原藤　健吾 （ハラトウ　ケンゴ）

Harato, Kengo

写真a

所属（所属キャンパス）

研究所・センター等 スポーツ医学研究センター （日吉）

職名

准教授
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学歴 【 表示 ／ 非表示 】

  • 1993年04月
    -
    1999年03月

    慶應義塾大学, 医学部

    大学, 卒業

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学位 【 表示 ／ 非表示 】

  • 医学博士, 慶應義塾大学

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研究分野 【 表示 ／ 非表示 】

  • ライフサイエンス / 整形外科学

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研究キーワード 【 表示 ／ 非表示 】

  • 膝関節

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著書 【 表示 ／ 非表示 】

  • Surgical Approach

    Harato K., Advances in Total Knee Arthroplasty, 2024年01月

    　概要を見る

    In TKA, the position of the incision and the approach method are extremely important, and a skilled surgeon can quickly perform skin incision to exposure [1]. Orthopedic surgeons need to be familiar with the differences in the position of the incision and various approach methods.

  • 変形性膝関節症とその鑑別疾患，X線像で診る下肢　第Ⅲ章膝関節

    南江堂, 2011年

  • リハビリテーションプロトコール第２版　整形外科疾患へのアプローチ　４膝の損傷

    メディカルサイエンスインターナショナル, 2010年

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論文 【 表示 ／ 非表示 】

  • Targeted hip abductor fatigue alters trunk and lower limb biomechanics during Single-Leg landing

    Harato K., Nishizawa K., Imai S., Kobayashi S., Kaneda K., Matsumoto T., Nagura T.

    Scientific Reports 15 （ 1 ）  2025年12月

    　概要を見る

    Fatigue of the hip abductor muscles may influence lower limb biomechanics and potentially contribute to anterior cruciate ligament (ACL) injury risk. However, the effects of targeted hip abductor fatigue on trunk, pelvis and lower limb coordination during landing tasks remain unclear. The present study aimed to investigate how targeted hip abductor fatigue alters the biomechanics of the trunk, pelvis, and lower extremity during single-leg landing (SLL). Twenty healthy male recreational athletes performed SLL before and after a targeted hip abductor fatigue protocol. Kinematic and kinetic data were collected using a three-dimensional motion capture system and force plates, with analysis focused on the timing of peak vertical ground reaction force. Following fatigue, participants exhibited increased hip abduction angle and trunk right inclination, as well as decreased hip flexion and external hip abduction moment. Notably, the external knee abduction moment significantly increased post-fatigue, though it remained negative in absolute value. Increased pelvic left rotation was also observed, indicating compensatory adjustments in trunk-pelvis coordination. These adaptations indicate that targeted muscle fatigue induces complex biomechanical responses across the kinetic chain, rather than uniformly increasing injury risk through valgus-prone mechanics. While the observed changes may reflect stabilizing strategies under fatigue, their implications for ACL loading require further clarification. The current study highlights the relevance of considering whole-body biomechanical responses to targeted fatigue and contributes to a more detailed understanding of neuromuscular control during landing. These findings may support the refinement of injury prevention approaches that address segmental coordination under fatigued conditions.

  • Phase-Specific Analysis of Robotic-Assisted Knee Arthroplasty: Identifying Critical Learning Curves Across Three Implant Types

    Harato K., Kobayashi S., Kaneda K., Matsumoto T., Niki Y.

    Journal of Arthroplasty 40 （ 10 ） 2623 - 2629 2025年10月

    ISSN  08835403

    　概要を見る

    Background: Robotic-assisted total and unicompartmental knee arthroplasties (RA-TKA, RA-UKA) are increasingly used to enhance surgical precision and improve clinical outcomes. Despite their advantages, these systems introduce a learning curve, particularly for surgeons adapting to different procedural phases. The current literature lacks detailed analyses of phase-specific contributions to the learning curve and how these differ among implant designs. This study aimed to identify critical phases within RA-TKA and RA-UKA that contributed most to operative efficiency and to propose tailored educational strategies for each device. We hypothesized that device-specific learning curves could notably impact procedural durations. Methods: A total of 204 surgeries of RA-TKAs (bicruciate retaining [BCR] and stabilized [BCS]) and RA-UKAs were done using an image-free robotic platform by three experienced surgeons. Operative time was divided into eight procedural phases. Learning curves were evaluated for each device and phase using linear regression. The slopes of the regression lines were analyzed to quantify learning effects, with statistical significance assessed for each phase. Phase-specific contributions were interpreted based on the relative steepness of significant slopes. Results: The learning curve varied across devices and phases. The BCR exhibited the steepest learning curve, particularly in phase 5 (bone resection), whereas BCS demonstrated significant improvements in phase 5 as well, but to a lesser extent. The UKA showed notable learning effects in earlier phases, particularly in phase 3 (three-dimensional model creation). These findings highlighted device-specific differences in learning effects and underscored the critical importance of phase-specific training. Conclusions: The present study identified device-specific and phase-specific differences in the learning curve for image-free robotic systems. Both BCR and BCS required focused training in later phases, such as bone resection, whereas UKA benefited from targeted improvements in earlier phases like model creation. These insights emphasized the need for tailored training protocols to optimize outcomes in robotic knee arthroplasty.

  • Surgical field contamination analysis in various artificial joint arthroplasties

    Oya A., Matsumura N., Fujie A., Kobayashi S., Harato K., Kaneda K., Matsumoto T., Yagi M., Suzuki T., Nakayama R., Matsumoto M., Nakamura M.

    Journal of Joint Surgery and Research 3 （ 3 ） 159 - 163 2025年09月

    　概要を見る

    Purpose: Joint arthroplasty has shown favorable outcomes across various anatomical sites; however, complications such as peri-prosthetic joint infection (PJI) remain challenging. Despite the importance of understanding surgical field contamination, many details are unclear. This study aimed to evaluate the contamination status of the surgical field during joint arthroplasty procedures. Methods: A prospective study was conducted on 150 joint arthroplasty cases at a single institution, involving 38 men and 112 women with a mean age of 68.8 years. The cohort included 41 total shoulder arthroplasty (TSA), 31 total knee arthroplasty (TKA), and 78 total hip arthroplasty (THA) procedures. Bacterial cultures, including anaerobic cultures, were obtained from three sites: (1) the surgical scalpel immediately after skin incision; (2) the surface of the surgical tray where the instruments were placed at the end of the procedure; and (3) the hands and chest area of the surgeon's gown. Results: No early PJIs or bacterial growth was observed post-surgery. However, bacterial contamination was detected in 7 cases (4.7%), primarily in surgical trays. Cutibacterium acnes was identified in two TSA cases and one case each of TKA and THA. Other bacterial species detected included Staphylococcus hominis and Corynebacterium species. Additionally, Micrococcus luteus was found on the surgical gown of one TKA case. Contaminated cases showed significantly higher body weight (p ​= ​0.036) and longer surgery time (p ​= ​0.044) compared with non-contaminated cases. Conclusion: Maintaining an aseptic surgical environment, particularly in trays and gowns, is essential in preventing bacterial contamination, particularly C. acnes, during joint arthroplasty procedures.

  • A Modified Arthroscopic Approach for Localized Pigmented Villonodular Synovitis in the Posterior Knee Compartment

    Harato K., Kobayashi S., Matsumoto T., Kaneda K.

    Arthroscopy Techniques 14 （ 7 ）  2025年07月

    　概要を見る

    Localized pigmented villonodular synovitis of the posterior knee compartment presents a surgical challenge due to limited arthroscopic access and the complex anatomy of the posterior knee. We describe a modified arthroscopic approach that enhances visualization and facilitates efficient resection by enlarging the posteromedial portal. This technique allows simultaneous use of the arthroscope and surgical instruments within the same portal, optimizing maneuverability and precision. The procedure involves careful portal placement, strategic use of a 70° arthroscope, and a combination of curettage, shaving, and radiofrequency ablation to achieve complete resection while minimizing iatrogenic injury. Compared to traditional approaches using both posteromedial and posterolateral portals, our method is less invasive yet provides adequate exposure for thorough lesion removal. Additionally, resection performed solely from anterior portals has been reported, but it frequently results in incomplete excision due to restricted access. This technique offers distinct advantages, including improved visualization, efficient instrument handling, and reduced operative time, making it particularly suitable for novice surgeons. By refining arthroscopic accessibility to the posterior knee compartment, this approach represents a safe, effective, and reproducible method for managing localized pigmented villonodular synovitis with minimal morbidity.

  • Evaluating tibial rotation in recurrent patellar dislocation with four-dimensional computed tomography

    Kaneda K., Harato K., Oki S., Morishige Y., Kobayashi S., Nakamura M., Nagura T.

    Skeletal Radiology 54 （ 6 ） 1283 - 1289 2025年06月

    ISSN  03642348

    　概要を見る

    Objective: This study is to investigate the three-dimensional (3D) kinematic changes in the knee joint in patients with recurrent patellar dislocation using four-dimensional computed tomography (4DCT) imaging and the 3D-3D surface registration technique. Materials and methods: Ten knees from nine patients with recurrent patellar dislocation and seven knees from seven controls (unaffected side of patients with unilateral anterior cruciate ligament injury) were analyzed using 4DCT. The patients were asked to extend their knees from 60° of flexion to full extension for 10 s in the CT gantry. We used the 3D-3D registration technique, and the 3D angles of the patella and tibia relative to the femur were evaluated. Results: In the dislocation group, the patellar lateral tilt increased as the knee extended. Significant differences were found between the two groups at 0°–20° of knee flexion. The tibia rotated externally as the knee extended in the dislocation group. Significant differences between the two groups were found at 0°–10° of knee flexion. Conclusion: This study demonstrated significant differences in the timing and magnitude of tibial external rotation between patients with recurrent patellar dislocation and controls. Specifically, the tibia began to externally rotate during the early phase of knee extension in the dislocation group. These findings provide new insights into knee kinematics that may inform future treatment strategies for patellar dislocation.

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KOARA（リポジトリ）収録論文等 【 表示 ／ 非表示 】

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研究発表 【 表示 ／ 非表示 】

  • What are the differences of surgical time between beginners and experts in primary total knee arthroplasty?

    第28回ＩＳＴＡ, 

    2015年10月

  • What are the important surgical factors affecting the wound healing after primary total knee arthroplasty?

    第28回ＩＳＴＡ, 

    2015年10月

  • 初心者の人工膝関節置換術における自分の指導は適切だったか？

    第64回東日本整形災害外科学会, 

    2015年09月

  • What Is the Important Maneuver Necessary for Novice Surgeons to Minimize a Surgical Time in Total Knee Arthroplasty?

    第2回ICJR, 

    2015年07月

  • 駆血を使用しない前十字靭帯再建術とその評価

    第7回JOSKAS, 

    2015年06月

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競争的研究費の研究課題 【 表示 ／ 非表示 】

  • 前十字靭帯損傷および再建術後再損傷予防のための新たな動的評価法の開発

    2021年04月
    -
    2026年03月

    文部科学省・日本学術振興会, 科学研究費助成事業, 原藤 健吾, 基盤研究(C), 補助金,  研究代表者

  • 関節圧に基づく新しい人工膝関節手技の確立

    2016年04月
    -
    2019年03月

    文部科学省・日本学術振興会, 科学研究費助成事業, 原藤　健吾, 基盤研究(C), 補助金,  研究代表者

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担当授業科目 【 表示 ／ 非表示 】

  • 体育学講義Ⅱ

    2025年度

  • 老年医学・高齢者スポーツ医学

    2025年度

  • バイオメカニクス・動作解析

    2025年度

  • 整形外科学講義

    2024年度

  • 整形外科学講義

    2023年度

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担当経験のある授業科目 【 表示 ／ 非表示 】

  • 整形外科　膝から下腿

    慶應義塾

    2017年04月
    -
    2018年03月
    , 

    講義, 専任

  • 膝関節・下腿

    慶應義塾

    2015年04月
    -
    2016年03月
    , 

    通年, 講義, 50人

    膝

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