Yuichi Mochida

Yokohama City University, Yokohama, Kanagawa, Japan

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Publications (15)26.21 Total impact

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    ABSTRACT: BACKGROUND: The mobile bearing knee system was introduced to lessen contact stress on the articular bearing surface and reduce polyethylene wear. The purpose of the current study was to investigate the mid-term results of patients undergoing total knee arthroplasties (TKAs) using Scorpio Plus Mobile Bearing Knee System (Stryker, Mahwah, NJ), and compare the outcomes between patients with osteoarthritis and osteonecrosis (OA.ON group) and patients with rheumatoid arthritis (RA group). METHODS: Eight males and 58 females were followed up for a period of 4.4- 7.6 years from June 1, 2003 to December 31, 2005. There were 53 knees with osteoarthritis, 17 knees with rheumatoid arthritis, and 6 knees with osteonecrosis. Clinical and radiographic follow- up was done using The Japanese Orthopedic Association knee rating score (JOA score) and Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. RESULTS: With regard to the JOA score, there was significant improvement in both groups. The postoperative range of motion was between 0.8[degree sign]and 116.8[degree sign] in OA.ON group, and between 0.0[degree sign] and 113.7[degree sign] in RA group. There were no significant differences with the radiographic evaluation between two groups. Spontaneous dislocation of a polyethylene insert occurred in one patient, and deep infection was occurred in one patient. CONCLUSION: There was significant improvement with regard to the clinical and radiographic results of patients undergoing TKAs using the model. The risk of polyethylene insert dislocation related to the mobile bearing TKA is a cause for concern.
    Sports Medicine Arthroscopy Rehabilitation Therapy & Technology 10/2012; 4(1):38.
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    ABSTRACT: Synovectomy is an effective procedure for management of the rheumatoid elbow at radiographically early stages (Larsen grades 1 and 2). However, its efficacy for advanced stages (Larsen grades 3-5) is controversial. We investigated the outcome of synovectomy for advanced stages of the rheumatoid elbow. Between May 1985 and September 1994, synovectomy was performed for 67 rheumatoid elbows in 59 patients (mean age 52 (26-72) years, 54 women). 3 elbows (3 patients) were lost to follow-up after mean 15 (10-23) years. Thus, 64 elbows were evaluated clinically and radiographically. The mean Mayo elbow performance score (MEPS) improved from 42 (15-75) points preoperatively to 78 (45-100) points at the final follow-up examination. In cases of Larsen grade 5, the mean MEPS at final follow-up examination (69 points) was lower than those of Larsen grade 3 and 4 cases (80 and 79 points, respectively) (p < 0.01). Recurrence of synovitis was obvious in 20/67 elbows. 12 cases had a total elbow arthroplasty mean 13 years after the synovectomy. The 10-year, 15-year, and 20-year survival rates were 97%, 75%, and 70%, respectively. Our findings suggest that synovectomy for the rheumatoid elbow gives a good long-term outcome for radiographically judged destroyed joints of Larsen grades 3-4.
    Acta Orthopaedica 08/2012; 83(4):374-8. · 2.45 Impact Factor
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    ABSTRACT: OBJECTIVES: Porous tantalum is a biomaterial newly applied for artificial joints. We present here 5-years follow-up report of a multicenter clinical trial of total hip arthroplasties (THA) with porous tantalum modular acetabular component (modular PTC). METHODS: Study participants received 82 hips in 79 cases, with 61.2 months follow-up on average. Age at operation was 60.9 years. Clinical results were evaluated using Merle d'Aubigne Postel score. Presence of implant loosening, periacetabular radiolucency, osteolysis, and gap filling were examined for radiographic results. RESULTS: Merle d'Aubigne Postel score improved from 10.0 to 16.4 points. All PTC were radiographically stable, with no evidence of progressive radiolucencies. Average polyethylene wear rate was 0.004 mm/year, with no periacetabular osteolysis. Fifteen hips (18.3%) showed a gap >1 mm; however, all showed bone filling within 12 months. PTC with oversized reaming was significantly less likely to have a gap. No implant failure was noted related to modularity. Resulting survival rate of modular PTC was 100% at 5 years. CONCLUSIONS: Modular PTC showed excellent results at 5-years of follow-up. Some hips showed periacetabular gaps, which were filled with bone within 1 year. Further follow-up was needed to determine long-term efficacy.
    Modern Rheumatology 03/2012; · 2.21 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the change in pelvic tilt angle (PA) in the sagittal plane in the standing and supine positions for 2 to 4 years after total hip arthroplasty (THA). Anteroposterior pelvic radiographs of 21 male and 65 female patients were investigated before and after THA yearly over 2 to 4 years. Both the standing and supine PA significantly posteriorly tilted after THA. The difference in PA between the standing and supine positions (dPA) significantly increased after THA. Although the PA in the standing and supine positions plateaued 1 year after THA, the dPA gradually increased. In addition, the percentage of patients who showed a difference of more than 10° in dPA tended to increase yearly. In particular, elderly female patients who showed posterior tilt in PA in the standing or supine positions or a large dPA before THA tended to show a dPA of more than 10° after THA.
    The Journal of arthroplasty 11/2011; 27(6):940-4. · 2.37 Impact Factor
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    ABSTRACT: Since biologic agents were introduced to treat rheumatoid arthritis (RA) in 2003, the number of orthopedic surgical procedures under treatment with biologic agents has been increasing in Japan. However, whether biologic agents cause an increase in the prevalence of postoperative complications is as yet unknown. The Committee on Arthritis of the Japanese Orthopedic Association investigated the prevalence of postoperative complications in patients with RA in teaching hospitals in Japan. Between January 2004 and November 2008, surveillance forms about medications and surgical procedures in patients with RA were sent to 2,019 teaching hospitals. Data were analyzed by the Rheumatoid Arthritis Committee. Biologic agents were administered to RA patients in 632 of 1,245 hospitals (50.8%); 430 of the 1,245 hospitals (34.5%) used surgical intervention under treatment with biologic agents. The number of surgical procedures under treatment with biologic agents was 3,468, and the prevalence of infection was 1.3% (46 cases). The prevalence of infection was 1.0% (567 procedures) in 56,339 procedures under treatment with nonbiologic disease-modifying anti-rheumatic drugs. There were no significant differences between biological and nonbiological treatment groups with respect to the prevalence of infection. In the joint arthroplasty group, the number of procedures under biological and nonbiological treatment was 1,626 and 29,903, and the prevalence of infection was 2.1% (34 procedures) and 1.0% (298 procedures), respectively. There was a significant difference between groups. The odds ratio was 2.12 (95% confidence interval 1.48-3.03, P < 0.0001). The chance of having biological treatment with joint arthroplasty was more than twofold greater in patients with surgical-site infections compared with those treated with nonbiologic agents. Caution is required for surgical procedure, perioperative course, and obtaining consent for joint arthroplasty for patients with RA undergoing surgery under biological agents.
    Journal of Orthopaedic Science 08/2011; 16(6):778-84. · 1.01 Impact Factor
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    ABSTRACT: Total elbow arthroplasty (TEA) with the GSB III prosthesis was performed in 32 patients (36 elbows) with rheumatoid arthritis between 2001 and 2009. At final follow-up, 31 patients (35 TEAs) were available for clinical and radiological evaluation. The mean follow-up period was 6.3 (2.0-10.3) years, with a minimum follow-up of 2 years. The mean Mayo elbow performance score was significantly improved from 48 points preoperatively to 83 points at final follow-up. The radiographic loosening rate was 14.3% for humeral components and 5.7% for ulnar components. There were 4 cases of intraoperative fracture and 1 case of humeral shaft fracture at 4 months after surgery. The rates for loosening and fracture were relatively low when compared with those in other studies of linked TEA. There were 2 cases of ulnar nerve palsy, but there was no deep infection or triceps disruption. The clinical results of TEA using the GSB III prosthesis in patients with rheumatoid arthritis were found to be satisfactory.
    Modern Rheumatology 08/2011; 22(2):223-7. · 2.21 Impact Factor
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    ABSTRACT: The correction angle after high tibial osteotomy (HTO) depends on an accurate preoperative planning and an accurate intraoperative technique. We hypothesized that the use of a navigation system in opening wedge HTO would improve the intraoperative target angles in the coronal and sagittal planes. Postoperative femoro-tibial angle (FTA) and tibial posterior slope (TPS) in 28 knees with navigated opening wedge HTO were compared to those in 31 knees with the conventional method. Intraoperative correction angle was determined by the predicted medial opening width in the conventional group, and by the change of hip-knee-ankle angle in the navigated group. We defined lateral unstable knee as the knees with lateral cortex breakage or lateral tibial plateau fracture. Mean postoperative FTA was higher in the conventional group than in the navigated group (P < 0.037). In the conventional group, 4 lateral unstable knees were corrected to 174.6°. In the navigated group, 5 lateral unstable knees were corrected to 170.3° and no knees showed FTA > 173°. Mean change in TPS was greater in the conventional group than in the navigated group (P = 0.001). The navigation system in opening wedge HTO might reduce undercorrection in the knees with lateral cortex breakage or lateral tibial plateau fracture, and provide the better intraoperative FTA and TPS. III.
    Knee Surgery Sports Traumatology Arthroscopy 07/2011; 20(3):586-93. · 2.68 Impact Factor
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    ABSTRACT: We report a rare case of dystrophic calcinosis in a patient with rheumatoid arthritis in bilateral buttock lesions and the right elbow joint. The calcinosis was surgically removed because it caused severe local pain, possible infection, and difficulty in sitting. Because no recommended standard pharmacotherapy exists for dystrophic calcinosis, surgical treatment should be taken into consideration when calcinosis causes severe local pain or restricts activities of daily life.
    Modern Rheumatology 02/2011; 21(1):85-8. · 2.21 Impact Factor
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    ABSTRACT: We report a case of primary cervical epidural malignant lymphoma with rheumatoid arthritis. Because of the acute progression of paralysis in both legs, surgical decompression and stabilization of the cervical spine were performed. The resected specimen showed proliferation of lymphoblastic cells diagnosed as malignant lymphoma. Four series of chemotherapy were administered after surgery, and the patient recovered from paralysis.
    Modern Rheumatology 02/2007; 17(3):239-42. · 2.21 Impact Factor
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    ABSTRACT: We performed total hip arthroplasty using the non-cement impaction auto-bone-grafting method with the resected femoral head for acetabular protrusion that is not combined with the destruction of acetabular rim or dysplasia of the hip joint. Ten patients (eight women and two men) with rheumatoid arthritis who showed acetabular protrusion underwent total hip arthroplasty using this method. All patients were able to walk with full weight within 5 days after surgery. The short-term results of our cases were very good. The postoperative periods of the radiographic-bone incorporation of the grafting bone were 2 months after surgery in four joints, 3 months after surgery in four joints, and 4 months after surgery in three joints. There were no cases that showed any migration or radiolucency around the acetabular component at the time of follow-up. Our operative technique is simple and easy, and it is a useful method for the treatment of protrusion in patients with rheumatoid arthritis.
    Modern Rheumatology 02/2007; 17(3):235-8. · 2.21 Impact Factor
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    ABSTRACT: Orthopedic wear debris has been thought to be an important factor associated with osteolysis and loosening of total joint arthroplasties. Previous in vitro studies have reported that particles of wear debris induce the release of pro-inflammatory cytokines and other inflammatory mediators from macrophages and other cells. Several recent investigations, however, have suggested that the wear particles themselves may not be primarily responsible for the inflammatory cellular responses, but that the observed cytokine release in vitro may be caused by endotoxin adsorbed to commercially available particle preparations. The intracellular pathways involved in macrophage signal transduction also are poorly understood. The purposes of this study are to use isolated orthopedic wear debris particles to evaluate pro-inflammatory cytokine release and nuclear factor kappa B (NFkappaB) activation from macrophages. Cells from human monocyte/macrophage cell line (THP-1) were differentiated and incubated with particles of debris that had been isolated from a failed human total hip arthroplasty. The titanium-alloy particles did not evoke release of TNF-alpha or IL-1beta whereas lipopolysaccharide (LPS) or LPS-treated debris particles induced both TNF-alpha and IL-1beta. LPS-treated particles, but not particles alone, stimulated NFkappaB activation. Our results suggest that at the concentrations tested in this study, endotoxin-free wear debris particles may not themselves initiate inflammatory cellular responses in differentiated THP-1 cells. It is unclear whether adsorbed endotoxin is clinically associated with osteolysis and/or loosening in total joint arthroplasties, but several factors, including adsorbed endotoxin, need to be investigated to explore the cellular responses responsible for osteolysis and/or loosening.
    Journal of Biomedical Materials Research 04/2002; 59(3):507-15.
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    ABSTRACT: Orthopedic wear debris has been thought to be an important factor associated with osteolysis and loosening of total joint arthroplasties. Previous in vitro studies have reported that particles of wear debris induce the release of pro-inflammatory cytokines and other inflammatory mediators from macrophages and other cells. Several recent investigations, however, have suggested that the wear particles themselves may not be primarily responsible for the inflammatory cellular responses, but that the observed cytokine release in vitro may be caused by endotoxin adsorbed to commercially available particle preparations. The intracellular pathways involved in macrophage signal transduction also are poorly understood. The purposes of this study are to use isolated orthopedic wear debris particles to evaluate pro-inflammatory cytokine release and nuclear factor kappa B (NFκB) activation from macrophages. Cells from human monocyte/macrophage cell line (THP-1) were differentiated and incubated with particles of debris that had been isolated from a failed human total hip arthroplasty. The titanium-alloy particles did not evoke release of TNF-α or IL-1β whereas lipopolysaccharide (LPS) or LPS-treated debris particles induced both TNF-α and IL-1β. LPS-treated particles, but not particles alone, stimulated NFκB activation. Our results suggest that at the concentrations tested in this study, endotoxin-free wear debris particles may not themselves initiate inflammatory cellular responses in differentiated THP-1 cells. It is unclear whether adsorbed endotoxin is clinically associated with osteolysis and/or loosening in total joint arthroplasties, but several factors, including adsorbed endotoxin, need to be investigated to explore the cellular responses responsible for osteolysis and/or loosening. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 507–515, 2002
    Journal of Biomedical Materials Research 03/2002; 59(3):507-515.
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    ABSTRACT: Alendronate is a pyrophosphate analogue of bisphosphonate that has been shown to inhibit osteoclastic bone resorption. Bone formation and remodeling are necessary to establish initial fixation of uncemented implants, especially those coated with a bioactive surface such as hydroxyapatite. Because the process of bone-remodeling that culminates in new-bone formation is thought to be initiated by osteoclastic bone resorption, it is appropriate to test the influence of osteoclast-inhibiting medications on bone apposition to hydroxyapatite-coated implants. Twelve dogs underwent staged bilateral total hip arthroplasty, with twenty weeks between the first and second operations, with use of a titanium-alloy femoral stem that had a proximal macrotextured surface and a plasma-sprayed hydroxyapatite coating. Six of the dogs received oral alendronate therapy from the time of the surgery until they were killed; the other six dogs were untreated controls. The animals were killed four weeks after the second operation. Sections from matched implant sites (proximal, middle, and distal) were histologically analyzed. The linear extent of bone apposition, the linear extent and the thickness of the hydroxyapatite coating, and the total amount of cortical and trabecular bone were measured with the use of an interactive image analysis system. There were no significant differences in radiographic or histologic findings between the two groups at either four or twenty-four weeks. Although the extent of the hydroxyapatite coating decreased significantly with time in both groups (p < 0.01), we identified no significant influence of alendronate on the extent of bone apposition, the extent or thickness of the hydroxyapatite coating, or the cortical or trabecular bone area around the implants. Many patients who are receiving alendronate for osteoporosis or other disorders may also be candidates for cementless total joint arthroplasty. Although bone formation is generally thought to be initiated by and coupled with bone resorption, our results suggest that alendronate has no discernible effect on the initial fixation of or the short-term bone-remodeling around hydroxyapatite-coated femoral total joint implants.
    The Journal of Bone and Joint Surgery 02/2002; 84-A(2):226-35. · 4.31 Impact Factor
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    ABSTRACT: We histologically analyzed tissue biopsy specimens obtained from 4 cases of revised cementless ceramic knee prostheses. Particles were isolated from the specimens, and their size and composition were determined. Implants were removed for aseptic loosening at an average of 64 months. Histologically, polyethylene particles were seen in all cases. The concentration of the particles showed wide variation among cases. The concentration of the particles also showed a wide variation among different biopsy locations, suggesting that the particles were not distributed uniformly around the knee prostheses. Although we analyzed only 4 cases, our results show good correlation between radiographic evidence of geographic osteolysis and the concentration of wear particles. Multiple biopsy specimens may be necessary to characterize adequately particle migration around knee prostheses.
    The Journal of Arthroplasty 02/2002; 17(1):121-8. · 2.37 Impact Factor
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    ABSTRACT: A prospective and quantitative animal study was performed to evaluate the production of wear particles from a spinal fixation device, and to test the hypothesis that the concentration of wear debris particles adjacent to spinal fixation hardware is correlated with the stiffness of the spinal fusion construct and local bone formation at the fusion site. An established canine segmental spinal fusion model with three interfacet fusions was used in this study. Several bone substitute materials were grafted to the area of the interfacet fusion. Internal fixation was performed on both sides of the spinous processes at each site using a stainless steel plate system in 19 dogs. After 12 weeks, spinal segments were excised, then 3-dimensional computerized tomography was used to measure bone volume and bone area of the individual fusion sites. The stiffness of each segment was tested using a servohydraulic materials testing machine. Biopsies were obtained from the soft tissues immediately around the plate system, and wear particles were collected and characterized using an electrical resistance particle analyzer, light and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX). Biopsies from para-spinal tissue from adjacent, unoperated spinal levels served as negative controls. Histologically, 24 of 57 specimens (42.1%) showed only fibrous tissue with no recognizable macrophages, inflammation, or debris. Fourteen of 57 specimens (24.6%), however, contained many particles that were composed of Fe, Cr, and Ni, corresponding to elements found in the fixation hardware. Another 19 specimens showed only occasional particles. The mean concentration of particles from the tissue around the plate system was 2.8 x 10(9) per gram dry tissue weight, compared to 0.5 x 10(9) particles per gram for controls (p < 0.05). Statistical analyses showed significant inverse correlation between the log particle number and stiffness (r = -0.41, p < 0.01), bone volume (r = -0.28, p < 0.05), and bone area (r = -0.34, p < 0. 05) of the corresponding segments. The concentration of particles in the tissue showed a significant inverse correlation with stiffness, bone volume, and bone area of the fusion constructs.
    Journal of Biomedical Materials Research 02/2000; 53(3):193-8.