SAGE Publications Acta Medica Okayama 1022-5536 34 1 2026 Similar functional outcomes but different remodeling patterns: A minimum 5-years radiographic comparison of short fit-and-fill stem and quadrangular taper stem 1 10 EN Yasutaka Masada Department of Orthopaedic Surgery, Section of Medicine, Division of Medicine, Dentistry and Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Tomonori Tetsunaga Department of Musculoskeletal Health Promotion, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Kazuo Fujiwara Department of Orthopaedic Surgery, Okayama City General Medical Center, Okayama City Hospital Kazuki Yamada Department of Orthopaedic Surgery, Okayama University Hospital Tomohiro Inoue Department of Orthopaedic Surgery, Section of Medicine, Division of Medicine, Dentistry and Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Ryuichiro Okuda Department of Orthopaedic Surgery, Section of Medicine, Division of Medicine, Dentistry and Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Tomoko Tetsunaga Department of Sports Medicine, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yuki Okazaki Center for Education in Medicine and Health Sciences, Okayama University Toshifumi Ozaki Department of Orthopaedic Surgery, Section of Medicine, Division of Medicine, Dentistry and Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Purpose: ACTIS and CORAIL are cementless titanium femoral stems with hydroxyapatite (HA) coating but differing macro-geometries: ACTIS features a variable triple-taper with a medial collar, whereas CORAIL is a straight double-tapered design available with or without a collar. We compared mid-term clinical and radiographic outcomes of these stems with a minimum 5-years follow-up.<br> Methods: We retrospectively reviewed 114 primary total hip arthroplasties using ACTIS (63 hips) or CORAIL (51 hips). Clinical outcomes and standardized radiographic parameters were assessed and compared between groups.<br> Results: The canal-fill ratio (CFR) was significantly greater at the proximal, middle, and distal levels in the ACTIS group. Spot-weld formation was more frequent with ACTIS than with CORAIL (58.7% vs 35.3%). In logistic regression, proximal CFR significantly predicted spot-weld formation for ACTIS, with an optimal cutoff of 66.2% (sensitivity 91.9%, specificity 72.0%). Rates of subsidence, radiolucent lines, and pedestal formation did not differ significantly between groups. No severe stress shielding was observed with ACTIS, whereas three CORAIL hips demonstrated severe stress shielding (0% vs 5.9%). Clinical scores improved significantly in both groups, with no significant between-group differences at final follow-up.<br> Conclusions: Both stems yielded favorable radiographic and clinical mid-term outcomes. In ACTIS, greater proximal canal fill was associated with radiographic osseointegration, suggesting proximal CFR as a probabilistic radiographic marker of stem ingrowth. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 69 5 2015 For Vol.69, No.4, pp205-212 Venous Thromboembolism after Total Hip Arthroplasty Diagnosed by Enhanced Computed Tomography : Comparison of Selective Thromboprophylaxis and No Thromboprophylaxis 325 325 EN Yoshiki Okada Hirosuke Endo Shigeru Mitani Kazuo Fujiwara Tomonori Tetsunaga Yohei Kagawa Yosuke Fujii Toshiyuki Kunisada Toshifumi Ozaki Erratum 10.18926/AMO/53680 Total hip arthroplasty (THA) is the most effective treatment for advanced or end-stage hip osteoarthritis. However, venous thromboembolism (VTE) remains one of its unresolved complications. We reviewed the records of 322 patients undergoing primary THA and investigated the efficacy of anticoagulant prophylaxis for VTE. Our study cohort consisted of 60 patients who received no anticoagulants, 100 patients who received a factor Xa inhibitor (fondaparinux), 100 patients who received low molecular weight heparin (enoxaparin), and 62 patients who selectively received no anticoagulant prophylaxis due to perioperative bleeding, weight, and/or hemoglobin concentration. Enhanced 64-slice multidetector row computed tomography was performed postoperatively for 7 days in all cases. The incidence of VTE in the four groups was 15%, 9.0%, 6.0%, and 6.4%, respectively. The incidence of VTE was significantly lower in the groups receiving anticoagulant prophylaxis and the group selectively receiving no anticoagulant prophylaxis than in the group receiving no anticoagulants. Complications of fondaparinux therapy included hepatic dysfunction in 4 cases (4.0%), minor bleeding in 2 cases (2.0%), persistent wound drainage in 3 cases (3.0%), and eruption in 1 case (1.0%). The complications of enoxaparin therapy were persistent wound drainage in 1 case (1.0%) and progression of anemia in 1 case (1.0%). The incidence of VTE was low in patients who selectively received no anticoagulant prophylaxis, so we conclude that anticoagulant prophylaxis should be used selectively in THA cases. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 69 4 2015 Venous Thromboembolism after Total Hip Arthroplasty Diagnosed by Enhanced Computed Tomography : Comparison of Selective Thromboprophylaxis and No Thromboprophylaxis 205 212 EN Yoshiki Okada Hirosuke Endo Shigeru Mitani Kazuo Fujiwara Tomonori Tetsunaga Yohei Kagawa Yosuke Fujii Toshiyuki Kunisada Toshifumi Ozaki Original Article 10.18926/AMO/53556 Total hip arthroplasty (THA) is the most effective treatment for advanced or end-stage hip osteoarthritis. However, venous thromboembolism (VTE) remains one of its unresolved complications. We reviewed the records of 322 patients undergoing primary THA and investigated the efficacy of anticoagulant prophylaxis for VTE. Our study cohort consisted of 60 patients who received no anticoagulants, 100 patients who received a factor Xa inhibitor (fondaparinux), 100 patients who received low molecular weight heparin (enoxaparin), and 62 patients who selectively received no anticoagulant prophylaxis due to perioperative bleeding, weight, and/or hemoglobin concentration. Enhanced 64-slice multidetector row computed tomography was performed postoperatively for 7 days in all cases. The incidence of VTE in the four groups was 15µ, 9.0µ, 6.0µ, and 6.4µ, respectively. The incidence of VTE was significantly lower in the groups receiving anticoagulant prophylaxis and the group selectively receiving no anticoagulant prophylaxis than in the group receiving no anticoagulants. Complications of fondaparinux therapy included hepatic dysfunction in 4 cases (4.0µ), minor bleeding in 2 cases (2.0µ), persistent wound drainage in 3 cases (3.0µ), and eruption in 1 case (1.0µ). The complications of enoxaparin therapy were persistent wound drainage in 1 case (1.0µ) and progression of anemia in 1 case (1.0µ). The incidence of VTE was low in patients who selectively received no anticoagulant prophylaxis, so we conclude that anticoagulant prophylaxis should be used selectively in THA cases. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 67 6 2013 A New Navigation System for Minimally Invasive Total Knee Arthroplasty 351 358 EN Yusuke Yokoyama Nobuhiro Abe Kazuo Fujiwara Masahiko Suzuki Yoshikazu Nakajima Naohiko Sugita Mamoru Mitsuishi Yoshio Nakashima Toshifumi Ozaki Original Article 10.18926/AMO/52008 A computer-assisted navigation system to be used for total knee arthroplasties (TKAs) was reported to improve the accuracy of bone resection and result in precise implant placement, but the concomitant surgical invasion and time consumption are clinical problems. We developed a computed tomography (CT)-based navigation system (NNS) to be used for minimally invasive TKA. It requires only the reference points from a small limited area of the medial femoral condyle and proximal tibia through a skin incision to obtain optical images. Here we evaluated the usefulness and accuracy of the NNS in comparison with the commercially available BrainLAB image-free navigation system (BLS). In a clinical experiment, the registration times obtained with the NNS tended to be shorter than those obtained with the BLS, but not significantly so. The NNS group tended to be in the extended position in the sagittal plane of the distal femur within 3 degrees, and the BLS group showed rather flexed deviation in the sagittal plane of the anterior femur. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 66 5 2012 Dynamic Finite Element Analysis of Impulsive Stress Waves Propagating from Distal End of Femur 409 415 EN Takaaki Sarai Takayuki Inoue Kazuo Fujiwara Koichi Kuramoto Original Article 10.18926/AMO/48965 The human femur is subjected to an impulsive load at its distal end during daily life. Femoral bone fracture caused by impact loading is common in elderly women. It is important to clarify the dynamic response of the femur and to evaluate the change in its stress state during impact loading. A 3-dimensional model of the femur was prepared in the present study, and the impulsive stress waves propagating from the distal end of the femur were analyzed by the dynamic finite element method. This model showed that the von Mises equivalent stress is large on the anterior and posterior sides of the mid-diaphysis when the impact direction is different from that of the bone axis. As for the femoral neck, the absolute value of minimum principal stress initially increases on the medial side;slightly later the maximum principal stress increases on the lateral side. In this case, the absolute value of the maximum principal stress was found to be larger than that of the minimum principal stress, and the absolute value of the principal stress decreased as the impact angle increased. Further, the femoral neck and the trochanter were shown to have a higher risk of bone fracture when the impact direction is coincident with the bone axis. No potential conflict of interest relevant to this article was reported.

‰ªŽRˆãŠw‰ï Acta Medica Okayama 0030-1558 122 2 2010 •ÏŒ`�«ŒÒŠÖ�ß�Ç 159 162 EN Kazuo Fujiwara Hirosuke Endo Yoshiaki Miyake Toshifumi Ozaki No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 62 3 2008 Novel magnetic resonance imaging evaluation for valgus instability of the knee caused by medial collateral ligament injury 185 191 EN Hisanori Ikuma Nobuhiro Abe Youichiro Uchida Takayuki Furumatsu Kazuo Fujiwara Keiichiro Nishida Toshifumi Ozaki Original Article 10.18926/AMO/30974 <p>Instability of the knee after the medial collateral ligament (MCL) injury is usually assessed with the manual valgus stress test, even though, in recent years, it has become possible to apply magnetic resonance imaging (MRI) to the assessment of the damage of the ligament. The valgus instability of 24 patients (12 isolated injuries and 12 multiple ligament injuries) who suffered MCL injury between 1993 and 1998 was evaluated with the Hughston and Eilers classification, which involves radiographic assessment under manual valgus stress to the injured knees. We developed a novel system for classifying the degree of injury to the MCL by calculating the percentage of injured area based on MRI and investigated the relationship between this novel MRI classification and the magnitude of valgus instability by the Hughston and Eilers classification. There was a significant correlation between the 2 classifications (p=0.0006). On the other hand, the results using other MRI based classification systems, such as the Mink and Deutsch classificaiton and the Petermann classification, were not correlated with the findings by the Hughston and Eilers classification in these cases (p0.05). Since MRI is capable of assessing the injured ligament in clinical practice, this novel classification system would be useful for evaluating the stability of the knee and choosing an appropriate treatment following MCL injury.</p> No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 60 6 2006 Assessment of Head Wear More Than Ten Years after Total Hip Arthroplasty: 22-mm Zirconia VS. Metal Heads. 311 318 EN Atsushi Inoue Koji Asaumi Hirosuke Endo Kazuo Fujiwara Shigeru Mitani Toshifumi Ozaki Original Article 10.18926/AMO/30721 The present retrospective study assessed radiographs to determine socket wear in total hip arthroplasty (THA) with 22-mm zirconia or COP (Cobalt-Chrome alloy rich in Cobalt and Phosphorous) heads, and in cemented stems at more than 10 years after operation. Sockets of ultra high molecular weight polyethylene were used in each of two THA groups (13 hips each) in a clinical trial in our hospital between 1989 and 1990. Three observers carried out masked assessments of the radiographs. Upon fi nal examination, there was no remarkable loosening in the zirconia or COP group, and no case had required revision surgery as of 2005. There was a statistically signifi cant diff erence between the 2 groups in average annual linear wear, at 0.093 mm/year and 0.046 mm/year in the zirconia and COP groups, respectively. Volume wear and average annual volume wear were also signifi cantly greater in the zirconia group despite its superior mechanical strength and toughness in vitro. Our present fi ndings do not confi rm early expectations of lower wear in long-term results of 22-mm zirconia femoral heads used in THA. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 2000 Electrophoretic and serologic characterization of 56 kDa antigen (M56) with autologous serum derived from a chondrosarcoma patient:A shared antigen of immunoresponses in cancer and autoimmune diseases EN No potential conflict of interest relevant to this article was reported.