Factors associated with diagnostic stage of hip osteoarthritis due to acetabular dysplasia among Japanese female patients: a cross-sectional study.

BACKGROUND: In Japan, the majority of hip osteoarthritis (OA) was caused by acetabular dysplasia, and about 90 % of patients were female. The present study focused on Japanese female patients with hip OA due to acetabular dysplasia, and examined the associated factors with OA staging at diagnosis, in special reference to body weight. METHODS: Study subjects were 336 Japanese women who were newly diagnosed with hip OA caused by acetabular dysplasia at 15 hospitals in 2008. The self-administered questionnaire elicited patients' body weight at age 20 and at OA diagnosis. Four ranked OA staging according to radiographic findings of the hip joint (pre-OA, initial stage, advanced stage or terminal stage) was regarded as the outcome index. Proportional odds models in logistic regression were used to calculate odds ratios (ORs) and 95 % confidence intervals (CIs) for severer stage of OA. RESULTS: At diagnosis, 45 % of patients suffered from terminal stage of OA, whereas 13 % and 14 % were categorized into pre-OA and initial stage, respectively. After adjustment for potential confounders, weight gain since age 20 revealed the increased ORs for severer OA stage at diagnosis (OR 2.02; 95 % CI, 1.07-3.80). Other significant characteristics were age (67+ vs. 20-49 years, OR 12.4), lower education (junior high school vs. junior college or higher, OR 4.00), parity (OR 2.19), lower acetabular head index (<60.0 vs. 71.1+, OR 2.36), and longer duration since symptom onset (6.0+ vs. <1.0 year, OR 2.94). CONCLUSIONS: Weight gain since age 20 might be involved in mechanisms of OA development, which is independent of age or severity of acetabular dysplasia.

Relationship of acetabular dysplasia in females with osteoarthritis of the hip to the distance between both anterior superior iliac spines.

BACKGROUND: Acetabular dysplasia (AD) is the main cause of hip osteoarthritis in Japan. A simple method to evaluate acetabular dysplasia would be helpful for early treatment or prevention of hip osteoarthritis. Acetabular dysplasia is reported to be associated with pathological transverse growth of the pelvis, indicating that the distance between the 2 anterior superior iliac spines might be useful for screening and detection of acetabular dysplasia. The purpose of this study was to determine if the acetabular dysplasia radiographic parameters are related to the distance between the 2 anterior superior iliac spines in patients with hip osteoarthritis. MATERIAL AND METHODS: In this study, data obtained in a previous multi-institutional examination of patients with hip osteoarthritis in Japan were evaluated. The anterior superior iliac spine distances of 176 female patients (mean age, 54 years; range, 18-85 years) were measured by physical examination. The relationship between the anterior superior iliac spine distance and acetabular dysplasia was analyzed, and the anterior superior iliac spine distances of the patients with acetabular dysplasia who were at relatively high risk for hip osteoarthritis were compared with that of the patients at lower risk. RESULTS: A statistically significant relationship between the anterior superior iliac spine distance and all of the acetabular dysplasia parameters was observed. The anterior superior iliac spine distances of the acetabular dysplasia patients with a relatively high risk for radiographic acetabular dysplasia parameters were significantly smaller than those of patients at lower risk. Even after adjustment for age, height, and weight, significantly increased relative risk for having high risk AD was found in patients with an ASIS distance of less than 24.5 cm. CONCLUSIONS: There was a significant relationship between the anterior superior iliac spine distance and the degree of acetabular dysplasia.

Physical performance and knee osteoarthritis among community-dwelling women in Japan: the Hizen-Oshima Study, cross-sectional study.

Osteoarthritis (OA) is the most common chronic joint disorder. Relationships between knee OA and physical performance have been examined, but mainly in patients with knee OA. Clarifying the relationship between knee OA and physical performance among community-dwelling individuals is thus important. Subjects comprised 563 community-dwelling Japanese women. Radiographic knee OA was defined as Kellgren-Lawrence criteria grade 2 or higher. Painful knee OA was defined as radiographic OA combined with knee pain. We evaluated performance-based measures of physical functioning. Student's t tests were used to compare continuous variables. Adjusted means of performance-based measures were compared between groups using general linear modeling methods. Mean age was 64.3 years. Women with radiographic OA were older than those without OA (P < 0.0001). BMI was greater in women with radiographic OA than in women without OA (P < 0.0001). In univariate analysis, women with radiographic OA displayed worse physical functioning than women without OA, with longer chair stand time, longer walking time, and shorter functional reach. Performance-based measurements with painful OA resembled those with radiographic OA. Age- and BMI-adjusted means of chair stand time and walking time were longer in women with radiographic or painful knee OA than in women without OA (P < 0.0001 each). Furthermore, chair stand and walking took longer for women with painful knee OA than for women with radiographic knee OA. Women with knee OA showed deteriorated performance of chair stand and walking. Painful knee OA was associated with poorer performance than radiographic knee OA.

A pilot project for the Japan arthroplasty register.

BACKGROUND: National arthroplasty registers are valuable tools for reporting on an updated epidemiologic survey of arthroplasties and for evaluating the performance of implants and operative procedures through the early identification of failure risk factors. More than ten registers have been launched globally, but no national register has been reported in Asia. METHODS: In February 2006, a pilot project of the Japan Arthroplasty Register (JAR) for total hip arthroplasty (THA) and total knee arthroplasty/unicompartmental knee arthroplasty (TKA/UKA) was launched by the Japanese Orthopaedic Association (JOA). Data obtained include information about patients, primary and revision arthroplasty operative procedures, and implants and materials used. The JAR office accumulated and processed all data and reports annually. RESULTS: Up to May 2011, 83 of 130 hospitals nominated by the JOA (64 %) participated in the JAR pilot project. From 2006 to 2011, 33,080 data collection forms were submitted; 17,534 for THA and 17,269 for TKA/UKA. A brief summary of the annual report of the JAR is available from The Japanese Society for Replacement Arthroplasty web site at http://jsra.info/ . CONCLUSION: A national arthroplasty register is a useful tool for evaluating the outcomes of interventions and the materials used in arthroplasties and for providing rapid feedback to practitioners and patients about any failure of THA and TKA/UKA. As the first national arthroplasty register in Asia, the JAR will help guide the development of registers of arthroplasty characteristics specific to Asian populations.

In Vivo Kinematics of the Anterior Cruciate Ligament Deficient Knee During Wide-Based Squat Using a 2D/3D Registration Technique.

Anterior cruciate ligament (ACL) deficiency increases the risk of early osteoarthritis (OA). Studies of ACL deficient knee kinematics would be important to reveal the disease process and therefore to find mechanisms which would potentially slow OA progression. The purpose of this study was to determine if in vivo kinematics of the anterior cruciate ligament deficient (ACLD) knee during a wide-based squat activity differ from kinematics of the contralateral intact knee. Thirty-three patients with a unilateral ACLD knee consented to participate in this institutional review board approved study with the contralateral intact knee serving as the control. In vivo knee kinematics during the wide-based squat were analyzed using a 2D/3D registration technique utilizing CT-based bone models and lateral fluoroscopy. Comparisons were performed using values between 0 and 100° flexion both in flexion and extension phases of the squat activity. Both the ACLD and intact knees demonstrated increasing tibial internal rotation with knee flexion, and no difference was observed in tibial rotation between the groups. The tibia in the ACLD knee was more anterior than that of the contralateral knees at 0 and 5° flexion in both phases (p < 0.05). Tibiofemoral medial contact points of the ACLD knees were more posterior than that of the contralateral knees at 5, 10 and 15° of knee flexion in the extension phase of the squat activity (p < 0.05). Tibiofemoral lateral contact points of the ACLD knees were more posterior than that of the contralateral knees at 0° flexion in the both phases (p < 0.05). The kinematics of the ACLD and contralateral intact knees were similar during the wide-based squat except at the low flexion angles. Therefore, we conclude the wide-based squat may be recommended for the ACLD knee by avoiding terminal extension.

Primary human bone marrow adipocytes support TNF-α-induced osteoclast differentiation and function through RANKL expression.

PURPOSE: In previous reports, it was demonstrated that bone marrow adipocytes were related to steroid osteoporosis through osteoclastogenesis induced by Receptor Activator of Nuclear factor κ-B Ligand (RANKL) expression. The purpose of this study was to evaluate the effect of Tumor necrosis factor-alpha (TNF-α) on RANKL expression in bone marrow adipocytes, and osteoclast differentiation supported by human bone marrow adipocytes. METHODS: RANKL, osteoprotegerin (OPG), and macrophage-colony stimulating factor (M-CSF) mRNA expression in bone marrow adipocytes and their regulation by TNF-α treatment were measured by real-time RT-PCR. Co-cultures of bone marrow adipocytes and osteoclast precursors were performed with or without TNF-α, and osteoclast differentiation was evaluated morphologically and functionally. RESULTS: RANKL expression and an increase in the RANKL/OPG ratio in bone marrow adipocytes were stimulated by TNF-α treatment. In co-culture of bone marrow adipocytes and osteoclast precursors with TNF-α, the number of TRAP-positive multinuclear cells and resorption cavity formations of calcium phosphate film were increased. Osteoclast differentiation was suppressed by anti-RANKL antibody treatment. In co-culture with non-cell-contact conditions, no TRAP-positive cells or resorption cavity formations were observed. CONCLUSIONS: TNF-α increased RANKL expression in primary human bone marrow adipocytes. TNF-α induced the ability of bone marrow adipocytes to promote osteoclast differentiation and activity in a manner directly related to RANKL expression.

Post-transcriptional regulation of IL-6 production by Zc3h12a in fibroblast-like synovial cells.

OBJECTIVES: Zc3h12a is an RNA binding protein with a CCCH-type finger motif and is known to regulate mRNA metabolism. Previous reports suggest that Zc3h12a acts as a negative regulator of inflammatory processes because it is involved in the degradation of IL-6 mRNA. We investigate the effect of Zc3h12a on IL-6 production in fibroblast-like synovial cells (FLS) from rheumatoid arthritis (RA) patients. METHODS: The expression of Zc3h12a in FLS was determined by polymerase chain reaction. To knock down Zc3h12a expression in FLS, siRNA for Zc3h12a was transfected by the lipofection method. The supernatants were collected after siRNA transfection for the quantification of IL-6 production. The phosphorylation of the signal transducer and activator of transcription 3 (STAT3) was examined by Western blotting. Cell proliferation was analysed by the Cell Counting Kit-8 assay after Zc3h12a knockdown. RESULTS: mRNA for Zc3h12a were demonstrated in FLS from RA patients. Zc3h12a transcripts were induced by LPS or IL-1ß in FLS. The production of IL-6 as well as its mRNA expression was significantly increased by the Zc3h12a knockdown. The Zc3h12a knockdown also induced the activation of STAT3, which the anti IL-6 receptor antibody inhibited. Proliferation of Zc3h12a-knockdown FLS increased significantly in the presence of recombinant soluble IL-6 receptor (sIL-6R). CONCLUSIONS: Our data suggest that Zc3h12a is a novel IL-6 regulator in FLS, which may be involved in the progression of RA.

Simvastatin suppresses dexamethasone-induced secretion of plasminogen activator inhibitor-1 in human bone marrow adipocytes.

BACKGROUND: Osteonecrosis of the femoral head is a common complication of high-dose glucocorticoid treatment. Intravascular thrombosis is thought to be associated with the ischemic state of the femoral head. Plasminogen activator inhibitor-1 (PAI-1) is an adipokine, which are physiologically active substances secreted from visceral and subcutaneous adipocytes. PAI-1 suppresses fibrinolysis by binding tissue-type plasminogen activator. Several reports have described the relationship between PAI-1 and steroid-induced osteonecrosis of the femoral head, and the preventive effects of lipid-lowering agents (statins) against steroid-induced osteonecrosis of the femoral head. We previously reported that adipokines and dexamethasone induced PAI-1 secretion from bone marrow adipocytes. The purpose of the present study is to examine the effects of simvastatin on PAI-1 secretion from human bone marrow adipocytes in vitro. METHODS: Primary bone marrow adipocytes were extracted from collagenase-treated bone marrow fluid obtained from the femoral necks of 40 patients (6 men, 34 women; age range, 52-81 years) undergoing hip joint replacement surgery. After suspended culture with or without dexamethasone or simvastatin, PAI-1 mRNA expression was assessed by real-time RT-PCR. Total PAI-1 protein secretion in culture medium was assessed by enzyme-linked immunosorbent assay. RESULTS: PAI-1 mRNA expression was up-regulated by 388% (P=0.002) with dexamethasone, and down-regulated by 45% (P=0.002) with simvastatin, as compared to control levels. Dexamethasone increased total PAI-1 secretion by 166% (P=0.001) and simvastatin decreased total PAI-1 secretion by 64% (P=0.002). No significant changes were observed in adiponectin mRNA expression and secretion by dexamethasone and simvastatin, while pre-treatment with simvastatin reversed dexamethasone induced PAI-1 secretion by 89%, as compared to control levels. CONCLUSION: The present study confirmed the suppressive effects of simvastatin on PAI-1 expression and secretion from bone marrow adipocytes. Furthermore, pre-treatment with simvastatin reversed dexamethasone induced PAI-1 secretion. Simvastatin may thus exhibit preventive effects against steroid-induced osteonecrosis of the femoral head by suppressing PAI-1 secretion.

IgG-class anti-PF4/heparin antibodies and symptomatic DVT in orthopedic surgery patients receiving different anti-thromboembolic prophylaxis therapeutics.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a thromboembolic complication that can occur with unfractionated heparin (UFH) or low molecular weight heparin (LMWH). Our objective was to determine and compare the incidence of IgG-class HIT antibodies in patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) with different antithrombotic prophylaxis therapies and their contributions to the occurrence of venous thromboembolism (VTE). METHODS: A prospective observational study was performed for 374 Japanese patients undergoing THA or TKA to determine the incidence of VTE. IgG-class anti-PF4/heparin antibodies were measured using IgG-specific EIA before and after the operation. RESULTS: In the clinical outcome, the incidence of symptomatic deep vein thrombosis (DVT) was 15.0% (56/374, TKA; 35, THA; 21) and pulmonary emboli (PE) were not observed. The total seroconversion incidence of IgG-class PF4/heparin antibodies was 19.8% (74/374). The seroconversion incidence of IgG-class PF4/heparin antibodies was higher in patients receiving UFH (32.7%) compared to those receiving LMWH (9.5%) or fondaparinux (14.8%). Furthermore, the seroconversion incidence was significantly higher in patients undergoing TKA compared to those undergoing THA. Based on multivariate analysis, seroconversion of the IgG-class PF4/heparin antibodies was independent a risk factor for symptomatic DVT. CONCLUSION: Our findings show that the seroconversion of IgG-class anti-PF4/heparin antibodies differed with various anti-thrombotic prophylaxis therapeutics and was associated with the risk of DVT in a subset of patients undergoing total joint arthroplasty (TKA and THA).

Factors associated with radiographic osteoarthritis of the knee among community-dwelling Japanese women: the Hizen-Oshima Study.

BACKGROUND: Osteoarthritis (OA) of the knee is the most common form of arthritis and is a major contributor to functional impairment and reduced independence in older adults. In Japan, knee OA is a frequent cause of pain and disability, but few epidemiological studies have examined the demographic or lifestyle factors that influence OA of the knee. We examine the risk factors for OA of the knee among Japanese community-dwelling women aged 40-89 years (mean age 64.2, SD 9.6 years). METHODS: Anteroposterior weight-bearing knee radiographs were graded according to the criteria described by Kellgren-Lawrence (K/L). We defined knee OA as a K/L grade of 2 or higher (using a 0-4 scale) based on the plain radiographs. History of knee injury, type of occupation, and daily intake of antioxidant nutrients including vitamin C and carotene were obtained from questionnaires. RESULTS: Among the 582 subjects, 195 women (33.5%) suffered from knee OA. Logistic regression analysis showed that older age [odds ratio (OR) 1.8, 95% confidence interval (95% CI) 1.6-2.1 per 5-year increase], higher body mass index (OR 2.2, 95% CI 1.7-3.0 per 5-unit increase) and previous knee injury (OR 3.1, 95% CI 1.7-5.6) were associated with knee OA. The occupation of farming and intake of antioxidant nutrients were not associated with knee OA. CONCLUSION: Older age, obesity and previous knee injury represent independent risk factors for knee OA among Japanese women.

Osteoarthritis hip joints in Japan: involvement of acetabular dysplasia.

BACKGROUND: We conducted a nationwide epidemiologic study regarding hip osteoarthritis (OA) in Japan, and a previous report found these patients to be unique in comparison to Caucasians. This report focused on the data regarding each hip joint, and the involvement of acetabular dysplasia with hip OA was analyzed. METHODS: Seven hundred twenty OA hips were examined. Sixty-five joints with osteonecrosis of the femoral head and 215 non-OA contralateral joints of the unilateral patients were examined as controls. The revised system of stage classification for hip OA of the Japanese Orthopedic Association (JOA) was used according to the reproducibility in order to ensure reliable data from the multiple institutions. The acetabular dysplasia indexes were also chosen according to the reproducibility and measured in the radiograph of bilateral hip joints. The clinical score was assessed using the JOA scoring system. The relative risk of the grade of acetabular dysplasia indexes for hip OA was calculated as the odds ratio and the 95% confidence interval. RESULTS: The stage of the OA joints deteriorated with increasing age. The clinical scores also decreased. The grade of the acetabular dysplasia indexes of the OA joints was significantly higher than that of the control joints. Each index of acetabular dysplasia demonstrated significantly increased odds ratios for hip OA. Among the OA joints, the deterioration of the OA stage was found to be significantly associated with an increasing grade of acetabular dysplasia. The odds ratio for OA deterioration in the acetabular dysplasia index was also obtained. The joints of females tended to have a higher grade and prevalence of acetabular dysplasia than those of males. CONCLUSIONS: These findings confirmed a high prevalence of acetabular dysplasia in hip OA joints in Japan. Acetabular dysplasia was one of the most important factors associated with hip OA.

Revision with impacted bone allografts and the Kerboull cross plate for massive bone defect of the acetabulum.

We retrospectively reviewed 31 hips with massive bone defect because of aseptic loosening of the acetabulum treated with impacted bone allografts with the Kerboull-type acetabular device. Mean age at surgery was 67.9 years, and mean duration of follow-up was 6.3 years. Thickness of the bone graft was evaluated by postoperative radiography. Seven hips showed radiological failure associated with 6 breakages of the device, and 24 hips showed stability on follow-up radiographs. Of the 13 hips showing a bone graft thickness of greater than 20 mm on follow-up radiographs, 7 were classified as failure group. If an acetabular reinforcement device with a bone graft of more than 20 mm thickness is necessary, then a structural allograft should be considered in the weight-bearing area of the support ring in addition to the morselized bone graft.

Analysis of interobserver reliability for radiographic staging of coxarthrosis and indexes of acetabular dysplasia: a preliminary study.

BACKGROUND: We are planning a multicenter survey on coxarthrosis and acetabular dysplasia in Japan. To collect reliable data, we performed a preliminary study to elucidate the observer agreement on assessment items. METHODS: We collected radiographs of hip joints in eight patients with various findings of coxarthrosis. Twelve registered orthopedic specialists evaluated them regarding the roentgenographic stage of coxarthrosis and five indexes of acetabular dysplasia (acetabular angle, center-edge angle, acetabular roof obliquity, acetabular head quotient, approximate acetabular quotient). To assess observer agreement, we calculated the value of the kappa statistic for stages and the coefficient of variation for the indexes. The same 12 specialists then assessed the coxarthritis stage on the same radiographs 1 month after the first evaluation based on our own descriptions of the roentgenographic stages. RESULTS: For the first evaluation of the roentgenographic stage, the value of the kappa statistic was 0.448; and for the second evaluation it was 0.600. The results of the coefficient of variation for the indexes of acetabular dysplasia, ranked in ascending order, were as follows: acetabular angle, acetabular head quotient, acetabular roof obliquity, center-edge angle, approximate acetabular quotient. CONCLUSIONS: For the upcoming multicenter survey, clear descriptions of the stages of coxarthrosis and selection of appropriate indexes can be helpful for collecting dependable results.

Joint congruency in abduction before surgery as an indication for rotational acetabular osteotomy in early hip osteoarthritis.

We conducted a retrospective review of the results of rotational acetabular osteotomy (RAO) procedures in 92 hips of 89 patients (81 females and eight males) with early-stage osteoarthritis. In this study, we discuss the indications for this surgery based on the preoperative congruency in abduction. The mean postoperative follow-up was 12.2 (7-19) years. The mean age at operation was 32.5 (13-54) years. Two hips with apparent technical failure were excluded. During follow-up, the osteoarthritic stage remained unchanged in 76 hips (good group) and progressed in 14 hips (poor group). Preoperative joint congruency in abduction was excellent in 20 hips, good in 62, and fair in eight. All eight hips with fair joint congruency showed progression to osteoarthritis at follow-up. Patients without good congruency in abduction may experience progression of osteoarthritis after RAO procedures even in early-stage osteoarthritis.

Bone marrow adipocytes support dexamethasone-induced osteoclast differentiation.

The purpose of this study was to examine the ability of bone marrow adipocytes to support osteoclast differentiation in vitro. The primary bone marrow adipocytes were obtained from bone marrow fluid during prosthesis insertion. NFkappa-B ligand (RANKL), Osteoprotegerin (OPG), and macrophage colony stimulating factor (M-CSF) expressions in bone marrow adipocytes with or without dexamethasone were examined. In a co-culture system with bone marrow adipocytes and osteoclast precursor cells, osteoclast differentiation was assessed by the expression of titrate-resistant acid phosphatase (TRAP) staining. RANKL, OPG, and M-CSF mRNA expressions were confirmed in all individuals. Dexamethasone significantly induced RANKL and OPG expression. The RANKL/OPG ratio was increased by dexamethasone and was significant at 10(-7) M dexamethasone. With 10(-7) M dexamethasone, osteoclast precursor cells differentiated into multinucleated TRAP-positive cells when co-cultured with bone marrow adipocytes. The present study demonstrates for the first time that bone marrow adipocytes can support osteoclast differentiation in vitro.

Joint congruency as an indication for rotational acetabular osteotomy.

UNLABELLED: Long-term results of periacetabular osteotomy for advanced-stage osteoarthritis secondary to developmental dysplasia of the hip are reportedly unsatisfactory compared with results for early-stage osteoarthritis. Other preoperative information that can be used to determine indications for periacetabular osteotomy is therefore important to avoid performing osteotomy in young patients with advanced-stage osteoarthritis who would not likely achieve substantial benefit. We retrospectively reviewed 47 patients (49 hips) with advanced-stage osteoarthritis who underwent rotational acetabular osteotomy (RAO) using preoperative congruency in abduction. The minimum postoperative followup was 8 years (mean, 12.3 years; range, 8-20 years) and mean age at surgery was 43.1 years (range, 30-59 years). At followup, osteoarthritic stage was improved in 12 hips, unchanged in 24 hips, and had progressed in 13 hips. Preoperative joint congruency in abduction was good in 13 hips, poor in 32 hips, and narrowed in four hips. Patients with better congruency in abduction had better results. We believe osteoarthritis with good congruency in abduction preoperatively remains a good indication for RAO even in advanced stages of disease. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The bactericidal efficacy of a photocatalytic TiO(2) particle mixture with oxidizer against Staphylococcus aureus.

By proving the bactericidal effects of a low-concentration titanium dioxide (TiO(2)) particle mixture against Staphylococcus aureus, we hope to ultimately apply a mixture of this type as part of a clinical treatment regimen. A bacterial suspension of S. aureus 1 x 10(5) CFU/ml was added dropwise to a TiO(2) particle mixture (19 ppm TiO(2)) and irradiated by ultraviolet (UV) light. The colony-forming units were counted and the bacterial survival rate was calculated. In the control sample, the bacterial survival rate was 83.3% even after 120 min. In the TiO(2) mixture + UV sample, the bacteria count dropped sharply, reaching 17.3% of the baseline value at 30 min and 0.4% at 60 min. TiO(2) particles dispersed in water mixtures are known to elicit highly efficient UV absorption and greater bonding to bacteria. A reaction of the TiO(2) with another oxidizer altered the aqueous pH and accelerated the photocatalytic chemical reaction. The TiO(2) particle mixture showed high antibacterial action against S. aureus even at a low concentration.

Clinical relevance of heparin-PF4 complex antibody in DVT after total joint replacement.

BACKGROUND: Antibodies to the heparin-platelet factor-4 (HPF-4) complex (HIT antibodies) have been observed in patients with heparin-induced thrombocytopenia (HIT). These antibodies are thought to be involved in thrombosis through activation of platelet/endothelial cells. This prospective study was conducted to determine the incidence of post-operative HIT antibodies to assess the associated risk of deep vein thrombosis (DVT) in patients undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA). METHODS: We studied 104 patients who underwent unilateral primary TKA (n = 44) and primary THA (n = 60) with short-duration prophylaxis (1-2 days of a fixed dose of unfractionated heparin). HIT antibodies were assayed using a sandwich-type ELISA before the operation and after heparin treatment (post-operative day 7). RESULTS: In the clinical outcome, the incidence of symptomatic DVT was 15.4% (16/104, TKA; 10, THA 6) and pulmonary embolism (PE) was not observed. The total seroconversion rate of HIT antibodies at post-operative day 7 was 34.6% (36/104). Among 36 seroconverted patients, 11 (30.6%) developed symptomatic DVT and 5 out of 68 of the non-seroconverted patients (7.4%) developed symptomatic DVT. The incidence for DVT was significantly higher in the seroconverted patients compared with that of the non-seroconverted patients (odds ratio 5.5, 95%CI: 1.7-17.6 p = 0.0028). Furthermore, in the patients with symptomatic DVT, the titer of HIT antibodies at post-operative day 7 was significantly higher compared with those without symptomatic DVT. CONCLUSION: Our data therefore suggest that seroconversion for HIT antibodies generated by heparin is associated with a risk of DVT in patients undergoing total joint replacement.

Quantitative analysis of Staphylococcus epidermidis biofilm on the surface of biomaterial.

BACKGROUND: Staphylococcus epidermidis biofilm is considered to be an important cause of device-related infection. Polysaccharide intercellular adhesin (PIA), encoded by the icaADBC locus, has been found to be a functional component of S. epidermidis biofilm, but the sequential change of the ica gene expression during biofilm development is still unclear. We have established a quantitative experiment of biofilm formation on nontranslucent biomaterial surfaces using the biofilm coverage rate (BCR). In this study, we quantified the time course of biofilm formation on a biomaterial (stainless steel) surface by means of BCR, viable cell count (VCC) with colony-forming units, and ATP-bioluminescence (ATP) as relative light units, and investigated the time-course relationship between biofilm development process and ica gene expression using reverse transcription-polymerase chain reaction (RT-PCR). METHODS: S. epidermidis RP62A was inoculated on stainless steel washers and incubated for 0-8, 24, and 48 h. Biofilms attached to the washers were quantified by means of BCR, VCC, and ATP. RT-PCR of the ica gene was performed using total RNA isolated from biofilms at each incubation period. Results of these methods were compared. RESULTS: The amount of biofilms measured by BCR increased over time and particularly grew at 5-6 h into the incubation period. On the other hand, the results of VCC and ATP increased gradually, and at 24 h or 48 h the measurement values were very much greater than previously. Up to 8 h, there were significant correlations between BCR and VCC or ATP. The growth of BCR until 6 h is supported by RT-PCR of the ica gene. CONCLUSIONS: Compared with each result, two-dimensional biofilm occupation on a biomaterial surface is proposed to be rapidly completed within 6-8 h after bacterial attachment. Our data indicate that bacterial biofilms first grow two dimensionally with a producing matrix, and subsequently grow vertically and become mature.

Long-term outcome of Ludloff's medial approach for open reduction of developmental dislocation of the hip in relation to the age at operation.

We reviewed long-term outcomes after open reduction by the medial approach for developmental dislocation of the hip (DDH). Forty-five hips in 43 patients with more than ten years of follow-up were assessed clinically and radiologically. The mean age at surgery was 14.0 (range 6-31) months, and the follow-up period ranged from ten to 28 years (mean 16.4 years). We compared the good (18 hips) and poor groups (27 hips) as classified by the Severin classification. The mean age at surgery was significantly older in the poor group than the good group (17.1 and 9.4 months, respectively, P < 0.001). Thirteen (29%) of 45 hips had avascular necrosis (AVN) of the femoral head. The mean age at surgery was significantly older in the patients with AVN than without AVN (20.0 and 11.6 months, respectively, P < 0.001). Another approach, such as the wide exposure method, should be selected for DDH with increased age at operation.