Details of a Researcher - Iwamoto, Takuji

Papers - Iwamoto, Takuji

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Osteochondritis dissecans on the medial aspect of the humeral head

Mima, Y., Matsumura, N., Ogawa, K., Iwamoto, T., Ochi, K., Sato, K. and Toyama, Y.

Int J Shoulder Surg 10 ( 2 ) 89 - 91 2016.04

ISSN 0973-6042

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Three-dimensional anthropometric analysis of the glenohumeral joint in a normal Japanese population

Matsumura, N., Oki, S., Ogawa, K., Iwamoto, T., Ochi, K., Sato, K. and Nagura, T.

J Shoulder Elbow Surg 25 ( 3 ) 493 - 501 2016.03

ISSN 1058-2746

BACKGROUND: An understanding of normal glenohumeral geometry is important for anatomical reconstruction in shoulder arthroplasty. Unfortunately, the details of the glenohumeral joint in Asian populations have not been sufficiently evaluated. The purpose of this study was to evaluate the 3-dimensional geometry of the glenohumeral joint in the normal Japanese population and to clarify its morphologic features. METHODS: Anthropometric analysis of the glenohumeral joint was performed using computed tomography scans of 160 normal shoulders from healthy Japanese volunteers. The glenohumeral dimensions and orientation were analyzed 3-dimensionally. Sex differences and correlations between sides and among the respective parameters in the glenohumeral dimensions were evaluated. RESULTS: The normal Japanese humeral head has an average width of 41.4 mm, thickness of 13.2 mm, diameter of 42.9 mm, retroversion of 32 degrees , and inclination of 135 degrees . The glenoid has an average height of 31.5 mm, width of 23.1 mm, diameter of 62.0 mm, retroversion of 0 degrees , and inferior inclination of 2 degrees . The values of the glenohumeral dimensions were uniform in men and women, and the humeral head and glenoid were larger in men than in women. The glenohumeral size was well correlated between the 2 sides, and there were direct correlations among the heights, humeral length, humeral head size, and glenoid size. CONCLUSIONS: The present study revealed the glenohumeral geometry in the normal Japanese population. The present results would be useful to determine the size of implants and to improve the design of shoulder prostheses that reflect the normal anatomy of the Asian glenohumeral joint.

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Comparison of surgical treatments for triple extensor tendon ruptures in rheumatoid hands: A retrospective study of 48 cases

Suzuki, T., Iwamoto, T., Ikegami, H., Sakuma, Y., Ikari, K., Matsumura, N., Ochi, K., Sato, K., Nakamura, M., Matsumoto, M. and Momohara, S.

Mod Rheumatol 26 ( 2 ) 206 - 10 2016

ISSN 1439-7595

OBJECTIVE: This retrospective study was designed to evaluate the outcomes of four different surgical reconstructions for extensor tendon ruptures in ulnar three fingers in 48 patients with rheumatoid arthritis. METHODS: The following four techniques were performed; palmaris longus tendon grafting (PL group; n = 9), extensor indicis proprius (EIP) tendon transfers (EIP group; n = 8), end-to-side transfers with tension-reduced early mobilization (End-to-side group; n = 16), and a combination of end-to-side and EIP transfers (Combination group; n = 15). Loss of extension was evaluated to determine the mean postoperative range of motion of the metacarpophalangeal (MP) joint and clinical outcomes were categorized using modified Geldmacher criteria. RESULTS: Combination group demonstrated the best mean MP joint extension (-3 degrees ), followed by End-to-side group (-12 degrees ), EIP group (-16 degrees ), and PL group (-21 degrees ). Combination group yielded the best clinical outcomes with all cases showing good results. CONCLUSIONS: The combination of end-to-side and EIP transfer was an effective surgical reconstruction procedure for triple fingers extension loss.

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Reconstruction of the Scapholunate Ligament Using Capitohamate Bone-Ligament-Bone

Nakamura, T., Abe, K., Iwamoto, T., Ochi, K. and Sato, K.

J Wrist Surg 4 ( 4 ) 264 - 8 2015.11

ISSN 2163-3916

Background The biomechanical properties of the capitohamate (CH) ligament are equivalent to those of the scapholunate (SL) interosseous ligament. We reconstructed the SL ligament using the CH bone-ligament-bone substitute for chronic injury of the SL ligament. Patients and Methods Beginning in 2008, 15 wrists of 14 patients with an average age of 38 years underwent this procedure with a minimum follow-up of 2 years. Thirteen wrists had an SL joint gap more than 3 mm, and two had a complete SL ligament disruption with a severe dorsal intercalated segment instability (DISI) deformity. Kirschner wires (K-wires) were removed 8 weeks after the surgery, then active ROM exercise began. Pain (on visual analog scale [VAS]), wrist motion (angle), radiographic characteristics, such as SL gap (mm) and SL angle, and Modified Mayo Wrist Score (MMWS) were evaluated. Technique The SL joint was reduced by manipulation or with the use of joysticks, then temporary fixed with K-wires. A dorsal trough was then made between the scaphoid and the lunate. The proximal half of the CH ligament was harvested with attached bone from the capitate and hamate (CH bone-ligament-bone), inset into the SL trough, and fixed firmly with 1.2-mm diameter titanium screws in the scaphoid and lunate, respectively. Results The VAS improved from 77 preoperatively to 12 postoperatively. The average wrist extension/flexion was 74 degrees /60 degrees . There was no ossification of the reconstructed SL at the final follow-up. The SL gap improved from an average of 4.8 mm to an average of 2.1 mm, and the SL angle changed from 67 degrees to 55 degrees . The MMWS improved to 82 points postoperatively from a preoperative average of 47 with eight excellent, five good, and two fair results.

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Shoulder position increases ulnar nerve strain at the elbow of patients with cubital tunnel syndrome

Ochi, K., Horiuchi, Y., Horiuchi, K., Iwamoto, T., Morisawa, Y. and Sato, K.

J Shoulder Elbow Surg 24 ( 9 ) 1380 - 5 2015.09

ISSN 1058-2746

BACKGROUND: Previous studies have shown that the shoulder internal rotation elbow flexion (SIREF) test, which is a modified elbow flexion (EF) test, has significantly higher sensitivity than the EF test in patients with cubital tunnel syndrome (CubTS). Here, we hypothesized that this increase in sensitivity was due to increase in the ulnar nerve strain around the elbow introduced by the additional shoulder position. METHODS: Ulnar nerve strain at the elbow was intraoperatively measured at both the EF test and SIREF test positions in 20 patients with CubTS before simple decompression. Statistical analysis was performed with the Wilcoxon signed rank test at a confidence level of 99% (P < .001). RESULTS: Mean ulnar nerve strain in the EF test position was 18.9% +/- 12.1%, whereas that in the SIREF test position was 24.7% +/- 14.0%. Ulnar nerve strain was higher in the SIREF than in the EF test position in all cases, and the difference was significant (mean, 5.8% +/- 0.9%; 95% confidence interval, 3.90%-7.73%). CONCLUSION: This study indicated that increased sensitivity in the SIREF test compared with the EF test was due to the increase in ulnar nerve strain around the elbow. To the best of our knowledge, this is the first study showing that shoulder position changes the ulnar nerve strain around the elbow in living patients with CubTS.

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Construct validity, reliability, response rate, and association with disease activity of the quick disabilities of the arm, shoulder and hand questionnaire in the assessment of rheumatoid arthritis

Ochi, K; Iwamoto, T; Saito, A; Ikari, K; Toyama, Y; Taniguchi, A; Yamanaka, H; Momohara, S

MODERN RHEUMATOLOGY 25 ( 2 ) 241 - 245 2015.03

ISSN 1439-7595

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Arthroscopy of the distal radioulnar joint

Nakamura, T., Matsumura, N., Iwamoto, T., Sato, K. and Toyama, Y.

Handchir Mikrochir Plast Chir 46 ( 5 ) 295 - 9 2014.10

ISSN 0722-1819

Wrist arthroscopy is now widely indicated for diagnosis and treatment of acute or chronic wrist pain, especially for triangular fibrocartilage complex (TFCC) lesions, as a gold standard. In most cases radiocarpal and midcarpal arthroscopy was performed, while DRUJ arthroscopy has been rarely performed because of its difficulties. Recent anatomic and biomechanical studies demonstrated that the radioulnar ligament (RUL), which is the proximal component of the TFCC facing to the DRUJ, is the primary stabilizer of the distal radioulnar joint (DRUJ). Rupture of the radioulnar ligament (RUL) at the fovea area, where it is the main attaching portion to the ulna and is the isometric point during forearm rotation as the rotation axis passes, is responsible for DRUJ instability. Although physical examination and imaging diagnosis may indicate a foveal detachment of the TFCC, DRUJ arthroscopy is potential for visualizing the RUL at the fovea. Role of DRUJ arthroscopy should be more important not only for diagnosis of rupture of the RUL but also for decision making of treatment option for RUL tear. DRUJ arthroscopy also demonstrates the joint surface of both the sigmoid notch and ulnar head, and the proximal surface of the TFCC.

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Ununited Fracture of the Hook of Hamate Treated With Low-Intensity Pulsed Ultrasound in an Older Middle-aged Patient

Sakuma, Y; Iwamoto, T; Momohara, S

CLINICAL JOURNAL OF SPORT MEDICINE 24 ( 4 ) 358 - 359 2014.07

ISSN 1050-642X

An Obliquely Placed Headless Compression Screw for Distal Interphalangeal Joint Arthrodesis

Iwamoto, T., Matsumura, N., Sato, K., Momohara, S., Toyama, Y. and Nakamura, T.

J Hand Surg Am 38A ( 12 ) 2360 - 2364 2013.10

ISSN 1531-6564

PURPOSE: To assess the outcomes of our technique involving oblique headless compression screw for arthrodesis of the thumb interphalangeal joint and the distal interphalangeal joints of the other digits. METHODS: A total of 28 joints (19 thumb interphalangeal and 9 distal interphalangeal) in 23 patients with a mean age of 65 years (range, 58-74 y) were retrospectively analyzed. All operations were performed with the Acutrak2 micro-screw. After the resection of synovium and joint cartilage by a dorsal approach, a 0.88-mm diameter guide wire was inserted at the ulnar side of the proximal phalanx in the thumb and radial side of the middle phalanx in the other digits from proximal to distal to fix the joint obliquely. We verified its position under fluoroscopic control and placed the cannulated screw from proximal to distal over the guide wire. RESULTS: Intraoperative rigid fixation was obtained except for 1 case, which required additional K-wire fixation. The overall union rate was 96%. Average time to fusion was 11 weeks (range, 8-30 wk), with 76% achieving union within 3 months. There were 2 complications, 1 nonunion and 1 late infection. Other complications such as dorsal skin necrosis, nail deformity, and paresthesia did not occur. CONCLUSIONS: Efforts to avoid invasion of the nailbed can be technically demanding. We believe that our proximal to distal technique with oblique placement of the headless compression screw is a straightforward and effective method with a relatively low risk of complication. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

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Non-synonymous variant (Gly307Ser) in <i>CD226</i> is associated with susceptibility in Japanese rheumatoid arthritis patients

Suzuki, T; Ikari, K; Kawaguchi, Y; Yano, K; Iwamoto, T; Kawamoto, M; Toyama, Y; Taniguchi, A; Yamanaka, H; Momohara, S

MODERN RHEUMATOLOGY 23 ( 1 ) 200 - 202 2013.01

ISSN 1439-7595

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Meta-analysis identifies nine new loci associated with rheumatoid arthritis in the Japanese population

Okada, Y; Terao, C; Ikari, K; Kochi, Y; Ohmura, K; Suzuki, A; Kawaguchi, T; Stahl, EA; Kurreeman, FAS; Nishida, N; Ohmiya, H; Myouzen, K; Takahashi, M; Sawada, T; Nishioka, Y; Yukioka, M; Matsubara, T; Wakitani, S; Teshima, R; Tohma, S; Takasugi, K; Shimada, K; Murasawa, A; Honjo, S; Matsuo, K; Tanaka, H; Tajima, K; Suzuki, T; Iwamoto, T; Kawamura, Y; Tanii, H; Okazaki, Y; Sasaki, T; Gregersen, PK; Padyukov, L; Worthington, J; Siminovitch, KA; Lathrop, M; Taniguchi, A; Takahashi, A; Tokunaga, K; Kubo, M; Nakamura, Y; Kamatani, N; Mimori, T; Plenge, RM; Yamanaka, H; Momohara, S; Yamada, R; Matsuda, F; Yamamoto, K

NATURE GENETICS 44 ( 5 ) 511 - + 2012.05

ISSN 1061-4036

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Comparison of characteristics and therapeutic efficacy in rheumatoid arthritis patients treated by rheumatologists and those treated by orthopedic surgeons under a team medicine approach at the same institute

Momohara, S., Inoue, E., Ikari, K., Yano, K., Tokita, A., Honjo, Y., Sakuma, Y., Hiroshima, R., Iwamoto, T., Seto, Y., Tanaka, E., Taniguchi, A. and Yamanaka, H.

Mod Rheumatol 22 ( 2 ) 209 - 15 2012.04

ISSN 1439-7609

The treatment of rheumatoid arthritis (RA) has improved dramatically with the advent of the latest generation of disease-modifying antirheumatic drugs. Despite these advances, in some patients inflammation is not diminished sufficiently to prevent irreversible musculoskeletal damage, thereby necessitating surgical intervention to reduce pain and improve function. For RA treatment, Japanese orthopedic surgeons also prescribe medication. In this study, we examined whether this Japanese system is effective for RA treatment. We analyzed the clinical condition of RA patients treated by rheumatologists and those treated by orthopedists in a linked registry study using information from a large observational cohort of RA patients followed every half year from 2000 to 2010 (the IORRA cohort). Two groups of patients were compared: patients treated by rheumatologists (rheumatologic group) and patients treated by orthopedists (orthopedic group). The results revealed that patients in the orthopedic group were older, more likely to be female, and had a longer disease duration than patients in the rheumatologic group. The proportion of patients with a history of joint surgery was also much higher in the orthopedic group than in the rheumatologic group. The average scores on the Japanese version of the Health Assessment Questionnaire, and the remission ratio determined using a Boolean-based definition gradually increased from 2000 until 2010, and these findings were consistently better in the rheumatologic group than in the orthopedic group. These data suggest that patients treated primarily by orthopedists are more likely to have long-standing RA compared to patients treated by rheumatologists. Therefore, it is critical for rheumatologists and orthopedists to complement each other medically in the treatment of RA patients.

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【手指のリウマチに対する手術治療の現況】関節リウマチによる母指変形に対する手術療法

岩本卓士

整形・災害外科 55 ( 2 ) 135 - 139 2012.02

ISSN 0387-4095

上肢整形外科手術における、鎖骨上窩アプローチによる超音波ガイド下腕神経叢ブロックの有効性

佐久間悠, 岩本卓士, 鈴木拓, 鴇田朝海 and 桃原茂樹

日本手外科学会雑誌 28 ( 5 ) 441 - 444 2012.02

ISSN 2185-4092

関節リウマチにおける同一上肢に橈骨頭切除と尺骨遠位切除を施行した際の上肢機能の評価

鈴木拓, 岩本卓士, 佐久間悠, 鴇田朝海 and 桃原茂樹

日本手外科学会雑誌 28 ( 3 ) 275 - 277 2011.12

ISSN 2185-4092

【リウマチ手指診療】リウマチ手指に対する人工指関節置換術

岩本卓士

Orthopaedics 24 ( 12 ) 63 - 69 2011.11

ISSN 0914-8124

関節リウマチにおける手指変形は多種多様であり、使用機種の選択にも一定の見解は得られていないのが現状である。本邦において最も使用されているのはシリコンインプラントであり、MP関節における尺側偏位の治療として機能的・整容的改善により良好な成績が得られている。一方、PIP関節ではシリコンインプラントの成績不良例も報告されており、表面置換型の人工関節も多く使用される。手術に際しては変形の解剖学的機序を理解したうえで、変形の程度、各指の機能を考慮して人工関節の適応を決定し、いずれのインプラントを使用する場合でも十分な軟部組織再建を併用することが重要である。(著者抄録)

Pseudotumor from a metal-on-metal hip

Iwamoto, T., Ikari, K. and Momohara, S.

J Rheumatol 38 ( 10 ) 2265 2011.10

ISSN 0315-162X

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生物学的製剤が与えた関節リウマチの病態・治療の変化生物学的製剤時代の関節破壊制御と整形外科手術

岩本卓士 and 桃原茂樹

臨床整形外科 46 ( 9 ) 799 - 803 2011.09

ISSN 0557-0433

関節リウマチの治療は早期からの強力な薬物治療により寛解を導入し関節破壊の進行を抑制することが目標となってきている.疾患活動性を十分にコントロールすることで,破壊された関節が修復する可能性も示されており,手術適応も変化してきている.傾向として滑膜切除術は漸減している一方で,足趾の関節形成術,手指の人工関節といった小関節の形成手術が増加しており,より高い目標に向けた機能回復へと今後さらに変遷していくものと思われる.しかしながら生物学的製剤使用下での手術は感染の発症に十分な注意が必要であり,術前術後に一定期間の休薬を行うことが望ましいが,いずれの生物学的製剤に関しても休薬期間に関するエビデンスが不足しており,整形外科医からの情報発信が必要である.(著者抄録)

目でみるシリーズ　リウマチ手の尺側偏位

岩本卓士 and 桃原茂樹

Frontiers in Rheumatology & Clinical Immunology 5 ( 3 ) 144 - 146 2011.08

ISSN 1882-1472

Recent trends in orthopedic surgery performed in Japan for rheumatoid arthritis

Momohara, S., Tanaka, S., Nakamura, H., Mibe, J., Iwamoto, T., Ikari, K., Nishino, J., Kadono, Y., Yasui, T., Takahashi, K., Takenouchi, K., Hashizume, K., Nakahara, R., Kubota, A., Nakamura, T., Nishida, K. and Suguro, T.

Mod Rheumatol 21 ( 4 ) 337 - 42 2011.08

ISSN 1439-7609

The aim of this report was to review the use of orthopedic surgeries performed to manage rheumatoid arthritis (RA). Our review of studies published in English indicates that there has been a decrease in RA-associated surgeries in Western countries. Improvements in medical treatment may partly explain the reduction in numbers of orthopedic joint surgeries, which also suggests a worldwide trend toward improved long-term outcomes. However, the results of our multicenter study in Japan indicate that the number of RA-associated operations has not decreased, and that the numbers of operations performed annually have been relatively stable from 1998 to 2008. Although there definitely has been a decline in the numbers of synovectomy surgeries, the numbers of operations on the upper limbs and foot arthroplasties have increased. With the trend toward milder disease because of improved medical treatment, we speculate that RA patients may want and need better function for the activities of daily living. The combination of medical treatment and surgical intervention is thought to improve outcomes in RA patients who will develop joint destruction. Additional studies, including analyses of RA databases containing long-term data on a variety of surgical interventions, are needed.

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