Kentaro Aritomi

Toho University, Edo, Tōkyō, Japan

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Publications (13)38.45 Total impact

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    ABSTRACT: We hypothesized that posterior approach (PA) dissecting the short external rotators and anterior approach (AA) not dissecting these have different influences on the pelvic floor muscles and subsequently affect urinary incontinence. The objective of this study was to investigate whether AA advantageously influences symptoms of urinary incontinence. The subjects were 76 female patients who underwent their primary total hip arthroplasty. The presence or absence of urinary incontinence before and after surgery was surveyed by a direct interview at the time of outpatient examination within a period from 1.5 year after surgery using the international consultation on incontinence questionnaire-short form. Urinary incontinence improved after surgery in eight patients (22.2 %), slightly improved in one (2.8 %), remained unchanged in 26 (72.2 %), slightly aggravated in one (2.8 %) in the AA group. In the PA group, urinary incontinence improved after surgery in one (2.5 %), remained unchanged in 30 (75 %), slightly aggravated in four (10 %), and aggravated in five (12.5 %). Symptoms of urinary incontinence were significantly improved in the AA group and aggravated in the PA group (Mann-Whitney U test, P = 0.0057). As the anatomical characteristic of the short external rotators, the root of the internal obturator muscle is connected to the levator ani muscle. Among the pelvic floor muscles, this levator ani muscle is closely involved in supporting the pelvic organs. Since the short external rotators may have been atrophied due to hip joint dysfunction before surgery, if the strength of this muscle group recovers, support of the pelvic organs and urinary incontinence may be improved. It was assumed that surgery through AA improved external rotation contracture of the hip joint and leg length, which increased tension of the internal obturator muscle, with which tension of the pelvic floor muscle also increased and improved urinary incontinence.
    European Journal of Orthopaedic Surgery & Traumatology 01/2014; · 0.18 Impact Factor
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    ABSTRACT: Background The outcome of cementless total hip arthroplasty depends on many factors. We must not forget fundamental things those are design of outer surface of the component, that leads bone ingrowth into the prosthesis, better initial stability, and better insertional techniques. The purpose of this study was to review our experience with metal-on-metal total hip arthroplasty with a Wagner standard cup for patients who had acetabular dysplasia. Patients and methods Fifty-four patients with 55 hips underwent primary metal-on-metal total hip arthroplasty (Metasul prosthesis) with a Wagner standard cup (44–48 mm in outer diameter) and were followed for a minimum of 10 years. All patients received the same type of cementless femoral component (Natural hip stem) and femoral head (28 mm in diameter). Results Seventeen of the 55 Wagner standard cups (30.9%) showed aseptic loosening over a mean period of 3.6 years after surgery, and there were no bone anchors on the outer surface of the 16 retrieved cups. Conclusion From our experience, the small Wagner standard cup does not achieve sufficient osteointegration and we do not recommend the use of this cup, especially for patients with acetabular dysplasia and/or those with a small stature.
    Journal of Orthopaedics. 01/2014;
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    ABSTRACT: PURPOSE. To evaluate the chromium level of the salvaged blood in patients undergoing revision total hip arthroplasty (THA). METHODS. Records of 7 women and one man aged 54 to 83 (mean, 64.3) years who underwent revision THA for aseptic loosening of the acetabular component (n=6), osteolysis of the acetabulum (n=1), or migration of the outer head (n=1) were reviewed, as were 2 controls who underwent primary THA. The initial THA entailed a metal-on-metal prosthesis (n=4), a metal-on-polyethylene prosthesis (n=3), and a bipolar head prosthesis (n=1). Chromium levels in the preoperative peripheral blood and intraoperative salvaged blood were measured using atomic absorption analysis. RESULTS. For controls and the patient with a bipolar head prosthesis, the mean chromium level in salvaged blood was 0.4 (range, 0.2-0.6) micrograms/l, which was significantly lower than that in the remaining 7 patients undergoing revision THA (mean, 5.6 micrograms/l; range, 1.2-9.8 micrograms/l). CONCLUSION. Salvaged blood of patients with a metal-on-metal prosthesis undergoing revision THA contained higher levels of chromium.
    Journal of orthopaedic surgery (Hong Kong) 08/2013; 21(2):195-8.
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    ABSTRACT: We describe a new technique of pedicle freezing of the distal radius with malignant bone tumour and osteotomy of the normal ulna. The distal radius was sufficiently elevated to enable freezing without damaging adjacent tissues by releasing the distal radio-ulnar and radio-carpal joint and cutting the middle third of the ulna. The distal radius (including the tumour) was soaked in liquid nitrogen and the defect filled with iliac grafts. The ulna was repaired with plate and screws and was united at month 2. There was no local recurrence and the postoperative function score was 93%. This technique decreases the risk of non-union of the osteotomy site of the tumorous bone.
    Journal of orthopaedic surgery (Hong Kong) 04/2012; 20(1):98-102.
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    ABSTRACT: The roles of chemokines CCL19 and CCL21 in Ab production were investigated using plt mutant mice, which lack expression of CCL19 and CCL21-ser in their lymphoid organs. In these mice, the Th response has been shown to tend towards the Th1 type because of accumulation of inflammatory dendritic cells. When plt mice were immunized with 100 μg OVA in CFA, the number of Ab-forming cells in the draining LN, and serum concentrations of OVA-specific IgM and IgG Ab, were very close to those of the control, yet IgG2a Ab in plt mice was increased. In vitro IFN-γ production by the draining LN cells of plt mice was increased. In addition, the ability of helper T cells from plt mice to stimulate Ab production in vitro was prolonged. Also, in the plt mice, in vivo challenge with OVA in incomplete Freund's adjuvant elicited a stronger IgG2a response and a weaker IgG1 response, which is suggestive of a Th1-dominant response. Similar findings were obtained when mice were immunized with 100 μg OVA in alum, except that with alum the increases observed in plt mice were IgG1 produced in vivo and IL-4 produced in vitro by draining LN cells. Furthermore, immunization with alum adjuvant also induced a prolonged in vitro recall response of IFN-γ and IL-4. These findings indicate that plt mice mount an anti-OVA Ab response, and suggest that CCL19 and CCL21 induce prompt Ab responses to antigen, and negatively regulate helper T cell responses in vivo.
    Microbiology and Immunology 11/2010; 54(11):691-701. · 1.55 Impact Factor
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    ABSTRACT: Although many authors have reported the serum concentrations of metal ions in patients who had metal-on-metal coupling prostheses, most of the studies were not longitudinal, and the follow-up periods were short. We evaluated the longitudinal changes of serum chromium levels in 44 patients who had undergone unilateral metal-on-metal total hip arthroplasty for a minimum of 7 years postoperatively. Although there was a consistent increase in the mean serum chromium level until 3 years after implantation, there was little difference in the levels from years 3 to 7 postoperatively. Although the serum chromium concentration was low throughout postoperative follow-up for 7 years in about 25% of patients, the serum chromium level stayed high or showed gradual elevation in 16.3% of our patients.
    The Journal of arthroplasty 10/2009; 25(8):1196-200. · 1.79 Impact Factor
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    ABSTRACT: CCL19 and CCL21 are thought to be critical for experimental autoimmune encephalomyelitis (EAE) induction, but their precise role is unknown. We examined the role of these chemokines in inducing EAE. C57BL/6 mice lacking expression of these chemokines (plt/plt mice) or their receptor CCR7 were resistant to EAE induced with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG(35-55)) and pertussis toxin. However, passive transfer of pathogenic T cells from wild-type mice induced EAE in plt/plt mice, suggesting a defect independent of the role of CCR7 ligands in the migration of immune cells. Examination of draining lymph node (DLN) cells from MOG(35-55)-immunized plt/plt mice found decreased IL-23 and IL-12 production by plt/plt dendritic cells (DCs) and a concomitant defect in Th17 cell and Th1 cell generation. In contrast, production of the Th17 lineage commitment factors IL-6 and TGF-beta were unaffected by loss of CCR7 ligands. The adoptive transfer of in vitro-generated Th17 cells from DLN cells of MOG(35-55)-immunized plt/plt mice developed EAE in wild-type recipient mice, whereas that of Th1 cells did not. Pathogenic Th17 cell generation was restored in plt/plt DLNs with the addition of exogenous IL-23 or CCL19/CCL21 and could be reversed by inclusion of anti-IL-23 mAb in cultures. Exogenous CCL19/CCL21 induced IL-23p19 expression and IL-23 production by plt/plt or wild-type DCs. Therefore, CCR7 ligands have a novel function in stimulating DCs to produce IL-23 and are important in the IL-23-dependent generation of pathogenic Th17 cells in EAE induction.
    The Journal of Immunology 09/2009; 183(4):2513-21. · 5.52 Impact Factor
  • Journal of shoulder and elbow surgery / American Shoulder and Elbow Surgeons ... [et al.] 12/2008; 18(4):e17-20. · 1.93 Impact Factor
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    ABSTRACT: The treatment of osteonecrosis of the femoral head in younger patients varies among orthopaedic surgeons. In particular, the optimal treatment of extensive osteonecrosis associated with femoral head collapse remains controversial. Since 1995, we have performed rotational acetabular osteotomy on 70 hips, including those of 3 patients with extensive osteonecrosis of the femoral head after intracapsular fracture of the neck of the femur. In all 3 patients, adequate coverage of the femoral head by the osteotomized acetabulum was obtained, and their symptoms (especially pain) showed marked improvement at latest follow-up.
    Journal of orthopaedic trauma 11/2008; 22(9):658-62. · 1.78 Impact Factor
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    ABSTRACT: Marked activation of thrombosis is common in patients undergoing total hip arthroplasty, especially during reaming of the femur and after insertion of the femoral prosthesis. This suggests that management designed to minimize deep vein thrombosis and fatal pulmonary embolism after total hip arthroplasty should be focused on the period during insertion of the femoral component. In some previous studies, a low dose of heparin administered intraoperatively was shown to suppress the formation of fibrin. The present study was performed to evaluate the influence of intraoperative heparin administration on the D-dimer level and on the prevention of pulmonary embolism after total hip arthroplasty. A total of 22 and 26 consecutive patients respectively underwent total hip arthroplasty with and without intraoperative administration of unfractionated heparin. Postoperatively, all patients wore knee-high elastic stockings and were fitted with calf-to-thigh intermittent pneumatic compression devices. Active ankle flexion and extension exercises were commenced as soon as motor function recovered. None of the 48 patients received prophylactic anticoagulants postoperatively. There was a significant difference of the mean D-dimer level on the 1st day between the patients with and without intraoperative administration of heparin (8.9 +/- 6.6 vs. 15.7 +/- 12.7, P < 0.05). Although there were no patients with symptomatic deep venous thrombosis and pulmonary embolism, asymptomatic pulmonary embolism was detected by pulmonary perfusion scintigraphy in three patients who did not receive intraoperative heparin. The operative blood loss and postoperative drainage were similar in both groups and no bleeding complications were observed. In conclusion, we recommend a safe and inexpensive regimen comprising 1,000 U of intravenous unfractionated heparin intraoperatively, postoperative pneumatic compression, and early active mobilization for prevention of thoromboembolic complications after total hip arthroplasty.
    Archives of Orthopaedic and Trauma Surgery 02/2008; 128(1):37-40. · 1.36 Impact Factor
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    ABSTRACT: Secondary lymphoid organs (SLOs) provide a niche for the initiation and regulation of T-cell responses, but the mechanisms have been poorly understood. We investigated the influence of chemokines CCL19 and CCL21 constitutively expressed in SLOs on activation-induced cell death (AICD) of CD4+ T cells. When paucity of lymph node T cells (plt) mutant mice lacking expression of CCL19/CCL21 were primed with OVA/CFA, both expansion of OVA-responding CD4+ T cells in the draining lymph nodes and an in vitro recall response were prolonged as compared with responses in wild-type (WT) mice. The apoptotic cell frequency among OVA-responding CD4+ T cells was similarly low in plt/plt and WT mice during the clonal expansion phase. However, during the clonal contraction phase, the frequency never increased in plt/plt mice, whereas in WT mice it continuously increased to a peak 18 days after immunization. The presence of CCL19/CCL21 during the in vitro stimulation of CD4+ T cells with anti-CD3 plus anti-CD28 significantly enhanced in vitro AICD induction of the restimulated T cells, partially through enhancing expression of Fas ligand. Our results suggest that CCL19/CCL21 produced by stromal cells and antigen-presenting cells regulate CD4+ T-cell immune responses in SLOs by promoting AICD.
    Blood 02/2007; 109(2):449-56. · 9.78 Impact Factor
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    ABSTRACT: The operative procedures chosen to treat arthrosis in patients with severe acetabular dysplasia vary among orthopaedic surgeons, particularly in younger patients. We operated on 450 hips with acetabular dysplasia by using the rotational acetabular osteotomy (RAO) method of Ninomiya and Tagawa by Ninomiya (Clin Orthop 247:127-137, 1989). In this report, we describe our technique of performing RAO with hydroxyapatite tricalcium phosphate-composite (HAP-TCP) blocks to achieve good acetabular coverage and the results of this procedure in 16 hips with severe dysplasia, including nine with advanced arthrosis. Adequate coverage of the osteotomized acetabulum was maintained and symptoms, especially pain, showed marked improvement at the latest follow up.
    Archives of Orthopaedic and Trauma Surgery 09/2006; 126(6):421-4. · 1.36 Impact Factor
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    ABSTRACT: The paucity of lymph node T cells (plt) mutation leads to a loss of CCL21 and CCL19 expression in secondary lymphoid organs. plt mice have defects in the migration of naive T cells and activated dendritic cells into the T cell zones of lymphoid organs, suggesting that they would have defects in T cell immune responses. We now demonstrate T cell responses in plt mice are delayed but ultimately enhanced. Responses to contact sensitization are decreased at day 2 after priming but increased at day 6. After subcutaneous immunization, antigen-specific T cell proliferation and cytokine production in plt mice are increased and remain markedly elevated for at least 8 wk. Compared with wild-type mice, a proportion of T cell response in plt mice are shifted to the spleen, and prior splenectomy reduces the T cell response in draining lymph nodes. After immunization of plt mice, T cells and dendritic cells colocalize in the superficial cortex of lymph nodes and in splenic bridging channels, but not in T cell zones. These results demonstrate that plt mice mount robust T cell responses despite the failure of naive T cells and activated dendritic cells to enter the thymus dependent areas of secondary lymphoid organs.
    Journal of Experimental Medicine 02/2001; 193(2):207-18. · 13.21 Impact Factor