Faculty Profiles - KOBAYASHI Koichi

Papers - KOBAYASHI Koichi

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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。

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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

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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.
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DOI： 10.1007/s00167-016-4166-2

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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。

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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

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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

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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.
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DOI： 10.1007/s00167-014-3296-7

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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。

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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

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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

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Papers - KOBAYASHI Koichi