岡山医学会 Acta Medica Okayama 0030-1558 133 1 2021 整形外科領域におけるAI 58 61 EN Ryuuichi Nakahara Department of Orthopaedic Surgery, Okayama University Hospital No potential conflict of interest relevant to this article was reported.

岡山医学会 Acta Medica Okayama 0030-1558 132 3 2020 人工知能の歩み 144 147 EN Ryuuichi Nakahara Department of Orthopaedic Surgery, Okayama University Hospital No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 71 1 2017 Results of Total Elbow Arthroplasty with Cementless Implantation of an Alumina Ceramic Elbow Prosthesis for Patients with Rheumatoid Arthritis 41 47 EN Keiichiro Nishida Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenzo Hashizume Department of Rehabilitation, Japan Labour Health and Welfare Organization, Okayama Rosai Hospital Masatsugu Ozawa Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ayumu Takeshita Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Daisuke Kaneda Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryuichi Nakahara Department of Musculoskeletal Traumatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoshihisa Nasu Department of Medical Materials for Musculoskeletal Reconstruction, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yasunori Shimamura Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hajime Inoue Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Original Article 10.18926/AMO/54824 We investigated the long-term clinical results of total elbow arthroplasty (TEA) by cementless fixation of alumina ceramic unlinked elbow prostheses (J-alumina ceramic elbows: JACE) for the reconstruction of elbow joints with rheumatoid arthritis (RA). Seventeen elbows in 17 patients (aged 44-72 years, average 54.8) replaced by JACE TEA without bone cement were investigated. The average follow-up period was 10.7 (range, 1.0-19.3) years. Clinical conditions of each elbow before and after surgery were assessed according to the Mayo Elbow Performance Index (MEPI). Radiographic loosening was defined as a progressive radiolucent line of more than 1 mm that was completely circumferential around the intramedullary stem. The average MEPI significantly improved from 46.8 points preoperatively to 66.8 points at final follow-up (p=0.0226). However, aseptic loosening was noted in 10 of 17 elbows (58.8%) and revision surgery was required in 7 (41.2%). Most loosening was observed on the humeral side. With radiographic loosening and revision surgery defined as the end points, the likelihoods of prosthesis survival were 41.2% and 51.8%, respectively, up to 15 years by Kaplan-Meier analysis. The clinical results of JACE implantation without bone cement were disappointing, with high revision and loosening rates of the humeral component. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 70 6 2016 Shortening Oblique Osteotomy with Screw Fixation for Correction of the Lesser Metatarsophalangeal Joints of Rheumatoid Forefoot 477 483 EN Keiichiro Nishida Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takahiro Machida Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masahiro Horita Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenzo Hashizume Department of Rehabilitation, Japan Labour Health and Welfare Organization, Okayama Rosai Hospital Ryuichi Nakahara Department of Musculoskeletal Traumatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoshihisa Nasu Department of Medical Materials for Musculoskeletal Reconstruction, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hideki Ohashi Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kenta Saiga Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Original Article 10.18926/AMO/54811 The metatarsophalangeal (MTP) joints are often and predominantly affected in rheumatoid arthritis. The aim of the current study was to describe surgical techniques of shortening oblique osteotomy for lesser metatarsal bone with screw fixation at the osteotomy site, and to investigate the short-term clinical outcomes of our procedure. Twenty-seven feet (78 toes) of 24 RA patients underwent the shortening oblique osteotomy for the correction of deformity at the lesser MTP joints. The average Japanese Society of Surgery of the Foot (JSSF) standard rating system for the RA foot and ankle scale improved significantly from 59.6 points preoperatively to 88.3 points postoperatively (p＜0.001). Twenty-four feet (89 ) were free from metatarsalgia and symptomatic callosities at the lesser MTP joint after surgery. Our present findings showed satisfactory early clinical outcomes of the shortening oblique osteotomy of the metatarsal bone with screw fixation for RA forefoot. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 70 5 2016 Quantitative Analysis of the Effects of a Bangerter Filter on Gross Stereopsis in Experimental Models of Reduced Visual Acuity 339 344 EN Manabu Miyata Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine Ryuichi Nakahara Departments of Orthopedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ichiro Hamasaki Departments of Ophthalmology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Satoshi Hasebe Department of Ophthalmology 2, Kawasaki Hospital, Kawasaki Medical School Takashi Furuse Department of Ophthalmology 2, Kawasaki Hospital, Kawasaki Medical School Hiroshi Ohtsuki Okayama Saiseikai General Hospital Original Articles 10.18926/AMO/54591 Although a 0.3 Bangerter filter, which reduces visual acuity, is frequently used for treating moderate amblyopia, the effects on gross stereopsis are not well known. This study quantitatively evaluated whether gross stereopsis is degraded by a Bangerter filter. Seven healthy subjects (median age: 29 years) participated in this psychophysical study. Targets with crossed disparities of 1°, 2°, 3°, 4°, and 5° were randomly presented on a three-dimensional television display. The subjects indicated the point at which the targets popped out from the television screen (matching method). The distance from the screen to the point was defined as the degree of stereopsis. This experiment was performed with and without a 0.3 Bangerter filter. The corrected monocular visual acuities were decreased to about 20/63 by the filter in all subjects. No significant difference was observed for any of the disparities (1°-5°), between the degree of stereopsis visualized with and without filters for either the dominant or the non-dominant eye. The degree of stereopsis was not degraded by the reduced visual acuity induced by the use of 0.3 Bangerter filters. In this regard, the use of 0.3 Bangerter filters may be considered safer than occlusion eye patches for the patients with normal binocular vision. No potential conflict of interest relevant to this article was reported.