Faculty Profiles - KOBAYASHI Koichi

Papers - KOBAYASHI Koichi

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成長期における跳躍型疲労骨折に関係する脛骨の彎曲と皮質骨厚の3次元評価

青木一磨, 林智彦, 渡邉聡, 林豊彦, 齋藤大寛, 齊藤将, 森清友亮, 古賀良生, 大森豪, 小林公一

臨床バイオメカニクス 45 60 - 66 2024.10

Language：Japanese Publisher：(一社)日本臨床バイオメカニクス学会

脛骨の跳躍型疲労骨折は,反復的な変形ストレスによりその中央部に好発する難治性疾患である.我々はその素因として「形状特徴の成長期における変化」があるという仮説を立て,その検証の第一歩としてCT画像から構築した脛骨3次元モデルを用いて,下腿骨形状異常を認めない10代-20代の男女を対象に脛骨形状を分析した.特徴パラメータとして前方最大皮質骨厚および髄腔彎曲度の2つを分析した結果,前方最大皮質骨厚は男女ともに10代前半から後半にかけて遠位部では有意に増加したが,近位部では増加しなかった.その境界部が骨幹中央部だった.一方,髄腔彎曲度は10代前半と20代で骨幹中央部の極大位置に違いがみられたが,すべての骨幹位置で年齢による有意な差はみられなかった.「髄腔の3次元形状」および「形状分析とメカニカルストレスとの関係の分析」が今後の課題である.(著者抄録)

Accuracy of an image matching technique for assessing knee alignment during the stance phase of gait using single-plane anteroposterior radiography. International journal

Koichi Kobayashi, Makoto Sakamoto, Tatsuya Soeno, Takashi Sato

Bio-medical materials and engineering 2024.8

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Accurate measurement of bone alignment of the knee during walking provides ideal clinical information for diagnosis and treatment of knee joint disorders. To bring this ideal closer to clinical reality, we developed an image matching technique to measure the three-dimensional (3D) position of bones using anteroposterior radiography during the stance phase of treadmill walking. OBJECTIVE: To develop and validate an image matching method for evaluation of 3D knee alignment using anteroposterior radiography of artificial femoral and tibial bones. METHODS: The 3D position of each bone was recovered by minimizing the difference between the projected outline and the contour of the bone in the anteroposterior radiograph. The true value of the position was measured using a 3D coordinate measuring machine. RESULTS: The mean values ± standard deviation and root mean squares (RMS) of translation errors were within -1.6 ± 2.1 mm and 2.6 mm, respectively, for femur, and 2.1 ± 1.9 mm and 2.8 mm for tibia. The mean values ± standard deviation and RMS of errors in rotation were within 0.3 ± 0.7° and 0.7°, respectively, for femur, and -0.3 ± 0.9° and 0.9°, respectively, for tibia. CONCLUSION: Our method is suitable for evaluating 3D knee alignment on anteroposterior radiography.

DOI： 10.3233/BME-240059

Assessment of spinal alignment in standing position using Biplanar X-ray images and three-dimensional vertebral models

Koichi Kobayashi, Makoto Sakamoto, Keisuke Sasagawa, Masaaki Nakai, Masashi Okamoto, Kazuhiro Hasegawa, Kengo Narita

Porto Biomedical Journal 9 ( 3 ) 2024.5

Publishing type：Research paper (scientific journal) Publisher：Ovid Technologies (Wolters Kluwer Health)

Abstract

We developed two methods for three-dimensional (3D) evaluation of spinal alignment in standing position by image matching between biplanar x-ray images and 3D vertebral models. One used a Slot-Scanning 3D x-ray Imager (sterEOS) to obtain biplanar x-ray images, and the other used a conventional x-ray system and a rotating table. The 3D vertebral model was constructed from the CT scan data. The spatial position of the vertebral model was determined by minimizing the contour difference between the projected image of the model and the biplanar x-ray images. Verification experiments were conducted using a torso phantom. The relative positions of the upper vertebrae to the lowest vertebrae of the cervical, thoracic, and lumbar vertebrae were evaluated. The mean, standard deviation, and mean square error of the relative position were less than 1° and 1 mm in all cases for sterEOS. The maximum mean squared errors of the conventional x-ray system and the rotating table were 0.7° and 0.4 mm for the cervical spine, 1.0° and 1.2 mm for the thoracic spine, and 1.1° and 1.2 mm for the lumbar spine. Therefore, both methods could be useful for evaluating the spinal alignment in standing position.

DOI： 10.1097/j.pbj.0000000000000256

3D Whiteside's Line計測健常膝と変形性膝関節症膝の検討

谷藤理, 望月友晴, 小林公一, 佐藤卓, 渡辺聡, 前田圭祐, 川島寛之

日本整形外科学会雑誌 97 ( 3 ) S853 - S853 2023.3

コーンビームCTを用いた上下顎歯の三次元歯軸角度の特徴

石井義人, 坂本信, 坂上勇太, 亀田剛, 森清友亮, 小林公一, 坂井幸子, 遠藤英昭, 平元和彦

臨床バイオメカニクス 43 339 - 344 2022.10

Language：Japanese Publisher：(一社)日本臨床バイオメカニクス学会

正常咬合者13名の上下顎骨を撮影したコーンビームCT画像の三次元骨モデルの3点の特徴点から口腔内に三次元ワールド座標系を設定し,横断面,冠状面および矢状面を定めた.そして,歯形状より主成分分析法によって三次元歯軸を求めた.歯軸を3平面上に投影して,各平面内での上下顎全歯の対向する同名歯種の歯軸のなす角度である交角度を求めた.さらに,異なる歯種間の交角度の関係について示した.その結果,投影した平均交角度は3平面内においていずれも正中面に対してほぼ左右対称の傾向を示した.横断面および矢状面内の交角度は前歯では小さく,第二小臼歯,第一大臼歯,第二大臼歯では,他歯種と比べて交角度は大きい.一方,異なる歯種間の交角度の相関は,横断面内の中切歯,側切歯,犬歯では隣接する歯種間に有意な正の相関が認められた.矢状面内では,第二大臼歯以外は多くの歯種間で交角度の相関がみられることを明らかにした.(著者抄録)

膝前後X線像による皮質骨幅測定の精度検証

高根沢佑斗, 森清友亮, 坂上勇太, 森隆裕, 古賀良生, 望月友晴, 古賀寛, 坂本信, 小林公一, 田邊裕治, 佐々木朋裕

臨床バイオメカニクス 43 253 - 257 2022.10

Language：Japanese Publisher：(一社)日本臨床バイオメカニクス学会

骨幅・皮質骨幅X線測定により骨粗鬆症や荷重負荷状況の解明が可能とされる.我々は疫学調査で立位正面X線画像において脛骨・大腿骨皮質骨幅変化が変形性膝関節症の進行に関連することを報告した.しかし,横断面上の内外側方向の厚さとして測定すべき皮質骨の厚さが,正背面方向の単純X線画像からどの程度定量的に推定,評価可能であるかは明らかではない.本研究では,下肢正面X線像における骨幅及び皮質骨幅測定精度について骨格人体ファントムを対象としてX線およびCT撮影を行い,X線照射角度の変化が皮質骨幅の測定値に与える影響を調べた.その結果,大腿骨において骨幅と内外側における各々の皮質骨幅との比は,X線およびCT撮影ともに照射角度によらずほぼ一定となるが,X線撮影の方がやや厚く評価される傾向を認めた.臨床上のX線撮影では,内外旋20°以内の照射角度であれば皮質骨幅比に及ぼす入射方向の影響は少ないことを示した.(著者抄録)

コーンビームCTを用いた上下顎歯の三次元歯軸角度の特徴

石井義人, 坂本信, 坂上勇太, 亀田剛, 森清友亮, 小林公一, 坂井幸子, 遠藤英昭, 平元和彦

臨床バイオメカニクス 43 339 - 344 2022.10

Language：Japanese Publisher：(一社)日本臨床バイオメカニクス学会

正常咬合者13名の上下顎骨を撮影したコーンビームCT画像の三次元骨モデルの3点の特徴点から口腔内に三次元ワールド座標系を設定し,横断面,冠状面および矢状面を定めた.そして,歯形状より主成分分析法によって三次元歯軸を求めた.歯軸を3平面上に投影して,各平面内での上下顎全歯の対向する同名歯種の歯軸のなす角度である交角度を求めた.さらに,異なる歯種間の交角度の関係について示した.その結果,投影した平均交角度は3平面内においていずれも正中面に対してほぼ左右対称の傾向を示した.横断面および矢状面内の交角度は前歯では小さく,第二小臼歯,第一大臼歯,第二大臼歯では,他歯種と比べて交角度は大きい.一方,異なる歯種間の交角度の相関は,横断面内の中切歯,側切歯,犬歯では隣接する歯種間に有意な正の相関が認められた.矢状面内では,第二大臼歯以外は多くの歯種間で交角度の相関がみられることを明らかにした.(著者抄録)

Assessment of knee collateral ligament stiffness by strain ultrasound elastography

Surangika Wadugodapitiya, Makoto Sakamoto, Masaei Tanaka, Yuta Sakagami, Yusuke Morise, Koichi Kobayashi

Bio-Medical Materials and Engineering 1 - 13 2022.3

Publishing type：Research paper (scientific journal) Publisher：IOS Press

BACKGROUND: Knowledge of the biomechanics of the normal collateral ligaments is important to secure optimal stability of the knee following injury. Various in vitro methods have been described in evaluating the biomechanics of these ligaments. However, a method of direct evaluation has not been reported. OBJECTIVE: To determine the stiffness characteristics of the collateral ligaments of the knee using strain ultrasound elastography. METHODS: Strain ultrasound elastography was performed on different components of the collateral ligaments in various angles of knee flexion in 18 healthy males (36 ligaments). We measured relative stiffness of the ligaments using strain ratio (SR = target tissue strain/reference strain). A lower strain ratio indicates higher relative stiffness. RESULTS: There was moderate to excellent intra- and inter-rater agreement for strain ratio measurements in all ligament portions. Strain ratios were lowest at 0° in all three ligaments, indicating high relative stiffness. In the superficial and deep medial collateral ligaments, the strain ratio increased with increasing knee flexion, whereas in the lateral collateral ligament, stiffness showed a tendency to fluctuate. CONCLUSION: Strain ultrasound elastography is a reliable tool for monitoring relative stiffness of the collateral ligaments of the knee and is easily applied to the routine clinical setting.

DOI： 10.3233/bme-211282

Experimental determination of static and dynamic Young’s moduli of healthy and degenerated bovine articular cartilage using the split-Hopkinson pressure bar

Takahiro MORI, Hiroto SAKURAI, Koichi KOBAYASHI, Makoto SAKAMOTO, Yuji TANABE

Mechanical Engineering Journal 9 ( 2 ) 21 - 00400 2022

コーンビームCTによる三次元歯軸の解析

坂上勇太, 坂本信, 森清友亮, 亀田剛, 小林公一, 坂井幸子, 遠藤英昭, 田邊裕治

臨床バイオメカニクス 42 79 - 85 2021.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

本研究では、成人10名の上下顎骨を撮影したコーンビームCT画像から骨モデルを三次元再構成し、解剖学的特徴箇所である下顎両側オトガイ孔2点および上顎切歯管1点を利用して口腔内に三次元ワールド座標系を構築し、全ての歯の三次元モデルを作成した。各歯の幾何学的重心(COG)と主成分分析法で計算した歯軸(PC-A)を求め、空間内のCOGとPC-Aを横断面、冠状面および矢状面上に投影して、各平面内でのPC-A角度とCOGによる歯列を示した。その結果、冠状面では、上顎歯は全て頬側に歯が傾き、下顎歯は、中切歯、側切歯、犬歯、第一小臼歯は頬側に向いているが、第二小臼歯、第一、第二大臼歯は舌側を向く。矢状面では、上顎歯は第二大臼歯だけが遠心側に傾いているのに対し、下顎歯は全て近心側に傾くという一般的な正常咬合者の特徴を定量的に明らかにした。さらに、3平面内におけるCOG位置とPC-A角度との関係を表す回帰曲線は、簡潔な多項式で表現できることを示した。(著者抄録)

荷重-非荷重における大腿骨脛骨間の相対位置変化解析変形性膝関節症の進行との関連

森清友亮, 森隆裕, 古賀良生, 望月友晴, 大森豪, 小林公一, 坂本信, 田邊裕治

臨床バイオメカニクス 42 63 - 66 2021.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

変形性膝関節症(膝OA)の異常運動lateral thrust(LT)はOA進行要因として主に歩行解析や筋力との関連で検討される。3次元アライメント評価を行った非OAと進行期OA女性各15例に対し、非荷重位(臥位:CT撮像位)と荷重位(立位:2方向X線画像と骨3DCTモデルのマッチング)間における大腿骨・脛骨間の相対位置変化を冠状面方向で評価した。非OA、OAの両例において非荷重位と立位荷重位を比較すると、荷重により脛骨内側関節面が大腿骨関節面に接近した位置にあり、脛骨は大腿骨に対して外側に位置していた。また、側方への移動量は非OAに比してOAが大きいことを確認した。膝OAのLTは脛骨近位内側関節面への偏荷重を荷重面水平化の方向に位置修正を行い、その際大腿骨内側関節接触点を中心とした脛骨の相対位置移動としての評価が可能なことを示唆した。(著者抄録)

Other Link： https://search-tp.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2021&ichushi_jid=J05471&link_issn=&doc_id=20211007090011&doc_link_id=%2Fcx9biomc%2F2021%2F004200%2F012%2F0063-0066%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fcx9biomc%2F2021%2F004200%2F012%2F0063-0066%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

膝前後単純X画像における変形性膝関節症進行度の定量的評価システムの開発と信頼性の検討

森隆裕, 坂上勇太, 望月友晴, 古賀良生, 森清友亮, 古賀寛, 大森豪, 小林公一, 坂本信, 田邊裕治

臨床バイオメカニクス 42 39 - 43 2021.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

大規模集団検診(松代膝検診)で確認した変形性膝関節症(膝OA)進行に伴う膝前後単純X線画像上の下腿骨位置や形状の定量的評価で膝OA進行度判定が可能と考え、半自動評価システムを開発した。松代膝検診第5回(2007年)から12年間の5回をすべて受診した対象のうち、任意で抽出した男女各10名の単純X線画像を対象に測定の信頼性を評価および従来の手動デジタイズ法との測定精度と測定時間を比較検討した。測定の信頼性として検者内では級内相関係数:ICC=0.98、検者間ではICC=0.96、従来法との比較でもICC=0.96と高い信頼性を示した。また、評価指標で、脛骨関節面傾斜、関節裂隙幅比の減少、脛骨内側皮質骨幅比の増加、FTAの増加など過去に報告した膝OA進行に伴う変化が算出された。特に、骨の参照軸の自動抽出により測定値の安定とこれによる測定時間が約1/3に短縮した。(著者抄録)

Other Link： https://search-tp.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2021&ichushi_jid=J05471&link_issn=&doc_id=20211007090007&doc_link_id=%2Fcx9biomc%2F2021%2F004200%2F008%2F0039-0043%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fcx9biomc%2F2021%2F004200%2F008%2F0039-0043%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

コーンビームCTによる三次元歯軸の解析

坂上勇太, 坂本信, 森清友亮, 亀田剛, 小林公一, 坂井幸子, 遠藤英昭, 田邊裕治

臨床バイオメカニクス 42 79 - 85 2021.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

本研究では、成人10名の上下顎骨を撮影したコーンビームCT画像から骨モデルを三次元再構成し、解剖学的特徴箇所である下顎両側オトガイ孔2点および上顎切歯管1点を利用して口腔内に三次元ワールド座標系を構築し、全ての歯の三次元モデルを作成した。各歯の幾何学的重心(COG)と主成分分析法で計算した歯軸(PC-A)を求め、空間内のCOGとPC-Aを横断面、冠状面および矢状面上に投影して、各平面内でのPC-A角度とCOGによる歯列を示した。その結果、冠状面では、上顎歯は全て頬側に歯が傾き、下顎歯は、中切歯、側切歯、犬歯、第一小臼歯は頬側に向いているが、第二小臼歯、第一、第二大臼歯は舌側を向く。矢状面では、上顎歯は第二大臼歯だけが遠心側に傾いているのに対し、下顎歯は全て近心側に傾くという一般的な正常咬合者の特徴を定量的に明らかにした。さらに、3平面内におけるCOG位置とPC-A角度との関係を表す回帰曲線は、簡潔な多項式で表現できることを示した。(著者抄録)

Other Link： https://search-tp.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2021&ichushi_jid=J05471&link_issn=&doc_id=20211007090014&doc_link_id=%2Fcx9biomc%2F2021%2F004200%2F015%2F0079-0085%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fcx9biomc%2F2021%2F004200%2F015%2F0079-0085%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

荷重-非荷重における大腿骨脛骨間の相対位置変化解析変形性膝関節症の進行との関連

森清友亮, 森隆裕, 古賀良生, 望月友晴, 大森豪, 小林公一, 坂本信, 田邊裕治

臨床バイオメカニクス 42 63 - 66 2021.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

変形性膝関節症(膝OA)の異常運動lateral thrust(LT)はOA進行要因として主に歩行解析や筋力との関連で検討される。3次元アライメント評価を行った非OAと進行期OA女性各15例に対し、非荷重位(臥位:CT撮像位)と荷重位(立位:2方向X線画像と骨3DCTモデルのマッチング)間における大腿骨・脛骨間の相対位置変化を冠状面方向で評価した。非OA、OAの両例において非荷重位と立位荷重位を比較すると、荷重により脛骨内側関節面が大腿骨関節面に接近した位置にあり、脛骨は大腿骨に対して外側に位置していた。また、側方への移動量は非OAに比してOAが大きいことを確認した。膝OAのLTは脛骨近位内側関節面への偏荷重を荷重面水平化の方向に位置修正を行い、その際大腿骨内側関節接触点を中心とした脛骨の相対位置移動としての評価が可能なことを示唆した。(著者抄録)

膝前後単純X画像における変形性膝関節症進行度の定量的評価システムの開発と信頼性の検討

森隆裕, 坂上勇太, 望月友晴, 古賀良生, 森清友亮, 古賀寛, 大森豪, 小林公一, 坂本信, 田邊裕治

臨床バイオメカニクス 42 39 - 43 2021.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

大規模集団検診(松代膝検診)で確認した変形性膝関節症(膝OA)進行に伴う膝前後単純X線画像上の下腿骨位置や形状の定量的評価で膝OA進行度判定が可能と考え、半自動評価システムを開発した。松代膝検診第5回(2007年)から12年間の5回をすべて受診した対象のうち、任意で抽出した男女各10名の単純X線画像を対象に測定の信頼性を評価および従来の手動デジタイズ法との測定精度と測定時間を比較検討した。測定の信頼性として検者内では級内相関係数:ICC=0.98、検者間ではICC=0.96、従来法との比較でもICC=0.96と高い信頼性を示した。また、評価指標で、脛骨関節面傾斜、関節裂隙幅比の減少、脛骨内側皮質骨幅比の増加、FTAの増加など過去に報告した膝OA進行に伴う変化が算出された。特に、骨の参照軸の自動抽出により測定値の安定とこれによる測定時間が約1/3に短縮した。(著者抄録)

In vivo stiffness assessment of patellar and quadriceps tendons by strain ultrasound elastography

Surangika Wadugodapitiya, Makoto Sakamoto, Sayaka Suzuki, Yusuke Morise, Koichi Kobayashi

Bio-Medical Materials and Engineering 1 - 10 2021.5

Publishing type：Research paper (scientific journal) Publisher：IOS Press

BACKGROUND: The patellar and quadriceps tendons are responsible for the extension mechanism of the knee joint and frequently become inflamed during sports. Diagnosis and determination of when an athlete can return to sports following these injuries are usually performed by assessing morphological features and functional outcomes. Nevertheless, mechanical properties are not being assessed. OBJECTIVE: To describe the stiffness characteristics of these two tendons over the range of knee flexion and to test the feasibility of using strain ultrasound elastography (SE). METHODS: SE with an acoustic coupler as the reference was performed for nine healthy males. Relative stiffness measurements were obtained using the strain ratio (SR = target tissue strain/reference strain) by placing the knee in five different flexion angles. Lower SR indicates higher relative stiffness. RESULTS: This study showed reliable measurement with good intra- and inter-rater agreement for SR at 30°. SR of the quadriceps tendon decreases as knee flexion increases, indicating increased relative stiffness. In the patellar tendon, no significant difference was observed between 30° and 60°. Beyond 60°, relative stiffness increased constantly. CONCLUSIONS: SE is a reproducible and feasible tool to monitor relative stiffness of the patellar and quadriceps tendons in routine clinical settings.

DOI： 10.3233/bme-206016

Influence of lumbosacral transitional vertebrae on spinopelvic parameters using biplanar slot scanning full body stereoradiography―analysis of 291 healthy volunteers

Masashi Okamoto, Kazuhiro Hasegawa, Shun Hatsushikano, Koichi Kobayashi, Makoto Sakamoto, Masayuki Ohashi, Kei Watanabe

Journal of Orthopaedic Science 2021.5

【運動器のバイオメカニクス-Cutting Edge 2021:新しい解析手法と知見】その他の新しい手法コーンビームCT画像を用いた新たな三次元歯列決定法

坂本信, 坂上勇太, 森清友亮, 亀田剛, 小林公一, 田邊裕治

整形・災害外科 64 ( 5 ) 691 - 697 2021.4

Language：Japanese Publisher：金原出版(株)

＜文献概要＞本解説では,上下顎骨を撮影したコーンビームCT画像を用いてわれわれが考案した個人特有の三次元口腔内ワールド座標系に基づき,歯の形状重心から求めた三次元歯列を表現し,歯の三次元形状から主成分分析法で数学的に求めた歯の長軸方向である三次元歯軸も併せて示す新たな解析方法について述べた。はじめに,コーンビームCT画像の下顎の両側オトガイ孔2点と上顎切歯管1点を用いた解剖学的特徴点から構築した個人ごとの三次元口腔内ワールド座標系を新たに定義した。次に,正常咬合者を対象に歯列曲線や歯軸を口腔内座標系に基づいて定量的に表現した解析結果例より,上下顎歯列に対して,横断面では4次偶多項式,冠状面では6次偶多項式,矢状面では3次多項式でそれぞれの面内の歯列を数学的に表現できることを示した。

New evaluation indices for rotational knee angles in standing anteroposterior knee radiographs. International journal

Takahiro Mori, Tomoharu Mochizuki, Yoshio Koga, Hiroshi Koga, Koichi Kobayashi, Ryota Katsumi, Makoto Sakamoto, Go Omori, Yuji Tanabe

Bio-medical materials and engineering 32 ( 2 ) 85 - 99 2021

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Identifying the time course of rotational knee alignment is crucial for elucidating the etiology in knee osteoarthritis. OBJECTIVE: The aim of this study was to propose new rotational indices for calculating the change in relative rotational angles between the femur and tibia in standing anteroposterior (AP) radiographs. METHODS: Forty healthy elderly volunteers (20 women and 20 men; mean age, 70 ± 6 years) were assessed. The evaluation parameters were as follows: (1) femoral rotational index: the distance between the sphere center of the medial posterior femoral condyle and the lateral edge of the patella, and (2) tibial rotational index: the distance between the medial eminence of the tibia and the lateral edge of the fibula head. The indices were standardized by the diameter of the sphere of the medial posterior femoral condyle. This study (1) identified the relationship between changes in rotational indices and the simulated rotational knee angles in the standing position, (2) proposed a regression equation for the change in relative rotational angles between the femur and tibia in standing AP radiographs, and (3) verified the accuracy of the regression equation. RESULTS: The rotational indices increased in direct proportion to simulated rotational knee angles (femoral index: r > 0.9,p < 0.0001; tibial index: r > 0.9, p < 0.0001). Based on the results, the regression equation with the accuracy of 0.45 ± 0.26° was determined. CONCLUSIONS: The proposed regression equations can potentially predict the change in relative rotational angles between the femur and tibia in a pair of standing AP radiographs taken at different dates in longitudinal studies.

DOI： 10.3233/BME-201138

The inclination of the femoral medial posterior condyle was almost vertical and that of the lateral was tilted medially. International journal

Sho Hokari, Osamu Tanifuji, Koichi Kobayashi, Tomoharu Mochizuki, Ryota Katsumi, Takashi Sato, Naoto Endo

Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA 28 ( 12 ) 3858 - 3864 2020.12

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: The purpose of this study was to three-dimensionally analyse the size and shape of the femoral posterior condyles of the normal knee. METHODS: A total of 62 healthy Japanese volunteers (37 males and 25 females) providing a sample of 124 normal knee joints, who had no knee-related symptoms and no history of major trauma, underwent computed tomography scans of the bilateral femur and tibia. Three-dimensional digital models of the femur were constructed from computed tomography data using visualisation and modelling software. The following parameters were evaluated: (1) the radii of the posterior condyles approximated to spheres and (2) the inclination angle of the posterior condyles in the coronal plane of the femoral coordinate system. RESULTS: The radii of the medial and lateral condyles approximated to spheres were 17.0 ± 1.6 and 17.1 ± 1.8 mm, respectively and were not different. The inclination angles of the medial and lateral condyles in the coronal plane were - 0.6° ± 4.6° and 9.7° ± 5.7°, respectively. The medial condyle was almost vertical, whereas the lateral one was medially tilted. CONCLUSIONS: This study found an asymmetrical inclination between medial and lateral condyles. This may be related to the asymmetrical motion of the knee, which is known as medial pivot motion. This finding provides valuable morphological information and may be useful for implant designs for total knee arthroplasty. LEVEL OF EVIDENCE: IV.

DOI： 10.1007/s00167-020-05856-2

Cortical thickness of the tibial diaphysis reveals age- and sex-related characteristics between non-obese healthy young and elderly subjects depending on the tibial regions. International journal

Keisuke Maeda, Tomoharu Mochizuki, Koichi Kobayashi, Osamu Tanifuji, Keiichiro Someya, Sho Hokari, Ryota Katsumi, Yusuke Morise, Hiroshi Koga, Makoto Sakamoto, Yoshio Koga, Hiroyuki Kawashima

Journal of experimental orthopaedics 7 ( 1 ) 78 - 78 2020.10

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: This study aimed to evaluate the age- and sex-related characteristics in cortical thickness of the tibial diaphysis between non-obese healthy young and elderly subjects as reference data. METHODS: The study investigated 31 young subjects (12 men and 19 women; mean age, 25 ± 8 years) and 54 elderly subjects (29 men and 25 women; mean age, 70 ± 6 years). Three-dimensional estimated cortical thickness of the tibial diaphysis was automatically calculated for 5000-9000 measurement points using the high-resolution cortical thickness measurement from clinical computed tomography data. In 12 assessment regions created by combining three heights (proximal, central, and distal diaphysis) and four areas of the axial plane at 90° (medial, anterior, lateral, and posterior areas) in the tibial coordinate system, the standardized thickness was assessed using the tibial length. RESULTS: As structural characteristics, there were no differences in the medial and lateral thicknesses, while the anterior thickness was greater than the posterior thickness in all groups. The sex-related difference was not shown. As an age-related difference, elderly subjects showed greater or lesser cortical thickness than the young subjects, depending on the regions of the tibia. CONCLUSIONS: Cortical thickness was different depending on sex, age, and regions in the tibia. The results of this study are of clinical relevance as reference points to clarify the causes of various pathological conditions for diseases. LEVEL OF EVIDENCE: Level 3.

DOI： 10.1186/s40634-020-00297-9

Articular surface of the medial proximal tibia is aligned parallel to the ground in three-dimensional space under weight-bearing conditions in healthy and varus osteoarthritic knees. International journal

Tomoharu Mochizuki, Yoshio Koga, Takahiro Mori, Katsutoshi Nishino, Koichi Kobayashi, Osamu Tanifuji, Takashi Sato, Ryota Katsumi, Hiroshi Koga, Go Omori, Yuji Tanabe

Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA 28 ( 10 ) 3232 - 3239 2020.10

Language：English Publishing type：Research paper (scientific journal)

PURPOSE: To test the hypothesis that an inclined articular surface on the medial proximal tibia is aligned more parallel to the ground in three-dimensional (3D) space under weight-bearing (WB) conditions (parallel phenomenon) than under non-WB (NWB) conditions in healthy and varus osteoarthritic knees. METHODS: We examined 55 healthy knees (26 women, 29 men; mean age, 70 ± 6 years) and 108 varus osteoarthritic knees (66 women, 16 men; mean age, 74 ± 7 years). For the evaluation under WB conditions, a 3D assessment system was used on biplanar long-leg radiographs and 3D bone models using a 3D-to-2D image registration technique. In addition, the least square method was used to determine the approximation plane. The angles between the normal vector for the approximation plane of an articular surface on the medial proximal tibia and each axis of the tibial or world coordinate system were calculated. RESULTS: Morphologically, the inclination of the approximation plane was steeper in osteoarthritic knees than in healthy knees (p < 0.0001). The approximation plane was aligned more parallel to the ground under WB conditions than under NWB conditions in healthy (p < 0.0001) and osteoarthritic knees (p < 0.0001). CONCLUSIONS: The parallel phenomenon in the medial proximal tibia was confirmed for healthy and varus osteoarthritic knees. The medial proximal tibia plays an important role in the parallel phenomenon, assumingly associated with varus alignment and varus thrust. The inclination of the medial proximal tibia may become a new parameter for imaging investigations. LEVEL OF EVIDENCE: III.

DOI： 10.1007/s00167-019-05829-0

変形性膝関節症初期変化のX線前後画像についての定量的縦断検討

森隆裕, 古賀良生, 望月友晴, 古賀寛, 小林公一, 大森豪, 田邊裕治

臨床バイオメカニクス 41 121 - 126 2020.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

変形性膝関節症の初期における下肢アライメントや骨形態変化を明らかにするために、大規模集団検診(松代膝検診)の第5回から8回目(2007年から2016年)においてK-L分類grade 0および1からgrade 2へと移行した142名237膝(男性65名111膝、女性77名126膝、平均年齢71.2±7.4歳)の立位膝前後X線画像を調査した。1)内外側関節裂隙幅比、2)脛骨軸傾斜角度、3)FTA、4)大腿骨と脛骨間の相対的な回旋角度を縦断的に評価した。その結果、内側関節裂隙の狭小、外側の拡大、FTAの増加、脛骨軸傾斜角度の減少はgradeの進行に伴いすべて有意な変化を示し、加えて大腿骨が脛骨に対して外旋する傾向がみられた。また、脛骨軸傾斜がFTAと外側関節裂隙幅比との相関を示し、脛骨の内側傾斜の増大が膝関節の内反変形の初期変化として、大腿-脛骨間のアライメント変化に影響を及ぼし、内反変形の進行の一因となっていることが示唆された。(著者抄録)

変形性膝関節症初期変化のX線前後画像についての定量的縦断検討

森隆裕, 古賀良生, 望月友晴, 古賀寛, 小林公一, 大森豪, 田邊裕治

臨床バイオメカニクス 41 121 - 126 2020.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

変形性膝関節症の初期における下肢アライメントや骨形態変化を明らかにするために、大規模集団検診(松代膝検診)の第5回から8回目(2007年から2016年)においてK-L分類grade 0および1からgrade 2へと移行した142名237膝(男性65名111膝、女性77名126膝、平均年齢71.2±7.4歳)の立位膝前後X線画像を調査した。1)内外側関節裂隙幅比、2)脛骨軸傾斜角度、3)FTA、4)大腿骨と脛骨間の相対的な回旋角度を縦断的に評価した。その結果、内側関節裂隙の狭小、外側の拡大、FTAの増加、脛骨軸傾斜角度の減少はgradeの進行に伴いすべて有意な変化を示し、加えて大腿骨が脛骨に対して外旋する傾向がみられた。また、脛骨軸傾斜がFTAと外側関節裂隙幅比との相関を示し、脛骨の内側傾斜の増大が膝関節の内反変形の初期変化として、大腿-脛骨間のアライメント変化に影響を及ぼし、内反変形の進行の一因となっていることが示唆された。(著者抄録)

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Age- and sex-related characteristics in cortical thickness of femoral diaphysis for young and elderly subjects. Reviewed

Keiichiro Someya, Tomoharu Mochizuki, Sho Hokari, Osamu Tanifuji, Ryota Katsumi, Hiroshi Koga, Yuki Takahashi, Koichi Kobayashi, Yusuke Morise, Makoto Sakamoto, Yoshio Koga, Naoto Endo

Journal of bone and mineral metabolism 38 ( 4 ) 533 - 543 2020.1

Language：English Publishing type：Research paper (scientific journal)

INTRODUCTION: Cortical thickness of the femoral diaphysis is assumed to be a preferred parameter in the assessment of the structural adaptation by mechanical use and biological factors. This study aimed to investigate the age- and sex-specific characteristics in cortical thickness of the femoral diaphysis between young and elderly non-obese people. MATERIALS AND METHODS: This study investigated 34 young subjects (21 men and 13 women; mean age: 27 ± 8 years) and 52 elderly subjects (29 men and 23 women; mean age: 70 ± 6 years). Three-dimensional (3D) cortical thickness of the femoral diaphysis was automatically calculated for 5000-8000 measurement points using the high-resolution cortical thickness measurement from clinical CT data. In 12 assessment regions created by combining three heights (proximal, central, and distal diaphysis) and four areas of the axial plane at 90° (medial, anterior, lateral, and posterior areas) in the femoral coordinate system, the standardized thickness was assessed using the femoral length. RESULTS: As per the trends, (1) there were no differences in medial and lateral thicknesses, while the posterior thickness was greater than the anterior thickness, (2) the thickness in men was higher than that in women, and (3) the thickness in young subjects was higher than that in elderly subjects. CONCLUSIONS: The results of this study are of clinical relevance as reference points to clarify the causes of various pathological conditions for diseases of the lower extremities.

DOI： 10.1007/s00774-019-01079-9

Three-dimensional In Vivo Analysis of the Trapeziometacarpal Joint Contact Behavior Using Magnetic Resonance Imaging Reviewed

MORISE Yusuke, SAKAMOTO Makoto, SAKAGAMI Yuta, KAZAMA Kiyoko, KOBAYASHI Koichi, TANABE Yuji

Journal of the Japanese Society for Experimental Mechanics 20 ( 1 ) 39 - 44 2020

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Experimental Mechanics

<p> Trapeziometacarpal joint (TMC joint) of thumb is one of the joints having a complicated shape which enables to generate a wide variation of finger movements in daily life. It is important to clarify the accurate in vivo contact behavior of healthy TMC joint when evaluating post-operative joint movements. Thus, author analyzed TMC joint contact behavior in 4 different finger positions of 8 healthy adult males using magnetic resonance imaging (MRI) system. From MR images, three-dimensional bone models were constructed and a three-dimensional coordinate system was defined by the characteristic shape of each bone model. Then, three bone axial angles and three-dimensional bone motion of each 4 positions in the TMC joint were calculated: abduction-adduction, extension-flexion, pronation-supination, and Euler angles. Furthermore, contact areas of the articular cartilage in each of 4 positions were clarified from MR images. Results have shown that, the contact area changed with changing of the thumb position and it was maximum oat the thumb extension. In addition, it was clarified that the contact area moved according to the thumb position.</p>

DOI： 10.11395/jjsem.20.39

Evaluation of dynamic knee joint alignment using a one-way frontal video method Reviewed

Kensaku KAWAKAMI, Takahiko NAKAMURA, Katsumi HAMA, Koichi KOBAYASHI, Makoto SAKAMOTO

Journal of Biomechanical Science and Engineering 2020

大腿脛骨関節における立位屈曲初期での相対運動と軟骨接触挙動評価 Reviewed

中原大輔, 小林公一, 坂本信, 佐藤卓, 渡邉聡, 大森豪, 古賀良生, PRAMUDITA Jonas Aditya, 田邊裕治

臨床バイオメカニクス 40 95‐100 2019.10

コーンビームCTを用いた新たな三次元歯列弓の定義 Reviewed

坂上勇太, 坂本信, 森清友亮, 亀田剛, 小林公一, 坂井幸子, 遠藤英昭, 田邊裕治

臨床バイオメカニクス 40 281‐288 - 288 2019.10

立位下肢アライメントと床反力測定による下肢機能軸と荷重方向の三次元評価法の提案 Reviewed

藤原靖, 森清友亮, 中原大輔, 小林公一, 坂本信, 田邊裕治, PRAMUDITA Jonas, Aditya, 佐藤卓, 大森豪, 湊泉, 古賀良生

臨床バイオメカニクス 40 121‐125 - 125 2019.10

早期変形性膝関節症の立位膝X線画像における大腿骨・脛骨間の相対的回旋変化の縦断的評価

森隆裕, 古賀良生, 大森豪, 望月友晴, 古賀寛, 小林公一, プラムディタ・ジョナス・アディティヤ, 田邊裕治

臨床バイオメカニクス 40 107 - 111 2019.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

二次元X線画像から大腿・脛骨間の相対的な回旋を評価するため、変形性膝関節症疫学調査(松代膝検診)の第5回から8回(2007年から2016年)においてK-L分類grade 0からgrade 2へ移行した26名41膝の立位膝X線像を対象とし、大腿骨内側顆長軸の長さ(M)、大腿骨内側顆長軸から膝蓋骨外側縁までの距離(P)、脛骨内側顆間隆起近位端から腓骨頭外側縁までの距離(F)を用いた「大腿骨回旋指標(P/M)」および「脛骨回旋指標(F/M)」を用いて大腿・脛骨間の相対回旋角度を算出した。その結果、grade 0からgrade 2へと進行する過程で、41膝中31膝(76%)が大腿骨に対して脛骨が内旋傾向であった。健常から早期OAへの過程で大腿骨・脛骨間の相対的な回旋変化がOAの進行の要因の一つとして推察され、内反変形との関連の調査が必要である。(著者抄録)

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大腿骨後顆関節形状の検討

穂苅翔, 谷藤理, 望月友晴, 小林公一, 遠藤直人

日本整形外科学会雑誌 93 ( 8 ) S1717 - S1717 2019.9

Relative position of sacral base in the pelvis and its correlation with spino-pelvic parameters. Reviewed

Okamoto M, Hasegawa K, Hatsushikano S, Watanabe K, Shimoda H, Kobayashi K, Sakamoto M

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society 29 ( 3 ) 446 - 454 2019.8

A Dynamic Method of Measuring the Length of the Patellar Tendon Using Cine Magnetic Resonance Imaging Reviewed

Tatsuya KONDO, Makoto SAKAMOTO, Koichi KOBAYASHI, Surangika, WADUGODAPITIYA

Advanced Experimental Mechanics 4 157 - 162 2019.8

In Vivo Stiffness Characteristics of the Medial Collateral Ligament with Varying Knee Flexion Angles Using Strain Ultrasound Elastography Reviewed

Surangika WADUGODAPITIYA, Makoto SAKAMOTO, Masaei TANAKA, Yuta SAKAGAMI, Yusuke MORISE, Koichi KOBAYASHI

Advanced Experimental Mechanics 4 147 - 152 2019.8

破壊力学の展開円形き裂の三次元弾性理論解析

坂本信, 三浦鴻太郎, 小林公一, PRAMUDITA Jonas A, 田邊裕治

非破壊検査 68 ( 4 ) 173‐179 - 179 2019.4

Effect on inclined medial proximal tibial articulation for varus alignment in advanced knee osteoarthritis. Reviewed International journal

Mochizuki T, Koga Y, Tanifuji O, Sato T, Watanabe S, Koga H, Kobayashi K, Omori G, Endo N

Journal of experimental orthopaedics 6 ( 1 ) 14 - 14 2019.3

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: The inclination of the medial compartment of the proximal tibia (MCT) is assumed to be a critical factor for varus alignment in advanced knee osteoarthritis (OA). This study was aimed at investigating; (1) whether the inclination of MCT is aligned parallel to the ground under weight-bearing (WB) conditions; (2) whether this is associated with the change in alignment and the relative position between the bones; and (3) whether the tibia or femur mainly contributes to the changes. METHODS: We examined 102 knees (84 women, 18 men; mean 75 years). A three-dimensional (3D) assessment system was applied on biplanar whole lower extremity radiographies using 3D-to-2D image registration technique. The evaluation parameters were 1) MCT angle, 2) femorotibial angle (FTA), 3) medial-lateral femoral location to the tibia (M-L femoral location), 4) WB line passing point, and 5) tibial position to WB line (tibial position) and 6) femoral postion to WB line (femoral position). Each parameter was evaluated in non-WB and WB conditions, and the differences (Δ-parameters). RESULTS: MCT angle in the world coordinate system was larger than that in the tibial coordinate system (p < 0.0001). ΔMCT angle was correlated with ΔFTA (p = 0.002) and ΔM-L femoral location (p = 0.004). The tibial position was the more dominant factor for ΔMCT angle (p = 0.001), ΔFTA (p < 0.0001), and ΔWB line passing point (p < 0.0001) . CONCLUSIONS: The inclination in MCT was aligned parallel to the ground under WB conditions (tibial parallel phenomenon). The parallel phenomenon was associated with the change of alignment and the relative position between the bones in the coronal plane. These phenomena were produced mainly by the tibia, not the femur. LEVEL OF EVIDENCE: Level IV.

DOI： 10.1186/s40634-019-0180-x

進行期変形性膝関節症患者における脛骨近位内側関節面の水平化機序三次元評価による臥位と立位の比較

望月友晴, 谷藤理, 古賀良生, 森隆弘, 小林公一, 古賀寛, 大森豪, 遠藤直人

日本整形外科学会雑誌 93 ( 3 ) S587 - S587 2019.3

健常例における三次元大腿骨皮質骨幅計測と比較検討若年男女vs.高齢男女

染矢圭一郎, 望月友晴, 穂苅翔, 谷藤理, 遠藤直人, 小林公一

日本整形外科学会雑誌 93 ( 3 ) S743 - S743 2019.3

MRIの3次元撮像法とCine法のイメージマッチングを用いた膝蓋腱の長さ変化測定

近藤達也, 坂本信, 小林公一, 金沢勉, 斉藤宏明

日本放射線技術学会総会学術大会予稿集 75回 149 - 149 2019.3

Ultrasound elastographic assessment of the stiffness of the anteromedial knee joint capsule at varying knee angles. Reviewed International journal

Surangika Wadugodapitiya, Makoto Sakamoto, Kaito Sugita, Yusuke Morise, Masaei Tanaka, Koichi Kobayashi

Bio-medical materials and engineering 30 ( 2 ) 219 - 230 2019

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: In vivo evaluation of the elastic properties of the knee joint capsule has not been adequately performed. OBJECTIVES: To establish a methodology to assess the stiffness of the normal knee joint capsule over a range of knee flexion angles using ultrasound elastography. METHODS: Ultrasound elastography with an acoustic coupler was used to assess the stiffness of the anteromedial capsule of the knee joints of 10 male (mean age 22.63 ± 1.02 years) and 10 female (mean age 21.6 ± 0.8 years) subjects at static knee flexion angles of 0°, 45°, 90°, and 120°. Relative stiffness of the capsule was obtained using the strain ratio (SR), defined as the ratio of the strain in the capsule to that in the acoustic coupler. RESULTS: The intraclass correlation coefficient (1, 3) ranged from 0.95 to 0.96, and the correlation coefficient between examiners (2, 3) was 0.94. SR values decreased significantly as the flexion angle increased (P < 0.01). At 90° and 120°, it was significantly higher in female than in male subjects (P < 0.01). CONCLUSIONS: This study established a feasible and reproducible method to obtain the stiffness characteristics of the anteromedial knee joint capsule using ultrasound elastography with an acoustic coupler.

DOI： 10.3233/BME-191046

In Vivo Strain Ultrasound Elastographic Assessment of the Stiffness of the Medial Collateral Ligament at Varying Knee Flexion Angles

SAKAMOTO Makoto, WADUGODAPITIYAI Surangika, MORISE Yusuke, TANAKA Masaei, KOBAYASHI Koichi

The Proceedings of Mechanical Engineering Congress, Japan 2019 J02513 2019

DRR画像を用いた二次元画像上の大腿骨・脛骨間の回旋評価法の精度検証

森隆裕, 古賀良生, 小林公一, 古賀寛, 望月友晴, 勝見亮太, 大森豪, PRAMUDITA Jonas Aditya, 田邊裕治

臨床バイオメカニクス 39 125‐129 - 129 2018.10

コーンビームCTによる前歯部の三次元自動歯軸および歯列決定法

坂本信, 坂上勇太, 森清友亮, 亀田剛, 小林公一, 坂井幸子, 遠藤英昭

臨床バイオメカニクス 39 207‐216 - 216 2018.10

核磁気共鳴画像法を用いた母指指節間関節および中手指節関節の三次元生体内接触運動解析

杉田魁人, 坂本信, 森清友亮, 風間清子, 小林公一, 田邊裕治

臨床バイオメカニクス 39 237‐246 - 246 2018.10

骨盤姿勢を考慮した三次元下肢アライメント評価の精度検証

五十嵐良樹, 佐藤卓, 小林公一, 田邊裕治, PRAMUDITA Jonas Aditya

臨床バイオメカニクス 39 149‐152 2018.10

大腿脛骨軟骨間の接触動態と相対滑り量の検討

中原大輔, 小林公一, 坂本信, 佐藤卓, 渡邉聡, 大森豪, 古賀良生, PRAMUDITA Jonas Aditya, 田邊裕治

臨床バイオメカニクス 39 299‐303 2018.10

二方向スロットラジオグラフィを用いた自動イメージマッチング法の開発

岡庭大祐, 中原大輔, 小林公一, 坂本信, 田邊裕治, PRAMUDITA Jonas, Aditya, 佐藤卓, 大森豪, 湊泉, 古賀良生

臨床バイオメカニクス 39 143‐148 2018.10

Analytical solution of axisymmetric indentation of an elastic layer-substrate body Reviewed

Kotaro MIURA, Makoto SAKAMOTO, Koichi KOBAYASHI, Jonas A, PRAMUDITA, Yuji TANABE

Theretical and Applied Mechanics 67 81 - 101 2018.10

Language：English Publishing type：Research paper (scientific journal) Publisher：National Committee for IUTAM

We focus on an elastic contact problem for indentation of a layer-substrate body. An elastic layer assumed to be perfectly bonded to an elastic semi-infinite substrate. The elastic layer is smoothly indented with a flat-ended cylindrical indenter and a spherical indenter. The analytical and exact solutions are obtained by solving an infinite system of simultaneous equations using the method to express a normal contact stress at the upper surface of the elastic layer as an appropriate series. This paper presents not only the axial load but also the distribution of the dimensionless normal contact stress under cylindrical and spherical indentation, the distribution of the dimensionless normal displacement at the upper surface of the elastic layer and the stress singularity factor. Numerical results are given for several combinations of the ratio of shear modulus and Poisson’s ratios of the elastic layer and substrate, and the thickness of the elastic layer.

DOI： 10.11345/nctam.64.81

Correlation between posterior tibial slope and sagittal alignment under weight-bearing conditions in osteoarthritic knees Reviewed International journal

Mochizuki Tomoharu, Tanifuji Osamu, Koga Yoshio, Sato Takashi, Kobayashi Koichi, Watanabe Satoshi, Fujii Toshihide, Yamagiwa Hiroshi, Katsumi Ryota, Koga Hiroshi, Omori Go, Endo Naoto

PLOS ONE 13 ( 9 ) e0202488 2018.9

Language：English Publishing type：Research paper (scientific journal)

INTRODUCTION: Posterior tibial slope (PTS) and sagittal alignment are important factors in the etiology of knee osteoarthritis and knee surgery. Clinically, sagittal alignment, which indicates flexion contracture of the knee, contributes to knee function in weight-bearing (WB) conditions. PTS and sagittal alignment under WB conditions in varus osteoarthritic knees are presumed to affect each other, but their association remains unclear. In this study, we aimed to clarify the association. MATERIAL AND METHODS: In total, 140 osteoarthritic varus knees were investigated. Under WB conditions, a three-dimensional (3D) alignment assessment system was applied via biplanar long-leg X-rays, using 3D-to-2D image registration technique. The evaluation parameters were as follows: 1) 3D mechanical flexion angle (3DMFA) in regards to sagittal alignment, 2) passing point in the WB line (PP), and 3) medial and lateral PTS. RESULTS: The medial and lateral PTS showed a positive correlation with 3DMFA and PP, respectively (medial PTS-3DMFA, p = 0.001; medial PTS-PP, p < 0.0001; lateral PTS-3DMFA, p < 0.0001; lateral PTS-PP, p = 0.002). The flexion contracture group with 3DMFA >5° demonstrated greater PTS than non-flexion contracture group (medial PTS, p = 0.006; lateral PTS, p = 0.006). CONCLUSIONS: Both medial and lateral PTS were correlated with sagittal alignment under WB conditions and were larger in the flexion contracture group. This finding can explain the function to take the load articular surface parallel to the ground for holding the balance in WB conditions in the sagittal plane for osteoarthritic knees. Moreover, surgeons may be required to decrease the PTS during knee arthroplasty to restore full extension in knees of patients with fixed flexion contracture.

DOI： 10.1371/journal.pone.0202488

脛骨近位内側関節面傾斜の健常者と進行期変形性膝関節症患者の三次元評価―臥位と立位での変化―

望月友晴, 谷藤理, 古賀良生, 森隆裕, 佐藤卓, 渡辺聡, 大森豪, 小林公一, 西野勝敏, 田邊裕治, 遠藤直人

日本整形外科学会雑誌 92 ( 8 ) S2016 - S2016 2018.8

Analysis of in vivo static contact surface motion of thumb interphalangeal joint Reviewed

Yusuke MORISE, Makoto SAKAMOTO, Kaito SUGITA, Kiyoko KAZAMA, Koichi KOBAYASHI, Yuji TANABE

Advenced Experimental Mechanics 3 209 - 214 2018.8

Contribution of sex and body constitution to three-dimensional lower extremity alignment for healthy, elderly, non-obese humans in a Japanese population. Reviewed International journal

Katsumi R, Mochizuki T, Sato T, Kobayashi K, Watanabe S, Tanifuji O, Endo N

Journal of experimental orthopaedics 5 ( 1 ) 32 - 32 2018.8

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Humans support their bodies exclusively by vertical balance in bipedal locomotion, and the body, especially the lower extremity, generally changes with age. Sex and body constitution are assumed to be associated with lower extremity alignment, but this association remains to be elucidated. This study sought to clarify this association in healthy, elderly, non-obese humans in a Japanese population. METHODS: The present study investigated 55 healthy volunteers (mean age: 70 ± 6 years). A 3D extremity alignment system was applied under weight-bearing conditions on biplane long lower extremities X-rays using a 3D-to-2D image registration technique. The evaluation parameters included 3D hip-knee-ankle angle (3DHKA) alignment in the coronal (coronal alignment) and sagittal planes (sagittal alignment) and rotational alignment between the femur and tibia. The influences of sex and body constitution on all the alignment were analyzed. RESULTS: Multiple linear regression analysis with the dependent variable of each alignment showed that sex was the dominant factor for coronal and rotational alignment (coronal: p < 0.01; rotational: p < 0.01), and body weight was the dominant factor for sagittal alignment (p < 0.01). CONCLUSIONS: The association of sex with coronal and rotational alignment and of body constitution with sagittal alignment were proved in healthy, elderly, non-obese humans in a Japanese population. This finding can lead to further understanding of the etiology of many diseases and age-related changes.

DOI： 10.1186/s40634-018-0147-3

Extrinsic Factors as Component Positions to Bone and Intrinsic Factors Affecting Postoperative Rotational Limb Alignment in Total Knee Arthroplasty Reviewed

Tomoharu Mochizuki, Takashi Sato, Osamu Tanifuji, Satoshi Watanabe, Koichi Kobayashi, Naoto Endo

Journal of Arthroplasty 33 ( 7 ) 2100 - 2110 2018.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Churchill Livingstone Inc.

Background: This study aimed to identify the factors affecting postoperative rotational limb alignment of the tibia relative to the femur. We hypothesized that not only component positions but also several intrinsic factors were associated with postoperative rotational limb alignment. Methods: This study included 99 knees (90 women and 9 men) with a mean age of 77 ± 6 years. A three-dimensional (3D) assessment system was applied under weight-bearing conditions to biplanar long-leg radiographs using 3D-to-2D image registration technique. The evaluation parameters were (1) component position
(2) preoperative and postoperative coronal, sagittal, and rotational limb alignment
(3) preoperative bony deformity, including femoral torsion, condylar twist angle, and tibial torsion
and (4) preoperative and postoperative range of motion (ROM). Results: In multiple linear regression analysis using a stepwise procedure, postoperative rotational limb alignment was associated with the following: (1) rotation of the component position (tibia: β = 0.371, P &lt
.0001
femur: β = −0.327, P &lt
.0001), (2) preoperative rotational limb alignment (β = 0.253, P =.001), (3) postoperative flexion angle (β = 0.195, P =.007), and (4) tibial torsion (β = 0.193, P =.010). Conclusion: In addition to component positions, the intrinsic factors, such as preoperative rotational limb alignment, ROM, and tibial torsion, affected postoperative rotational limb alignment. On a premise of correct component positions, the intrinsic factors that can be controlled by surgeons should be taken care. In particular, ROM is necessary to be improved within the possible range to acquire better postoperative rotational limb alignment.

DOI： 10.1016/j.arth.2018.02.009

関節のバイオメカニクス核磁気共鳴画像法による示指中手指節関節の三次元生体内接触運動の解析

坂本信, 小林公一, 春日勇人, 風間清子

非破壊検査 67 ( 4 ) 174‐179 - 179 2018.4

An analytical solution for the axisymmetric problem of a penny-shaped crack in an elastic layer sandwiched between dissimilar materials Reviewed

Miura Kotaro, Sakamoto Makoto, Kobayashi Koichi, Pramudita Jonas A, Tanabe Yuji

MECHANICAL ENGINEERING JOURNAL 5 ( 3 ) 18 - 00125-18-00125 2018

Language：English Publisher：The Japan Society of Mechanical Engineers

<p>Herein, we consider the axisymmetric problem of a penny-shaped crack in an elastic material sandwiched between other materials. It is assumed that the central substance is composed of an elastic layer held between two semi-infinite bodies with different elastic constants, and that the crack is situated in the central plane of the elastic layer and subjected to uniform pressures on its internal surfaces. We consider two contact conditions; perfectly bonded and frictionless contact at the interfaces with the dissimilar materials. Dual integral equations are reduced to an infinite system of simultaneous equations by expressing normal displacements on the crack surfaces as an appropriate series function. Numerical results were obtained to examine the effects of the elastic constants of the layer and semi-infinite bodies and contact conditions on the stress intensity factor at the tip of the penny-shaped crack, the distribution of normal displacement, and stress on the crack plane. Based on the results of these numerical calculations, several conclusions can be made, as follows. 1) The distributions of normal displacement and stress at the crack plane and the stress intensity factor at the tip of the crack become larger than the results for an infinite solid when the ratio of the shear modulus of the layer to that of the semi-infinite bodies is larger than 1. 2) The numerical results for normal displacement and stress, and for stress intensity factors, in the frictionless case are higher than for the perfectly bonded case regardless of the shear modulus ratio and layer thickness ratio. The difference between the perfectly bonded and frictionless cases becomes greater as the layer thickness ratio becomes smaller. 3) There is a slight difference in the stress intensity factor values obtained from the present work and the corresponding results previously reported in the literature.</p>

DOI： 10.1299/mej.18-00125

Three-Dimensional Elastic Problem of a Penny-Shaped Crack in an Elastic Layer Sandwiched Between Dissimilar Materials

MIURA Kotaro, SAKAMOTO Makoto, KOBAYASHI Koichi, PRAMUDITA Jonas A., TANABE Yuji

The Proceedings of Mechanical Engineering Congress, Japan 2018 G0300401 2018

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

<p>Herein, we consider the axisymmetric problem of a penny-shaped crack in an elastic material sandwiched between other materials. It is assumed that the central substance is composed of an elastic layer held between two semi-infinite bodies with different elastic constants, and that the crack is situated in the central plane of the elastic layer and subjected to uniform pressures on its internal surfaces. Dual integral equations are reduced to an infinite system of simultaneous equations by expressing normal displacements on the crack surfaces as an appropriate series function. Numerical results were obtained to examine the effects of the elastic constants of the layer and semi-infinite bodies on the stress intensity factor at the tip of the penny-shaped crack, the distribution of normal displacement, and stress on the crack plane. As a result, there is a slight difference in the stress intensity factor values obtained from the present work and the corresponding results previously reported in the literature.</p>

DOI： 10.1299/jsmemecj.2018.G0300401

Viscoelastic behavior of bovine femoral articular cartilage in relaxation indentation test

OYAMA Chihiro, MIURA Kotaro, SAKAMOTO Makoto, KOBAYASHI Koichi, A. PRAMUDITA Jonas, TANABE Yuji

The Proceedings of the Materials and Mechanics Conference 2018 OS0604 2018

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

<p>The indentation test has been widely used to evaluate mechanical properties of industrial and biological materials in many studies. In this study, we obtained an analytical solution of axisymmetric contact problem of viscoelastic layer bonded on rigid substrate indented by flat-ended cylindrical punch using elastic-viscoelastic corresponding principle. The relaxation indentation tests were conducted for silicon rubber, Echo PAD which is a soft material used for elastography, and articular cartilage of bovine femoral head. For articular cartilage, fresh articular cartilage was treated by collagenase after a relaxation indentation test and was then used again in same test. The viscoelastic models in this study were selected as three-element model (standard linear solid model) and five-element model (generalized Maxwell model) and viscoelastic parameters of the models were determined by fitting the analytical solution to applied load varying with time collected from the relaxation indentation test. As the results, it was suggested that the five-element model was more appropriate than three-element model to reproduce the behavior of relaxation indentation of silicon rubber, Echo PAD, and articular cartilage. Furthermore, the viscoelastic parameters of treated articular cartilage decreased sufficiently compared with those of fresh articular cartilage. From these results, it was suggested that the method of evaluating the time-dependent mechanical properties of articular cartilage based on the analytical solutions of the relaxation indentation test obtained from this study could be a useful tool for evaluating the state of degenerated cartilage.</p>

DOI： 10.1299/jsmemm.2018.OS0604

Biplanar slot radiography for three-dimensional evaluation of implant position in THA. Reviewed

岡庭大祐, 中原大輔, 小林公一, 坂本信, 田邊裕治, 佐藤卓, 大森豪, 湊泉, 古賀良生

臨床バイオメカニクス 38 291‐298 - 298 2017.10

In vivo three-dimensional analysis of the contact behavior of the metacarpophalangeal joint of the middle finger. Reviewed

杉田魁人, 坂本信, 森清友亮, 風間清子, 小林公一, 田邊裕治

臨床バイオメカニクス 38 103‐111 - 111 2017.10

A method for automatic definition of three-dimensional anterior tooth axis using in vivo cone-beam computed tomographic images. Reviewed

坂上勇太, 坂本信, 森清友亮, 亀田剛, 小林公一, 坂井幸子, 遠藤英昭

臨床バイオメカニクス 38 27‐33 - 33 2017.10

膝前後X線像における大腿骨・脛骨回旋評価法の検討

森隆裕, 田邊裕治, 古賀寛, 望月友晴, 小林公一, 古賀良生

臨床バイオメカニクス 38 313 - 318 2017.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

立位膝前後X線像から大腿骨と脛骨の相対的かつ経時的な回旋変化を評価するための指標を求める目的で、膝OA患者2例(男性1例、女性1例)のデータを用いて解析を行った。結果、標準化指標として「大腿骨内側顆における長軸の長さ」、大腿骨回旋指標として「内顆長軸から膝蓋骨外縁までの距離」、脛骨回旋指標として「脛骨内側顆間隆起先端から腓骨頭外側縁までの距離」を使用することで回旋位置変化を相対的に定量化できると考えられ、三次元CT骨モデルを用いたシミュレーションによってその妥当性が示された。

Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2017&ichushi_jid=J05471&link_issn=&doc_id=20171016110048&doc_link_id=%2Fcx9biomc%2F2017%2F003800%2F048%2F0313-0318%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fcx9biomc%2F2017%2F003800%2F048%2F0313-0318%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

External torsion in a proximal tibia and internal torsion in a distal tibia occur independently in varus osteoarthritic knees compared to healthy knees Reviewed

Tomoharu Mochizuki, Osamu Tanifuji, Yoshio Koga, Ryosuke Hata, Takahiro Mori, Katsutoshi Nishino, Takashi Sato, Koichi Kobayashi, Go Omori, Makoto Sakamoto, Yuji Tanabe, Naoto Endo

JOURNAL OF ORTHOPAEDIC SCIENCE 22 ( 3 ) 501 - 505 2017.5

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER JAPAN KK

Introduction: The relative torsional angle of the distal tibia is dependent on a deformity of the proximal tibia, and it is a commonly used torsional parameter to describe deformities of the tibia; however, this parameter cannot show the location and direction of the torsional deformity in the entire tibia. This study aimed to identify the detailed deformity in the entire tibia via a coordinate system based on the diaphysis of the tibia by comparing varus osteoarthritic knees to healthy knees.
Methods: In total, 61 limbs in 58 healthy subjects (age: 54 18 years) and 55 limbs in 50 varus osteoarthritis (OA) subjects (age: 72 7 years) were evaluated. The original coordinate system based on anatomic points only from the tibial diaphysis was established. The evaluation parameters were 1) the relative torsion in the distal tibia to the proximal tibia, 2) the proximal tibial torsion relative to the tibial diaphysis, and 3) the distal tibial torsion relative to the tibial diaphysis.
Results: The relative torsion in the distal tibia to the proximal tibia showed external torsion in both groups, while the external torsion was lower in the OA group than in the healthy group (p < 0.0001). The proximal tibial torsion relative to the tibial diaphysis had a higher external torsion in the OA group (p = 0.012), and the distal tibial torsion relative to the tibial diaphysis had a higher internal torsion in the OA group (p = 0.004) in comparison to the healthy group.
Conclusion: The reverse torsional deformity, showing a higher external torsion in the proximal tibia and a higher internal torsion in the distal tibia, occurred independently in the OA group in comparison to the healthy group. Clinically, this finding may prove to be a pathogenic factor in varus osteoarthritic knees. Level of evidence: Level Ill. (C) 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jos.2017.01.002

Sex differences in femoral deformity determined using three-dimensional assessment for osteoarthritic knees Reviewed

Tomoharu Mochizuki, Osamu Tanifuji, Yoshio Koga, Takashi Sato, Koichi Kobayashi, Katsutoshi Nishino, Satoshi Watanabe, Akihiro Ariumi, Toshihide Fujii, Hiroshi Yamagiwa, Go Omori, Naoto Endo

KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY 25 ( 2 ) 468 - 476 2017.2

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

To characterize femoral deformities and determine sex differences in varus knee osteoarthritis (OA), femoral morphology and limb alignment were evaluated by using three-dimensional (3D) assessment, comparing healthy, elderly volunteers with osteoarthritic knees.
A total of 178 lower limbs of 169 subjects with knee osteoarthritis (136 women, 33 men; mean age 74.9 +/- 5.2 years) and 80 lower limbs of 45 healthy, elderly subjects (24 women, 21 men; mean age 65 +/- 4.9 years) were examined. A 3D extremity alignment assessment system was used to examine the subjects under weight-bearing conditions on biplanar long-leg radiographs using a 3D-to-2D image registration technique. The evaluation parameters were (1) femoral bowing in the coronal plane, (2) femoral bowing in the sagittal plane, (3) femoral neck anteversion, (4) hip-knee-ankle angle, and (5) femoral torsion.
Higher femoral lateral bowing and slightly higher femoral internal torsion in the proximal diaphysis were observed in women with OA compared with healthy subjects. No difference in the higher varus malalignment, no alteration in the femoral anterior bowing, and no difference in the lower femoral neck anteversion were found between men and women when comparing healthy and OA subjects.
The higher femoral lateral bowing and slightly higher femoral internal torsion in the proximal diaphysis in women are possibly a structural adaptation to mechanical use. The clinical significance is that the femoral deformities and the sex differences in knee OA have the potential to improve the understanding of the aetiology of primary varus knee OA.
IV.

DOI： 10.1007/s00167-016-4166-2

Determination of Elastic Modulus of Bovine Articular Cartilage Using Indentation Test

Daisuke HIRAKI, Makoto SAKAMOTO, Koichi KOBAYASHI, Jonas A. PRAMUDITA, Yuji TANABE

The Proceedings of Conference of Hokuriku-Shinetsu Branch 2017.54 2017

大腿骨遠位成長軟骨板と3次元下肢荷重線との位置関係

田中翔太, 林豊彦, 棚橋重仁, 渡邉聡, 佐藤卓, 小林公一, 古賀良生, 大森豪

臨床バイオメカニクス 37 121 - 128 2016.9

Language：Japanese Publisher：日本臨床バイオメカニクス学会

膝関節は可動域が広い関節で、成長軟骨板(GP)にも圧縮力や剪断力が加わるため、GP障害の治療では、荷重環境とGP形態との関連性の把握が重要である。しかし、両者の関連性に関する報告は見られないことから、膝関節の治療目的で通院中の男性6名(年齢10.8±1.3歳)6膝を対象に、MRI撮影および2方向からのコンピューターX線撮影(CR)を行い、GPの三次元形態と荷重環境との関連について定量的に検討した。MRIでは膝関節を撮像し、CRでは三次元アライメント評価法にしたがって下肢全体を撮影した。次に、GPにおける下肢荷重線の通過位置を求め、GPの規格化および補間、GP形態の分析を行った。その結果、正常な下肢アライメントの場合、冠状面ではGPの顆間部に最も荷重がかかり、この部分のGPは平坦度が高く、わずかに前傾しており、これにより、荷重応力の集中を低減し、剪断力を低くしていると推定された。

Three-dimensional in vivo dynamic motion analysis of anterior cruciate ligament-deficient knees during squatting using geometric center axis of the femur Reviewed

Takayuki Murayama, Takashi Sato, Satoshi Watanabe, Koichi Kobayashi, Osamu Tanifuji, Tomoharu Mochizuki, Hiroshi Yamagiwa, Yoshio Koga, Go Omori, Naoto Endo

JOURNAL OF ORTHOPAEDIC SCIENCE 21 ( 2 ) 159 - 165 2016.3

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER JAPAN KK

Background: Anterior cruciate ligament (ACL) injury often leads to symptoms of instability, which may cause meniscus injury, osteochondral lesions, and degenerative changes. For thorough evaluation of the effects of abnormal motion of ACL-deficient (ACLD) knees on the meniscus and articular cartilage, it is necessary to assess tibiofemoral motion in the medial and lateral compartments separately. Our aim was to determine if in vivo three-dimensional (3D) dynamic motion of ACLD knees differs from that of contra lateral uninjured knees by assessing knee motion in the medial and lateral compartments respectively.
Methods: A total of 22 patients with an isolated ACL-injured knee were examined. 3D to two-dimensional registration was used to determine 3D knee motion during squatting from full knee extension to full flexion for both ACLD and contralateral uninjured knees. The knee motion was evaluated by the movement of the geometric center axis of the femur projected onto the tibial axial plane.
Results: In ACLD knees the lateral femoral condyle was located significantly more posteriorly during nearly full extension than in contralateral uninjured knees. The range of anteroposterior translation of the medial femoral condyle was significantly greater than those of contralateral uninjured knees. Almost all of the contralateral uninjured knees demonstrated medial pivot motion, while the ACLD knees showed higher variance.
Conclusions: The ACLD knees exhibited a motion pattern different from those of contralateral uninjured knees with higher variance. During nearly full extension of the ACLD knees, the lateral femoral condyle translated posteriorly and the screw-home movement seemed to be impaired. The ACL might have an important role in maintaining normal knee function, especially during the early flexion phase. The larger range of anteroposterior translation of the medial femoral condyle in ACLD knees may be associated with a risk of secondary meniscal injury and degenerative change in the articular cartilage. Level of evidence: Level IV. (C) 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jos.2015.11.001

Accurate determination of set position of artificial knee joint through automatically operated 3D-3D image matching technique

桐本喬晴, 佐藤卓, 小林公一, プラムディタジョナス, 田邊裕治

臨床バイオメカニクス 37 257 - 260 2016

Assessment of 3D lower extremity alignment in standing posture using biplanar slot radiography

高橋匠, 岡庭大祐, 小林公一, 坂本信, 田邊裕治, 佐藤卓, 大森豪, 古賀良生

臨床バイオメカニクス 37 143 - 148 2016

In vivo three-dimensional analysis of the contact area of the proximal interphalangeal joint of the index finger using MRI

風間清子, 坂本信, 森清友亮, 小林公一, 近藤達也, 田邊裕治

臨床バイオメカニクス 37 103 - 108 2016

In vivo three-dimensional analysis of distal radioulnar joint kinematics during forearm pronation-supination

Kiyoko Kazama, Koichi Kobayashi, Makoto Sakamoto

Journal of Biomechanical Science and Engineering 11 ( 1 ) 2016

Language：English Publishing type：Research paper (scientific journal) Publisher：Japan Society of Mechanical Engineers

The action of the forearm is to transfer force and torque across the elbow and wrist, resulting in axial rotation at the distal and proximal radioulnar joints, called pronation and supination. Pronation and supination are important functions as they allow many kinds of activities of daily living. Three-dimensional (3D) motion analysis of pronation and supination is essential for a better understating of the biomechanics of the forearm to describe the physiological range of motion and optimize clinical options for disorders of the forearm. Although numerous in vitro studies have contributed to gain insights into the forearm pronation and supination, in vivo investigations are still limited. In this study, three-dimensional (3D) motion of the distal radioulnar joint (DRUJ) during forearm pronation and supination was analyzed in vivo using biplanar radiography and 3D models of the ulna and radius. Twelve healthy subjects (6 men and 6 women) were recruited for the study. Each subject's right forearm (dominant hand) underwent a computed tomography (CT) scan to create 3D surface models of the ulna and radius. Each subject was imaged using a calibrated biplanar radiographic system at 90° pronation, 45° pronation, neutral, 45° supination, and 90° supination while the elbow was in extension or flexion. The 3D positions of the radius and ulna were obtained using a 2D-to-3D image registration method. The relative translations of the radius in the radioulnar, dorsopalmar, and proximodistal directions and the relative rotations of the radius about the radioulnar, dorsopalmar, and proximodistal axes were evaluated with respect to the ulna during pronation and supination. In general, the radius translated towards the ulnar side throughout forearm rotation, and moved towards the palmar side as pronation increased and moved dorsally as supination increased, and was positioned proximally during pronation and distally during supination. The rotation of the radius was dominant about the proximodistal axis. These kinematic variables were affected by elbow position and sex of the subject. The current findings regarding the 3D kinematics of the DRUJ during forearm pronation and supination may contribute to further understanding of the physiological biomechanics of the upper limb.

DOI： 10.1299/jbse.15-00364

1方向正面動画による歩行解析の提案

川上健作, 浜克己, 小林公一, 坂本信

実験力学 16 ( 2 ) 116‐121(J‐STAGE) - 121 2016

Language：Japanese Publisher：日本実験力学会

In the clinical, it is difficult to carry out the motion analysis because it requires a large place. The purpose of this study is to examine the gait analysis method by one direction frontal video that can be easily measured in clinical. The subjects were five healthy persons attached four markers at both shoulders and both anterior superior iliac spine (ASIS). The walking motion of each subject toward a camera was analyzed. Body trunk tilt and centroid sway of the upper body part were calculated and compared with the results of three-dimensional gait analysis methods. The result showed the same tendency of the body trunk tilt and the centroid sway changes based on each method. The result suggested that the gait analysis by one direction frontal video could evaluate the large abnormal gait. Further, authors evaluated OA knee joint thrust using one direction frontal video. The change of the knee joint alignment and the distance between the loading axis of lower extremity and knee joint center were calculated as knee joint thrust. Results showed that knee adduction angle and distance of knee joint center from lower limb loading axis of OA patient were increased. The result suggested that this method could evaluate the knee joint thrust of OA patient.

DOI： 10.11395/jjsem.16.116

核磁気共鳴画像による膝関節の屈曲に伴うヒト後十字靱帯の生体内力学挙動解析 Reviewed

近藤達也, 近藤達也, 小林公一, 坂本信

実験力学 16 ( 2 ) 127‐133(J‐STAGE) - 133 2016

Language：Japanese Publisher：日本実験力学会

The posterior cruciate ligament (PCL) functions as the primary restraint to posterior tibial movement and the stabilizer for axial rotation of the knee joint. It is, therefore, important to know the mechanical characteristics of the PCL. The objective of this study was to evaluate the in vivo characteristics of the three-dimensional (3D) deformation and orientation of the PCL during knee flexion using magnetic resonance imaging (MRI). Ten normal knees were visualized using MRI at full extension (FE), 10°, 20°, 30° and 60° of static knee flexion. The length, strain, elevation and deviation of the PCL were measured using the 3D models of the femur, tibia and PCL reconstructed from the MR images. The PCL length was measured in three portions (Medial: M, Central: C, Lateral: L) to consider its 3D shape. Tendencies of the PCL elongation and strain during knee flexion were different among these 3 portions. The PCL length in M portion was shortest in 10° or 20° and extended in FE and 60°. The PCL length in L portion, on the other hand, extended from FE to 60°. These 3D deformation characteristics were consisted with the changes in the elevation and deviation of the PCL during knee flexion.

DOI： 10.11395/jjsem.16.127

2方向スロットラジオグラフィと3次元形状モデルによる人工膝関節アライメントと人工関節設置位置評価法 Reviewed

小林公一, 高橋匠, 岡庭大祐, 坂本信, 田邊裕治, 佐藤卓, 大森豪, 古賀良生

実験力学 16 ( 2 ) 134‐139(J‐STAGE) - 139 2016

Language：Japanese Publisher：日本実験力学会

The purpose of this study was to develop a method for evaluation of the three-dimensional (3D) alignment and position of the artificial knee joint using a biplanar slot radiography (SR) system and 3D models. A SR system uses collimated fan beam x-rays synchronized with the movement of a flat-panel detector. This system allows to obtain a full length x-ray image of the body with reduced dose and smaller image distortion compared with conventional x-ray systems. The biplanar SR system used a rotation table positioned at 0 deg and 60 deg relative to the optical axis of an X-ray source. Camera calibration was performed using an acrylic frame with 72 radiopaque markers. The femoral and tibial components of a total knee replacement system were immobilized and imaged using the biplanar SR system. Then, the femoral component was installed on a sawbone femur and imaged again. The 3D positions of the components and femur were recovered using an interactive 2D to 3D image registration method. Overall, the largest estimation errors were within 1 mm in translation and 1 deg in rotation, demonstrating that this method has an adequate accuracy for the clinical usage.

DOI： 10.11395/jjsem.16.134

Unicompartmental knee arthroplasty cannot restore the functional flexion axis of a living knee to normal Reviewed

Tomoharu Mochizuki, Takashi Sato, Osamu Tanifuji, Koichi Kobayashi, Hiroshi Yamagiwa, Satoshi Watanabe, Yoshio Koga, Go Omori, Naoto Endo

KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY 23 ( 12 ) 3736 - 3742 2015.12

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The purpose of this study was to investigate the hypothesis that a medial unicompartmental knee arthroplasty might restore the functional flexion axis of a knee to normal. The flexion axis can be indirectly identified by tracking the vertical translation of anatomic landmarks that basically move around the flexion axis during a knee motion. If a unicompartmental knee could help restore the normal flexion axis, the anatomic landmarks after the arthroplasty would show the vertical translation similar to those of normal knees during a knee flexion.
While performing a squatting motion, the kinematics of 17 knees were determined before and after a medial unicompartmental arthroplasty to calculate the vertical translation of a clinical epicondylar axis, using a three- to two-dimensional registration technique through a single-plane fluoroscopic system incorporating a biplanar static radiography. The results were compared with a normal data, and a statistical analysis including a two-way repeated-measured analysis of variance was performed.
For the medial end, from 10A degrees to 100A degrees knee flexion, normal, osteoarthritic, and unicompartmental knees had the average superior vertical translation of 7.3 +/- A 4.2, 4.3 +/- A 7.2, and 2.4 +/- A 3.1 mm, respectively, with statistical significance between normal and unicompartmental knees (p < 0.001). The vertical translation did not return to normal post-implantation.
A unicompartmental knee could not reproduce the normal flexion axis. As for clinical relevance, the changes of the implant design and surgical procedure may be necessary to obtain the normal flexion axis reproducing a normal motion.
IV.

DOI： 10.1007/s00167-014-3296-7

車いすハンドル高さと降坂移送をする介助者の上肢負担に関する検討

水谷都, 坂本信, 川上健作, 定方美恵子, 小林公一

臨床バイオメカニクス 36 259 - 265 2015.10

Language：Japanese Publisher：日本臨床バイオメカニクス学会

車いすハンドル高さと降坂移送をする介助者の上肢負担について検討した。身長の異なる健常者5例を対象とした。坂前進下りにおいて、介助者はハンドルを引きながら車いすの前進下りをし、上肢の負荷が少ないハンドル高さは関節モーメントの最小値から肘関節の最大モーメントが0となるハンドル高さ割合80%付近であると考えられた。坂後進下りにおいて、介助者はハンドルを押しながら車いすの後進下りをし、上肢の負荷が少ないハンドル高さは関節モーメントの最小値からハンドル高さ割合90%前後であると考えられた。ハンドル高さ割合90%とは、100%で移送者の肩高さに相当することから、移送者の胸よりも少し高い位置に相当した。坂路降坂における介助者の上肢負担は移送方法により大きく異なることが判明し、適切なハンドル高さも異なっていた。

Other Link： http://search.jamas.or.jp/link/ui/2016096444

MRIを用いた示指中手指節間関節における接触領域および関節運動の三次元生体内解析 Reviewed

坂本信, 春日勇人, 風間清子, 風間清子, 小林公一, 小林公一

臨床バイオメカニクス 36 7 - 15 2015.10

コーンビームCTによる三次元歯軸の自動決定 Reviewed

坂本信, 春日勇人, 坂井幸子, 小林公一, 小林公一, 遠藤英昭

臨床バイオメカニクス 36 119 - 125 2015.10

Three-dimensional dynamic analysis of knee joint during gait in medial knee osteoarthritis using loading axis of knee Reviewed

Katsutoshi Nishino, Go Omori, Yoshio Koga, Koichi Kobayashi, Makoto Sakamoto, Yuji Tanabe, Masaei Tanaka, Masaaki Arakawa

GAIT & POSTURE 42 ( 2 ) 127 - 132 2015.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER IRELAND LTD

We recently developed a new method for three-dimensional evaluation of mechanical factors affecting knee joint in order to help identify factors that contribute to the progression of knee osteoarthritis (KOA). This study aimed to verify the clinical validity of our method by evaluating knee joint dynamics during gait. Subjects were 41 individuals (14 normal knees; 8 mild KOAs; 19 severe KOAs). The positions of skin markers attached to the body were captured during gait, and bi-planar X-ray images of the lower extremities were obtained in standing position. The positional relationship between the markers and femorotibial bones was determined from the X-ray images. Combining this relationship with gait capture allowed for the estimation of relative movement between femorotibial bones. We also calculated the point of intersection of loading axis of knee on the tibial proximal surface (LAK point) to analyze knee joint dynamics. Knee flexion range in subjects with severe KOA during gait was significantly smaller than that in those with normal knees (p = 0.011), and knee adduction in those with severe KOA was significantly larger than in those with mild KOA (p < 0.000). LAK point was locally loaded on the medial compartment of the tibial surface as KOA progressed, with LAK point of subjects with severe KOA rapidly shifting medially during loading response. Local loading and medial shear force were applied to the tibial surface during stance phase as medial KOA progressed. Our findings suggest that our method is useful for the quantitative evaluation of mechanical factors that affect KOA progression. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.gaitpost.2015.04.018

In vivo three-dimensional analysis of radioulnar motion during pronation supination

風間清子, 春日勇人, 小林公一

臨床バイオメカニクス 36 17 - 22 2015

MRIボリュームデータのレンダリングによる膝関節の3次元位置推定法 Reviewed

小林公一, 坂本信, 田邊裕治, 佐藤卓, 大森豪, 古賀良生

臨床バイオメカニクス 35 131 - 135 2014.10

マイクロCTを用いた三次元歯軸の評価 Reviewed

坂本信, 春日勇人, 坂井幸子, 小林公一, 遠藤英昭

臨床バイオメカニクス 35 99 - 104 2014.10

Kinematics of the knee after unicompartmental arthroplasty is not the same as normal and is similar to the kinematics of the knee with osteoarthritis Reviewed

Tomoharu Mochizuki, Takashi Sato, John David Blaha, Osamu Tanifuji, Koichi Kobayashi, Hiroshi Yamagiwa, Satoshi Watanabe, Munenori Matsueda, Yoshio Koga, Go Omori, Naoto Endo

KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY 22 ( 8 ) 1911 - 1917 2014.8

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

It is common to assert that restoration of normal knee kinematics is essential for the best functional result after knee arthroplasty. Previous studies using the progression of the geometric centre axis have suggested that kinematics after unicompartmental arthroplasty is markedly different from the normal. For this study, the transepicondylar axis was used because this axis is closer to the flexion axis and should be a better reference for motion. The following hypothesis was tested: the transepicondylar axis would again show that the postoperative kinematics does not restore normal motion and is closer to that before replacement.
Seventeen osteoarthritic knees were tested before and after unicompartmental arthroplasty using a three-dimensional to two-dimensional registration technique tracking the transepicondylar axis to calculate translation and rotation of this axis. Results were compared for the seventeen knees before and after arthroplasty and were compared to the normal knee as measured in our previous study.
Similar motion patterns in the pre- and postoperative knees were shown but both the pre- and postoperative motion were markedly different from the normal knee.
This result supported our hypothesis. The clinical relevance is that medial unicompartmental arthroplasty cannot restore the motion of the knee to normal in the living knee. Therefore, it would be expected that the patient for unicompartmental knee might not feel normal. It may not be possible depending on ligaments alone to restore the knee to normal, and the changes in the articular shapes and the surgical procedure may also be necessary.
IV.

DOI： 10.1007/s00167-013-2767-6

Biomechanical effects of push handle heights on upper limbs during attendant propelled wheelchair ramp transportation Reviewed

Mizutani M, Kawakami K, Sadakata M, Kobayashi K, Sakamoto M

Journal of the Japanese Society of Experimental Mechanics 14 s291 - s295 2014.8

The clinical epicondylar axis is not the functional flexion axis of the human knee Reviewed

Tomoharu Mochizuki, Takashi Sato, John David Blaha, Osamu Tanifuji, Koichi Kobayashi, Hiroshi Yamagiwa, Satoshi Watanabe, Yoshio Koga, Go Omori, Naoto Endo

JOURNAL OF ORTHOPAEDIC SCIENCE 19 ( 3 ) 451 - 456 2014.5

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER JAPAN KK

The functional flexion axis (FFA) is the principal axis around which the knee moves and thus, by definition, does not move in vertical displacement relative to the tibia. The transepicondylar axis (TEA) has been reported to coincide with the FFA. If that is not true, the TEA should show vertical displacement during motion, and this hypothesis was investigated.
Three-dimensional knee kinematics of 20 healthy volunteers were determined during a squatting motion via a 3-dimensional to 2-dimensional image registration technique by calculating the vertical displacement of the clinical epicondylar axis (CEA) through the full range of motion.
From 0A degrees to 90A degrees knee flexion, the average vertical displacement of the lateral end of the CEA was < 3 mm, whereas that of the medial end was large (7.6 mm).
The large vertical displacement of the medial end of the CEA suggests that the CEA is not the FFA. This finding implies that the CEA may not be an appropriate axis for a TKA prosthesis having a "single radius" design.
Level IV.

DOI： 10.1007/s00776-014-0536-0

Automatic construction of an anatomical coordinate system for three-dimensional bone models of the lower extremities--pelvis, femur, and tibia. Reviewed

Kai S, Sato T, Koga Y, Omori G, Kobayashi K, Sakamoto M, Tanabe Y

Journal of biomechanics 47 ( 5 ) 1229 - 1233 2014.3

Theoretical model analysis of joint contact stress : Estimation of normal contact stress on joint surface

坂本信, 小林公一

臨床バイオメカニクス 35 387 - 394 2014

Image registration method for assessing 3D hip alignment and implant position during standing posture Reviewed

Koichi Kobayashi, Shin Kai, Makoto Sakamato, Yuji Tanabe, Kunihiko Tokunaga, Izumi Minato, Takashi Sato, Yoshio Koga

Journal of Biomechanical Science and Engineering 9 ( 2 ) 2014

Language：English Publishing type：Research paper (scientific journal) Publisher：Japan Society of Mechanical Engineers

The range of motion (ROM) resulting from total hip arthroplasty (THA) depends on the relative orientation of the femoral and acetabular components, and malpositioning of components is a possible cause of several complications. The purpose of this study was to validate a 3-dimensional (3D) lower extremity alignment assessment system (3D LAAS) for the measurement of alignment of natural and implanted hip joints and implant position with respect to the target bone with the subject in a standing position. Sawbone femur and pelvis and femoral and acetabular components of a total hip arthroplasty system were used. Three spherical markers were attached to each sawbone and each component to define the local coordinate system. Outlines of the 3D bone models and component computer-aided design models were projected onto extracted contours of the femur, pelvis, and implants in calibrated frontal and oblique X-ray images. The 3D position of each model was recovered by minimizing the differences between projected outlines and contours. Mean absolute errors were less than 1.27 ± 0.79 mm and 0.99 ± 0.52° for femur and pelvis, 1.64 ± 0.66 mm and 1.54 ± 0.39° for femoral and acetabular components, 1.58 ± 0.29 mm and 1.75 ± 0.69° for femur and femoral component, and 1.51 ± 0.49 mm and 1.24 ± 0.14° for pelvis and acetabular component, indicating that the 3D LAAS is applicable to measure the alignment of natural and implanted hip joints and implant position after THA.

DOI： 10.1299/jbse.13-00162

Three-dimensional in vivo motion analysis of normal knees employing transepicondylar axis as an evaluation parameter Reviewed

Osamu Tanifuji, Takashi Sato, Koichi Kobayashi, Tomoharu Mochizuki, Yoshio Koga, Hiroshi Yamagiwa, Go Omori, Naoto Endo

KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY 21 ( 10 ) 2301 - 2308 2013.10

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The transepicondylar axis (TEA) has been used as a flexion axis of the knee and a reference of the rotational alignment of the femoral component. However, no study has showed dynamic normal knee kinematics employing TEA as the evaluation parameter throughout the full range of motion in vivo. The purpose of this study was to analyze dynamic kinematics of the normal knee through the full range of motion via the 3-dimensional to 2-dimensional registration technique employing TEA as the evaluation parameter.
Dynamic motion of the right knee was analyzed in 20 healthy volunteers (10 female, 10 male; mean age 37.2 years). Knee motion was observed as subjects squatted from standing with knee fully extended to maximum flexion. The following parameters were determined: (1) Anteroposterior translations of the medial and lateral ends of the TEA; and (2) changes in the angle of the TEA on the tibial axial plane (rotation angle).
The medial end of the TEA demonstrated anterior translation (3.6 +/- A 3.0 mm) from full extension to 30A degrees flexion and demonstrated posterior translation (18.1 +/- A 3.7 mm) after 30A degrees, while the lateral end of the TEA demonstrated consistent posterior translation (31.1 +/- A 7.3 mm) throughout knee flexion. All subjects exhibited femoral external rotation (16.9 +/- A 6.2A degrees) relative to the tibia throughout knee flexion.
Compared to previously used parameters, the TEA showed bicondylar posterior translation from early flexion phase. These results provide control data for dynamic kinematic analyses of pathologic knees in the future and will be useful in the design of total knee prostheses.

DOI： 10.1007/s00167-012-2010-x

In Vivo Kinematics of the Extensor Mechanism of the Knee During Deep Flexion Reviewed

Koichi Kobayashi, Ali Hosseini, Makoto Sakamoto, Wei Qi, Harry E. Rubash, Guoan Li

JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME 135 ( 8 ) 81002 2013.8

Language：English Publishing type：Research paper (scientific journal) Publisher：ASME

While various factors have been assumed to affect knee joint biomechanics, few data have been reported on the function of the extensor mechanism in deep flexion of the knee. This study analyzed the patellofemoral joint contact kinematics and the ratio of the quadriceps and patellar tendon forces in living subjects when they performed a single leg lunge up to 150 deg of flexion. The data revealed that in the proximal-distal direction, the patellofemoral articular contact points were in the central one-third of the patellar cartilage. Beyond 90 deg of flexion, the contact points moved towards the medial-lateral edges of the patellar surface. At low flexion angles, the patellar tendon and quadriceps force ratio was approximately 1.0 but reduced to about 0.7 after 60 deg of knee flexion, implying that the patella tendon carries lower loads than the quadriceps. These data may be valuable for improvement of contemporary surgical treatments of diseased knees that are aimed to achieve deep knee flexion.

DOI： 10.1115/1.4024284

外科的通顆軸をパラメターとして用いた三次元膝運動解析有用性の検討

谷藤理, 佐藤卓, 望月友晴, 山際浩史, 小林公一, 渡辺聡, 古賀良生, 大森豪

JOSKAS 38 ( 4 ) 153 - 153 2013.6

外科的通顆軸をパラメターとして用いた三次元膝運動解析正常膝

谷藤理, 佐藤卓, 望月友晴, 山際浩史, 小林公一, 渡辺聡, 古賀良生, 大森豪

JOSKAS 38 ( 4 ) 153 - 153 2013.6

人工膝関節置換術後のキネマティクス外科的通顆軸をパラメターとして用いた三次元膝運動解析 UKA術前後運動

望月友晴, 佐藤卓, 谷藤理, 小林公一, 渡辺聡, 山際浩史, 大森豪, 古賀良生, 遠藤直人

JOSKAS 38 ( 4 ) 119 - 119 2013.6

In-vivo patellar tendon kinematics during weight-bearing deep knee flexion Reviewed

Koichi Kobayashi, Makoto Sakamoto, Ali Hosseini, Harry E. Rubash, Guoan Li

JOURNAL OF ORTHOPAEDIC RESEARCH 30 ( 10 ) 1596 - 1603 2012.10

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

This study quantified in-vivo 3D patellar tendon kinematics during weight-bearing deep knee bend beyond 150 degrees. Each knee was MRI scanned to create 3D bony models of the patella, tibia, femur, and the attachment sites of the patellar tendon on the distal patella and the tibial tubercle. Each attachment site was divided into lateral, central, and medial thirds. The subjects were then imaged using a dual fluoroscopic image system while performing a deep knee bend. The knee positions were determined using the bony models and the fluoroscopic images. The patellar tendon kinematics was analyzed using the relative positions of its patellar and tibial attachment sites. The relative elongations of all three portions of the patellar tendon increased similarly up to 60 degrees Beyond 60 degrees, the relative elongation of the medial portion of the patellar tendon decreased as the knee flexed from 60 degrees to 150 degrees while those of the lateral and central portions showed continuous increases from 120 degrees to 150 degrees. At 150 degrees, the relative elongation of the medial portion was significantly lower than that of the central portion. In four of seven knees, the patellar tendon impinged on the tibial bony surface at 120 degrees and 150 degrees of knee flexion. These data may provide useful insight into the intrinsic patellar tendon biomechanics during a weight-bearing deep knee bend and could provide biomechanical guidelines for future development of total knee arthroplasties that are intended to restore normal knee function. (c) 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:15961603, 2012

DOI： 10.1002/jor.22126

透過型近赤外分光法によるヒト関節軟骨含水率の定量的評価 Reviewed

山岸英大, 佐藤光, 田邊裕治, 菊池達哉, 坂本信, 小林公一, 古賀良生

臨床バイオメカニクス 33 13 - 17 2012.10

MRIを用いた膝蓋腱長さ変化の生体内解析 Reviewed

坂本信, 長田郁美, 吉田秀義, 風間清子, 川上健作, 小林公一

臨床バイオメカニクス 33 81 - 87 2012.10

UKA 人工膝単顆置換術における下肢アライメント変化と置換側コンパートメントJoint line変化との関係

望月友晴, 佐藤卓, 山際浩史, 小林公一, 有海明央, 渡辺聡, 谷藤理, 大森豪, 古賀良生, 遠藤直人

日本人工関節学会誌 41 446 - 447 2011.12

Language：Japanese Publisher：(一社)日本人工関節学会

人工膝単顆置換術を施行した内側型変形性膝関節症9例11膝(男3膝、女9膝、平均75.3歳)を対象に、術前後の下肢アライメント変化と置換側コンパートメントJoint line変化との関係について検討した。下肢アライメント変化は、三次元下肢アライメント測定システムを使用し、術前のCTから三次元モデルを構築して座標軸を設定後、下肢全長立位2方向CR像に三次元骨形成モデルを重ね合わせて評価した。大腿骨および脛骨のmechanical axisのなす角であるHip Knee Ankle angle(HKA)は、術前平均188.1°が術後184.2°に、荷重軸%通過位置は内側66.3%が35.5%に変化し、アライメントは術後有意に外反化していた。置換側コンパートメントの脛骨joint line変化量は、平均2.1mm、最大6.4mm上昇していた。術前後のHKA変化量および荷重軸%通過位置の変化量と、脛骨joint line変化量とは有意な相関が認められた。

Three-dimensional in vivo motion analysis of normal knees using single-plane fluoroscopy Reviewed

Osamu Tanifuji, Takashi Sato, Koichi Kobayashi, Tomoharu Mochizuki, Yoshio Koga, Hiroshi Yamagiwa, Go Omori, Naoto Endo

JOURNAL OF ORTHOPAEDIC SCIENCE 16 ( 6 ) 710 - 718 2011.11

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER TOKYO

Analysis of the movement of anatomically defined reference axes at the femoral condyles relative to the tibia is appropriate for evaluating knee kinematics. However, such parameters have been previously employed only in studies utilizing stop-motion techniques. The purpose of this study was to evaluate in vivo dynamic kinematics for full range of motion in normal knees using the three-dimensional to two-dimensional registration technique and to compare them with previously reported normal knee kinematics obtained via stop-motion techniques.
Dynamic motion of the right knee was analyzed in 20 healthy volunteers (10 female, 10 male; mean age 37.2 years). Knee motion was observed when subjects squatted from standing with the knee fully extended to maximum flexion. We determined the following parameters: (1) changes to angles of the geometric center axis (GCA) on the tibial axial plane (rotation angle); (2) anteroposterior translations of the medial and lateral ends of the GCA; and (3) motion patterns in each phase during knee flexion.
All subjects exhibited femoral external rotation (26.1A degrees) relative to the tibia throughout knee flexion. The medial femoral condyle demonstrated anterior translation (5.5 mm) from full extension to 100A degrees flexion, and demonstrated posterior translation (3.9 mm) after 100A degrees, while the lateral femoral condyle demonstrated consistent posterior translation (15.6 mm) throughout knee flexion. All subjects showed medial pivot motion from full extension to nearly 120A degrees flexion. From 120A degrees flexion, bicondylar rollback motion was observed.
Although the behavior of the medial femoral condyle in our analysis differed somewhat from that seen in previous cadaver studies, the results obtained using dynamic analysis were generally equivalent to those obtained in previous studies employing stop-motion techniques. These results provide control data for future dynamic kinematic analyses of pathological knees.

DOI： 10.1007/s00776-011-0149-9

3次元下肢アライメント評価システムを用いた人工股関節ステム挿入管理法の開発 Reviewed

窪田陽介, 藤原諒, 坂本信, 小林公一, 古賀良生, 湊泉, 落合清秀, 清徳則雄

臨床バイオメカニクス 32 339 - 345 2011.10

MRIを用いた脛距関節における接触領域のIn Vivo解析 Reviewed

坂本信, 牧岡諒太, 吉田秀義, 小林公一, 笹川圭右, 田邊裕治

臨床バイオメカニクス 32 215 - 223 2011.10

人工股関節摺動面における応力分布の数値解析 Reviewed

解晨, 坂本信, 西野勝敏, 湊泉, 古賀良生, 佐藤卓, 小林公一, 大森豪, 田邊裕治

臨床バイオメカニクス 32 283 - 289 2011.10

Validation of near infrared spectroscopy for measurement of water content in human articular cartilage using gelatin model Reviewed

Yamagishi E, Tanabe Y, Kikuchi T, Sakamoto M, Kobayashi K

Journal of the Japanese Society of Experimental Mechanics 11 ss239 - ss243 2011.8

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Experimental Mechanics

This paper deals with the applicability of the near infrared (NIR) spectroscopy to quantitative measurement of the water content in human articular cartilage using gelatin model. We developed the device using NIR light at a wave length of 970nm, and investigated whether or not the device was useful for the measurement of the water content in articular cartilage. The gelatin was used as materials for the specimens with single, two- and three-layers. The absorbance defined as the intensity ratio between emitting and receiving NIR lights, the variation of receiving light intensity with the water content, and that with the distance between two probes of the light source and sensor were measured. The absorbance increased with increasing water content and with increasing probe distance (R<SUP>2</SUP>=0.86&sim;0.91). In the layered specimens, the light was supposed to pass through the surface layer and then reach the adjacent layer. These results showed that the device was useful for the measurement of the water content in the single and layered specimens. This study suggested that the device developed in this study have some possibilities of acquiring the quantitative data of water content at any point from the surface of articular cartilage.

DOI： 10.11395/jjsem.11.s239

Other Link： http://hdl.handle.net/10191/26369

透視X線画像を用いた人工膝関節単顆置換術前後のTEAからみた三次元運動解析

望月友晴, 佐藤卓, 山際浩史, 渡辺聡, 谷藤理, 小林公一, 大森豪, 古賀良生, 遠藤直人

JOSKAS 36 ( 4 ) 332 - 332 2011.6

透視X線画像を用いた人工膝関節単顆置換術前後の三次元運動解析

望月友晴, 佐藤卓, 山際浩史, 谷藤理, 小林公一, 古賀良生, 大森豪, 松枝宗則, 遠藤直人

日本整形外科学会雑誌 85 ( 3 ) S352 - S352 2011.3

Experimental validation of femorotibial contact behavior assessed by the image matching method

豊田貴嗣, 小林公一, 坂本信

Japanese journal of clinical biomechanics 32 483 - 487 2011

Estimation of in-vivo quadriceps forces of the KNEE - A combined in-vivo patellofemoral joint kinematics measurement and finite element prediction Reviewed

Koichi Kobayashi, Guoan Li

ASME 2011 Summer Bioengineering Conference, SBC 2011 851 - 852 2011

TKAにおけるTransepicondylar Axisからみた大腿骨顆部形状変化

望月友晴, 佐藤卓, 山際浩史, 小林公一, 渡辺聡, 谷藤理, 大森豪, 古賀良生, 遠藤直人

日本人工関節学会誌 40 592 - 593 2010.12

Language：Japanese Publisher：(一社)日本人工関節学会

従来の方法で人工膝関節全置換術(TKA)を施行した大腿骨における、大腿骨上顆軸(TEA)からみた三次元的な関節表面までの距離とインプラントの三次元的設置角度を評価し、Single radius型のインプラント設置法を再検討した。TKAを施行した40例40膝を対象とした。TKA後、下肢全長2方向CR像に骨とインプラントの三次元形状モデルを重ね合わせ、実際の設置状態を正確に再現した骨-インプラントの三次元モデル複合体を生成した。術後の大腿骨インプラント内外側穎部最遠位点からTEAまでの距離(遠位径)と同最後方点からのTEAまでの距離(後方径)と、インプラント三次元設置角度を評価した。内側においては遠位径-後方径間に有意差は認めなかったが、外側においては後方径が遠位径に比して有意に短かった。内外反・屈曲伸展は概ね良好であったが、回旋角度がTEAに対して内旋傾向であった。

Accuracy of image-matching in a setting method for the stem during total hip arthroplasty using a three-dimension leg alignment assessment systems

KUBOTA Yosuke, SAKAMOTO Makoto, KOBAYASHI Koichi, KOGA Yoshio, MINATO Izumi, ITO Tomoyuki, SEITOKU Norio

Japanese journal of clinical biomechanics 31 313 - 319 2010.9

Development of Automatic Method for Construction of Joint Coordinate System on Tibial 3D Bone Model

KAI Shin, SASAGAWA Keisuke, KOGA Yoshio, SATO Takashi, TANIFUJI Osamu, SAKAMOTO Shin, KOBAYASHI Koichi, TANABE Yuji

Japanese journal of clinical biomechanics 31 333 - 340 2010.9

Transmission characteristics of near-infrared light in articular cartilage

MATSUMOTO Go, ODASHIMA Koki, KIKUCHI Tatsuya, KOBAYASHI Koichi, SAKAMOTO Makoto, TANABE Yuji, KOGA Yoshio

Japanese journal of clinical biomechanics 31 73 - 77 2010.9

In Vivo Structural Analysis of Trabecular Bone of Talus and Calcaneus Using Magnetic Resonance Imaging

SAKAMOTO Makoto, SASAGAWA Keisuke, KUBOTA Yosuke, KOBAYASHI Koichi, YOSHIDA Hidenori

Japanese journal of clinical biomechanics 31 13 - 20 2010.9

Analysis of contact behavior of knee joint using image registration method

ODAGAWA Kenichi, TOYODA Takatsugu, KOBAYASI Koichi, TANIFUJI Osamu, SASAGAWA Keisuke, SATO Takashi, SAKAMOTO Makoto, KOGA Yoshio, TANABE Yuji, OMORI Go

Japanese journal of clinical biomechanics 31 349 - 355 2010.9

Accuracy Estimation of Three-Dimensional Lower Extremity Alignment Assessment System Using MRI Models for Bone and Cartilage

SASAGAWA Keisuke, SAKAMOTO Makoto, KOBAYASHI Koichi, KOGA Yoshio, TANABE Yuji, OMORI Go, SATO Takashi

Japanese journal of clinical biomechanics 31 341 - 348 2010.9

Numerical analysis of pressure on cup surface after THA Reviewed

Kai S, Sakamoto M, Kobayashi K, Minato I, Koga Y, Tanabe Y

Journal of the Japanese Society of Experimental Mechanics 10 ss251 - ss255 2010.8

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Experimental Mechanics

Estimation of the artificial hip joint contact area and pressure distribution during motions of daily life is important in predicting joint degeneration mechanism and implant wear. The purpose of this study was to develop a method of applying discrete element analysis (DEA) based on a rigid body spring model to artificial hip joint, and to analyze contact area and pressure distribution during different motions. Post-operative motion analyses of four basic motions, such as fast walking, slow walking, standing up and sitting down were performed by using VICON system and Kistler force plate. Implant orientation was obtained by matching the contours of 3D bone model and implant CAD model to those of the biplanar CR images. Triangular mesh at interior surface of cup model was considered as liner surface and used for applying DEA to artificial hip joint.Because stem model was considered to be a rigid body and consequential transformations occurred only inside the liner model, triangular mesh was considered to be a compressive spring respectively.The change of contact area and the pressure distribution under dynamic condition were calculated easily through these considerations, and rapid increase accompanied with change of area was observed in knee bending motions.

DOI： 10.11395/jjsem.10.s251

Other Link： http://hdl.handle.net/10191/26374

In vivo contact areas of tibiotalar joint measured with magnetic resonance imaging Reviewed

Sakamoto M, Nodaguchi Y, Tanabe Y, Sasagawa K, Kubota Y, Kobayashi K

Journal of the Japanese Society of Experimental Mechanics 10 ss247 - ss250 2010.8

Accuracy verification of image-matching in a setting method for the stem during total hip arthroplasty Reviewed

Kubota Y, Sakamoto M, Kobayashi K, Koga Y, Tanabe Y

Journal of the Japanese Society of Experimental Mechanics 10 ss234 - ss239 2010.8

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Experimental Mechanics

Currently, stem insertion during total hip arthroplasty (THA) is not well controlled. The present study investigated a method for improving stem setting in accordance with preoperative planning using a three-dimensional (3-D) computed tomography (CT) model of the femur and RGB images of the excised femoral head. We utilized three femoral heads removed during THA and modeled each head using three spherical acrylic markers. Each femoral head was osteotomized using a parallel jig and three rectangular images of the osteotomized head were taken using a CCD camera. Each femoral head was then set on a camera base and RGB images were taken from three orthogonal directions using the CCD camera. The B-images of the femoral head and the 3-D bone model were processed through image-matching software using an automatic outline extraction and downhill simplex method. The position of the contralateral side of the jig, related to the femur, was measured using a 3-D measuring system in order to validate the accuracy of the image-matching. However, since validation of the accuracy of the image-matching is difficult once the femoral head is excised, a six-degree-of-freedom board was used to facilitate the accuracy validation.

DOI： 10.11395/jjsem.10.s247

Other Link： http://hdl.handle.net/10191/26371

Three-dimensional In vivo contact analysis of the wrist joint during wrist motion Reviewed

Sasagawa K, Sakamoto M, Yoshida H, Kobayashi K, Tanabe Y

Journal of the Japanese Society of Experimental Mechanics 10 ss261 - ss266 2010.8

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Experimental Mechanics

The wrist joint is condyloid and capable of movement through two axes: palmar/dorsal flexion and radial/ulnar deviation. Knowledge of <i>in vivo</i> joint mechanics is important for understanding pathological mechanisms and the treatment of various joint problems. The purpose of this study was to investigate the <i>in vivo</i> wrist joint mechanism during wrist motion. <i>In vivo</i> wrist joint contact and the kinematics of the scaphoid and lunate during palmar/dorsal flexion and radial/ulnar deviation were examined using magnetic resonance imaging (MRI). The wrist joints of 15 healthy young volunteers were scanned at 8 positions (.30 deg of palmar flexion; neutral; 30, 60, and 90 deg of dorsal flexion; .20 deg of radial deviation; neutral; and 20 deg of ulnar deviation). Contact of the wrist joint was estimated quantitatively from the derived MR images. Using three-dimensional surface models of the carpal bones, the kinematics of the scaphoid and lunate were analyzed three-dimensionally.

DOI： 10.11395/jjsem.10.s261

Other Link： http://hdl.handle.net/10191/26375

人工膝関節単顆置換術適応症例における術前の三次元膝運動解析

望月友晴, 佐藤卓, 山際浩史, 谷藤理, 小林公一, 古賀良生, 大森豪, 遠藤直人

JOSKAS 35 ( 4 ) 312 - 312 2010.6

Three-dimensional lower extremity alignment in the weight-bearing standing position in healthy elderly subjects Reviewed

Akihiro Ariumi, Takashi Sato, Koichi Kobayashi, Yoshio Koga, Go Omori, Izumi Minato, Naoto Endo

JOURNAL OF ORTHOPAEDIC SCIENCE 15 ( 1 ) 64 - 70 2010.1

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER TOKYO

Although assessment of lower extremity alignment is important for the treatment and evaluation of diseases that present with malalignment of the lower extremity, it has generally been performed using only plain radiographs seen in two dimensions (2D). In addition, there is no consensus regarding the criteria for quantitative three-dimensional (3D) evaluation of the relative angle between the femur and tibia. The purpose of this study was to establish assessment methods and criteria for quantitatively evaluating lower extremity alignment in 3D and to obtain reference data from normal elderly subjects.
The normal alignment of 82 limbs of 45 healthy elderly subjects (24 women, 21 men; mean age 65 years, range 60-81 years) was analyzed in 3D with regard to flexion, adduction-abduction, and rotational angle of the knee in the weight-bearing, standing position. The obtained computed tomography (CT) and biplanar computed radiography (CR) data were used to define several anatomical axes of the femur and tibia as references.
In the sagittal plane, the mean extension-flexion angle was significantly more recurvatum in women than in men. In the coronal plane, the mean 3D hip-knee-ankle angle was more varus by several degrees in this Japanese series than that in a Caucasian series reported previously. Regarding rotational alignment, the mean angle between the anteroposterior axis of the tibia and the transepicondylar axis of the femur in this series was slightly larger (externally rotated) than that of previously reported Japanese series examined in the supine position.
These data are believed to represent important references for 3D evaluation of morbid lower extremity alignment in the weight-bearing, standing position and are important for biomechanical research (e.g., 3D analyses of knee kinematics) because the relative angles between the femur and tibia are assessed three-dimensionally.

DOI： 10.1007/s00776-009-1414-z

Automated image registration for assessing three-dimensional alignment of entire lower extremity and implant position using bi-plane radiography Reviewed

Koichi Kobayashi, Makoto Sakamoto, Yuji Tanabe, Akihiro Ariumi, Takashi Sato, Go Omori, Yoshio Koga

JOURNAL OF BIOMECHANICS 42 ( 16 ) 2818 - 2822 2009.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

An automated image-matching technique is presented to assess alignment of the entire lower extremity for normal and implanted knees and the positioning of implants with respect to bone. Sawbone femur and tibia and femoral and tibial components of a total knee arthroplasty system were used. Three spherical markers were attached to each sawbone and each component to define the local coordinate system. Outlines of the three-dimensional (3D) bone models and component computer-aided design (CAD) models were projected onto extracted contours of the femur, tibia, and implants in frontal and oblique X-ray images. Three-dimensional position of each model was recovered by minimizing the difference between the projected outline and the contour. Median values of the absolute error in estimating relative positions were within 0.5 mm and 0.6 degrees for the femur with respect to the tibia, 0.5 mm and 0.5 degrees for the femoral component with respect to the tibial component, 0.6 mm and 0.6 degrees for the femoral component with respect to the femur, and 0.5 mm and 0.4 degrees for the tibial component with respect to the tibia, indicating significant improvements when compared to manually obtained results. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jbiomech.2009.08.022

Determination of Joint Contact Area Using MRI

YOSHIDA Hidenori, KOBAYASHI Koichi, SAKAMOTO Makoto, TANABE Yuji

Japanese Journal of Radiological Technology 65 ( 10 ) 1407 - 1414 2009.10

Language：Japanese Publisher：Japanese Society of Radiological Technology

Elevated contact stress on the articular joints has been hypothesized to contribute to articular cartilage wear and joint pain. However, given the limitations of using contact stress and areas from human cadaver specimens to estimate articular joint stress, there is need for an <i>in vivo</i> method to obtain such data. Magnetic resonance imaging (MRI) has been shown to be a valid method of quantifying the human joint contact area, indicating the potential for <i>in vivo</i> assessment. The purpose of this study was to describe a method of quantifying the tibiofemoral joint contact area using MRI. The validity of this technique was established in porcine cadaver specimens by comparing the contact area obtained from MRI with the contact area obtained using pressure-sensitive film (PSF). In particular, we assessed the actual condition of contact by using the ratio of signal intensity of MR images of cartilage surfaces. Two fresh porcine cadaver knees were used. A custom loading apparatus was designed to apply a compressive load to the tibiofemoral joint. We measured the contact area by using MRI and PSF methods. When the ratio of signal intensity of the cartilage surface was 0.9, the error of the contact area between the MR image and PSF was about 6%. These results suggest that this MRI method may be a valuable tool in quantifying joint contact area<i> in vivo</i>.

DOI： 10.6009/jjrt.65.1407

Three-Dimensional Trabecular Bone Structure Analysis Using Magnetic Resonance Imaging

SAKAMOTO Makoto, HIGO Yusuke, SASAGAWA Keisuke, KOBAYASHI Koichi, YOSHIDA Hidenori, MIYAO Masunao

Japanese journal of clinical biomechanics 30 27 - 34 2009.9

Accuracy of 2D-3D image registration of bone using single-plane fluoroscopic images

ODAGAWA Kenichi, KOBAYASI Koichi, SAKAMOTO Makoto, TANIFUJI Osamu, TANABE Yuji, KOGA Yoshio, SATO Takashi, OMORI Go

Japanese journal of clinical biomechanics 30 457 - 462 2009.9

Development of a setting method for the stem during total hip arthroplasty using a three-dimensional leg alignment assessment system

KUBOTA Yosuke, SAKAMOTO Makoto, KOBAYASHA Koichi, KOGA Yoshio, SATO Takashi, TANABE Yuji, KAI Shin, SEITOKU Norio

Japanese journal of clinical biomechanics 30 301 - 306 2009.9

Development of a three-dimensional motion analysis technique of femorotibial joint by means of motion capture system : Application of a three-dimensional leg alignment assessment system to three-dimensional joint motion analysis

KIMURA Taro, NISHINO Katsutoshi, KAI Shin, OMORI Go, TANABE Yuji, SAKAMOTO Makoto, KOBAYASHI Koichi, SEITOKU Norio, KOGA Yoshio

Japanese journal of clinical biomechanics 30 487 - 492 2009.9

Application of MRI Model for Three-Dimensional Lower Extremity Alignment Assessment System

SASAGAWA Keisuke, ISHIYA Shuichi, SAKAMOTO Makoto, KOBAYASHI Koichi, HAYASHI Toyohiko, TANABE Yuji, SATO Takashi, OMORI Go, KOGA Yoshio

Japanese journal of clinical biomechanics 30 479 - 486 2009.9

Analysis of Three-Dimensional Contact Area of Radiocarpal Joint Using Magnetic Resonance Imaging

SASAGAWA Keisuke, SAKAMOTO Makoto, KOBAYASHI Koichi, YOSHIDA Hidenori, TANABE Yuji

Japanese journal of clinical biomechanics 30 89 - 96 2009.9

Three-dimensional contact analysis of human wrist joint using MRI Reviewed

Sasagawa K, Sakamoto M, Yoshida H, Kobayashi K, Tanabe Y

Japanese Society of Experimental Mechanics 9 ss167 - ss171 2009.8

Imaged-based matching for natural knee kinematics measurement using single-plane fluoroscopy Reviewed

Kobayashi K, Tanaka N, Odagawa K, Sakamoto M, Tanabe Y

Journal of the Japanese Society of Experimental Mechanics 9 ss162 - ss166 2009.8

Viscoelastic properties of microstructural components of rat cortical bone tissue measured by dynamic nanoindentation Reviewed

Sakamoto M, Kobayashi K

Journal of the Japanese Society of Experimental Mechanics 9 ss151 - ss155 2009.8

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Experimental Mechanics

Dynamic nanoindentation was used to determine microstructural viscoelastic properties of single osteons and interstitial lamellae of rat cortical bone tissue. The effects of mineral, organic and water contents on macrostructural viscoelastic properties were also investigated. Compared to interstitial lamellae, the storage moduli of osteons were significantly lower; however, loss tangents were higher. The storage modulus and mineral content were correlated, and the loss tangent and the organic and water contents were linearly correlated.

DOI： 10.11395/jjsem.9.s151

Development of Controlling Stem Setting Using Image-matching in Total Hip Arthroplasty Reviewed

KUBOTA YOUSUKE, Sakamoto M, Kobayashi K, Koga Y, Sato T, Tanabe Y, Kai S, Seitoku N

4th Asian Pacific Conference on Biomechanics 337 2009.4

Accuracy of single plane X-ray image-based technique for assessment of knee kinematics Reviewed

Koichi Kobayashi, Ken-ichi Odagawa, Makoto Sakamoto, Yuji Tanabe

Journal of Biomechanical Science and Engineering 4 ( 2 ) 192 - 200 2009

Language：English Publishing type：Research paper (scientific journal)

The purpose of the present study is to develop a direct and accurate method for measuring knee kinematics by using single-plane fluoroscopy. The study was carried out on a human cadaver femur. Computed tomography (CT) scan data of the femur was taken in order to construct 3D bone volume model of the femur. The femur was placed on an acrylic holder that was attached to a micromanipulator. The femur was rotated about in each orthogonal axis of the micromanipulator over a range of ±2° in 1° increments and then translated along each orthogonal axis over a range of ±2 mm in 1-mm increments. The 3-dimensional (3D) position of the femur (in other words, the 6 degree-of-freedom (DOF) parameters) was recovered by matching the digitally reconstructed radiographs (DRRs) generated from the 3D volume model of the femur and single-plane fluoroscopic images taken from the 25 positions generated by using the micromanipulator. The root-mean-square error (RMSE) of the overall rotation parameters was within 1.4°. For the translation parameters RMSE took its maximal value of 7.8 mm in the out-of-plane direction. This indicates that the present method has potential for clinical application. Copyright © 2009 by The Japan Society of Mechanical Engineers.

DOI： 10.1299/jbse.4.192

Accuracy Examination of Three-Dimensional Bone Surface Model Using MRI and CT

SASAGAWA Keisuke, WATANABE Satoshi, KOBAYASHI Koichi, SAKAMOTO Makoto, TANABE Yuji, SATO Takashi, KOGA Yoshio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 29 397 - 402 2008.11

Accuracy of automated image matching technique of bone and implants using biplanar radiography

KOBAYASHI Koichi, TANAKA Nobuaki, ODAGAWA Ken-ichi, SATO Takashi, SAKAMOTO Makoto, TANABE Yuji, OMORI Go, KOGA Yoshio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 29 421 - 426 2008.11

Estimation of Mineral Density and Viscoelastic Properties of Human Dentin

SAKAMOTO Makoto, KITAMURA Takuya, SASAGAWA Keisuke, KOBAYASHI Koichi, ENDO Hideaki, ITOH Hidemi

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 29 153 - 160 2008.11

Measurement of water content in articular cartilage using near infrared spectroscopic meter : Attenuation characteristics of near infrared ray

SATO Shinya, HAMADA Kazunari, TANABE Yuji, SAKAMOTO Makoto, KOBAYASHI Koichi, KIKUCHI Tatsuya, KOGA Yoshio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 29 81 - 86 2008.11

Accuracy of 3-D pose estimation of bone using an image matching technique with fluoroscopic images and 3-D bone model

TANAKA Nobuaki, KOBAYASHI Koichi, TANABE Yuji, SATO Takashi, KOGA Yoshio, OMORI Go, SAKAMOTO Makoto

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 29 403 - 408 2008.11

Dynamic Viscoelastic Properties of Human Dentin

SAKAMOTO Makoto, SASAGAWA Keisuke, KOBAYASHI Koichi, ENDO Hideaki, ITOH Hidemi

Journal of JSEM 8 ( 2 ) 121 - 126 2008.6

Basic Research for Quantitative Measurement of Water Content in Articular Cartilage Using Near Infrared Spectroscopic Meter

HAMADA Kazunari, SATO Shinya, KIKUCHI Tatsuya, TANABE Yuji, SAKAMOTO Makoto, KOBAYASHI Koichi, KOGA Yoshio

非破壊検査 = JOURNAL OF THE JAPANESE SOCIETY FOR NON-DESTRUCTIVE INSPECTION 57 ( 2 ) 89 - 95 2008.2

Effect of Low-Gamma Irradiation on the Impact Compressive Properties of Ultra High Molecular Weight Polyethylene and Its Constitutive Model Reviewed

小林公一, 坂本信, 田邊裕治

材料 57 ( 9 ) 882-886 (J-STAGE) - 886 2008

Language：Japanese Publisher：日本材料学会

The effects of low-gamma irradiation on the impact compressive properties of ultra high molecular weight polyethylene (UHMWPE) were investigated. Gamma irradiation was performed at 30kGy in nitrogen or at 29kGy in air without post-irradiation treatment. Impact compressive tests using the split-Hopkinson pressure-bar (SHPB) technique were performed to measure stress&ndash;strain relations up to a true strain of 8% at a strain rate of 260s<SUP>-1</SUP>. Gamma irradiation in air significantly increased the Young's modulus and the 0.5% yield stress, and gamma irradiation in N<SUB>2</SUB> significantly increased the 0.5% yield stress, as determined by impact compressive testing. The impact stress-strain behaviors of both unirradiated and gamma irradiated UHMWPE specimens were compared by the elasto-viscoplastic model proposed by Bergstr&ouml;m [Biomaterials Vol.23 p.2329 (2002)]. We found that the elasto-viscoplastic model had a potential to predict the observed impact stress-strain responses.

DOI： 10.2472/jsms.57.882

Analysis of Patellofemoral Joint Contact Area Using Magnetic Resonance Imaging

SAKAMOTO Makoto, SHIMODA Masaru, KOBAYASHI Koichi, YOSHIDA Hidenori, TANABE Yuji

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 28 161 - 166 2007.11

Development of computer-assisted Total Hip Arthroplasty : New method for femur component setting

KAI Shin, TANABE Yuji, KOGA Yoshio, SATO Takashi, WATANABE Satoshi, KOBAYASHI Koichi, MINATO Izumi, SEITOKU Norio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 28 263 - 268 2007.11

Accuracy of 3-D pose estimation of bone using an image matching technique with fluoroscopic images and 3-D bone model

TANAKA Nobuaki, KOBAYASHI Koichi, TANABE Yuji, SATO Takashi, WATANABE Satoshi, KOGA Yoshio, OMORI Go, SAKAMOTO Makoto, SEITOKU Norio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 28 335 - 339 2007.11

Accuracy improvement of the cup-position setting of total hip arthroplasty in an arthroscopic image-based assistance system

TAKEDA Yuya, KOGA Yoshio, MINATO Izumi, TANABE Yuji, HAYASHI Toyohiko, KOBAYASHI Koichi

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 28 275 - 279 2007.11

Evaluation of CT Slice Effect on Surface Modeling for Three-Dimensional Lower Extremity Alignment Assessment

YAMAZAKI Yoshihiro, SAKAMOTO Makoto, KOBAYASHI Kouichi, TANABE Yuji, SATO Takashi, WATANABE Satoshi, KOGA Yoshio, SEITOKU Norio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 28 369 - 373 2007.11

Accuracy of three-dimensional surface models of the knee reconstructed from magnetic resonance imaging

SASAGAWA Keisuke, WATANABE Satoshi, KOBAYASHI Koichi, SAKAMOTO Makoto, SATO Takashi, KOGA Yoshio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 28 349 - 354 2007.11

Experimental research into a method of assisting total knee arthroplasty

MIZUOCHI Yusuke, KAI Shin, KOGA Yoshio, SATO Takashi, WATANABE Satoshi, TANABE Yuji, KOBAYASHI Koichi, SEITOKU Norio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 28 219 - 223 2007.11

The elastic contact between a circular rigid punch and a transversely isotropic layer bonded to a rigid foundation Reviewed

SAKAMOTO Makoto

Theoretical and Applied Mechanics 56 15 - 28 2007.10

The effects of strain rate and low-gamma irradiation on the compressive properties of UHMWPE. Reviewed

Kobayashi K, Kakinoki T, Sakamoto M, Tanabe Y

Bio-medical materials and engineering 17 ( 2 ) 87 - 95 2007

Accuracy of the 3D-pose estimation using fluoroscopic images of total knee arthroplasty

KOBAYASHI Koichi, SATO Takashi, OMORI Go, KOGA Yoshio, SAKAMOTO Makoto, TANABE Yuji

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 27 225 - 229 2006.10

Measurements of Viscoelastic Properties of Cortical Bone Using Dynamic Nanoindentation

SAKAMOTO Makoto, MURATA Fuyuki, IWATA Takayuki, KOUDA Fumikazu, KOBAYASHI Koichi, OMORI Go, TANABE Yuji, HARA Toshiaki

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 27 53 - 59 2006.10

Quantitative Evaluation of Water Content in Articular Cartilage Using Near Infrared Spectrometer

HAMADA Kazunari, TANABE Yuji, KIKUCHI Tatsuya, KOBAYASHI Koichi, SAKAMOTO Makoto, KOGA Yoshio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 27 35 - 38 2006.10

New method of controlling cup setting of total hip arthroplasty using an arthroscopic image matching

SHIMURA Masashi, KOGA Yoshio, OMORI Go, MINATO Izumi, SATO Takashi, KOBAYASHI Koichi, SEITOKU Norio, NAKAMURA Yasuo, HAYASHI Toyohiko

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 27 247 - 252 2006.10

The axisymmetric problem of an elastic layer indented by an infinite rigid punch with a circular hole Reviewed

Sakamoto M, Kobayashi K

Theoretical and Applied Mechanics 55 61 - 71 2006.10

Analysis of Tibio-Femoral Joint Kinematics and Contact Area Using MRI

Yoshida Hidenori, Watanabe Keichi, Tanabe Yuji, Kobayashi Koichi, Sakamoto Makoto

実験力学 6 ( 1 ) 31 - 35 2006.3

Language：Japanese

This study analyzed tibio-femoral joint kinematics and contact area during knee flexion at 0ｰ, 30ｰ, 60ｰ, 90ｰ and 135ｰ using magnetic resonance imaging with a 3D-fat-suppressed fast low angle shot sequence (3D-FLASH). At a 200N loading situation, knee flexion angles were chosen to be 0ｰ, 30ｰand 60ｰ. Sagittal and coronal images were obtained under the loading and unloading situations from 6 healthy male Japanese volunteers. At unloading situation, from 0ｰ to 90ｰ the centroids of the medial and lateral contact areas translated backward and outside. From 90ｰ to 135ｰ the centroids of the medial and lateral contact areas translated backward and inside. The contact areas tended to decrease, but from 60ｰ to 135ｰ knee flexion the medial contact area was not changed generally. At loading situation, almost the same results as observed at unloading situation for each translation were obtained. However, the translation of centroids of the medial and lateral contact areas decreased with an increase of knee flexion, and the centroids moved roughly straight backward as well. The contact areas increased at each knee flexion angle as compared to unloading situation. These results showed good correlation with previous ones found in the other studies of knee kinematics.

DOI： 10.11395/jjsem.6.31

Analysis of tibio-femoral joint kinematics and contact area using MRI

H. Yoshida, Y. Tanabe, K. Kobayashi, M. Sakamoto

PROCEEDINGS OF THE 5TH WORLD CONGRESS OF BIOMECHANICS 6 ( 1 ) 139 - + 2006

Language：English Publishing type：Research paper (international conference proceedings) Publisher：MEDIMOND S R L

This study analyzed tibio-femoral(TF) joint kinematics and contact area(CA) during knee flexion at 0 degrees, 30 degrees, 60 degrees, 90 degrees and 135 degrees using MRI. At a 200N loading situation, knee flexion angles were chosen to be 0 degrees, 30 degrees and 60 degrees. At unloading situation, from 0 to 90 the centroids of the medial and lateral CAs were translated backward and outside. From 90 degrees to 135 degrees, the centroids of both CAs translated backward and inside. The CAs tended to decrease, but from 60 degrees to 135 degrees knee flexion the medial CA was not changed generally. At loading situation, almost the same results as observed at unloading situation for each translation were obtained. However, the translation of the centroids of both CAs decreased with an increase of knee flexion. The CAs increased at each knee flexion angle as compared to unloading situation.

DOI： 10.11395/jjsem.6.31

Relationship between viscoelastic properties and composition of dentin

HASEGAWA Hiroshi, KOBAYASHI Koichi, SAKAKI Jun, KOUDA Fumikazu, KUROE Toshifumi, OHATA Noboru, TANABE Yuji, SAKAMOTO Makoto

接着歯学 = Adhesive dentistry 23 ( 4 ) 269 - 269 2005.12

Analysis of load-speed dependence of mechanical properties in human root dentin

HASEGAWA Hiroshi, KOBAYASHI Koichi, SAKAI Jun, KODA Fumikazu, KUROE Toshifumi, OHATA Noboru, TANABE Yuji, SAKAMOTO Makoto

北海道歯学雑誌 26 ( 2 ) 237 - 245 2005.12

Determination of Mechanical Properties of Articular Cartilage at High Strain Rate Using the Split-Hopkinson Pressure-Bar Technique

KAKINOKI Toshihiko, KOBAYASHI Koichi, SAKAMOTO Makoto, WAKUI Takashi, TANABE Yuji, KIKUCHI Tatsuya, OMORI Go, KOGA Yoshio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 26 65 - 70 2005.10

Radiographic assessment of trabecular structure around total knee arthroplasty

KOBAYASHI Koichi, SAKAMOTO Makoto, TANABE Yuji, OMORI Go, KOGA Yoshio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 26 41 - 46 2005.10

Correlation of Volumetric Bone Mineral Density with Mechanical Properties of Rat Femoral Cortical Bone Using Nanoindentation

SAKAMOTO Makoto, SATO Kenji, TANABE Yuji, MURATA Fuyuki, KOBAYASHI Koichi, SAKAI Jun, HARA Toshiaki, OMORI Go

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 26 35 - 40 2005.10

Accuracy Verification of a Newly Developed Turntable X-ray System in Three-Dimensional Leg Alignment Assessment System

YAMAZAKI Yoshihiro, KOBAYASHI Kouichi, SAKAMOTO Makoto, TANABE Yuji, OMORI Go, KOGA Yoshio, SATOU Takashi, SOBUE Ten

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 26 181 - 186 2005.10

The axisymmetric contact problem of a transversely isotropic layer subjected to a tensile stress applied over a circular region Reviewed

Sakamoto M, Kobayashi K

Theoretical and Applied Mechanics 54 3 - 15 2005.10

Relationships between Mechanical Properties and Volumetric Bone Mineral Density of Rat Femoral Cortical Bone

SAKAMOTO Makoto, SATO Kenji, TANABE Yuji, KOBAYASHI Koichi, MURATA Fuyuki, SAKAI Jun

Journal of JSEM 5 ( 1 ) 40 - 44 2005.3

Relationships between Mechanical Properties and Volumetric Bone Mineral Density of Rat Femoral Cortical Bone

Sakamoto Makoto, Sato Kenji, Tanabe Yuji, Kobayashi Koichi, Murata Fuyuki, Sakai Jun

実験力学 5 ( 1 ) 40 - 44 2005.3

Language：Japanese

The mechanical properties of cortical bone are a consequence of the interaction between the mineral and collagen components. Small variations in the amount of mineral present in a section of bone can have a large influence on its mechanical properties. Studies have shown the correlations between Vickers microhardness and mineral content, and Vickers microhardness and elastic modulus using three-point and four-point bending tests. However, the precise nature of statistical relationship has yet to be established. Nanoindentation, which evolved from Vickers microhardness test, allows for measurement of mechanical properties of cortical bone at the nanometer scale. The nanoindentation technique has been applied to estimate mechanical properties of bone at a microscopic length scale, overcoming the limitations of traditional mechanical tests for small specimens. In this study, the relationships between mechanical properties measured by nanoindentation and volumetric Bone Mineral Density (vBMD) measured by peripheral Quantitative Computed Tomography (pQCT) in femoral cortical bone from a variety of ages of rats were investigated. The specimen of rat cortical bone used here was Haversian bone. Experimentally measured elastic modulus was correlated with vBMD (r=0.80). It was found that a good correlation also existed between hardness and vBMD (r=0.81).

DOI： 10.11395/jjsem.5.40

Relationship between 3D structural and torsional properties of bovine trabecular bone

KOBAYASHI Koichi, KAITOH Takanori, YAMADA Mayu, SAKAMOTO Makoto, TANABE Yuji, HARA Toshiaki

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 25 1 - 6 2004.11

Measurement of Water Content in Articular Cartilage Using Near Infrared Spectroscopy (2^<nd> Report) : Relationship between cartilage degeneration and recovery rate of NIR absorbance for cartilage

HAMADA Kazunari, TANABE Yuji, KIKUCHI Tatsuya, KOBAYASHI Koichi, SAKAMOTO Makoto, KOGA Yoshio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 25 103 - 107 2004.11

Nano-Mechanical Properties of Hard Tooth Tissues

SAKAI Jun, KODA Fumikazu, SAKAMOTO Makoto, KOBAYASHI Koichi, HARA Toshiaki, ITOH Hidemi, HASEGAWA Hiroshi, KUROE Toshifumi, OHATA Noboru

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 25 229 - 233 2004.11

Biomechanical Evaluation of Anterior Cruciate Ligament by Tensile and Tensile-Torsional Tests

TAKAYANAGI Tsutomu, KOBAYASHI Koichi, SAKAMOTO Makoto, TANABE Yuji, SEGAWA Hiroyuki, OOMORI Go, KOGA Yoshio

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 25 167 - 171 2004.11

Measurements of Elastic Modulus and Hardness of Bovine Vertebral Shell Using Nanoindentation

SAKAMOTO Makoto, MURATA Fuyuki, KOBAYASHI Koichi, SATO Kenji, SAKAI Jun, TANABE Yuji, HARA Toshiaki, OMORI Go

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 25 19 - 24 2004.11

The axisymmetric contact problem of an elastic layer subjected to a tensile stress applied over a circular region Reviewed

Sakamoto M, Kobayashi K

Theoretical and Applied Mechanics 53 27 - 36 2004.10

Mechanical Properties of Ultra High Molecular Weight Polyethylene under Impact Compression : Property Change with Gamma Irradiation and Dynamic Stress-Strain Analysis of Artificial Hip Joint

KOBAYASHI Koichi, KAKINOKI Toshihiko, TANABE Yuji, SAKAMOTO Makoto

Journal of JSEM 3 ( 4 ) 225 - 229 2003.12

Evaluation of Microhardness of Permanent and Primary Tooth

SAKAI Jun, KOUDA Fumikazu, SAKAMOTO Makoto, KOBAYASHI Koichi, MARUYAMA Yasuo, ITOH Hidemi, HARA Toshiaki

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 24 133 - 137 2003.11

Measurements of Mechanical Properties of Cortical Bone Using Nanoindentation Tests

SAKAMOTO Makoto, SATO Kenji, KOBAYASHI Koichi, SAKAI Jun, TAKANO Eisuke, HARA Toshiaki

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 24 1 - 5 2003.11

超微小押込み試験を用いた硬組織の力学的性質測定

坂本信, 佐藤憲二, 甲田文一, 坂井淳, 小林公一, 田辺裕治, 伊藤秀美

日本実験力学会講演論文集 ( 3 ) 127 - 130 2003.7

Split-Hopkinson Pressure-Bar Test using Striker Bar With Variable Cross Section

KOBAYASHI Koichi, TANABE Yuji

Journal of JSEM 2 ( 2 ) 35 - 39 2002.6

Strength Criterion for Bovine Tibial Trabecular Bone under Multiaxial Stress Reviewed

KOBAYASHI Koichi, SAKAI Jun, SAKAMOTO Makoto

Theoretical and Applied mechanics 50 91 - 96 2001.10

Mechanical Behaviour of Bovine Trabecular Bone Subjected to Impact Compressive Load

KOBAYASHI Koichi, TANABE Yuji, HARA Toshiaki

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A 63 ( 616 ) 2624 - 2630 1997.12

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Dynamic compressive behaviour of bovine trabecular bone was investigated. Compression tests on cylindrical specimens of bovine distal femurs were carried out using the split-Hopkinson pressurebar (SHPB) technique at strain rates ranging from 100 to 700 s<SUP>-1</SUP>. Quasi-static compression tests were also performed using an Instron-type materials testing machine at strain rates of 2&times;10<SUP>-4</SUP> and 2&times;10<SUP>-3</SUP> s<SUP>-1</SUP>. Stiffness and ultimate strength were greater at greater apparent density and at higher strain rate. Both stress relaxation and creep functions were determined based on stress-time and strain-time relations obtained by the SHPB tests. Relaxation time and retardation time had no correlation with apparent density. The three-element standard linear solid model was then validated by these functions. The elastic spring stiffness of the model, E<SUB>1</SUB>, had a strong positive correlation with apparent density, while the elastic spring stiffness, E<SUB>2</SUB>, and the viscosity coefficient, &eta;, showed less correlation with apparent density. No significant differences in the relaxation and retardation times, the elastic spring stiffnesses, E<SUB>1</SUB>, E<SUB>2</SUB>, and the viscosity coefficient, &eta;, were observed between the specimens with and without marrow.

DOI： 10.1299/kikaia.63.2624

Mechanical Properties of Articular Cartilage Under Confined and Unconfined Compressions

KOBAYASHI Koichi

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 17 343 - 348 1996.10

Tempertaure dependence of viscoelastic properties of bovine compact bone

ONISHI Masafumi

日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 16 433 - 436 1995.10

Anisotropy in the dynamic non-linear viscoelastic properties of bovine compact bone Reviewed

Yuji Tanabe, Koichi Kobayashi

Journal of Materials Science: Materials in Medicine 5 ( 6-7 ) 397 - 401 1994.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Kluwer Academic Publishers

A non-linear model is proposed to characterize the mechanical behaviour of compact bone and has been validated by mechanical tests on bovine femoral compact bone. The model consists of a non-linear spring and a non-linear dashpot in parallel. The method of identifying the viscoelastic parameters in the model is discussed. Impact and quasi-static compressive mechanical tests have shown that the model can be applied to bone to represent its mechanical behaviour at strain rates up to 100 s-1. The directional dependence of the viscoelastic parameters for the bone are determined and discussed. © 1994 Chapman &amp
Hall.

DOI： 10.1007/BF00058972

IDENTIFICATION OF THE DYNAMIC PROPERTIES OF BONE USING THE SPLIT-HOPKINSON PRESSURE-BAR TECHNIQUE Reviewed

Y TANABE, K KOBAYASHI, M SAKAMOTO, T HARA, H TAKAHASHI

BIOMATERIALS MECHANICAL PROPERTIES 1173 127 - 141 1994

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