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ABSTRACT: Stress shielding after total hip arthroplasty (THA) remains an unsolved issue. Various patterns of mechanical stress appear according to the type of femoral stem used. To compare differences in mechanical stress conditions between Zweymuller type and fit-and-fill type stems, finite element analysis (FEA) was performed. Differences in bone mineral density (BMD) changes in the femur were also compared. Maximum stress was confirmed in Gruen zone 4, whereas zone 1 had the minimum amount of stress with both types of implant. The Zweymuller stem group had less mechanical stress and lower BMD in zone 7 than the fit-and-fill stem group. In conclusion, differences in mechanical stress may be related to changes in BMD after THA.
The Journal of arthroplasty 05/2013; · 1.79 Impact Factor
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ABSTRACT: PURPOSE: Recent studies have reported the acceleration of subchondral bone remodeling during the development of osteoarthritis (OA). However, it is not possible to evaluate such molecular abnormalities using conventional radiographic techniques. We have applied F-fluoride PET to the analysis of painful or dysplastic hips at various stages of OA and then compared this with radiographic findings and clinical findings. METHODS: A consecutive series of 65 joints from 48 patients (average age, 40 years; range, 19-72 years) with a hip joint complaint or radiographic dysplastic hip were enrolled in this study. Twenty-five contralateral joints without any evidence of OA or clinical symptoms were assigned as a normal control group. Radiographic evaluations were performed on the basis of Kellgren and Lawrence grade and the minimum joint space. Clinical evaluations were performed using the grading scale for pain severity and the SUVmax was measured for each joint. The association between SUVmax and the radiographic or clinical findings was evaluated. RESULTS: F-fluoride PET shows a significantly higher uptake value for progressive-stage OA cases than for early-stage cases and also shows a significantly higher uptake value in cases with severe pain. Even in early-OA-stage patients who do not show joint space narrowing on a plain x-ray, cases with severe pain show a significantly higher uptake value. CONCLUSIONS: F-fluoride PET has great potential as an imaging method for diagnosing early-stage OA without any marked radiographic changes.
Clinical nuclear medicine 04/2013; · 3.92 Impact Factor
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ABSTRACT: BACKGROUND:: Diagnosis and identification of the etiological agent of septic arthritis (SA) in children is an important issue, as early treatment based on accurate diagnosis of joint infections can prevent potentially disabling complications. The purpose of this study was to evaluate the efficacy of real-time polymerase chain reaction (PCR) for the diagnosis of SA in children. PATIENTS AND METHODS:: Twenty children with suspected SA who had joint pain and underwent surgical treatment were enrolled in this study. Their preoperative clinical and laboratory findings were investigated. Tissues obtained during operation were subjected to microbiological culture and real-time PCR, including methicillin-resistant Staphylococcus (MRS)-specific PCR and broad range universal PCR. Infection was confirmed if the result of microbiological culture was positive. Furthermore, abnormal clinical and laboratory findings and improvement in the symptoms and posttreatment data were also defined as the final diagnosis of infection. RESULTS:: Out of the 20 patients, 19 were diagnosed with the infection. The remaining patient was postoperatively diagnosed with juvenile idiopathic arthritis. Abnormal preoperative body temperatures, white blood cell counts, C-reactive protein levels, and erythrocyte sedimentation rates were observed in 6, 9, 15, and 12 cases, respectively. The results of microbiological culture, MRS-PCR, and universal PCR were positive in 9, 2, and 15 cases, respectively. Analysis of the melting peak in universal PCR revealed that of the 15 cases, 10 had gram-positive and 5 had gram-negative infections. The sensitivity and specificity for the diagnosis of SA were, respectively, 0.47 and 1.00 in microbiological culture and 0.79 and 1.00 in real-time PCR. CONCLUSIONS:: Successful diagnosis of infection and differentiation between gram-positive and gram-negative bacteria were achieved using MRS-PCR and universal PCR. Hence, real-time PCR is useful and has greater sensitivity than microbial culture for diagnosing SA in children. LEVEL OF EVIDENCE:: Level II diagnostic study investigating a diagnostic test.
Journal of pediatric orthopedics 04/2013; 33(3):e28-e33. · 1.23 Impact Factor
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ABSTRACT: Several recent studies have demonstrated the limited accuracy of conventional culture methods for diagnosing periprosthetic infections. We have applied real-time polymerase chain reaction (PCR) assays for the rapid identification of bacteria around implants and reported its utility. However, the capability of quantification is also a useful feature of this type of assay. The aim of our study was to validate the usefulness of quantitative analyses using real-time PCR of cases with clinical periprosthetic infections in comparison with more established tests, such as C-reactive protein (CRP) levels, microbiologic cultures, and histopathology. Fifty-six joints with suspected infections were reviewed retrospectively. A universal PCR assay was used to perform the quantitative analyses. The differences in the threshold cycles between clinical samples and a negative control (∆Ct) in each case were calculated. The results of the quantitative PCR assay were compared with CRP levels, microbiologic cultures, and histopathology. There was a significant correlation found between the CRP and ∆Ct values. There were also significant differences found in the ∆Ct values according to CRP levels, with higher CRP levels showing higher ∆Ct values. Similarly, there were significant differences in the ∆Ct measurements in our culture results and among our pathologic evaluations. We confirmed that quantification by universal PCR based on the ∆Ct correlated with preoperative CRP levels and was associated with the microbiologic culture results and pathologic severity. This quantification method may be valuable for assessing infection severity.
Diagnostic microbiology and infectious disease 07/2012; 74(2):125-30. · 2.45 Impact Factor
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ABSTRACT: Fondaparinux (FPX), a selective inhibitor of factor Xa, is widely used for the prophylaxis of venous thromboembolism (VTE) after total joint arthroplasty. However, the association between plasma FPX concentration and adverse events and the occurrence of VTE has not been clarified thus far. We aimed to prospectively evaluate these associations by measuring anti-Xa activity of FPX in patients undergoing total hip arthroplasty (THA) and investigate whether factors such as age, body weight, and renal function influence the anti-Xa levels. We enrolled 85 patients who underwent primary THA. All patients received subcutaneous FPX (2.5 mg/day for 14 days) after surgery. Anti-Xa activity was measured on postoperative days 1, 3, 7, and 14. To assess VTE, multidetector row computed tomography was performed in all patients at 1 week after surgery. The median levels of anti-Xa activity increased as follows (medians with 95 % confidence interval): 0.00 (0.00-0.01) mg/L, 0.13 (0.11-0.14) mg/L, 0.19 (0.17-0.20) mg/L, and 0.24 (0.22-0.25) mg/L on postoperative days 1, 3, 7, and 14, respectively. The plasma accumulation of FPX was more likely in patients with renal impairment than in those with normal renal function. In contrast, a poor correlation was observed between the plasma levels of anti-Xa activity and age or body weight. No differences were observed in the anti-Xa activity in patients with and without postoperative VTE or bleeding. Substantial increase in the levels of anti-Xa activity was observed, especially in patients with renal impairment, after subcutaneous administration of FPX 2.5 mg after THA.
Journal of Thrombosis and Thrombolysis 07/2012; 34(4):526-32. · 1.48 Impact Factor
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ABSTRACT: Markers of coagulation and fibrinolysis, such as soluble fibrin (SF), D-dimer, and plasminogen activator inhibitor 1 (PAI-1), have been developed in order to determine thrombotic tendency. We investigated whether these markers could be used to diagnose venous thromboembolism (VTE) in the early phase after primary total hip arthroplasty (THA).
This prospective study involved 2 groups: an intermittent pneumatic compression (IPC) group (67 patients who underwent IPC only as prophylaxis for VTE) and a fondaparinux (FPX) group (103 patients who received IPC and FPX postoperatively). Plasma levels of SF and PAI-1 were measured on postoperative day 1. To diagnose postoperative VTE, multi-detector row computed tomography (MDCT) and duplex ultrasonography (US) were performed on postoperative day 7.
VTE was detected postoperatively in 17 cases in the IPC group (25%) and in 8 cases in the FPX group (6%). In the IPC group, plasma levels of SF and PAI-1 were higher in patients with VTE (p < 0.01) than in those without VTE. On the other hand, in the FPX group there were no differences in the levels of SF or PAI-1 measured before administration of FPX on postoperative day 1. The diagnostic criterion of an increase in SF or PAI-1 above the cutoff level (19.8 µg/mL and 53.5 ng/mL, respectively) provided a sensitivity of 100% and a specificity of 67% in the IPC group. In addition, when this criterion was applied to FPX patients, 7 of the 8 patients with VTE met the criterion, and there was a negative agreement rate of 48/49.
Screening using the cutoff levels of SF and PAI-1 may be useful and shows high sensitivity in predicting postoperative VTE in the early phase after THA.
Acta Orthopaedica 02/2012; 83(1):14-21. · 2.17 Impact Factor
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ABSTRACT: The preoperative differentiation of aseptic and septic loosening following a total hip arthroplasty (THA) remains a challenging issue for clinicians to which several molecular imaging techniques have been applied. In our current study, we used F-18 fluoride positron emission tomography (PET) to evaluate THA cases with stable, septic or septic loosened implants to assess the possibility of differentiating these clinical settings using a novel uptake-type classification approach.
A total of 65 joints were enrolled in this prospective study comprising 27 asymptomatic stable hips (control group), 11 painful hips conservatively treated after THA due to a suspicion of loosening, and 27 painful hips surgically treated after THA. PET imaging was classified into 3 types according to the uptake pattern. The maximum standardized uptake value (SUVmax) was then measured for each joint. A final diagnosis was made via tissue examinations of surgically treated cases, and by serological and radiographic findings in conservatively treated cases.
There were significant differences found between the SUVmax values for the aseptic and septic loosening THA cases. In the diagnosis of infection with type 3 pattern, the sensitivity and specificity were measured at 0.95 and 0.98 for all cases, and 0.95 and 0.88 for surgically treated cases, respectively.
The results of our current study demonstrate that F-18 fluoride PET has considerable potential as a method for differentiating septic from aseptic loosening following a THA. The type classification of the uptake pattern can be performed relatively simply, and quantifications using the SUVmax values can then provide an objective evaluation.
Clinical nuclear medicine 11/2011; 36(11):e156-61. · 3.92 Impact Factor
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ABSTRACT: It is important to understand chronological changes in pelvic tilt after total hip arthroplasty (THA). In this study, we first investigated changes in pelvic tilt after THA. Second, we determined the correlation between preoperative pelvic tilt and the extent of postoperative changes in the pelvic tilt. Third, we evaluated the effects of changes in pelvic tilt on postoperative function and disability.
We examined 149 patients who received primary THA over a follow-up period of 1 year. We compared postoperative changes with the preoperative pelvic tilt on the basis of the anterior pelvic plane (APP) defined by DiGioia and patient demographics.
A significant correlation was observed between preoperative APP and the amount of postoperative change in APP, suggesting that patients with severe preoperative pelvic tilt generally experience greater postoperative changes in pelvic tilt. Our data showed that patients with preoperative anterior pelvic tilt generally exhibit posterior changes in pelvic tilt after operation, while patients with preoperative posterior pelvic tilts did not experience significant postoperative changes in pelvic tilt. The 1-year postoperative function scores in patients with preoperative anterior pelvic tilt were lower than those in patients with preoperative posterior pelvic tilt.
Pelvic tilt changed by varying degrees following THA. Special attention must be paid when positioning the acetabular component, particularly in patients with severe pelvic tilt prior to surgery. A greater understanding of the postoperative changes in pelvic tilt may improve the outcome of THA.
Journal of Orthopaedic Science 09/2011; 16(6):682-8. · 0.84 Impact Factor
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ABSTRACT: Several previous studies have demonstrated that bone mineral density loss around femoral implants is common, particularly in the proximal part of the femur, soon after total hip arthroplasty. The purpose of the present study was to compare the effects of alendronate and alfacalcidol on bone mineral density loss around the femoral implant and in the lumbar spine after total hip arthroplasty.
The present study included sixty patients with osteoarthritis of the hip who had undergone a primary cementless total hip arthroplasty. We assigned these individuals to treatment with alendronate (n = 20), alfacalcidol (n = 18), or no medication (n = 22). Periprosthetic and lumbar spine bone mineral density was measured one week after surgery, and biochemical markers (bone-specific alkaline phosphatase and serum N-terminal telopeptides of type-1 collagen) were measured before surgery as a reference baseline. Subsequent measurements were performed at twelve, twenty-four, and forty-eight weeks after surgery. The periprosthetic measurement area in the femur was defined as Regions 1 to 7, which are consecutively located around the implant from the greater trochanter to the lesser trochanter and calcar.
Bone mineral density in the alendronate group was maintained in all regions. In the alfacalcidol and no-medication groups, bone mineral density in Region 7 was lower than in Regions 3 to 6 throughout the study period (p < 0.0001 as a result of repeated measures analysis of variance). Bone mineral density in the lumbar spine in the alendronate and alfacalcidol groups was higher than in the no-medication group at forty-eight weeks. The serum level of N-terminal telopeptides of type-1 collagen in the alendronate group was lower than that in the no-medication group throughout the study period (p = 0.003, 0.02 and 0.005).
Alendronate prevented bone mineral density loss around femoral implants, particularly in Region 7 (calcar), but alfacalcidol did not show any effects in any regions. However, bone mineral density losses in the lumbar spine were effectively prevented by either alendronate or alfacalcidol.
The Journal of Bone and Joint Surgery 07/2011; 93(13):1203-9. · 3.27 Impact Factor
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Hyonmin Choe,
Yutaka Inaba, Naomi Kobayashi,
Hiroyuki Ike,
Chie Aoki,
Kazuya Shizukuishi,
Naoyuki Iwamoto,
Yohei Yukizawa,
Takashi Ishida,
Tomio Inoue,
Tomoyuki Saito
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ABSTRACT: The accurate diagnosis of periprosthetic infection requires assessment of intraoperative tissues. These must be sampled from the appropriate sites. We used (18)F-fluoride positron emission tomography (PET) to identify sites of inflammation in order to improve the sensitivity of histopathology, microbiological culture, and real-time PCR in total hip arthroplasty (THA) patients.
23 THA patients (23 hips) scheduled for revision surgery (the revision group) and 17 uninfected THA patients (23 hips; control group) were enrolled. Uptake was classified into major, minor, and no uptake. To evaluate the association between the (18)F-fluoride uptake and intraoperative tissue results in the revision group, we calculated their sensitivity on each of the major, minor, and no-uptake sides.
17 revision patients showed major uptake and all were diagnosed as having septic loosening from intraoperative tissue results. Minor uptake was observed in the other 6 revision patients and all were diagnosed as having aseptic loosening. Apart from 3 cases that showed minor uptake regions, control subjects showed no uptake. In the revision group, the sensitivities of histopathology, microbiological culture, real-time PCR separately and also in combination were 0.78, 0.58, 0.96, and 0.96, respectively, on the major (18)F-fluoride uptake sides, 0.0, 0.0, 0.1, and 0.1 on the minor-uptake sides, and 0, 0, 0.18, and 0.18 on the no-uptake sides.
Our findings suggest that preoperative assessment of major uptake of (18)F-fluoride markedly improves the accuracy of tissue sampling, and thus the sensitivity of subsequent tissue examinations. More definitive diagnosis of periprosthetic infection is therefore possible.
Acta Orthopaedica 06/2011; 82(4):427-32. · 2.17 Impact Factor
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ABSTRACT: This study compared the clinical outcomes of total hip arthroplasty using a minimally invasive anterolateral approach with a muscle-sparing technique (modified Watson-Jones approach) and the modified mini-incision direct lateral approach. We randomly assigned 102 patients to the muscle-sparing group (n = 52) or the mini-incision direct lateral group (n = 50). Muscle strength recovery of hip abduction at 6 weeks after surgery was better, and creatine kinase level at 1 day after surgery was lower in the muscle-sparing group than in the mini-incision direct lateral group (P < .01). However, there was no difference in the Harris hip score, pain visual analog scale, the Western Ontario and McMaster Universities Osteoarthritis Index, and Medical Outcomes Study Short Form 36 score between the 2 groups throughout the 1-year study period.
The Journal of arthroplasty 05/2011; 26(7):1117-22. · 1.79 Impact Factor
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ABSTRACT: Periprosthetic infection is one of the most serious complications of arthroplasty, and low-grade infections are particularly difficult to diagnose with use of conventional culture methods. Real-time polymerase chain reaction is a potentially viable way to overcome this detection problem as it is a more rapid and sensitive technique. In the current study, we used intraoperative polymerase chain reaction identification combined with a simple DNA-release method with ultrasonication to diagnose periprosthetic infections during revision surgery.
Thirty revision arthroplasty procedures were included in this prospective study. Surgical specimens were obtained intraoperatively, treated with ultrasonication, and then analyzed with real-time polymerase chain reaction. Methicillin-resistant Staphylococcus-specific polymerase chain reaction and 16S rRNA gene universal polymerase chain reaction were performed simultaneously to facilitate both specific and broad-range detection. Specimens obtained from the same sites were also analyzed with microbiologic culture and histopathological evaluation.
The specific polymerase chain reaction revealed methicillin-resistant Staphylococcus infection in specimens from six of the thirty operations analyzed in the present study, and the 16S rRNA gene universal polymerase chain reaction analysis was positive for specimens from thirteen operations. Conventional cultures revealed six methicillin-resistant Staphylococcus infections, two Staphylococcus aureus infections, one infection with another Staphylococcus species, and two Streptococcus infections. The sensitivity of the polymerase chain reaction method was 0.87 and the specificity was 0.8 when compared with the combined results of microbiologic culture and histopathological evaluation.
The ultrasonication method that we developed for accelerated DNA sample preparation as a replacement for conventional extraction made possible the potential intraoperative identification of periprosthetic infection during revision surgery. The simultaneous detection of methicillin-resistant Staphylococcus and broad-range bacterial infections would be invaluable for the informed selection of antibiotics and also for the formulation of the subsequent treatment strategy (a one-stage or two-stage revision) for the patient.
The Journal of Bone and Joint Surgery 12/2009; 91(12):2896-902. · 3.27 Impact Factor
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ABSTRACT: The aim of this study was to validate the accuracy, sensitivity, and specificity of a methicillin-resistant Staphylococcus (MRS) real-time polymerase chain reaction (PCR) assay in clinical periprosthetic infection cases. A total of 36 cases of revision arthroplasty were enrolled in this prospective study, and the primer and probe set of a methicillin-resistant Staphylococcus aureus detection kit were used for the specific detection of the MecA gene with a LightCycler system. The specimens were also tested in microbiologic cultures and histopathologic evaluations. Of the 36 cases tested, 14 were found to be PCR positive for MRS infection. Of these 14 cases, however, only 8 were also found to be MRS infected using the culture method, whereas 3 were culture negative and 3 samples showed growth of another organism. The accuracy, sensitivity, and specificity were 0.83, 1.00, and 0.79, respectively. We conclude that the use of this approach will improve the diagnosis of MRS having a direct impact in the management of cases of periprosthetic infections.
Diagnostic microbiology and infectious disease 05/2009; 64(2):172-6. · 2.45 Impact Factor
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ABSTRACT: To examine the effects of basic fibroblast growth factor (bFGF) gene-transduced chondrocytes on the repair of articular cartilage defects.
LacZ gene or bFGF gene was transduced into primary isolated rabbit chondrocytes with the use of a recombinant adeno-associated virus (AAV) vector. These gene-transduced chondrocytes were embedded in collagen gel and transplanted into a full-thickness defect in the articular cartilage of the patellar groove of a rabbit. The efficiency of gene transduction was assessed according to the percentage of LacZ-positive cells among the total number of living cells. The concentration of bFGF in the culture supernatant was measured by enzyme-linked immunosorbent assay to confirm the production by bFGF gene-transduced chondrocytes. At 4, 8, and 12 weeks after transplantation, cartilage repair was evaluated histologically and graded semiquantitatively using a histologic scoring system ranging from 0 (complete regeneration) to 14 (no regeneration) points.
LacZ gene expression by chondrocytes was maintained until 8 weeks in >85% of the in vitro population. LacZ-positive cells were found at the transplant sites for at least 4 weeks after surgery. The mean concentration of bFGF was significantly increased in bFGF gene-transduced cells compared with control cells (P < 0.01). Semiquantitative histologic scoring indicated that the total score was significantly lower in the bFGF-transduced group than in the control group throughout the observation period.
These results demonstrated that gene transfer to chondrocytes by an ex vivo method was established with the AAV vector, and transplantation of bFGF gene-transduced chondrocytes had a clear beneficial effect on the repair of rabbit articular cartilage defects.
Arthritis & Rheumatism 01/2005; 52(1):164-70. · 7.87 Impact Factor
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ABSTRACT: To evaluate both the potential for transferring genes to periosteal cells using an adeno-associated virus (AAV) vector and the potential for gene expression after transplantation of those cells to a cartilage defect in vivo.
Periosteum was obtained from the tibia of 6-week-old rabbits and enzymatically digested. The isolated periosteum derived cells were cultured and the subconfluence cells were infected with a recombinant AAV expressing the LacZ gene (AAV-LacZ). Collagen gel containing the LacZ transferred, periosteum derived cells was transplanted into a full thickness articular cartilage defect in 10 rabbits.
Infected cells still growing on the plate continued to express LacZ at least 12 weeks after AAV infection, with the highest percentage of LacZ positive cells reaching 74.4%. The LacZ positive cells were recognized at the transplant sites in 8 out of 10 knees.
Gene expression in periosteum derived cells was sustained in vitro for at least 12 weeks using the AAV vector, and for 2 weeks ex vivo after transplantation into a cartilage defect.
The Journal of Rheumatology 11/2002; 29(10):2176-80. · 3.69 Impact Factor
