Faculty Profiles - KOBAYASHI Koichi

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

Scopus

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