Okayama University Medical School Acta Medica Okayama 0386-300X 80 2 2026 Consistent Clinical Outcomes of Anteroinferior Minimally Invasive Plate Osteosynthesis for Midshaft Clavicle Fractures Across AO/OTA Fracture Types 99 107 EN Nguyen Trung Thanh Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryo Nakamichi Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yasunori Shimamura Department of Orthopaedic Surgery, Kousei Hospital Taichi Saito Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takeshi Ishihara Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomoki Furutani Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hisakazu Shitozawa Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomoyuki Noda Department of Orthopaedic Surgery, Kawasaki Medical School General Medical Center Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Original Article 10.18926/AMO/70452 Although the performance of minimally invasive plate osteosynthesis (MIPO) via the anteroinferior approach is increasingly adopted for midshaft clavicle fractures, the influence of fracture morphology on clinical outcomes under a standardized protocol is unclear. We retrospectively analyzed the cases of 54 patients who underwent anteroinferior MIPO for an acute midshaft clavicle fracture (AO/OTA types B1, B2, B3) performed by a single surgeon across three affiliated institutions (2009-2022). We evaluated the clinical outcomes, i.e., the surgical time, incision length, radiographic union, reduction accuracy, range of motion, pain (visual analog scale [VAS]), and complications and compared them among the three AO/OTA subtypes. The mean incision length (3.4 cm) and surgical time (71-79 min) were similar among the groups (both p>0.2). All fractures achieved radiographic union at a mean of 3.5 months. Postoperative alignment and clavicular length were maintained (length reduction −1.0±2.2 mm [B1], −0.5±2.0 mm [B2], −0.6±1.8 mm [B3]; p=0.825; angulation −0.8±3.4°, −1.1±3.1°, −0.3±3.3°; p=0.888). At 3 months, shoulder elevation and abduction were 169°-175° (p=0.079) and 164°-175° (p=0.324). Pain was minimal (100-mm VAS: ≤1 mm; p=0.782). One plate-fatigue failure occurred; no supraclavicular-nerve symptoms were recorded. Anteroinferior MIPO yielded consistent outcomes across AO/OTA types, with excellent union rates, functional recovery, and few complications, indicating that this technique is safe and reproducible for the surgical management of midshaft clavicle fractures. No potential conflict of interest relevant to this article was reported.

Wiley Acta Medica Okayama 2398-8835 9 3 2026 Effects of Overload on Imiquimod‐Induced Psoriasis Model Mice: A Basic Experimental Study e72040 EN Tomoki Furutani Department of Orthopaedic Surgery, Section of Medicine, Division of Medicine, Dentistry, and Pharmaceutical Sciences, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Taichi Saito Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Asahi Ikeda Okayama University Medical School Faculty of Medicine Kenta Mashima Okayama University Medical School Faculty of Medicine Natsumi Yukihiro Okayama University Medical School Faculty of Medicine Satoki Kusakabe Okayama University Medical School Faculty of Medicine Okayama Japan Ryo Nakamichi Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Aki Yoshida Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Keiichiro Nishida Locomotive Pain Center, Okayama University Hospital Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Background and Aim: Psoriasis is a skin disorder complicated by arthritis and enthesitis. The cytokines interleukin (IL)-17, IL-23, and tumor necrosis factor (TNF)-α are reportedly key effectors of psoriasis. Additionally, gamma delta (γδ) T cells exacerbate inflammation by producing inflammatory cytokines such as IL-17 and TNF-α. However, details regarding the mechanisms linking pathogenesis and mechanical stress remain unclear. This study aimed to investigate the effect of strenuous exercise on the pathology of psoriasis using mouse models of imiquimod (IMQ)-induced psoriasis. Methods: Twenty mice were randomly assigned to four groups: IMQ − TRED− (control), IMQ − TRED+ (treadmill running mice), IMQ + TRED− group (IMQ treated mice), and IMQ + TRED+ group (IMQ treated and treadmill running mice). The tissue sections from back skin and thymus were immunostained with antibodies against IL-17, IL-23, and γδ T cells. Shoulder sections were stained using hematoxylin and eosin, and Toluidine Blue and Picrosirius Red. Additionally, the shoulder tissue sections were immunostained with antibodies against TNF-α and matrix metalloproteinase (MMP)-13. Serum cytokine level was measured to evaluate systemic inflammation. Results: Strenuous exercise exacerbated pathological changes associated with psoriasis, including increased γδ T cell infiltration and upregulated IL-17 and IL-23 expression in the skin, as well as enhanced γδ T cell development and IL-17 expression in the thymus. Although strenuous exercise did not further worsen the modified PASI scores, histological and immunological markers of inflammation were significantly enhanced. Serum levels of TNF-α and IL-17 were significantly elevated in IMQ-induced psoriasis model mice. Moreover, pathological changes induced by strenuous exercise were observed in the enthesis, including angiogenesis and upregulated expression of TNF-α and MMP-13. Conclusion: This study revealed that strenuous exercise exacerbates pathological changes in IMQ-induced psoriasis model mice. No potential conflict of interest relevant to this article was reported.

Wiley Acta Medica Okayama 2572-1143 9 1 2026 Mechanosensitive Ion Channel PIEZO1 Suppresses BMP2-Induced Ossification of the Annulus Fibrosus Cells e70168 EN Hisakazu Shitozawa Department of Orthopaedic Surgery, Science of Functional Recovery and Reconstruction, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryo Nakamichi Department of Orthopaedic Surgery, Okayama University Graduate School Medicine, Dentistry, and Pharmaceutical Sciences Aki Yoshida Department of Orthopaedic Surgery, Science of Functional Recovery and Reconstruction, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masataka Ueda Department of Orthopaedic Surgery, Science of Functional Recovery and Reconstruction, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Taichi Saito Department of Orthopaedic Surgery, Okayama University Hospital Koji Uotani Department of Orthopaedic Surgery, Okayama University Hospital Yoshiaki Oda Department of Orthopaedic Surgery, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Ryo Takatori Department of Orthopaedic Surgery, Science of Functional Recovery and Reconstruction, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kazutaka Yamashita Department of Orthopaedic Surgery, Science of Functional Recovery and Reconstruction, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Toshifumi Ozaki Department of Orthopaedic Surgery, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Objective: Major cause of low-back pain is intervertebral disc degeneration (IVDD), with mechanical stress playing a crucial role in its progression. A mechanosensitive ion channel, PIEZO1, is involved in various musculoskeletal tissues, but its role in the annulus fibrosus (AF) remains unclear. This study aimed to elucidate the function of PIEZO1 in AF cells under mechanical stimulation. Methods: Primary rat AF cells were subjected to cyclic tensile strain (CTS) at low (2%) and high (12%) strain levels to investigate strain-dependent effects on osteogenic gene expression. We evaluated the effects of Piezo1, Piezo2, and Trpv4 knockdown by RNA interference to identify the upstream mechanotransducer. Furthermore, PIEZO1 was activated using the agonist Yoda1, followed by RNA-sequencing analysis and evaluation of its effects on BMP2-induced osteogenesis in rat AF cells. We also examined the effects of Yoda1 in primary human AF cells. Results: Low-strain CTS significantly suppressed osteogenic marker expression, which was not observed with high strain. Piezo1 knockdown reversed this suppression, whereas Piezo2 and Trpv4 had no effect. Piezo1 activation by Yoda1 produced similar anti-osteogenic effects in both rat and human AF cells. RNA sequencing revealed the enrichment of ossification and calcineurin signaling pathways in rat cells. Furthermore, Piezo1 activation inhibited BMP2-induced osteogenesis and nuclear translocation of p-Smad1/5/9. Conclusions: Piezo1 maintains AF cell homeostasis under mechanical stress by suppressing osteogenic changes via calcineurin-mediated inhibition of BMP signaling, which may represent a novel therapeutic target for IVDD. No potential conflict of interest relevant to this article was reported.

Elsevier BV Acta Medica Okayama 0020-1383 56 8 2025 Risk factors for extensor pollicis longus tendon rupture following non-displaced distal radius fractures 112454 EN Taichi Saito Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Tomoki Furutani Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Ryo Nakamichi Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Ryuichi Nakahara Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Hidenori Kondo Department of Orthopaedic Surgery, Kagawa Rosai Hospital Yasunori Shimamura Department of Orthopaedic Surgery, Kousei Hospital Junya Imatani Department of Orthopaedic Surgery, Saiseikai General Hospital Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Introduction: Distal radius fractures (DRFs) are common, with an increasing incidence, particularly among the elderly. Rupture of the extensor pollicis longus (EPL) tendon, essential for thumb extension, is a notable complication, especially in non-displaced DRFs. Several mechanisms, such as local adhesion, ischemic atrophy, and tendon laceration, are associated with EPL tendon rupture. This multicenter retrospective study aims to identify risk factors for EPL tendon rupture in non-displaced DRFs. Materials and methods: The study reviewed 20 cases of EPL tendon rupture and 52 control cases from 2005 to 2022, excluding those who underwent surgery or had incomplete computed tomography (CT) data. We investigated age, sex, location of fracture line, and the morphology of Lister’s tubercle as variables. Logistic regression and decision tree analyses were employed to determine the risk factors for EPL tendon rupture based on these variables. Results: Fracture lines distal to Lister’s tubercle and specific shapes of Lister’s tubercle, characterized by shallow peak height and a higher radial peak than the ulnar peak, increased the risk of EPL tendon rupture. Decision tree analysis confirmed them as major risk factors. There was a significant difference in the predicted probability rate of tendon rupture between the case with these factors and those without them (P < 0.001). Conversely, the location and size of Lister’s tubercle did not affect the incidence of EPL tendon rupture. Conclusion: The location of fracture line and the shape of Lister’s tubercle are key factors influencing EPL tendon rupture in non-displaced DRFs. Understanding these factors can help orthopedic surgeons predict and prevent EPL tendon ruptures, improving patient outcomes following these fractures. No potential conflict of interest relevant to this article was reported.

BMC Acta Medica Okayama 1471-2474 25 1 2024 Comparison of early clinical outcome in carpal tunnel release - mini-open technique with palmar incision vs. endoscopic technique with wrist crease incision- 251 EN Ryo Nakamichi Department of Rehabilitation Medicine, Okayama University Hospital Taichi Saito Department of Sports Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Yasunori Shimamura Department of Sports Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Masanori Hamada Department of Rehabilitation Medicine, Okayama University Hospital Keiichiro Nishida Department of Sports Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Toshifumi Ozaki Department of Sports Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine Background The purpose of this study was to examine two techniques for Carpal Tunnel Syndrome, mini-Open Carpal Tunnel Release (mini-OCTR) and Endoscopic Carpal Tunnel Release (ECTR), to compare their therapeutic efficacy. Methods Sixteen patients who underwent mini-OCTR in palmar incision and 17 patients who underwent ECTR in the wrist crease incision were included in the study. All patients presented preoperatively and at 1, 3, and 6 months postoperatively and were assessed with the Visual Analogue Scale (VAS) and the Disabilities of Arm, Shoulder and Hand Score (DASH). We also assessed the pain and cosmetic VAS of the entire affected hand or surgical wound, and the patient's satisfaction with the surgery. Results In the objective evaluation, both surgical techniques showed improvement at 6 months postoperatively. The DASH score was significantly lower in the ECTR group (average = 3 months: 13.6, 6 months: 11.9) than in the mini-OCTR group (average = 3 months: 27.3, 6 months: 20.6) at 3 and 6 months postoperatively. Also, the pain VAS score was significantly lower in the ECTR group (average = 17.1) than in the mini-OCTR group (average = 36.6) at 3 months postoperatively. The cosmetic VAS was significantly lower in the ECTR group (average = 1 month: 15.3, 3 months: 12.2, 6 months: 5.41) than in the mini-OCTR group (average = 1 month: 33.3, 3 months: 31.2, 6 months: 24.8) at all time points postoperatively. Patient satisfaction scores tended to be higher in the ECTR group (average = 3.3) compared to the mini-OCTR group (average = 2.7). Conclusions ECTR in wrist increase incision resulted in better pain and cosmetic recovery in an early postoperative phase compared with mini-OCTR in palmar incision. Our findings suggest that ECTR is an effective technique for patient satisfaction. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2077-0383 12 22 2023 The Effectiveness of Rehabilitation after Open Surgical Release for Trigger Finger: A Prospective, Randomized, Controlled Study 7187 EN Taichi Saito Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryo Nakamichi Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryuichi Nakahara Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Keiichiro Nishida 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 Background: It is not clear whether rehabilitation after surgery for trigger finger is effective. The aim of this study was to reveal its effectiveness for trigger finger. Methods: This study was a randomized, controlled trial that included patients who underwent operations for trigger fingers. The patients in the rehabilitation group had postoperative occupational therapy (OT) for 3 months, while the patients in the control group were not referred for rehabilitation but received advice for a range of motion exercises. We evaluated the severity of trigger finger, Disability of Arm-Shoulder-Hand (DASH) score, pain-visual analogue scale (VAS), grip strength, whether they gained a full range of motion (ROM), and complications before and after surgery. Results: Finally, 29 and 28 patients were included in the control and rehabilitation groups, respectively. At final follow-up, the DASH score, grip strength, and ROM were significantly improved in the rehabilitation group compared to that preoperatively. At final follow-up, pain was significantly improved in both groups from that preoperatively. There were no significant differences in the results, including the DASH score, grip strength, ROM and pain-VAS between the control and rehabilitation groups at the final follow-up. Subgroup analysis showed that there is a significant difference in the DASH score of patients doing housework or light work and those with a duration of symptoms >12 months between the control and rehabilitation groups at the final follow-up. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 77 2 2023 Fracture Line Distributions of Undisplaced Distal Radius Fractures in Relation to Rupture of the Extensor Pollicis Longus Tendon 179 184 EN Hidenori Kondo Department of Orthopaedic Surgery, Kagawa Rosai Hospital Taichi Saito Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryuichi Nakahara Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryo Nakamichi Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yasunori Shimamura Department of Sports Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryozo Harada Department of Orthopaedic Surgery, Kurashiki Sweet Hospital Junya Imatani Department of Orthopaedic Surgery, Saiseikai General Hospital Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Original Article 10.18926/AMO/65147 Rupture of the extensor pollicis longus (EPL) tendon is a known complication after undisplaced distal radius fracture (DRF). However, no report has revealed the relationship between EPL tendon rupture and the fracture pattern. Thus, this study aimed to investigate the characteristics of fractures at risk of EPL tendon rupture using fracture line mapping of undisplaced DRFs. This study used computed tomography imaging data of undisplaced DRFs with (n=18) and without EPL tendon rupture (n=52). Fracture lines obtained from 3D reconstruction data were drawn manually after matching with a 2D template wrist model. Fracture maps represented the fracture line distribution by superimposing the fracture lines of all 70 patients. Heat maps showed the relative frequency of the fracture lines as a gradual color change. Fracture lines of cases with EPL tendon rupture were concentrated in the proximal border of Lister’s tubercle. By contrast, fracture lines of cases without EPL tendon rupture were relatively dispersed. No potential conflict of interest relevant to this article was reported.

BMC Acta Medica Okayama 1471-2474 22 1 2021 Relationship between clinical outcomes and nerve conduction studies before and after surgery in patients with carpal tunnel syndrome 882 EN Masato Ise Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Taichi Saito Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoshimi Katayama Department of Rehabilitation Medicine, Okayama University Hospital Ryuichi Nakahara Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yasunori Shimamura Department of Sports Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masanori Hamada Department of Rehabilitation Medicine, Okayama University Hospital Masuo Senda Department of Rehabilitation Medicine, Okayama University Hospital Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Background Nerve conduction study (NCS) is the only useful test for objective assessment of carpal tunnel syndrome (CTS). However, the relationship between pre- and postoperative NCS and clinical outcomes was unclear. This study aimed to determine whether pre- and postoperative (6 months) NCS could predict patient-oriented and motor outcomes (6 and 12 months postoperatively) in patients with CTS. Method Of the 85 patients with CTS, 107 hands were analyzed from March 2011 to March 2020. All patients underwent open carpal tunnel release and were examined using the disabilities of the arm, shoulder and hand (DASH) questionnaire and grip strength (GS) preoperatively and 6 and 12 months postoperatively. Moreover, NCS was examined preoperatively and 6 months postoperatively. Distal motor latency (DML) and sensory conduction velocity (SCV) were the parameters used for NCS. The correlation coefficient between NCS and DASH or GS was calculated. A receiver operating characteristic curve was utilized to determine the NCS threshold value to predict DASH and GS improvement. Results The average scores of GS preoperatively and 6 and 12 months postoperatively were 21.3, 22.3, and 22.8, respectively. On the other hand, the average scores of DASH preoperatively and 6 and 12 months postoperatively were 28.8, 18.3, and 12.2, respectively. The average NCS scores (DML and SCV) preoperatively/6 months postoperatively were 7.3/5.4 and 27.8/36.7, respectively. Preoperative NCS did not correlate with DASH and GS. Postoperative SCV correlated with the change in grip strength (6–12 months, r = 0.67; 0–12 months, r = 0.60) and DASH (0–12 months, r = 0.77). Moreover, postoperative DML correlated with the change in DASH (6–12 months, r = − 0.33; 0–12 months, r = − 0.59). The prediction for the improvement of GS/DASH achieved a sensitivity of 50.0%/66.7% and a specificity of 100%/100%, at an SCV cutoff score of 38.5/45.0 or above. The prediction for improvement of GS/DASH achieved a sensitivity of 83.3%/66.7% and a specificity of 100%/66.7% at a DML cutoff score of 4.4/4.4 or below. Conclusion NCS at 6 months postoperatively can be used to predict the improvement of clinical outcome after 6 months postoperatively in patients with CTS. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 75 2 2021 Osteosynthesis for Geriatric Acetabular Fractures: An Epidemiological and Clinico-Radiological Study Related to Marginal or Roof Impaction 177 185 EN Madoka Inoue Department of Orthopedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomoyuki Noda Department of Emergency Healthcare and Disaster Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takenori Uehara Department of Medical Materials for Musculoskeletal Reconstruction, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tomonori Tetsunaga Department of Musculoskeletal Traumatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kazuki Yamada Department of Musculoskeletal Sports Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Taichi Saito Department of Musculoskeletal Traumatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yasunori Shimamura Department of Orthopedic Surgery, Kochi Health Sciences Center Yasuaki Yamakawa Department of Orthopedic Surgery, Kochi Health Sciences Center Toshifumi Ozaki Department of Musculoskeletal Traumatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Original Article 10.18926/AMO/61895 This retrospective study sought to elucidate the incidence rates of roof impaction (RI) and marginal impaction (MI) and radiological and clinical outcomes of open reduction and internal fixation (ORIF) for RI and MI in geriatric acetabular fractures. The cases of 68 patients aged ≥ 65 years (mean 71 years) treated with ORIF were analyzed. MI was present in 12 fractures (67%) and an RI of the weight-bearing surface was present in 24 (46%) of the potential fracture types. Regarding the reduction quality, 54% of the reductions were graded as anatomical, 37% as imperfect, and 9% as poor. In the clinical evaluations of the 45 patients who had > 1-year follow-up (follow-up rate: 66.2%), 18% were graded as excellent, 53% as good, 16% as fair, and 13% as poor. An anatomic reduction was strongly associated with good or excellent clinical and radiological outcomes. CT was superior to radiographs for detecting the residual displacement postoperatively. Postoperative deep infection occurred in four patients. Three patients (6.7%) underwent a total hip arthroplasty conversion due to secondary osteoarthritis of the hip. We recommend ORIF as the preferred surgical treatment option for displaced acetabular fractures in elderly patients. No potential conflict of interest relevant to this article was reported.

Elsevier Acta Medica Okayama 09492658 26 2 2020 Differences between the root and horn cells of the human medial meniscus from the osteoarthritic knee in cellular characteristics and responses to mechanical stress 230 236 EN Yuki Okazaki Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Takayuki Furumatsu Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Yusuke Kamatsuki Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Keiichiro Nishida Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Yoshihisa Nasu Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Ryuichi Nakahara Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Taichi Saito Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Toshifumi Ozaki Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Background Many histological, mechanical, and clinical studies have been performed on the medial meniscus posterior root attachment, as it often tears in patients with osteoarthritic knee. Medial meniscal root repair is recommended in clinical situations; however, to date, no studies have examined the differences between meniscal root and horn cells. The aim of this study was, therefore, to investigate the morphology, reaction to cyclic tensile strain, and gene expression levels of medial meniscal root and horn cells. Methods Meniscal samples were obtained from the medial knee compartments of 10 patients with osteoarthritis who underwent total knee arthroplasty. Root and horn cells were cultured in Dulbecco's modified Eagle's medium without enzymes. The morphology, distribution, and proliferation of medial meniscal root and horn cells, as well as the gene and protein expression levels of Sry-type HMG box 9 and type II collagen, were determined after cyclic tensile strain treatment. Results Horn cells had a triangular morphology, whereas root cells were fibroblast-like. The number of horn cells positive for Sry-type HMG box 9 and type II collagen was considerably higher than that of root cells. Although root and horn cells showed similar levels of proliferation after 48, 72, or 96 h of culture, more horn cells than root cells were lost following a 2-h treatment with 5% and 10% cyclic tensile. Sry-type HMG box 9 and α1(II) collagen mRNA expression levels were significantly enhanced in both cells after 2- and 4-h cyclic tensile strain (5%) treatment. Conclusions Medial meniscal root and horn cells have distinct morphologies, reactions to mechanical stress, and cellular phenotypes. Our results suggest that physiological tensile strain is important to activate extracellular matrix production in horn cells. No potential conflict of interest relevant to this article was reported.

Elsevier Acta Medica Okayama 0968-0160 27 3 2020 Comparison of the clinical outcomes of transtibial pull-out repair for medial meniscus posterior root tear: Two simple stitches versus modified Mason-Allen suture 701 708 EN Takaaki Hiranaka Department of Orthopaedic Surgery, Okayama University Hospital Takayuki Furumatsu Department of Orthopaedic Surgery, Okayama University Hospital Shinichi Miyazawa Department of Orthopaedic Surgery, Okayama University Hospital Yoshiki Okazaki Department of Orthopaedic Surgery, Okayama University Hospital Yuki Okazaki Department of Orthopaedic Surgery, Okayama University Hospital Shota Takihira Department of Orthopaedic Surgery, Okayama University Hospital Yuya Kodama Department of Orthopaedic Surgery, National Hospital Organization Iwakuni Clinical Center Yusuke Kamatsuki Department of Orthopaedic Surgery, National Hospital Organization Iwakuni Clinical Center Shin Masuda Department of Orthopaedic Surgery, Chikamori Hospital Taichi Saito Department of Orthopaedic Surgery, Okayama University Hospital Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Hospital Background Transtibial pullout repair of a medial meniscus posterior root tear (MMPRT) is a commonly used procedure, and several techniques have been reported. We hypothesised that pull-out repairs using two simple stitches (TSS) would have similar postoperative outcomes as those using the modified Mason-Allen suture with FasT-Fix (F-MMA). We aimed to investigate the clinical outcomes of these techniques, including the meniscal healing status and osteoarthritic change. Methods The data of 68 patients who underwent transtibial pull-out repair were retrospectively investigated. The patients were divided into two groups of 41 and 27 patients using F-MMA and TSS, respectively. The clinical outcomes were assessed preoperatively and at second-look arthroscopy (the mean period from surgery was one year) using the Knee injury and Osteoarthritis Outcome Score. The meniscal healing status, evaluated at second-look arthroscopy, was compared between the two groups. The cartilage damage was graded as per the classification of the International Cartilage Repair Society and compared at the primary surgery and second-look arthroscopy. Results Both groups showed significant improvement in each clinical score. No significant difference was seen in the clinical outcome scores and the meniscal healing status between the two groups at second-look arthroscopy. Moreover, no significant progression of cartilage damage was observed in both groups. Fourteen patients in the F-MMA group developed a complication of suture bar failures postoperatively; however, there were no complications in the TSS group. Conclusions The TSS and F-MMA techniques showed favourable clinical outcomes and would be established as clinically useful techniques for the MMPRT treatment. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 23526440 25 2020 The Masquelet technique for septic arthritis of the small joint in the hands: Case reports 100268 EN Taichi Saito Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Tomoyuki Noda Department of Musculoskeletal Traumatology, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Hiroya Kondo Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Koji Demiya Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Satoshi Nezu Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Suguru Yokoo Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Minami Matsuhashi Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Takenori Uehara Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Yasunori Shimamura Department of Sports Medicine, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Masayuki Kodama Mizushima Central Hospital Toshifumi Ozaki Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Density and Pharmaceutical Sciences Septic arthritis in distal interphalangeal (DIP) joints sometimes occurs in association with mucous cysts or after the surgical treatment of mallet fingers. Recently, several studies have demonstrated the effectiveness of the Masquelet technique in the treatment of bone defects caused by trauma or infection. However, only few studies have reported the use of this technique for septic arthritis in small joints of the hand, and its effectiveness in treating septic arthritis in DIP joints remains unclear. We report the clinical and radiological outcomes of three patients who were treated with the Masquelet technique for septic arthritis in DIP joints. One patient had uncontrolled diabetes and another had rheumatoid arthritis treated with methotrexate and prednisolone. The first surgical stage involved thorough debridement of the infection site, including the middle and distal phalanx. We placed an external fixator from the middle to the distal phalanx and then packed the cavity of the DIP joint with antibiotic cement bead of polymethylmethacrylate (40 g) including 2 g of vancomycin and 200 mg of minocycline. At 4-6 weeks after the first surgical stage, the infection had cleared, and the second surgical stage was performed. The external fixator and cement bead were carefully removed while carefully preserving the surrounding osteo-induced membrane. The membrane was smooth and nonadherent to the cement block. In the second surgical stage, an autogenous bone graft was harvested from the iliac bone and inserted into the joint space, within the membrane. The bone graft, distal phalanx, and middle phalanx were fixed with Kirschner wires and/or a soft wire. Despite the high risk of infection, bone union was achieved in all patients without recurrence of infection. Although the Masquelet technique requires two surgeries, it can lead to favorable clinical and radiological outcomes for infected small joints of the hand. No potential conflict of interest relevant to this article was reported.

Springer Acta Medica Okayama 0936-8051 140 4 2019 External iliac artery thrombosis following open reduction of acetabular fracture: a case report and literature review 481 485 EN Norio Yamamoto Department of Orthopedic Surgery, Kagawa Prefectural Central Hospital Tomoyuki Noda Department of Musculoskeletal Traumatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Taichi Saito Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Takenori Uehara Department of Emergency Healthcare and Disaster Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science Yasunori Shimamura Department of Sports Medicine, 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 Science BACKGROUND: Postoperative thrombosis of the external iliac artery (EIA) following open reduction and internal fixation for acetabular fracture is extremely rare. PURPOSE: To report a patient with EIA thrombosis following open reduction and internal fixation using the modified ilioinguinal approach for acetabular fractures. STUDY DESIGN: This is a case report of a 69-year-old male with a left acetabular fracture who was treated surgically. METHODS: A 69-year-old male presented with left hip pain after a 1.5-m fall. Radiographs revealed left acetabular anterior wall and posterior hemitransverse fractures with dome impaction. Computed tomography (CT) showed atherosclerotic changes in many arteries. Open reduction and internal fixation were performed using the modified ilioinguinal approach. Adhesion around the external iliac vessels was severe, and the external iliac vein (EIV) ruptured during exposure. After EIV repair, anatomical reduction was achieved and the fracture was fixed using a reconstruction plate. Nine hours after surgery, the left lower limb showed acute ischemic symptoms. Contrast-enhanced CT indicated complete occlusion of the left EIA. The patient was immediately taken for a thrombectomy via EIA cut-down using a Fogarty catheter. Postoperatively, he had palpable dorsalis pedis and posterior tibial pulses; however, post-reperfusion compartment syndrome developed. Fasciotomy of the left leg was performed. RESULTS: At the 2-year and 4-month follow-up, he was pain-free in his hip and leg. Although he was walking with a cane, activity was limited due to a mild foot drop. CONCLUSIONS: It is very important for surgeons to consider EIA thrombosis as a potential complication following open reduction and internal fixation. In this case, EIA thrombosis could be explained by preoperative atherosclerotic changes and intraoperative vascular handling procedures. Preoperative screening and management, and meticulous surgical procedures are necessary for patients with a high risk of thrombosis. No potential conflict of interest relevant to this article was reported.