4): 336.e1-336.e