Diagnosis Of Periprosthetic Infection Research Articles

Leukocyte cell population data (CPD) in the diagnosis of periprosthetic infection

Leukocyte cell population data (CPD) in the diagnosis of periprosthetic infection

Arthroscopic tissue biopsy as a preoperative diagnostic test for periprosthetic shoulder arthroplasty infections: a systematic review and meta-analysis.

The diagnosis of periprosthetic infection in shoulder arthroplasty remains a challenge. Conventional methods for evaluating periprosthetic joint infections are poor because of lower-virulence organisms affecting the shoulder. The aim of our systematic review was to evaluate the diagnostic accuracy of preoperative arthroscopic tissue cultures compared with tissue biopsy samples obtained at the time of revision surgery. We conducted a systematic search of the MEDLINE, Embase, and Cochrane Central databases. The inclusion criteria consisted of studies that used arthroscopy to obtain preoperative tissue cultures for the diagnosis of shoulder arthroplasty infections. Studies were excluded if they obtained non-arthroscopic tissue samples. We reported the sensitivity, specificity, positive predictive value, and negative predictive value. Culture findings from the arthroscopic biopsy samples were also compared with conventional tests of fluoroscopy-guided joint aspiration and serum inflammatory marker testing (positive erythrocyte sedimentation rate or C-reactive protein) within the included studies. A meta-analysis was performed to assess the overall diagnostic accuracy of the studies. Our search strategy yielded 795 potentially relevant publications; 572 underwent title and abstract screening, and 14 studies underwent full-text review, of which 7 were included in our systematic review. The studies represented a balance of shoulder arthroplasty types, including anatomic total shoulder arthroplasty (n=75, 38%), reverse total shoulder arthroplasty (n=60, 30%), and hemiarthroplasty (n=64, 32%). There were 56 of 120 arthroscopic procedures that returned positive tissue culture findings compared with 64 of 157 positive open biopsy culture findings obtained from revision surgery. The meta-analysis total for sensitivity and specificity for all studies combined indicated that arthroscopic tissue cultures (0.76 [95% confidence interval (CI), 0.57-0.88] and 0.91 [95% CI, 0.79-0.97], respectively) were superior to both aspiration (0.15 [95% CI, 0.03-0.48] and 0.93 [95% CI, 0.65-0.99], respectively) and a positive erythrocyte sedimentation rate or C-reactive protein level (0.14 [95% CI, 0.02-0.62] and 0.83 [95% CI, 0.56-0.95], respectively) in diagnosing periprosthetic shoulder infections. Our systematic review demonstrated that preoperative arthroscopic tissue biopsy used for microbiology cultures accurately predicts intraoperative culture findings obtained during revision surgery with high sensitivity and specificity. Additionally, arthroscopy appears to be superior to conventional techniques of joint aspiration and inflammatory marker testing. Therefore, arthroscopic tissue cultures may be an emerging useful tool to help guide the management of periprosthetic infections in shoulder arthroplasty.

Diagnostic Accuracy for Periprosthetic Joint Infection Does Not Improve by a Combined Use of Glucose and Leukocyte Esterase Strip Reading as Diagnostic Parameters.

The diagnosis of periprosthetic infections (PJI) can be challenging in clinical practice because the clinical presentations of aseptic loosening and low-grade infections are similar. Semiquantitative evaluation of leukocyte esterase (LE) in synovial fluid using a urine strip test has already established itself as a diagnostic method over the past decade. The analysis of LE in synovial fluid leads to a high number of false-positive test results. In the present study, the value of a combined semiquantitative determination of glucose and LE in synovial fluid to improve the diagnosis of PJI was investigated. Over a 4-year period, 145 synovial samples were collected from patients who developed joint effusion after arthroplasty. LE and glucose test strips were considered as an index test for the diagnosis of PJI. A ++ or +++ LE and a negative glucose test strip reading were considered as positive test results. Modified diagnostic criteria for PJI as recommended by the Musculoskeletal Infection Society (MSIS) served as the reference test, except that intraoperative findings were excluded. Forty-six out of 145 samples were classified as septic complication according to the reference test. In regard to PJI, our data showed that combined use of LE and glucose strip test reading displayed a 98.0% specificity (95% confidence interval (CI): 95.2% to 100%), a 50% sensitivity (95% CI: 35.6% to 64.4%), a 92% positive predictive value (95% CI: 81.4% to 100.0%), and an 80.3% negative predictive value (95% CI: 73.2% to 87.4%). In contrast, the exclusive analysis of LE on the urine strip to diagnose PJI demonstrated a 90.9% specificity (95% CI: 85.2% to 96.6%), a 67.4% sensitivity (95% CI: 53.8% to 80.9%), a 77.5% positive predictive value (95% CI: 64.6% to 90.4%), and an 85.7% negative predictive value (5% CI: 79.0% to 92.4%). A combination of LE and glucose test pad reading is considered superior as a potential “rule-in” method for the diagnosis of PJI compared with LE test pad analysis alone. However, combined LE and glucose synovial fluid testing also demonstrated lower test sensitivity and thus diagnostic accuracy compared with LE analysis alone. Therefore, combined glucose and LE test pad analysis does not represent a sufficient diagnostic standard to exclude PJI with certainty.

Биохимические и иммунологические маркеры крови пациентов после эндопротезирования коленного и тазобедренного суставов для ранней диагностики перипротезной инфекции

Актуальность. В современной медицинской практике отсутствует четкий перечень гематологических, биохимических и иммунологических тестов как для первичной оценки состояния пациентов, так и для контроля динамики метаболического статуса после эндопротезирования суставов. Цель исследования: определить и установить диагностическую чувствительность биохимических и иммунологических маркеров крови в динамике послеоперационного периода у пациентов после эндопротезирования тазобедренного и коленного суставов для ранней диагностики перипротезной инфекции. Материалы и методы. Исследование выполнялось на 53 пациентах, которым было проведено 61 оперативное вмешательство на коленном и тазобедренном суставах. Осуществлены эндопротезирование коленного (n = 41) и тазобедренного (n = 14) суставов, дебридмент (n = 6), из них первичных эндопротезирований — 42, ревизионных эндопротезирований — 13 (мужчин — 16, женщин — 37, возраст больных — от 35 до 79 лет). Все больные были разделены на три группы: I группа — пациенты, которым была диагностирована перипротезная инфекция в срок до 4 недель после операции (n = 7), II — пациенты, у которых инфекция была диагностирована при обращении в клинику, но послеоперационный период после выполнения ревизионного вмешательства протекал без осложнений (n = 8), III — пациенты, у которых было нормальное течение послеоперационного периода (n = 46). В сыворотке крови определяли содержание общего белка, гликопротеинов, хондроитинсульфатов, глюкозы и С-реактивного белка, интерлейкинов (ИЛ-1β и ИЛ-6). Диагностическую чувствительность (ДЧ) лабораторных показателей рассчитывали по формуле: ДЧ = (ТП/Д) × 100 %, где ТП — истинно положительные результаты исследования, Д — количество больных в группе. Результаты. Во всех группах пациентов было установлено наличие воспалительно-деструктивных нарушений в организме по содержанию гликопротеинов, хондроитинсульфатов, ИЛ-1β и ИЛ-6, которые имели высокие показатели ДЧ. Выводы. У больных всех исследуемых групп независимо от обнаружения перипротезной инфекции наблюдались острые воспалительно-деструктивные процессы в организме, которые отражались в повышении содержания гликопротеинов, хондроитинсульфатов, С-реактивного белка, ИЛ-1β и ИЛ-6 в крови после эндопротезирования тазобедренного и коленного суставов, исследованные биохимические и иммунологические маркеры крови не являются специфичными для диагностики перипротезной инфекции; ДЧ во всех группах больных в послеоперационный период была самой высокой у гликопротеинов, хондроитинсульфатов, С-реактивного белка, ИЛ-1β и ИЛ-6, что позволяет использовать данные лабораторные маркеры для оценки степени воспалительного процесса в организме ортопедических пациентов после эндопротезирования тазобедренного и коленного суставов.

Результати лабораторних досліджень рідини з колінних та кульшових суглобів після ендопротезування для ранньої діагностики перипротезної інфекції

Актуальність. Перипротезна інфекція є одним із найбільш тяжких ускладнень після тотального ендопротезування кульшових та колінних суглобів, тому визначення кількості лейкоцитів у синовіальній рідині при діагностиці перипротезної інфекції може зменшити кількість сумнівних результатів, що потребують додаткових досліджень. Мета дослідження — проведення клініко-мікроскопічного і біохімічного дослідження рідини, одержаної з колінних та кульшових суглобів після ендопротезування з подальшим визначенням діагностичної чутливості лабораторних показників для ранньої діагностики перипротезної інфекції. Матеріали та методи. Дослідження виконувалось на 53 пацієнтах, яким було проведено 61 оперативне втручання на колінному і кульшовому суглобах. Виконані ендопротезування колінного (n = 41) і кульшового (n = 14) суглобів, дебридмент (n = 6), із них первинних ендопротезувань — 42, ревізійних — 13. Чоловіків було 16, жінок — 37, вік хворих — від 35 до 79 років. Усіх хворих було розподілено на три групи: І група — пацієнти, яким було діагностовано перипротезну інфекцію в термін до 4 тижнів після операції (n = 7); ІІ група — пацієнти, в яких інфекцію було діагностовано при звернені в клініку, але післяопераційний період перебігав без ускладнень (n = 8); ІІІ група — пацієнти, у яких був нормальний перебіг післяопераційного періоду (n = 46). Одержану з колінних та кульшових суглобів рідину досліджували за такими показниками: цитоз, процент нейтрофілів, лімфоцитів, синовіоцитів та макрофагів, вміст загального білка, глікопротеїнів, хондроїтинсульфатів, глюкози, гіалуронової кислоти, С-реактивного білка та інтерлейкінів (ІЛ-1β та -6). Діагностичну чутливість (ДЧ) лабораторних показників розраховували за формулою ДЧ = (ТП/Д) × 100 %, де ТП — істинно позитивні результати дослідження, Д — кількість хворих у групі. Результати. У хворих було встановлено зміни в рідині з колінного та кульшового суглобів за цитологічними та біохімічними показниками на всіх термінах спостереження в післяопераційний період. Висновки. У хворих І групи було встановлено поступове збільшення рівня цитозу та нейтрофілів, загального білка, глікопротеїнів, хондроїтинсульфатів, зниження — лімфоцитів, глюкози і гіалуронової кислоти в післяопераційний період; у ІІ групі хворих рівень цитозу до операції був найвищим, проте після операції з 2-ї до 14-ї доби він суттєво зменшився, кількість нейтрофілів була збільшена до операції та в післяопераційний період; у ІІІ групі хворих рівень цитозу збільшився на 2-гу добу після операції та знизився на 7-му та 14-ту добу, кількість нейтрофілів збільшилась на 2-гу добу після операції, кількість синовіоцитів зменшилась порівняно з показником до операції; ДЧ була найвищою на 2-гу, 7-му та 14-ту добу після операції в показників цитозу, загального білка, С-реактивного білка, гіалуронової кислоти, хондроїтинсульфатів та інтерлейкінів.

Prevalence of idiopathically elevated ESR and CRP in patients undergoing primary total knee arthroplasty as a function of body mass index

BackgroundErythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are commonly used inflammatory markers utilized to aid in the diagnosis of periprosthetic infection (PJI). Patients with obesity, however, are known to have elevated baseline levels of these inflammatory markers. Therefore, this retrospective study aimed to determine the relationship between elevated ESR and CRP and body mass index (BMI) in patients undergoing total knee arthroplasty (TKA). In doing so, physicians can better determine whether BMI should be taken into account when evaluating the prognostic value of elevated preoperative ESR and CRP levels for risk of PJI in primary TKA patients. MethodsThis is a retrospective case series of 181 patients who had undergone primary TKA at a single institution. Patients undergoing primary unilateral TKA were eligible unless they had undergone previous TKA, contralateral knee symptoms, or elevated white blood cell (WBC) count. A linear regression model was utilized to demonstrate the relationship between proportions of patients with elevated biomarker values and categories of BMI. Analysis of variance and independent two-sample t-tests were utilized to assess differences in mean ESR, CRP, and WBC levels between the “healthy patients” and “patients with comorbidities” subgroups within each BMI category. ResultsEligible patients (n = 181) were stratified by BMI category. Elevated ESR was associated significantly with BMI (ESR: r2 = 0.89, P < 0.001) unlike elevated CRP (r2 = 0.82, P = 0.133) and WBC count (r2 = .01; P = .626). No statistically significant differences in ESR values and WBC count between the “healthy patients” versus “patients with comorbidities” were demonstrated within any BMI category. In patients of normal weight (BMI 20–25 kg/m2), “healthy patients” had a statistically significantly higher mean CRP level than “patients with comorbidities” (1.73 mg/L vs. 0.70 mg/L, P < 0.001). There were no other statistically significant differences in mean CRP levels by health status. ConclusionCaution is advised when utilizing ESR and CRP to diagnose periprosthetic joint infection without considering BMI given that increasing preoperative levels of ESR and CRP are correlated with higher BMI.

Diagnosis of Periprosthetic Infection: Recent Developments.

➤ There is no absolute test for the preoperative diagnosis of periprosthetic joint infection (PJI); thus, clinical practice relies on a combination of supportive tests and criteria.➤ Novel serum and synovial tests have improved our ability to diagnose PJI. The 2018 evidence-based algorithm for PJI diagnosis provides weighted scores for serum markers, as well as synovial markers, to facilitate diagnosis when major criteria such as positive cultures or a sinus tract are not present.➤ Culture-independent technologies such as next-generation sequencing can facilitate pathogen identification, particularly in the setting of culture-negative PJI.➤ Despite recent developments, PJI diagnosis remains challenging and warrants further innovation.

Burkholderia pseudomallei peri-prosthetic infection following medial malleolar internal fixation: a case report

BackgroundMelioidosis-associated peri-prosthetic infection is extremely rare. To date, melioidosis associated septic arthritis of the ankle joint following a medial malleolar internal fixation has not been reported.Case presentationWe describe a 49-year-old male with a history of long standing diabetes who presented with fever, constitutional symptoms and right ankle pain for 1 week. Ten years ago, he underwent a medial malleolar screw fixation following a traumatic closed fracture. His initial right ankle radiographs showed no evidence of osteomyelitis. He underwent a wound debridement and washout of the right ankle joint. The peripheral blood and pus from the ankle joint was culture positive for Burkholderia pseudomallei with very high antibody titres. His subsequent radiographs showed features of chronic osteomyelitis. He was treated with a prolonged course of antibiotics and repeated wound debridement. At follow up after 6 months, he had no clinical features of recurrent infection.ConclusionsMelioidosis should be entertained in the differential diagnosis of peri-prosthetic infections in high risk patients.

Оцінка динаміки гематологічних показників для ранньої діагностики періпротезної інфекції у хворих після ендопротезування колінного і кульшового суглобів

Оцінка динаміки гематологічних показників для ранньої діагностики періпротезної інфекції у хворих після ендопротезування колінного і кульшового суглобів

Diagnosis of periprosthetic infections: New tests and techniques

Periprosthetic joint infection of the shoulder is a substantial diagnostic challenge. Much of the difficulty in diagnosis is directly due to the high rates of positive Propionibacterium acnes cultures in both primary and revision shoulder arthroplasty. The purpose of this manuscript is to describe this diagnostic challenge and to review the traditional and emerging options for diagnostic testing.

The role of three-phase 99mTc-MDP bone scintigraphy in the diagnosis of periprosthetic joint infection of the hip and knee

Background/Aim. In the last five decades primary hip and knee arthroplasty is the most common and effective surgical intervention worldwide. Infection, although unfrequented, is the most serious complication. Nuclear medicine imaging, not affected by metallic hardware, is the current imaging modality of choice for the evaluation of suspected joint replacement infection. The aim of this study was to estimate the diagnostic accuracy of three phase 99m technetium methylene diphosphonate (99mTc-MDP) bone scintigraphy in periprosthetic hip and knee joint infection. Methods. Inclusion criteria of patients in the study were suspected knee or hip periprosthetic joint infections. In this study, we examined 45 patients (14 men and 31 women) with 39 hip and 24 knee prosthesis (total 63). In all patients, three-phase bone scintigraphy was performed after intravenous application of 555 MBq of 99mTc-MDP. The final confirmation of infection was microbiological or pathohistology finding. Results. Infection was confirmed in 29 prosthetic joints, in 13 (44.8%) knee and 16 (55.2%) hip joints while there was no infection in 34 prosthetic joints. The connection of different modalities of negative and positive findings 99mTc-MDP three-phase bone scintigraphy with the final confirmation of infection showed a high statistical significance (p &lt; 0.001). Three phase bone scintigraphy showed a high sensitivity of 90% but a modest specificity of 69.7% in the detection of periprosthetic infection with the diagnostic accuracy of 79%. The calculated positive predictive value was 73% but the negative predictive value was high 89%. Our results of three-phase bone scintigraphy with calculated sensitivity, specificity and diagnostic accuracy of 79% are in consent with the majority of published studies, or even slightly better. Conclusion. Bone scintigraphy is sensitive in the diagnosis of periprosthetic infection but insufficiently specific. In the detection of periprosthetic infections three-phase bone scan can be used as a diagnostic method of the first line only aimed at its exclusion. The only reasonable use of bone scintigraphy is in combination with other radionuclide methods with high specificity.

The Rule of Histology in the Diagnosis of Periprosthetic Infection: Specific Granulocyte Counting Methods and New Immunohistologic Staining Techniques may Increase the Diagnostic Value.

Objective:The current study investigates the diagnostic accuracy of the criteria described for frozen sections and whether modern leukocyte specific staining techniques including leukocyte peroxidase and Naphtol-AS-D-chloroacetate-esterase will improve the accuracy of the intra-operative histology.Method:77 patients undergoing revision total hip and knee arthroplasty were included in this retrospective study. Patients were grouped into septic and aseptic based on intraoperative cultures. Tissue samples were analyzed utilizing the Mirra, Feldman, Lonner, Banit and Athanasou criteria.Results:An experienced pathologist had a high specificity (96%), but rather low sensitivity (57%) diagnosing infection. By using the Banit-, Mirra-, or Athanasou-criteria the sensitivity is increased to 0.90. The Feldman- and Lonner-criteria have a lower sensitivity (0.48 and 0.38), however, an increased specificity of 0.96 and 0.98, respectively. The Banit cut off has the highest accuracy (86%). MPOX and NACE staining increased the sensitivity and accuracy up to 100% and 92% respectively.Conclusion:Banit’s cut off is the most accurate histologic criteria to diagnose infection. Modern leukocyte specific staining techniques slightly improve the accuracy. The synovial fluid white blood cell count appears to be the most accurate intraoperative test.

Diagnosis of Periprosthetic Infection - What's Obligation, What's Optional?

Periprothetic infection after primary or revision arthroplasty is of increasing importance. The incidence of infection in primary arthroplasty is approximately 1 %. Revision arthroplasty has higher infection rates, which increase with the number of revision surgeries. Aim of this Paper: An overview of the current diagnosis of periprosthetic infection. This selective analysis is based on a lecture by the author at the DKOU 2015. Periprosthetic infection is taken as having been demonstrated when either two periprosthetic cultures contain the same microorganism, or if there is a fistula communicating with a joint. If only minor criteria are met, the detection of an infection is more difficult. The medical history only provides supporting evidence, especially as regards the course of the pain. Physical examination is more helpful, especially if there is redness, swelling, heat or wound dehiscence. Radiological pathologies, such as osteolysis or bone resorption can only be found in advanced infections. Nuclear medicine scans only possess acceptable sensitivity and specificity in combination with leukocyte scintigraphy. ESR, CRP and leukocyte blood count of the blood are of poor specificity. Important and targeted diagnostic steps include joint aspiration under aseptic conditions, although this exhibits a relatively high rate of false negative results. The conditions for this must be stringently observed. This is usefully complemented by cytological examinations and biopsies for tissue culture. Sensitivity and specificity are then increased. Sonication can significantly enhance the detection of an infection. The leukocyte esterase test is inexpensive and easy to perform and is therefore very much in vogue at the moment; however it is useless if there is contamination with blood. Recent studies indicate that the alpha-defensin test possesses high sensitivity and specificity, but has the disadvantage of being expensive. In patients with suspected periprosthetic infection, the primary aim is either to exclude an infection, or to detect a pathogen. The essential components are careful evaluation of the medical history, accompanied by imaging and laboratory tests. A critical approach is essential. Joint aspiration has become the gold standard in detecting periprosthetic infections. This should be performed in conjunction with a cytological analysis of the synovial fluid. An improvement in sensitivity and specificity can be archived by taking tissue samples. Sonication significantly improves the results. The latter method, the leukocyte esterase test and the alpha-defensin test are optional. The essential components are a rigorous evaluation, a clear algorithm and interdisciplinary collaboration with microbiologists and possibly infectiologists.

Use of anti-granulocyte scintigraphy with 99mTc-labeled monoclonal antibodies for the diagnosis of periprosthetic infections

Use of anti-granulocyte scintigraphy with 99mTc-labeled monoclonal antibodies for the diagnosis of periprosthetic infections

Potential clinical implication of (18) F-FDG PET/CT in diagnosis of periprosthetic infection and its comparison with (18) F-Fluoride PET/CT.

The differentiation between septic and aseptic loosening of prosthetic hip joint is a major challenge for the clinician. This study assessed and compared the diagnostic accuracy of (18) F- flouro-deoxyglucose positron emission tomography/computed tomography ((18) F-FDG PET/CT) with (18) F-fluoride PET/CT for diagnosis of infection in the painful hip prosthesis. In this prospective study, we included the patients with painful hip prostheses with radiological or clinical suspicion of loosening, those who had given the written consent and scheduled for clinical and diagnostic evaluation before revision arthroplasty. To rule out the nature of loosening (septic vs. aseptic), all the patients underwent (18) F-Fluoride PET/CT and (18) F-FDG PET/CT. The reference standard for periprosthetic infection was based on histopathology and/or microbial culture and/or intraoperative findings. We prospectively evaluated 42 patients of hip prostheses before revision arthroplasty. Visual and semi-quantitative analysis of both the positron emission tomography (PET) images was done and the results were compared with a reference standard. The sensitivity, specificity, positive predictive value (PPV), negative predictive values (NPV) and accuracy of (18) F-FDG PET/CT were 93.7%, 92.3%, 88.2%, 96% and 92.8% respectively. The sensitivity, specificity, PPV, NPV and accuracy of (18) F-fluoride PET/CT were 75%, 96.1%, 92.3%, 86% and 88.1% respectively. FDG PET/CT has higher sensitivity, NPV and accuracy as compared to compared to Fluoride PET/CT and comparable specificity and PPV. Fluoride PET/CT had shown slightly higher specificity than FDG-PET/CT, but the overall diagnostic performance of FDG-PET/CT in periprosthetic infection is optimal in routine clinical practice and better than fluoride PET/CT.

Commentary on an evaluation of the role of nuclear medicine in the diagnosis of periprosthetic infections of the hip

Commentary on an evaluation of the role of nuclear medicine in the diagnosis of periprosthetic infections of the hip

Screening with angiographic images prior to 99mTc-HMPAO labelled leukocyte scintigraphy in the diagnosis of periprosthetic infection

AimTo evaluate the impact of the angioscintigrapy of the three phase bone scan as screening method to rule out infection of the hip and knee prosthesis prior to performing the 99mTc-HMPAO leukocyte scintigraphy. Material and methodsA total of 120 (70 women, 50 men; mean age 71±11years) with clinical suspicion of hip (n=63) or knee (n=57) infection of the prosthesis and clinical suspicion of infection were evaluated prospectively. All patients underwent three-phase bone scan (angioscintigraphy, vascular and bone phase) and 99mTc-HMPAO-labeled white blood cell scintigraphy. Final diagnosis of infection was made by microbiological documentation or clinical follow-up for at least 12 months. ResultsEighteen out of 120 patients were diagnosed of infection of hip prosthesis (n=10) or knee prosthesis (n=8). The angioscintigraphy was positive in 15/18 infected cases and in 21/102 of the non-infected cases with a sensitivity of 83%, specificity of 79% and negative predictive value of 97%. Sensitivity and specificity of 99mTc-HMPAO leukocyte scintigraphy were 72% and 95%, respectively. If the leukocyte labeled scintigraphies had been used exclusively for patients with positive angioscintigraphy, this would have saved up to 70% of the 99mTc-HMPAO leukocyte scintigraphies performed. There were no cases of infection with positive labeled leukocyte scintigraphy and negative angioscintigraphy. ConclusionAngioscintigraphy (blood flow phase of bone scan) is a useful technique for screening for hip and knee joint prosthesis infection, significantly reducing the need for 99mTc-HMPAO leukocyte scintigraphy without affecting the sensitivity of the technique.

Diagnosis of periprosthetic hip infections

The diagnosis of periprosthetic infection requires a clear definition itself and structured procedure concerning anamnesis, clinical examination, laboratory findings, puncture and imaging diagnostics. The clinical presentation may vary considerable due to the time of their occurrence as early, delayed, or late infection. Recognition of risk factors and knowledge of differential diagnoses facilitate and confirm the diagnosis. The synovial fluid is assessed with regard to leukocyte count, protein content, and glucose. Intraoperative tissue specimen sampling has to be performed correctly; the histopathological and microbiological studies must be assessed using specific criteria. The examination and classification of periprosthetic membranes make discrimination of the causal pathological mechanism possible, especially distinction between septic and aseptic loosening. In this manner statements with regard to etiology and prosthesis durability are possible. Different causative microorganisms appear postoperatively at specific times. Pathogens that grow as biofilms are of great significance, as they may compound diagnosis and therapy. Early infections are often caused by virulent microorganisms (S. aureus) with acute onset. Delayed (low grade) infections are usually caused by less virulent microorganisms, such as S. epidermidis or coagulase-negative staphylococci. Many diagnostic imaging methods have been used in the assessment of periprosthetic infection: plain radiographs, arthrography, ultrasonography, computed tomography, and magnetic resonance imaging. Nuclear medicine with bone scintigraphy or positron-emission tomography enhance diagnostic capabilities. Cultures of samples obtained by sonication of prostheses are more sensitive than conventional periprosthetic tissue culture. Multiplex PCR of sonication fluid is a promising test for diagnosis of periprosthetic joint infection. The promising diagnostic accuracy for interleukin-6 and procalcitonin has yet not been affirmed.

Leukocyte esterase analysis in the diagnosis of joint infection: can we make a diagnosis using a simple urine dipstick?

Analysis of joint fluid remains a key factor in the diagnosis of periprosthetic infection. Recent reports have shown that neutrophils in infected joint fluid release esterase, an enzyme that is a reliable marker for infection. Testing for leukocyte esterase is routinely done in the analysis of urine for the presence of urinary tract infection, by a simple "dipstick" method. We report our experience with this technique in the evaluation of patients suspected of having septic arthritis or periprosthetic joint infection (PJI) by comparing results of leukocyte esterase positivity with confirmed joint infection as defined by the American Academy of Orthopaedic Surgeons (AAOS). We retrospectively reviewed leukocyte esterase test results performed on synovial fluid aspirated from 57 patients with prosthetic (52) and native (5) joints. Patients either presented with unexplained painful arthroplasties, routine testing of PROSTALAC (PROSthesis with Antibiotic-Loaded Acrylic Cement) orthopedic implants, or clinical suspicion of periprosthetic infection or septic arthritis. Synovial fluid was percutaneously aspirated using a standard technique. The patient age range was 31-91years with a mean age of 69.1years, consisting of 30 women (52.6%) and 27 men (47.4%). The "gold standard" for the presence or absence of infection at our institution and in the study group was based on the most recent recommendations of the AAOS. Positive culture remained the "gold standard" for native joint infection. Of the total 57 joints aspirated and included in the study, 20 (35.1%) were read as positive (2+) on the leukocyte test strip and 37 (64.9%) were read as negative (negative, trace, or 1+). PJI was diagnosed in 19 patients and native joint septic arthritis was identified in one patient. Sensitivities were excellent at 100% with no false negatives in the entire cohort. There was one false positive in the periprosthetic group yielding a specificity, positive predictive value and negative predictive value of 97, 95, and 100%, respectively. The results for the native joints showed markedly less specificity and positive predictive value at 50 and 33%; however, its negative predictive value remained at 100%. Our test results confirm that the leukocyte esterase test can accurately detect PJI and that it can be used as a part of the traditional PJI workup. In the assessment of native joints, its high negative predictive value suggests that it is a valuable tool in excluding native joint septic arthritis.

Emerging Technologies for the Diagnosis of Periprosthetic Infection.

The diagnosis of periprosthetic joint infection remains challenging and relies on a combination of clinical history, physical examination findings, and laboratory tests. The Musculoskeletal Infection Society (MSIS) convened a panel of experts to develop criteria for diagnosing periprosthetic joint infection1. The criteria developed by the workgroup currently represent the most commonly used definition of periprosthetic joint infection. The workgroup identified two major criteria that were indicative of periprosthetic joint infection: (1) the presence of a communicating sinus tract with the prosthesis or (2) the isolation of a pathogen from two different tissue or fluid samples from the joint. In addition, the workgroup identified six minor criteria and indicated that diagnosis of periprosthetic joint infection was very likely when four of the following six criteria were present: (1) an elevated erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) level2, (2) an elevated synovial white blood-cell (WBC) count, (3) an elevated level of synovial polymorphonucleocytes (PMNs), (4) the presence of purulence, (5) the isolation of one pathogen in tissue or fluid, or (6) more than five neutrophils per high-powered field …