Stage diagnostics for postinfection revision of hip and knee replacement: value of laboratory parameters and antigranulocyte scintigraphy

AIM: In the case of two-stage infect revision arthroplasties of hip and knee joint, of primary resection arthroplasties and before implantation of arthroplasties after septic arthritis the accuracy of preoperative laboratory parameters and antigranulocyte scintigraphy was analysed. Furthermore, we stained the intraoperatively taken joint synovial samples with hematoxylin-eosin and also with antibodies against human neutrophil elastase in order to investigate if immunohistological examination provides further or different information. METHOD: In 24 patients with intraoperative verification of infection we calculated sensitivity, specificity, positive and negative predictive values for laboratory tests, antigranulocyte scintigraphy and the most suitable combination of both. The joint synovial samples stained with antibodies against human neutrophil elastase were compared to those stained with hematoxylin-eosin according to the criteria of Mirra. RESULTS: We observed the best results for the combination of C-reactive protein and antigranulocyte scintigraphy with a sensitivity of 1, a specificity of 0.92, a positive predictive value of 0.75 and a negative predictive value of 1. No additional or different information was observed by the immunohistological stained samples. CONCLUSION: Stage diagnostic using C-reactive protein and antigranulocyte scintigraphy provides accurate information to assess the status of infection before hip and knee replacement after infect revision. Additional immunohistological staining besides the routinely taken hematoxylin-eosin staining of joint synovial samples is not recommended.     

Usefulness of 16S rDNA polymerase-chain-reaction (PCR) in the intraoperative detection of infection in revision of failed arthroplasties

AIM: In this study the accuracy of the 16S DNA polymerase chain reaction (PCR) in revision arthroplasties was compared to that of conventional bacterial culture when correlated to intraoperative histological findings. Furthermore, the influence of antibiotic treatment and different ways of collecting samples was evaluated. METHOD: In a prospective study we collected samples of tissues, aspiration fluids and swabs during revision arthroplasty surgery and examined them with PCR as well as conventional bacterial culturing methods. Also, we correlated these two methods with the histological findings of intraoperative tissue samples. Two independent examiners evaluated the samples according to the criteria of Mirra et al. Sensitivity, specificity, positive and negative prediction value and the accuracy were calculated for the molecular biological and culture methods. Three groups were defined to evaluate the influence of accompanying antibiotic treatment and the way of collecting the microbiological samples. RESULTS: Nine periprosthetic infections could be detected by PCR as well as by conventional bacterial culturing. Correlated with the 25 positive histological findings this resulted in a sensitivity of 0.36, a specificity of 1.0, a negative prediction value of 0.61, a positive prediction value of 1.0 and an accuracy of 0.68 for both methods. Swabs compared to aspiration fluids and tissues samples showed the highest sensitivity with both methods. No higher sensitivity of PCR compared to conventional bacterial culturing could be observed in patients with accompanying antibiotic treatment. CONCLUSION: Although PCR is more rapidly available for the diagnosis of periprosthetic infection, a definite advantage of this more expensive method could not be demonstrated in view of the same low sensitivity of PCR and conventional bacterial culturing.     

Staged diagnosis of septic hip endoprosthesis loosening with laboratory parameters and antigranulocyte scintigraphy

AIM: The value of serial diagnosis of septic loosening of hip endoprosthesis using laboratory parameters and antigranulocytes scintigraphy was investigated and compared to joint aspiration. METHOD: In 35 patients with intraoperative verification of infection, we calculated sensitivity, specify and prevalence dependent positive and negative predictive values for antigranulocyte scintigraphy, laboratory tests and the most suitable combination of both. We also calculated predictive values of joint aspiration using sensitivity and specify values given in the literature. RESULTS: From negative and positive predictive values, of the sedimetation rate and leukocyte count provided no increase of information. We found the same result for positive predictive values of C-reactive protein. For antigranulocyte scintigraphy alone, we found a distinct but still unsatisfying increase of information. Nevertheless, in both cases infection could be excluded definitely. Therefore, the combination of C-reactive protein and antigranulocyte scintigraphy was suitable and the positive predictive values of this combination were only about 5% lower than those of joint aspiration. But with joint aspiration, infection could not be excluded. CONCLUSION: A positive result in serial diagnosis using C-reactive protein and antigranulocyte scintigraphy leads to an distinct increase in the probability of infection which is comparable to that of joint aspiration. The additional advantages of this procedure are the certain exclusion of infection and the absence of invasiveness.     

Diagnostische Strategien bei Verdacht auf periprothetische Infektion einer Kniegelenktotalendoprothese

Reliable confirmation of periprosthetic infection after total knee arthroplasty is a diagnostic challenge. The present work reviews published data evaluating the available diagnostic tools. Erythrocyte sedimentation rate and C-reactive protein serum levels are relatively sensitive methods with rather low specificity towards periprosthetic infection and are mainly applied to exclude infection. Studies evaluating scintigraphic methods – especially white cell scans – provide inconsistent data with varying accuracy. Consequently, white cell scans cannot be recommended as standard methods. Immunoscintigraphy with antigranulocyte antibodies and FDG-PET scans demonstrated promising results with particularly high sensitivities, but have to be validated in larger studies. Microbiological evaluation of joint aspirates proved high specificity for periprosthetic infection. However, an average of 20% of infected cases remained undetected. Nevertheless, aspiration is widely recommended for preoperative isolation of the infecting organism. Intraoperative frozen sections demonstrated excellent specificity with good sensitivity. The real accuracy of intraoperative culture and permanent histology cannot be determined due to the missing golden standard; however, a combination of both methods is recommended to define the final diagnosis. Large studies validating both methods and criteria for the final diagnosis of periprosthetic infection are necessary to optimize the diagnostic algorithm.     

Diagnostic strategies in cases of suspected periprosthetic infection of the knee. A review of the literature and current recommendations

Reliable confirmation of periprosthetic infection after total knee arthroplasty is a diagnostic challenge. The present work reviews published data evaluating the available diagnostic tools. Erythrocyte sedimentation rate and C-reactive protein serum levels are relatively sensitive methods with rather low specificity towards periprosthetic infection and are mainly applied to exclude infection. Studies evaluating scintigraphic methods--especially white cell scans--provide inconsistent data with varying accuracy. Consequently, white cell scans cannot be recommended as standard methods. Immunoscintigraphy with antigranulocyte antibodies and FDG-PET scans demonstrated promising results with particularly high sensitivities, but have to be validated in larger studies. Microbiological evaluation of joint aspirates proved high specificity for periprosthetic infection. However, an average of 20% of infected cases remained undetected. Nevertheless, aspiration is widely recommended for preoperative isolation of the infecting organism. Intraoperative frozen sections demonstrated excellent specificity with good sensitivity. The real accuracy of intraoperative culture and permanent histology cannot be determined due to the missing golden standard; however, a combination of both methods is recommended to define the final diagnosis. Large studies validating both methods and criteria for the final diagnosis of periprosthetic infection are necessary to optimize the diagnostic algorithm.     

The value of preoperative knee aspiration and arthroscopic biopsy in revision total knee arthroplasty

AIM: The accurate preoperative diagnosis of occult sepsis in endoprosthetic loosening of total knee arthroplasty is the key to successful management of revision total knee arthroplasties. The aim of this study was to evaluate the results of preoperative aspiration in comparison with preoperative arthroscopic biopsy of the synovial tissue. METHOD: From 2000 to 2004 eighty-six revision total knee arthroplasties in 86 patients were performed. 60 patients had only a knee aspiration, 15 an arthroscopic biopsy and an aspiration, 11 only arthroscopic biopsy. The results of both methods were compared with the intraoperative cultures during revision surgery. RESULTS: 69 aseptic and 17 septic knee exchange arthroplasties were performed. The preoperative aspiration of the prosthetic knee joint had a sensitivity of 68.8 %, specificity of 96.6 %, positive predictive value of 84.5 % and a negative predictive value of 92.2 %. The preoperative arthroscopic biopsy had a sensitivity of 100 %, specificity of 94.7 %, positive predictive value of 87.4 % and a negative predictive value of 100 %. CONCLUSION: Preoperative aspiration of the knee is a very helpful study for the diagnosis or exclusion of infection in a prosthetic knee joint and should be a standard procedure in the diagnosis of prosthetic loosening. If after aspiration a suspicion of infection remains, then the biopsy is an accurate procedure to diagnose or exclude periprosthetic sepsis.     

The value of synovial biopsy, joint aspiration and C-reactive protein in the diagnosis of late peri-prosthetic infection of total knee replacements

We analysed the serum C-reactive protein level, synovial fluid obtained by joint aspiration and five synovial biopsies from 145 knee replacements prior to revision to assess the value of these parameters in diagnosing late peri-prosthetic infection. Five further synovial biopsies were used for histological analysis. Samples were also obtained during the revision and incubated and analysed in an identical manner for 14 days. A total of 40 total knee replacements were found to be infected (prevalence 27.6%). The aspiration technique had a sensitivity of 72.5% (95% confidence interval (CI) 58.7 to 86.3), a specificity of 95.2% (95% CI 91.2 to 99.2), a positive predictive value of 85.3% (95% CI 73.4 to 100), a negative predictive value of 90.1% (95% CI 84.5 to 95.7) and an accuracy of 89%. The biopsy technique had a sensitivity of 100%, a specificity of 98.1% (95% CI 95.5 to 100), a positive predictive value of 95.2% (95% CI 88.8 to 100), a negative predictive value of 100% and an accuracy of 98.6%. C-reactive protein with a cut-off-point of 13.5 mg/l had a sensitivity of 72.5% (95% CI 58.7 to 86.3), a specificity of 80.9% (95% CI 73.4 to 88.4), a positive predictive value of 59.2% (95% CI 45.4 to 73.0), a negative predictive value of 88.5% (95% 81.0 to 96.0 CI) and an accuracy of 78.1%. We found that biopsy was superior to joint aspiration and C-reactive protein in the diagnosis of late peri-prosthetic infection of total knee replacements.     

Evaluation of the painful prosthetic joint. Relative value of bone scan, sedimentation rate, and joint aspiration

Seventy-two joint arthroplasties undergoing total hip or total knee surgery were studied prospectively with plain radiographs, three-phase bone imaging (3PBI), erythrocyte sedimentation rate (ESR), aspiration of the joint for culture, and multiple intraoperative cultures at the time of revision. Intraoperative cultures and the operative appearance were used to form a diagnosis of definite infection (unequivocal microbiology and gross sepsis), possible infection (positive microbiology or gross sepsis), or no infection (neither positive microbiology nor gross sepsis). For the preoperative diagnosis of infection, as opposed to aseptic loosening, 3PBI alone had a sensitivity of 33% and a specificity of 86%. In conjunction with plain radiographs, minimal improvement in accuracy was seen. A preoperative ESR greater than 30 had low sensitivity (60%) and a specificity of (65%). However, the ESR was statistically significantly higher in the joints with definite infection as compared to those joints without infection. The preoperative joint aspiration had a sensitivity of 67% and a specificity of 96% and, therefore, appears to be the most useful single test in the workup of a painful total joint arthroplasty.     

Hepatobiliary scintigraphy is superior to abdominal ultrasonography in suspected acute cholecystitis

BACKGROUND: Hepatobiliary scintigraphy is a very accurate test in the diagnosis of acute cholecystitis. However, ultrasonography is extensively used for the diagnosis of this disease. In this study, we directly compare the diagnostic accuracy of these techniques for acute cholecystitis.Materials and Methods: The diagnostic accuracy of scintigraphy and ultrasonography was evaluated in 107 consecutive patients with suspected acute cholecystitis who underwent both imaging modalities within one day. The incremental diagnostic value of each modality was determined. RESULTS: The sensitivity, specificity, positive and negative predictive values, and accuracy for the diagnosis of acute cholecystitis in the entire cohort were superior for scintigraphy compared with ultrasonography. The accuracy was 92% for scintigraphy and 77% for ultrasonography. Similarly, if only surgically treated patients were considered, the accuracy of scintigraphy was 91% versus 61% for ultrasonography. The diagnostic value of scintigraphy for the entire cohort was significantly superior to ultrasonography (global, chi(2) = 58.1 vs 9.7, respectively); the addition of the information derived from the latter did not further improve the diagnostic value of scintigraphy (global, chi(2) = 58.2). CONCLUSIONS: Hepatobiliary scintigraphy has superior diagnostic accuracy for acute cholecystitis compared with ultrasonography. The addition of ultrasonography does not further improve the diagnostic accuracy of scintigraphy alone.     

关节液与组织培养在髋膝关节置换术后感染诊断价值的Meta分析

目的 系统评价关节液和组织培养对关节置换术后感染的诊断价值及临床应用前景.方法 计算机检索Cochrane图书馆、Medline、Pubmed、中国生物医学文献数据库（CBM）、中文科技期刊全文数据库[维普（VIP）]等数据库,检索年限均从建库至2013年12月,收集关节液和组织培养对关节置换后感染的诊断试验,手工检索相关会议论文集、学位论文汇编等.根据Cochrane系统评价方法筛选研究并提取数据,采用Meta‐DiSc1.4软件进行Meta分析.结果 5篇文献符合纳入标准纳入本系统评价,总病例数748例.对临床诊断关节置换后感染有指导作用的组织培养总加权灵敏度和特异度分别为85.1%和96.9%;关节液培养的总加权灵敏度和特异度分别为77.4%和96.8%,合并数据中组织培养的敏感度和特异度存在异质性.组织培养在髋膝关节置换术后假体周围感染诊断的灵敏度显著优于关节液穿刺方法,两者比较,差异均有统计学意义（P〈0.05）,两者在阴性似然比及诊断效能比值比没有显著差异性（P〉0.05）.结论 组织培养在在对关节置换术后感染诊断的敏感度上明显优于关节液培养.     

Role of knee aspiration after resection of the infected total knee arthroplasty

Recognizing persistent infection after resection arthroplasty and implantation of cement spacers in the infected total knee arthroplasty is often difficult. The purpose of this study was to determine whether aspiration of the knee after resection arthroplasty is valuable for determining the presence of ongoing infection. Thirty-four previously infected knees that were aspirated and cultured after resection arthroplasty, implantation of cement spacers, and intravenous antibiotics for an average of 6.3 weeks were identified. There were 8 cases of persistent infection-none identified on preoperative aspiration. Two preoperative cultures were false positive for Staphylococcus epidermidis. Preoperative cultures were negative in 32 knees, with 8 false-negative results. The antibiotic-free interval among all cases averaged 20 days; the cases with false-negative results from aspiration had an antibiotic-free interval averaging 11.5 days, compared with an average of 26 days among all other cases. Aspiration of knees after resection arthroplasty had sensitivity of 0%, positive predictive value of 0%, and accuracy of 71%. Specificity was 92%, and negative predictive value was 75%. A negative result from joint aspiration after resection arthroplasty does not necessarily rule out the presence of ongoing infection. False-negative results may be observed if joint aspiration is not delayed more than 2 to 3 weeks.     

超声引导针吸活检术评价乳腺癌腋窝淋巴结转移

目的 研究超声引导针吸活检在术前判断乳腺癌腋窝淋巴结转移中的应用,评价该方法的可行性和诊断的准确率. 方法对40例腋窝触诊阴性的高度可疑乳腺癌患者的40个腋窝淋巴结进行超声引导针吸活检,将结果与前哨淋巴结活检或腋窝淋巴结清扫的组织学病理结果进行对照.分析超声引导针吸活检判断乳腺癌腋窝淋巴结转移的敏感性、特异性、阳性预测值、阴性预测值和诊断准确率.结果 40例患者全部经病理证实为浸润性乳腺癌.超声引导针吸活检判断腋窝淋巴结转移的敏感性、特异性、阳性预测值、阴性预测值和诊断准确率分别为52.2%、100%、100%、60.7%、72.5%.有12例(30%)术前细针穿刺活检阳性的患者避免了前哨活检,直接接受了腋窝清扫.结论 应用超声引导针吸活检在术前判断乳腺癌的腋窝淋巴结转移情况创伤小、特异性高,可以避免部分患者接受前哨淋巴结活检术.

Abstract：

Objective To study the utilization of preoperative ultrasound-guided fine-needle aspiration(USFNA) for axillary lymphnode(ALN) metastasis in breast cancer and to evaluate the feasibility and accuracy of the technique. Methods Forty ALNs in 40 armpit negative palpation highly suspective breast cancer patients underwent USFNA. The cytopathological results were compared with the histopathological results of sentinel lymphnode(SLN) biopsy or axillary lymphnode dissection(ALND). The sensitivity, specificity, positive predictive value(PPV), negative predictive value(NPV) and diagnostic accuracy of USFNA for the ALN metastasis were analysed. Results All the 40 patients were confirmed with breast cancer by pathology. Sensitivity of USFNA was 52. 2%, specificity was 100%, PPV was 100%,NPV was 60. 7% and diagnostic accuracy was 72. 5%. 12(30% ) patients with positive cytology proceeded to ALND, avoiding SLN biopsy. Conclusions USFNA is a minimally invasive, highly specified technique for prediction of breast cancer ALN metastasis before operation.     

Poor predictive value of broad-range PCR for the detection of arthroplasty infection in 92 cases

Background The diagnosis of prosthetic infection remains a challenge, as no test is 100% sensitive and 100% specific Recent advances in molecular biology have enabled the detection of infection in culture negative cases.

Patients and methods We evaluated the effectiveness of polymerase chain reaction (PCR) in detecting infection in failed joint replacements prospectively in 91 consecutive patients (92 prosthetic joints) undergoing revision total hip or knee arthroplasty. Synovial fluid was collected intraoperatively and examined by broad-range PCR assay for detection of bacterial DNA. The clinical diagnosis of infection was based on the results of blood tests, preoperative joint aspiration, culture and histology of multiple intraoperative tissue samples, as well as the surgeon's assessment.

12 joints (13%) were infected, but the PCR was positive in 32 cases. The sensitivity of the technique was 92%, the specificity 74%, the accuracy 76%, the positive predictive value 34%, and the negative predictive value was 98%.

Interpretation The PCR technique cannot be recommended for the routine detection of prosthetic infection. The large number of false positive results may represent sample contamination, or bacterial presence related to low-virulence organisms, low bacterial load, or a strong host immune response.     

Poor predictive value of broad-range PCR for the detection of arthroplasty infection in 92 cases

Background The diagnosis of prosthetic infection remains a challenge, as no test is 100% sensitive and 100% specific Recent advances in molecular biology have enabled the detection of infection in culture negative cases.

Patients and methods We evaluated the effectiveness of polymerase chain reaction (PCR) in detecting infection in failed joint replacements prospectively in 91 consecutive patients (92 prosthetic joints) undergoing revision total hip or knee arthroplasty. Synovial fluid was collected intraoperatively and examined by broad-range PCR assay for detection of bacterial DNA. The clinical diagnosis of infection was based on the results of blood tests, preoperative joint aspiration, culture and histology of multiple intraoperative tissue samples, as well as the surgeon's assessment.

12 joints (13%) were infected, but the PCR was positive in 32 cases. The sensitivity of the technique was 92%, the specificity 74%, the accuracy 76%, the positive predictive value 34%, and the negative predictive value was 98%.

Interpretation The PCR technique cannot be recommended for the routine detection of prosthetic infection. The large number of false positive results may represent sample contamination, or bacterial presence related to low-virulence organisms, low bacterial load, or a strong host immune response.     

Evaluation of sonicate fluid cultures in comparison to histological analysis of the periprosthetic membrane for the detection of periprosthetic joint infection

Purpose

The aim of this prospective study was to evaluate the diagnostic efficacy of sonicate fluid cultures (SFC) and the histological analysis of the periprosthetic membrane (PM) for the detection of periprosthetic joint infection (PJI).

Methods

The histological samples were evaluated according to the consensus classification of PM as defined by Morawietz and Krenn. All explanted endoprosthesis were subject to sonication. Additionally, a synovial aspiration and microbiological culture of tissue samples were performed for each patient. Twenty three of the 59 patients had an established PJI.

Results

Sonication achieved the highest sensitivity out of all diagnostic methods with 91 % and a specificity of 81 %. The PM achieved a sensitivity of 87 % and a specificity of 100 %. In three cases of PJI a pathogen was isolated solely by sonication while all other microbiological methods were negative. In seven cases there was a positive bacterial culture through sonication with negative histology.

Conclusions

Our results show a high correlation between the microbiological and histological results. In our patient group sonication achieved the highest sensitivity out of all diagnostic methods and was more sensitive than conventional microbiological methods.     

Diagnose septischer Hüftprothesenlockerung via LeukoScan

Diagnosis of septic loosening of hip endoprosthesis with antigranulocyte scintigraphy (AGS) was analysed. Twenty-one hip prostheses were studied using laboratory tests and, in cases of elevated values, three-phase bone scan (BS) and AGS. Elective SPECT/CT scans were performed. Histologic and microbiologic exams verified the diagnosis.The AGS analysis revealed sensitivity, specificity and accuracy of value 1, while positive and negative predictive values were also 1. BS showed sensitivity of 1 and specificity of 0.33. In three cases, SPECT/CT scans corroborated the AGS interpretation. This diagnostic algorithm proved effective in the detection of septic loosening of hip prostheses. AGS can be avoided without risk of infection being overlooked.     

Logistische Voraussetzungen und Probenentnahme bei periprothetischen Infektionen

Preoperative diagnosis of periprosthetic infections is particularly important before revision of knee and hip arthroplasties because of the therapeutic consequences. Therefore, periprosthetic infections should be ruled out before any revision surgery is performed. Of the different diagnostic methods direct techniques which allow the direct detection of microorganisms with testing of antibiotic sensitivity are recommended. This allows microorganism-specific systemic and local antibiotic therapies and helps to reduce the risk of development of resistance. In our studies it could be shown that the time for incubation to detect microorganisms should be 14?days and that biopsy of periprosthetic tissues is superior to aspiration alone because it combines several diagnostic methods (microbiological and histological). It is preferable to repeating an aspiration when data are unclear, i.e. in cases of potentially false positives or negatives results of aspiration.     

Clinical diagnosis of ventilator associated pneumonia revisited: comparative validation using immediate post-mortem lung biopsies

BACKGROUND: A study was undertaken to assess the diagnostic value of different clinical criteria and the impact of microbiological testing on the accuracy of clinical diagnosis of suspected ventilator associated pneumonia (VAP). METHODS: Twenty five deceased mechanically ventilated patients were studied prospectively. Immediately after death, multiple bilateral lung biopsy specimens (16 specimens/patient) were obtained for histological examination and quantitative lung cultures. The presence of both histological pneumonia and positive lung cultures was used as a reference test. RESULTS: The presence of infiltrates on the chest radiograph and two of three clinical criteria (leucocytosis, purulent secretions, fever) had a sensitivity of 69% and a specificity of 75%; the corresponding numbers for the clinical pulmonary infection score (CPIS) were 77% and 42%. Non-invasive as well as invasive sampling techniques had comparable values. The combination of all techniques achieved a sensitivity of 85% and a specificity of 50%, and these values remained virtually unchanged despite the presence of previous treatment with antibiotics. When microbiological results were added to clinical criteria, adequate diagnoses originating from microbiological results which might have corrected false positive and false negative clinical judgements (n = 5) were countered by a similar proportion of inadequate diagnoses (n = 6). CONCLUSIONS: Clinical criteria had reasonable diagnostic values. CPIS was not superior to conventional clinical criteria. Non-invasive and invasive sampling techniques had diagnostic values comparable to clinical criteria. An algorithm guiding antibiotic treatment exclusively by microbiological results does not increase the overall diagnostic accuracy and carries the risk of undertreatment.     

Histopathologische Diagnose der periprothetischen Gelenkinfektion nach Hüftgelenkersatz

Background

The distinction between aseptic and septic loosening of a total hip arthroplasty is a diagnostic challenge. Therapy and clinical success depend on the correct diagnosis. Histopathological evaluation of the periprosthetic interface membrane is one possible diagnostic parameter; detailed analysis of tissue characteristics may reflect the cause of failure. This study evaluated the diagnostic value of a published histopathological consensus classification for the periprosthetic interface membrane in the identification of periprosthetic joint infection (PJI).

Methods

Between 2004 and 2008, a prospective analysis was performed in 106 patients who had revisions because of assumed PJI. Based on clinical presentation, radiography, and haematological screening, infection was assumed, and a joint aspiration was performed. Based on these findings, a two-stage revision was performed, with intraoperative samples for culture and histological evaluation obtained. Final diagnosis of infection was based on the interpretation of the clinical presentation and the preoperative and intraoperative findings. The basis for histopathological evaluation was the consensus classification for the periprosthetic interface membrane. Sensitivity, specificity, and accuracy were calculated for each parameter.

Results

In 92 patients, a positive diagnosis of PJI could be made. Histopathology yielded the highest accuracy (0.93) in identification of PJI, identifying 86 of 92 infections (69 type II, 17 type III). In 13 of the 14 noninfected hips, histopathology correlated in 13 (93%) cases (10 type I, three type IV). The accuracies of microbiological culture, C-reactive protein, and aspiration were 0.82, 0.86, and 0.54, respectively.

Conclusion

In the diagnosis of PJI, histopathological evaluation of the periprosthetic interface membrane proved very effective. To analyse the cause of prosthesis loosening, tissue samples of the periprosthetic interface membrane should be evaluated on the basis of the consensus classification in all revision surgeries.     

The accuracy of diagnostic imaging for the assessment of chronic osteomyelitis: a systematic review and meta-analysis

BACKGROUND: A variety of diagnostic imaging techniques is available for excluding or confirming chronic osteomyelitis. Until now, an evidence-based algorithmic model for choosing the most suitable imaging technique has been lacking. The objective of this study was to determine the accuracy of current imaging modalities in the diagnosis of chronic osteomyelitis. METHODS: A systematic review and meta-analysis of the literature was conducted with a comprehensive search of the MEDLINE, EMBASE, and Current Contents databases to identify clinical studies on chronic osteomyelitis that evaluated diagnostic imaging modalities. The value of each imaging technique was studied by determining its sensitivity and specificity compared with the results of histological analysis, findings on culture, and clinical follow-up of more than six months. RESULTS: A total of twenty-three clinical studies in which the accuracy was described for radiography (two studies), magnetic resonance imaging (five), computed tomography (one), bone scintigraphy (seven), leukocyte scintigraphy (thirteen), gallium scintigraphy (one), combined bone and leukocyte scintigraphy (six), combined bone and gallium scintigraphy (three), and fluorodeoxyglucose positron emission tomography (four) were included in the review. No meta-analysis was performed with respect to computed tomography, gallium scintigraphy, and radiography. Pooled sensitivity demonstrated that fluorodeoxyglucose positron emission tomography was the most sensitive technique, with a sensitivity of 96% (95% confidence interval, 88% to 99%) compared with 82% (95% confidence interval, 70% to 89%) for bone scintigraphy, 61% (95% confidence interval, 43% to 76%) for leukocyte scintigraphy, 78% (95% confidence interval, 72% to 83%) for combined bone and leukocyte scintigraphy, and 84% (95% confidence interval, 69% to 92%) for magnetic resonance imaging. Pooled specificity demonstrated that bone scintigraphy had the lowest specificity, with a specificity of 25% (95% confidence interval, 16% to 36%) compared with 60% (95% confidence interval, 38% to 78%) for magnetic resonance imaging, 77% (95% confidence interval, 63% to 87%) for leukocyte scintigraphy, 84% (95% confidence interval, 75% to 90%) for combined bone and leukocyte scintigraphy, and 91% (95% confidence interval, 81% to 95%) for fluorodeoxyglucose positron emission tomography. The sensitivity of leukocyte scintigraphy in detecting chronic osteomyelitis in the peripheral skeleton was 84% (95% confidence interval, 72% to 91%) compared with 21% (95% confidence interval, 11% to 38%) for its detection of chronic osteomyelitis in the axial skeleton. The specificity of leukocyte scintigraphy in the axial skeleton was 60% (95% confidence interval, 39% to 78%) compared with 80% (95% confidence interval, 61% to 91%) for the peripheral skeleton. CONCLUSIONS: Fluorodeoxyglucose positron emission tomography has the highest diagnostic accuracy for confirming or excluding the diagnosis of chronic osteomyelitis. Leukocyte scintigraphy has an appropriate diagnostic accuracy in the peripheral skeleton, but fluorodeoxyglucose positron emission tomography is superior for detecting chronic osteomyelitis in the axial skeleton.