Yu Okuno’s research while affiliated with Tottori University and other places

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Publications (4)

Establishment of an Artificial Intelligence Image Evaluation System for Knee Osteoarthritis
  • Article

April 2025

Osteoarthritis and Cartilage

Kei Yokogawa

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Keita Nagira

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Yu Okuno

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Fig. 1 Evaluation method of pre-and postoperative Hounsfield unit (HU) values and cement penetration in computed tomography (CT) images. A Preoperative CT coronal section. (a) Sclerotic side and (b) nonsclerotic side. B Preoperative CT coronal section. Vertical and horizontal lines represent the tibial axis and the osteotomy line in operation, respectively. The shaded area is the estimated area of bone penetration by cement and was defined as the length of the base plate multiplied by 5 mm (the average HU values in the area are calculated by the imaging software). C Postoperative CT sagittal section. (1) Anterior edge of the keel, (2) center of the keel, and (3) extension of the posterior cortex. D Postoperative CT coronal section. The solid arrowhead indicates the cement penetration area of the sclerotic side (mm 2 ), The open arrowhead indicates the cement penetration area of the nonsclerotic side (mm 2 ). The single asterisk indicates the base of the sclerotic side (mm). The double asterisk indicates the base of the nonsclerotic side (mm). The single dagger presents the maximum penetration in the sclerotic side (mm). The double dagger refers to the maximum penetration in the nonsclerotic side (mm). Mean penetration: area/base (mm)
Fig. 2 Evaluation method of mean cement penetration on sagittal section in postoperative computed tomography (CT) image. A Postoperative CT axial section just under the tibial baseplate. B Postoperative CT coronal section at the most posterior level of the fin. In (A) and (B), the (1) lateral side of sagittal section and (2) the medial side of sagittal section level are shown. The level of the sagittal section was one slice lateral to the section in which the most posterior portion of the fin of the tibial component was delineated for the medial and lateral sides. C Postoperative CT sagittal section of the lateral side. D Postoperative CT sagittal section of the medial side. In (C) and (D), the area surrounded by the black dotted line represents the cement penetration area (mm 2 ). The single and double asterisks indicates the base of the lateral side (mm) and the base of the medial side (mm), respectively. Mean penetration: area/base (mm)
Fig. 3 Three-dimensional computed tomography (3D CT) image of the cement penetration area. A Postoperative 3D CT frontal view. B Postoperative 3D CT caudal view. In (A) and (B), (a) lateral side and (b) the medial side are shown. C Postoperative 3D CT lateral view from lateral side. D Postoperative 3D CT lateral view from medial side. The maximum penetration in 3D CT was defined as the distance from the baseplate to the most penetrated area in each true lateral view. In any images, cement surrounding 2 mm around the keel and fin is excluded when creating the 3D CT image to prevent overestimation of cement penetration
Fig. 5 Correlation between preoperative Hounsfield unit (HU) value of bone penetration area and mean depth of penetration. A Correlation between bone penetration and preoperative HU values in the HM group. B Correlation between bone penetration and preoperative HU values in the VM group. In both groups, the correlation between preoperative HU values and mean penetration was negative. The negative correlation was larger in the HM group than in the VM group. HM hand mixing + hand packing, HU Hounsfield unit, VM vacuum mixing + cement gun
Mean depths of cement penetration (mm)

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Comparison of different cementing techniques for cement penetration under tibial component in total knee arthroplasty: a retrospective observational study
  • Article
  • Full-text available

September 2024

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16 Reads

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1 Citation

Knee Surgery and Related Research

Yu Okuno

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Keita Nagira

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Koji Ishida

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[...]

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Purpose This study aimed to investigate the differences in cement penetration between cementing techniques in total knee arthroplasty (TKA). Materials and methods We retrospectively evaluated knee undergone TKA at our hospital for both preoperative and postoperative computed tomographic (CT) evaluations. Cementing was performed with hand mixing and hand packing (HM group) and with vacuum mixing and cement gun use (VM group). We measured the area under the tibial baseplate (sclerotic and nonsclerotic sides) and compared the mean and maximum depths of cement penetration at each area. Results Of the 44 knees evaluated, 20 and 24 knees were in the HM and VM groups, respectively. At the center of the sclerotic side, the mean penetration depths (2.0 ± 0.7 and 2.5 ± 0.7 mm, p = 0.02) and the maximum penetration depths (4.0 ± 0.9 and 5.0 ± 1.6 mm, p = 0.02) were significantly deeper in the VM group than in the HM group. The correlation between preoperative Hounsfield unit values and mean penetration were r = –0.617 ( p < 0.01) and –0.373 ( p = 0.01) in the HM and VM groups, respectively. Conclusion The cementing technique of vacuum mixing and using a cement gun allowed for deeper cement penetration compared with the hand mixing and hand packing technique, even in bone sclerotic sites.

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