Details of a Researcher - Iwamoto, Takuji

Iwamoto, Takuji

写真a

Affiliation: School of Medicine, Department of Orthopaedic Surgery (Shinanomachi)

Position: Associate Professor

Related Websites

http://www.keio-ortho.jp

External Links

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Licenses and Qualifications 【 Display / hide 】

医師免許証, 2000.04

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Research Areas 【 Display / hide 】

Life Science / Orthopedics

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Papers 【 Display / hide 】

The relationship between the morphological axis and the kinematic axis of the proximal radius

Oki S., Inaba N., Matsumura N., Iwamoto T., Yamada Y., Jinzaki M., Nagura T.

Surgical and Radiologic Anatomy (Surgical and Radiologic Anatomy) 41 ( 4 ) 423 - 429 2019.04

ISSN 09301038

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© 2018, Springer-Verlag France SAS, part of Springer Nature. Purpose: Surgical procedures for impaired forearm rotation such as for chronic radial head dislocation remain controversial. We hypothesized that the morphological axis of the proximal radius is important for stable forearm rotation, and we aimed to clarify the relationship between the morphological axis and the kinematic axis of the proximal radius using four-dimensional computed tomography (4DCT). Methods: Ten healthy volunteers were enrolled. Four-dimensional CT of the dominant forearm during supination and pronation was obtained. The rotation axis of forearm rotation was calculated from all frames during supination and pronation. The principle axis of inertia, which represents the most stable rotation axis of a rigid body, was calculated for the proximal radius by extending its surface data incrementally by 1% from the proximal end. The angle between the kinematic rotation axis and the morphological rotation axis of each length was calculated. Results: The rotation axis of the forearm was positioned on the radial head 0.0 mm radial and 0.4 mm posterior to the center of the radial head proximally and 2.0 mm radial and 1.2 mm volar to the fovea of the ulnar head distally. The principle axis at 15.9% of the length of the proximal radius coincided with the forearm rotation axis (kinematic axis). Individual differences were very small (SD 1.4%). Conclusion: Forearm rotation was based on the axis at 16% of the length of the proximal radius. This portion should be aligned in cases of severe morphological deformity of the radial head that cause “rattling motion” of the radial head after reduction procedures.
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Total finger joint arthroplasty with a costal osteochondral autograft: up to 11 years of follow-up

Sato K., Iwamoto T., Matsumura N., Suzuki T., Nishiwaki Y., Nakamura T.

Journal of Hand Surgery: European Volume (Journal of Hand Surgery: European Volume) 44 ( 2 ) 167 - 174 2019.02

ISSN 17531934

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© The Author(s) 2018. The purpose of this study was to evaluate the mid- to long-term clinical outcomes of total finger joint arthroplasty using a costal osteochondral autograft for joint ankylosis. Twenty-three joints (three metacarpophalangeal joints, 20 proximal interphalangeal joints) in 23 patients (19 men and four women) were treated with a costal osteochondral autograft and were evaluated after a mean follow-up of 77 months (60–138). Mean age was 33 years (18 to 55). Significant improvement in active finger extension/flexion was seen from a preoperative mean of −24°/26° (arc: 2°) to −13°/75° (arc: 63°) at latest follow-up. Mean preoperative Japanese Society for Surgery of the Hand version of the Disability of the Arm, Shoulder and Hand score was initially 24 and improved significantly to 5 at latest follow-up. Conclusion: total finger arthroplasty using a costal osteochondral autograft gave an anatomical and biological reconstruction and provided stable improvement at a mean follow-up of 77 months. Level of evidence: IV.
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Normal value and range of the humerus-elbow-wrist angle in a sample of healthy children with even distributions of age, sex, and laterality

Inaba N., Suzuki T., Iwamoto T., Matsumura N., Oki S., Nishiwaki M., Nakamura M., Matsumoto M., Sato K.

Journal of Pediatric Orthopaedics Part B (Journal of Pediatric Orthopaedics Part B) 28 ( 1 ) 57 - 61 2019.01

ISSN 1060152X

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© 2018 Wolters Kluwer Health, Inc. All rights reserved. This study was performed to evaluate the normal value of the humerus-elbow-wrist angle (HEWA) in a sample of healthy children with even distributions of age, sex, and laterality. A total of 168 radiographs of the elbows of healthy children with even distributions of age, sex, and laterality were reviewed. The mean HEWA was 12.1° (range: 5°-20°). The value of HEWA was significantly associated with increasing age. Neither sex nor side showed significant differences for the HEWA. The data should be useful for postoperative radiographic assessment of cubitus varus or valgus deformities.
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Computed tomography–based 3-dimensional preoperative planning for unlinked total elbow arthroplasty

Iwamoto T., Suzuki T., Oki S., Matsumura N., Nakamura M., Matsumoto M., Sato K.

Journal of Shoulder and Elbow Surgery (Journal of Shoulder and Elbow Surgery) 27 ( 10 ) 1792 - 1799 2018.10

ISSN 10582746

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© 2018 Journal of Shoulder and Elbow Surgery Board of Trustees Hypothesis: Three-dimensional (3D) surgical planning for unlinked total elbow arthroplasty (TEA) would be helpful for estimation of the implant size and accurate placement of implants. Methods: We included 28 patients who underwent TEA with an unlinked total elbow implant in this study. All patients underwent computed tomography scans of the elbow before surgery, and a 3D digital model of the elbow was reconstructed. After the appropriate size and position of the prosthesis were determined, 10 points around the bone tunnel (4 on the humerus and 6 on the ulna) were measured to plan the insertion of the humeral and ulnar stems. Two-dimensional planning was also performed using anteroposterior and lateral radiographs. Intraoperatively, the surgeon measured the planned parameters using a slide gauge to reproduce the 3D planned position of the stem insertion. Results: The stem sizes were accurately estimated in 57% of patients for the humerus and 68% for the ulna with 2-dimensional planning and in 86% for the humerus and 96% for the ulna with 3D planning. The mean differences between the positions of the prostheses after surgery with reference to the planned positions were 0.8° of varus and 1.5° of flexion for the humeral component and 0.7° of varus and 2.9° of flexion for the ulnar component. We did not evaluate rotational positioning in this study. Conclusions: The 3D surgical planning allowed accurate estimation of the implant size and appropriate placement of implants. This method may contribute to a reduced incidence of complications and improved long-term outcomes from TEA.
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Surgical Treatment for Chronic Tendon Mallet Injury

Suzuki T., Iwamoto T., Sato K.

Journal of Hand Surgery (Journal of Hand Surgery) 43 ( 8 ) 780.e1 - 780.e5 2018.08

ISSN 03635023

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© 2018 American Society for Surgery of the Hand A variety of surgical options for chronic tendon mallet fingers have been reported. There are advantages and disadvantages to current surgical approaches. We introduce a surgical treatment for chronic tendon mallet injury that involves anatomical reconstruction of the terminal tendon and lateral band with palmaris longus (PL) tendon grafting. Harvested PL tendon is folded in 2 or divided into 2 slips. The graft is attached to a remnant of the original terminal tendon at the distal interphalangeal joint. Both half-slip tendons are passed under the transverse retinacular ligament and sutured side to side to the lateral band at the level of the proximal phalanx. This surgical technique has these advantages: (1) it provides anatomical reconstruction of the terminal tendon; (2) it is indicated regardless of the condition of the terminal tendon and the interval from the initial injury; and (3) it is easy to determine the tension of the grafted tendon. Anatomical reconstruction of the terminal tendon and both lateral bands with PL tendon grafting is useful for chronic tendon mallet injury.
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Papers, etc., Registered in KOARA 【 Display / hide 】

Development of 3D printing orthosis based on CT images for finger osteoarthritis

Iwamoto, Takuji

科学研究費補助金研究成果報告書 2020
The establishment of computer assisted surgery for total elbow arthroplasty

Iwamoto, Takuji

科学研究費補助金研究成果報告書 2017
Detection of specific antibody in patients with rheumatoid arthritis negative for anti-CCP antibody

Iwamoto, Takuji

科学研究費補助金研究成果報告書 2012

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

ヒトiPS細胞由来神経突起束を用いた人工神経の規格化に向けた研究

2024.04

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2027.03

基盤研究(C), Principal investigator
外傷性異所性骨化の病態解明と新規治療法の探索

2021.04

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2024.03

MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator
手指変形性関節症に対するCT画像に基づく３Dプリンティング治療装具の開発

2018.04

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2021.03

MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator
The establishment of computer assisted surgery for total elbow arthroplasty

2015.04

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2018.03

MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator