Aim. White blood cell (WBC) scintigraphy for diagnosing fracture-related infections (FRIs) has only been investigated in small patient series. Aims of this study were (1) to establish the accuracy of WBC scintigraphy for diagnosing FRIs, and (2) to investigate whether the duration of the time interval between surgery and WBC scintigraphy influences its accuracy. Method. 192 consecutive WBC scintigraphies with . 99m. Tc-HMPAO-labelled autologous leucocytes performed for suspected peripheral FRI were included. The goldstandard was based on the outcome of microbiological investigation in case of surgery, or - when these were not available - on clinical follow-up of at least six months. The discriminative ability of the imaging modalities was quantified by several measures of diagnostic accuracy. A multivariable logistic regression analysis was performed to identify predictive variables of a false-positive or false-negative WBC scintigraphy test result. Results. WBC scintigraphy had a sensitivity of 0.79, a specificity of 0.97, a positive predicting value of 0.91, a negative predicting value of 0.93 and a diagnostic accuracy of 0.92 for detecting an FRI in the peripheral skeleton. The duration of the interval between surgery and the WBC scintigraphy did not influence its diagnostic accuracy; neither did concomitant use of antibiotics or NSAIDs. There were 11 patients with a false-negative (FN) WBC scintigraphy, the majority of these patients (n = 9, 82%) suffered from an infected nonunion. Four patients had a false-positive (FP) WBC scintigraphy. Conclusions. WBC scintigraphy showed a high diagnostic accuracy (0.92) for detecting FRIs in the peripheral skeleton. Duration of the time interval between surgery for the initial injury and the WBC did not influence the results which indicate that WBC scintigraphy is accurate shortly after surgery

Shoulder septic arthritis is uncommon and frequently misdiagnosed, resulting in severe consequences. This study evaluated the demographics, bacteriological profile, antibiotic susceptibility, treatment regimens, and clinical outcomes. This is a 10-year retrospective observational analysis of 30 patients (20 males and 10 females) who were treated for septic arthritis of the shoulder. The data collecting process utilised clinical records, laboratory archives, and x-ray archives. We gathered demographic information, pre- and post-intervention clinical data, serum biochemical markers, and the results of imaging examinations. All patients had a surgical arthrotomy and joint debridement in the operating room, and specimens were taken for culture and sensitivity testing. The specimens were cultivated for at least seventy-two hours. Shoulder joint ranges of motion, comorbidities, and the presence of osteomyelitis were assessed clinically to determine the outcome. All statistical analyses were conducted using the STATA 17 statistical software. Analysis of correlation between categorical variables was performed using the chi-squared test. The majority of the study patients were black Africans (97%). The age range of the group was from 8 days to 17 years. At presentation, 33% of patients had a low-grade fever, whereas the majority (60%) had normal body temperature. The average length of symptoms was 3.9 days (ranged from 1 day to 15 days), and the majority of patients had an increased white cell count (83%) and C-reactive protein (98%). There was accumulation of fluid in the joint of all individuals who received shoulder ultrasound imaging. We noted a significant incidence of gram-positive cocci, which were mostly susceptible to first-line antibiotics. Shoulder stiffness affected 63% of patients and chronic osteomyelitis affected 50% of individuals. Neither the severity nor the duration of the symptoms was related to an increased risk of osteomyelitis. The results of this study revealed that the clinical characteristics and bacterial profile of septic arthritis of the shoulder conform to typical patterns. The likelihood of osteomyelitis and an unfavourable prognosis is considerable

Abstract. Background. Distinction between foot and ankle wound healing complications as opposed to infection is crucial for appropriate allocation of antibiotic therapy. Our aim was to evaluate the diagnostic accuracy of white cell count (WCC) and C-reactive protein (CRP) as diagnostic tools for this distinction in the non-diabetic cohort. Methods. Data were reviewed from a prospectively maintained Infectious Diseases Unit database of 216 patients admitted at Leicester University Hospitals – United Kingdom between July 2014 and February 2020 (68 months). All diabetic patients were excluded. For the infected non-diabetic included patients, we retrospectively retrieved the inflammatory markers (WCCs and CRP) at the time of presentation. Values of CRP 0–10 mg/L and WCC 4.0–11.0 ×109 /L were considered normal. Results. 25 patients met our inclusion criteria. Infections were confirmed microbiologically with positive intra-operative culture results. 7 (28%) patients with foot osteomyelitis (OM), 11 (44%) with ankle OM, 5 (20%) with ankle septic arthritis, and 2 (8%) patients with post-surgical wound infection were identified. Previous bony surgery was identified in 13 (52%) patients. 21 (84%) patients did have raised inflammatory markers while 4 (16%) patients failed to mount an inflammatory response even with subsequent debridement and removal of metalwork. CRP sensitivity was 84%, while WCC sensitivity was only 28%. Conclusion. CRP had good sensitivity, whereas WCC is a poor inflammatory marker in the detection of such cases. In presence of a clinically high level of suspicion of foot or ankle infection, a normal CRP should not rule out the diagnosis of OM

We studied twelve parameters (physical appearance, mucin clot, fibrin clot, white cell count, differential count, red blood cell count, gram stain for bacteria, crystal microscopy, aerobic bacterial culture, anaerobic bacterial culture and ratio between synovial sugar and blood sugar) in over 300 samples of synovial fluid from patients with a variety of suspected pathologies (e.g. infection, inflammatory disease, infection adjacent to a joint, aseptic loosening of a prosthesis). The diagnosis of infection was further established using clinical signs, radiological features, full blood count, C-reactive protein and iron profile. Many of the patients came to surgery. This of course created further opportunity to establish or rule out the diagnosis of infection with greater certainty. Nine of the features of synovial fluid were analysed statistically, including turbidity, diminished viscosity, mucin clot, fibrin clot, total white cell count, polymorphs greater than 60%, bacteria observed on direct microscopy, bacteria yielded by culture and concentration of synovial sugar less than 40% of the simultaneous blood sugar. The positive or negative features of infection were determined to be true or false in the light of the cumulative overall features of infection. The data so obtained was analysed to establish sensitivity, specificity, positive predictive value, negative predictive value and accuracy. The mass of data so obtained cannot be meaningfully expressed in such a brief abstract. Important examples are when culturing synovial fluid there were 44% false negatives or no growth and 56% true positives. Looking at the ratio between synovial sugar and blood sugar we found that taking 40% as the critical value, this was 62% sensitive, the specificity was 89%, the accuracy was 73%, the positive predictive value was 89%, the negative predictive value was 62.4%. However we went further and separated those who were definitely infected or probably infected i.e. Groups 4 & 5 from those who were probably or definitely NOT infected according to the sum of clinical laboratory and radiological parameters. When thus separated the predictive value of a positive result was 100% in Group 4 & 5 and 0% in Group 1 & 2. The predictive value of a negative result in Group 1 & 2 was 98.7% accurate and 22.4% in Group 4 & 5

Guidelines for the use of preoperative blood tests for elective surgery were established. However, there is less evidence and no guidelines regarding using these tests when a young, healthy patient undergoes minor orthopaedic trauma surgery. Bloodwork is often ordered routinely, regardless of medical history or the nature of the injury. We hypothesized that unnecessary blood work is requested for younger pre-operative patients, and their results will not change peri-operative management. This practice is not a judicious use of healthcare resources. This study aimed to evaluate the frequency, type, cost, and impact on clinical decisions if standard preoperative bloodwork was completed in healthy patients requiring surgical management of a minor fracture or dislocation. After the approval of our institutional ethics board, a retrospective chart review was conducted. Inclusion criteria were patients aged 18-60 years, who had an isolated minor orthopaedic trauma requiring outpatient surgery, who were American Society of Anesthesiologists (ASA) class 1. ASA class 1 is defined as “a normal healthy patient, without any clinically important comorbidity and without a clinically significant past/present medical history.” Data records from January 1, 2016, to December 31, 2018, were extracted from a provincial database (the Analytics Data Integration, Measurement and Reporting) for five hospitals. Data including demographics, surgical treatment, type and number of blood tests ordered, and ordering physician were collected. Any abnormal test results were checked to see whether they led to a change in patient management or related to a postoperative adverse event. Independent samples t-tests and Chi-square tests were used to compare the characteristics of patients who had preoperative bloodwork versus those who did not. The cost of preoperative blood work was estimated. During these two years, 627 patients met inclusion criteria, and 27% (n=168) of these patients had bloodwork completed pre-operatively, while only 34% (n=57) of these had one or more abnormal laboratory parameters. These abnormalities were minor and did not alter clinical management or result in repeated bloodwork peri-operatively. Patients who had bloodwork were significantly older (40.2 years) compared with patients without preoperative blood work (37.8 years; p=0.03), but there was no difference in sex between those who had bloodwork (53.4% male) and those who did not (51.4% male; p=0.63). The most common blood test ordered was a complete blood count, and the most commonly abnormal result was a mildly elevated white blood cell count (19%; n= 29). The most common patients to receive bloodwork were those with ankle (34%) and distal radius (34%) fractures. The bloodwork was primarily ordered by clinical associates (26%; n=46) and emergency department physicians (22%; n=38). Without considering lab personnel, consumables, and analysis time, the cost of this bloodwork was approximately $7685, an average of $45 per patient. Pre-operative bloodwork in young, healthy, asymptomatic patients requiring outpatient surgery for minor orthopaedic trauma had no clinical significance and did not change patient management. Rigorous prospective research is warranted to establish national guidelines for appropriate pre-operative bloodwork ordering to minimize unnecessary and costly investigations

Aim. The diagnosis of septic arthritis mostly relies on clinical examination, several blood parameters including white blood cell count, C-reactive protein, sedimentation, and the analysis of the joint aspiration. However, the diagnosis can be difficult when the symptoms are vague and the information obtained from laboratory might be insufficient for definitive diagnosis. This study aimed to evaluate several ratios obtained from routine blood tests for a possible use in the diagnosis of septic arthritis. Method. The adult patients who were operated in our clinic due to septic arthritis between 2014–2020 were identified and retrospectively evaluated. The patients with any blood disorders or missing file information were excluded. A total of 36 patients were found to be eligible for inclusion. The control group included 40 patients without any sign of infection who underwent total knee arthroplasty due to knee osteoarthritis. Preoperative blood tests of each patients were examined. In addition to CRP and sedimentation values, neutrophil-lymphocyte, monocyte-lymphocyte, platelet-lymphocyte, and platelet count-mean platelet volume were calculated and receiving operating characteristics (ROC) curve analysis was made to determine the sensitivity, specificity and area under curve (AUC) values of these parameters. Results. The distribution of affected joint in septic arthritis group was as follow; 22 knees, 6 hips, 4 shoulders, 2 elbows, 1 wrist and 1 ankle. The cultures of joint aspiration yielded positive result in 19 patients while the cultures were negative in 17 patients. All of the analyzed parameters were significantly different between the groups (p<0.001). ROC curve analysis results are given in detail, in Table 1 and Figure 1. The AUC value was 97.3 when only CRP and sedimentation values were used but increased to 98.6 when neutrophile/ lymphocyte ratio was added and increased to 100 when all analyzed parameters were included. Conclusions. The analyzed parameters were found to increase the overall sensitivity and specificity when used together with acute phase reactants. However, when evaluated separately, CRP and sedimentation were still found as the most valuable parameters in the diagnosis of septic arthritis. In the diagnosis of septic arthritis, 35 mm/hr cut-off value for sedimentation and 10 mg/L cut-off value for CRP were found more sensitive and specific compared to standard laboratory cut-off values of 20 mm/hr and 5 mg/L. For any tables or figures, please contact the authors directly

While advances in laboratory and imaging modalities facilitate the diagnosis of periprosthetic joint infection (PJI), clinical suspicion and a thorough history and physical remain the basis of evaluation. If clinical suspicion is high, the evaluation should be more vigorous, and vice versa. The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are inexpensive as well as ubiquitous, and should be obtained as a preliminary screening tool. These tests have been found to be cost-effective and highly sensitive. If both tests are negative, there is a low risk of periprosthetic joint infection (i.e., good negative predictive value). Positive results on both tests, in contrast, are not as specific but again raise suspicion. When either the ESR or CRP is elevated, or if the clinical suspicion for infection is high, aspiration of the knee joint is suggested. Synovial fluid should be sent for a synovial fluid white blood cell count (WBC), differential and culture. Given the ability to get three data points from one intervention, arthrocentesis, is the best single maneuver the physician can perform to rule in or out PJI. The synovial fluid WBC count has demonstrated in multiple studies excellent specificity and sensitivity in the diagnosis of infection. Based on multiple recent studies, the proceedings of the International Consensus on PJI recommend cut-offs for the synovial fluid WBC count as >3000 cells/mL and > 80% neutrophils for the differential. Synovial fluid biomarkers represent an expanding area of clinical interests based on the unique cascade of gene expression that occurs in white blood cells in response to pathogens. Deirmegian et al. described the unique gene expression and biomarker production by neutrophils in response to bacteria that are detectable in synovial fluid. Specifically, alpha-defensin is one such antimicrobial peptide. Along with synovial CRP, alpha-defensin can be measured in a currently commercially-available immunoassays. The diagnosis of PJI can be difficult to make in spite of the variety of tests available. That being said, the diagnosis is easily made in our experience in 90% of patients by getting an ESR and CRP followed by selective aspiration of the joint if these values are elevated or if the clinical suspicion is high. Synovial fluid obtained should be sent for a synovial fluid WBC count, differential and cultures

Aim. Although established serum inflammatory biomarkers, such as serum C-reactive protein (CRP) and serum white blood cell count (WBC), showed low accuracies in the literature, they are still commonly used in diagnosing periprosthetic joint infections (PJI). For a sufficient preoperative diagnosis novel more accurate serum parameters are needed. The aim of our study was to evaluate the performances of the established and novel routinely available serum parameters in diagnosing periprosthetic joint infections when using the proposed European Bone and Joint Infection Society (pEBJIS) criteria. Method. In this retrospective study, 177 patients with an indicated revision surgery after a total joint replacement were included from 2015 to 2019. The easily accessible and routinely available serum parameters CRP, WBC, the percentage of neutrophils (%N), the neutrophils to lymphocytes ratio (NLR), fibrinogen and the platelet count to mean platelet volume ratio (PC/mPV) were evaluated preoperatively. The performances were examined via receiver operating characteristic (ROC) curve analysis (AUC). The curves were compared using the z-test. Seventy-five cases (42%) showed a PJI based on the pEBJIS-criteria. Results. The sensitivities of serum CRP (cut-off: ≥10mg/L), WBC (≥10×10^9 cells/L), %N (≥69.3%), NLR(≥ 3.82), fibrinogen (≥ 457 mg/dL), and PC/mPV (≥ 29.4) were calculated with 68% (95% CI: 57–78), 36% (26 – 47), 66% (54 – 76), 63% (51 – 73), 69% (57 – 78), and 43% (32 – 54), respectively. Specificities were 87% (79 – 93), 89% (81 – 94), 67% (57 76), 73% (63 – 81), 89% (80 – 93), and 81% (72 – 88), respectively. Serum CRP and fibrinogen showed better performances than the other evaluated serum parameters (p<0.0001). The median serum CRP (17.6 mg/L) in patients with PJI caused by a low virulence microorganism was lower compared with infections caused by high virulence organisms (49.2 mg/L; p=0.044). Synovial fluid leucocyte count and histology showed better accuracies than serum CRP, serum WBC, %N, NLR, serum fibrinogen, and PC/mPV (p<0.0001). Conclusions. Although serum CRP and fibrinogen showed the best performances among the evaluated serum inflammatory markers, their results should be interpreted with caution in clinical practice. Serum parameters may remain normal in chronic infections or may be elevated in patients with other inflammatory conditions. In addition, they also correlated poorly with synovial fluid leukocyte count and histology. Therefore, serum parameters are still insufficient to confirm or exclude a periprosthetic joint infection. Hence, they can only be recommended as suggestive criteria in diagnosing PJI

Aim. Diagnosing Fracture-Related Infections (FRI) is challenging. White blood cell (WBC) scintigraphy is considered the best nuclear imaging technique to diagnose FRI; a recent study by our group found a diagnostic accuracy of 92%. However, many centers use . 18. F-fluorodeoxyglucose positron emission tomography/computed tomography (. 18. F-FDG-PET/CT) which has several logistic advantages. Whether . 18. F-FDG-PET/CT has better diagnostic performance than white blood cell (WBC) scintigraphy is uncertain. Therefore, we aimed: 1) to determine the diagnostic performance of . 18. F-FDG-PET/CT for diagnosing FRI (defined as infection following an open fracture or fracture surgery) and 2) to determine cut-off values of standardized uptake values (SUV) that result in optimal diagnostic performance. Method. This retrospective cohort study included all consecutive patients who received . 18. F-FDG-PET/CT to diagnose FRI in two level 1 trauma centers. Baseline demographic- and surgical characteristics were retrospectively reviewed. The reference standard consisted of at least 2 representative microbiological culture results or the presence or absence of clinical confirmatory FRI signs in at least 6 months of clinical follow-up. A nuclear medicine specialist, blinded to the reference standard, re-reviewed all scans. Additionally, SUVs were measured using the “European Association of Nuclear Medicine Research Ltd. (EARL)” reconstructed . 18. F-FDG-PET/CT scans. Volume of interests were drawn around the suspected- and corresponding contralateral area to obtain the absolute values (SUVmax) and the ratio between suspected and contralateral area (SUVratio). Diagnostic accuracy of the re-reviewed scans was calculated (sensitivity and specificity). Additionally, diagnostic characteristics of the SUV measurements were plotted in the area under the receiver operating characteristics curve (AUROC). The sensitivity and specificity at the optimal threshold was deducted from the AUROC with the Q-point method. Results. 158 . 18. F-FDG-PET/CTs were included. Mean age was 46.2 years, 71.5% was male. Most cases (56.3%) were tibial shaft- or ankle fractures. Sixty patients (38.0%) had FRI. The sensitivity and specificity of the FDG-PET/CT scan was 70.0% (95% CI 56.8–81.2) and 79.6% (95% CI 70.3–87.1) respectively. Diagnostic accuracy was 76.0% (95% CI 68.5–82.4). AUROCs of SUVmax and SUVratio were 0.80 (95% CI 0.73–0.87) and 0.73 (95% CI 0.64–0.81), respectively. The optimal SUVmax threshold of 4.2 resulted in 80.0% sensitivity and 71.3% specificity, while an SUVratio of 2.9 resulted in 58.3% sensitivity and 80.9% specificity. Conclusions. The . 18. F-FDG-PET/CT has a sensitivity of 70.0%, specificity of 79.6% and a diagnostic accuracy of 76.0%. This makes . 18. F-FDG-PET/CT less accurate than WBC scintigraphy in diagnosing FRI, although adding SUV measurements may possibly increase its diagnostic accuracy

Aim. One of the most accurate and inexpensive tests in detection of prosthetic joint infection (PJI) is synovial fluid white blood cell (WBC) count and differential. Since leukocytes produce many different interleukins (IL) in situation of PJI, we hypothesized that ILs could be even more accurate in detection of PJI. The aim of the study was to test, if the synovial fluid IL-6 level is superior to WBC count and differential in detection of PJI. Methods. Unselected patients undergoing total hip or knee revision surgery were prospectively included. In perioperative assessment phase, WBC count, differential and IL-6 levels of synovial fluid were measured. Patients were labelled as positive or negative according to the predefined cut-off values for IL-6 (230pg/ml) and WBC count with differential (1,7 × 10. 9. WBC/ml with ≥65% of granulocytes). During the surgery, at least 4 intraoperative samples for microbiological and one for histopathological analysis were obtained. PJI was defined as presence of sinus tract, inflammation in histopathological samples, and growth of the same microorganism in at least two or more samples of periprosthetic tissue or synovial fluid. Binary diagnostic test was performed to check the diagnostic strength of both methods in detection of PJI. Results. 49 joints of 48 patients (mean age, 71 years; 53% females) undergoing artificial hip (n = 24) or knee (n = 25) revision surgery were included. 11 joints (22%) were infected. Sensitivity of synovial fluid WBC count with differential was 82%, specificity 97%, accuracy 94%, positive and negative predictive values were 90% and 95%, respectively. Sensitivity of IL-6 level was 73%, specificity 95%, accuracy 90%, positive and negative predictive values were 80% and 92%, respectively. There was a strong statistical agreement between both tests (Kappa value=0.749) and consequently there was no significant difference in detection of PJI comparing both tests (P=0.171). Conclusion. Our study revealed that synovial fluid IL-6 level is not superior to synovial fluid WBC count with differential in detecting PJI

Drainage from the knee wound after TKA is an obvious concern for the arthroplasty surgeon. One of the inherent problems with a total knee arthroplasty is there is a focus on obtaining maximum range of motion but at the same time the wound needs to heal in a timely fashion. Consistent knee drainage after a TKA is a source of concern. The quantity and quality of drainage needs to be assessed and there are certain questions that need to be answered including: 1) Is there bloody drainage which suggests fascial dehiscence?; 2) Is the patient too active?; 3) Is the drainage in some way related to DVT prophylaxis?; 4) Is the patient obese and could the drainage be secondary to fat necrosis or seroma? and 5) Is the drainage suggestive of an infection? The work-up can include C-reactive protein and sed rate, and possibly a knee aspiration. In general, C-reactive protein >100mg/L within the first six weeks after surgery suggests the presence of an infection. The sed rate is generally not useful in the early post-operative period. In the first six weeks after surgery if the number of white cells in the aspiration is >10,000 this suggests infection especially if there are 80–90% polymorphonuclear cells. Each day of prolonged wound drainage is noted to increase the risk of infection by 29%. Morbid obesity has been shown to be an independent risk factor for infection. Some anticoagulants (i.e. low molecular weight heparin) have been associated with increased wound drainage. In a retrospective review of 11,785 total joint arthroplasties, 2.9% of joints developed wound drainage, and of these patients, 28% required further surgery. It was noted that patients that were malnourished had a 35% failure rate with respect to controlling the drainage and preventing infection versus 5% in patients that were healthy. The International Consensus Conference on Infection concluded that a wound that has been persistently draining for greater than 5–7 days requires surgical intervention. The available literature provides little guidance regarding the specifics of this procedure. In general, if the wound is draining or is red, rest the leg for a day or two. In some instances a bulky Jones dressing can be helpful. If the drainage persists one could consider using a negative pressure dressing (wound vac) but there is little data on efficacy after TKA. If there is persistent drainage or cellulitis, then operative intervention is probably necessary. Evaluation of CRP and a knee joint aspiration can be helpful. The decision to return to the OR should be made within the first 7 days after the surgery. At the time of the procedure one will need to decide to perform either a superficial washout versus a washout and polyethylene exchange

Drainage from the knee wound after TKA is an obvious concern for the arthroplasty surgeon. One of the inherent problems with a total knee arthroplasty is there is a focus on obtaining maximum range of motion but at the same time the wound needs to heal in a timely fashion. Consistent knee drainage after a TKA is a source of concern. The quantity and quality of drainage needs to be assessed and there are certain questions that need to be answered including: 1) Is there bloody drainage which suggests fascial dehiscence?; 2) Is the patient too active?; 3) Is the drainage in some way related to DVT prophylaxis?; 4) Is the patient obese and could the drainage be secondary to fat necrosis or seroma? and 5) Is the drainage suggestive of an infection? The work up can include C-reactive protein and sed rate, and possibly a knee aspiration. In general, C-reactive protein >100 mg/L within the first six weeks after surgery suggests the presence of an infection. The sed rate is generally not useful in the early post-operative period. In the first six weeks after surgery if the number of white cells in the aspiration is >10,000 this suggests infection especially if there are 80–90% polymorphonuclear cells. Each day of prolonged wound drainage is noted to increase the risk of infection by 29%. Morbid obesity has been shown to be an independent risk factor for infection. Some anticoagulants (i.e. low molecular weight heparin) have been associated with increased wound drainage. In a retrospective review of 11,785 total joint arthroplasties, 2.9% of joints developed wound drainage, and of these patients, 28% required further surgery. It was noted that patients that were malnourished had a 35% failure rate with respect to controlling the drainage and preventing infection versus 5% in patients that were healthy. The International Consensus Conference on Infection concluded that a wound that has been persistently draining for greater than 5–7 days requires surgical intervention. The available literature provides little guidance regarding the specifics of this procedure. In general, if the wound is draining or is red, rest the leg for a day or two. In some instances a bulky Jones dressing can be helpful. If there is persistent drainage or cellulitis, then operative intervention is probably necessary. Evaluation of CRP and a knee joint aspiration can be helpful. The decision to return to the OR should be made within the first 7 days after the surgery. At the time of the procedure one will need to decide to perform either a superficial washout versus a washout and polyethylene exchange

The infected joint arthroplasty continues to be a very challenging problem. No test has 100% diagnostic accuracy for PPI and the treating surgeon must correlate the clinical and radiographic presentation with a combination of blood tests, synovial fluid analysis, microbiological and histopathological evaluation of periprosthetic tissue and intra-operative inspection to reach a definitive diagnosis. Diagnosis should begin with a high index of suspicion for new onset of pain or symptoms in well-functioning joints. Plain radiographs may identify osteolysis or early signs of implant failure and should be promptly investigated further for PPI. Peripheral blood ESR and CRP remain the most widely used next step for the diagnosis of PPI. Both these tests are widely available, inexpensive, and have a rapid turnaround time in laboratories. The results should be interpreted with caution due to their relative lack of specificity. The sensitivity and specificity values for CRP are approximately 88 and 74%, respectively; while that of ESR is slightly lower at 75 and 70%, respectively. The combined ESR and CRP tests are 96% sensitive for ruling out PPI but the specificity of this combination is as low as 56%. Advanced imaging modalities may be used as a part of the diagnostic algorithm. However, they require expert interpretation and are limited by availability and high costs. When available they have high sensitivity and specificity but their routine use is not recommended and indications have to be individualised in the light of clinical presentation. In the presence of high clinical suspicion, the clinician should plan synovial fluid analysis. This provides a synovial fluid white cell count with differential cell count, specimen for culture and possibility of analyzing other synovial fluid markers. It is important to note that failed metal-on-metal hip arthroplasties can give a falsely elevated synovial fluid cell count when using automated cell counters. This can be overcome by manually counting cell numbers. Synovial fluid should be directly into blood culture bottles, and antibiotics should be withheld at least 2 weeks prior to aspiration, whenever possible. Cultures also help establish the organism, virulence and sensitivities that help plan subsequent treatment algorithm. Periprosthetic tissue biopsy provides valuable information in microbiological diagnosis and workup of PPI. Routine use of gram staining is not recommended due to poor sensitivity. However, frozen section may have some role especially when performed by a skilled pathologist. Tissue culture remains the gold standard for diagnosis despite false-positive and false-negative results. Whenever possible multiple samples should be obtained to aid interpretation. A threshold of 2 to 3 positive specimens yielding indistinguishable microorganisms has been recommended to improve sensitivity. Acute inflammation, evidenced by neutrophilic infiltrate on fixed or frozen tissue, is suggestive of PPI and is defined as the presence of at least 5 neutrophils per high-powered field, in at least 5 separate microscopic fields. Sonication of removed prosthetic components is used to dislodge the biofilm and the associated bacteria from the surface of the implant. The fluid surrounding the implant can be used for culture or analysis. PCR testing: Synovial fluid aspirate, periprosthetic tissue or sonicate fluid may be subject to molecular diagnosis to amplify genetic material and improve microbiological diagnosis of PPI. This technique has shown increased sensitivity in patients who had received antibiotics within 14 days before implant removal. Results have to carefully interpreted with due consideration for possibility of false positive results

Introduction. A previous study in South Africa showed the prevalence of HIV related osteo-articular sepsis in children to be around 20% with a high prevalence of Streptococcus pneumoniae (38%) in HIV positive patients. This initial study was conducted at the same time that the polyvalent S pneumoniae vaccine was introduced to the EPI in South Africa (2009). The aim of the current study was to review the epidemiology of osteo-articular infections at two hospitals after the introduction of this vaccine. Methods. A retrospective review of patients presenting to two hospitals, between July 2009 and January 2013, with acute osteo-articular sepsis and pus at arthrotomy. The NHLS laboratory results were reviewed for microscopy, culture and sensitivity as well as white cell count (WCC), C reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Results. A total of 100 cases of acute osteo-articular sepsis were identified during this period. The prevalence of HIV was 15%. The most common bacterial isolate was Staphylococcus aureus (22%). There were no Streptococcus pneumoniae isolates grown in either of the two groups. There was no difference in the WCC, CRP and ESR between the HIV negative and positive groups. Conclusion. We have seen a dramatic shift in the bacteriology in paediatric patients with osteo-articular sepsis since the original study in 2009. The incidence of HIV in our study population has declined. This may be due to the introduction of mother to child transmission programmes and increased use of anti-retrovirals. Staphylococcus aureus is now the most common isolated organism in patients with osteo-articular sepsis, regardless of HIV status. The empiric antibiotic therapy of choice in paediatric patients with osteo-articular sepsis remains Cloxacillin. NO DISCLOSURES

The infected joint arthroplasty continues to be a very challenging problem. No test has 100% diagnostic accuracy for PPI and the treating surgeon must correlate the clinical and radiographic presentation with a combination of blood tests, synovial fluid analysis, microbiological and histopathological evaluation of periprosthetic tissue and intra-operative inspection to reach a definitive diagnosis. Diagnosis should begin with a high index of suspicion for new onset of pain or symptoms in well-functioning joints. Plain radiographs may identify osteolysis or early signs of implant failure and should be promptly investigated further for PPI. Peripheral blood ESR and CRP remain the most widely used next step for the diagnosis of PPI. Both these tests are widely available, inexpensive, and have a rapid turnaround time in laboratories. The results should be interpreted with caution due to their relative lack of specificity. The sensitivity and specificity values for CRP are approximately 88 and 74%, respectively; while that of ESR is slightly lower at 75 and 70%, respectively. The combined ESR and CRP tests are 96% sensitive for ruling out PPI but the specificity of this combination is as low as 56%. Advanced imaging modalities may be used as a part of the diagnostic algorithm. However, they require expert interpretation and are limited by availability and high costs. When available they have high sensitivity and specificity but their routine use is not recommended and indications have to be individualised in the light of clinical presentation. In the presence of high clinical suspicion, the clinician should plan synovial fluid analysis. This provides a synovial fluid white cell count with differential cell count, specimen for culture and possibility of analyzing other synovial fluid markers. It is important to note that failed metal-on-metal hip arthroplasties can give a falsely elevated synovial fluid cell count when using automated cell counters. This can be overcome by manually counting cell numbers. Synovial fluid should be directly into blood culture bottles, and antibiotics should be withheld at least 2 weeks prior to aspiration, whenever possible. Cultures also help establish the organism, virulence and sensitivities that help plan subsequent treatment algorithm. Periprosthetic tissue biopsy provides valuable information in microbiological diagnosis and workup of PPI. Routine use of gram staining is not recommended due to poor sensitivity. However, frozen section may have some role especially when performed by a skilled pathologist. Tissue culture remains the gold standard for diagnosis despite false-positive and false-negative results. Whenever possible multiple samples should be obtained to aid interpretation. A threshold of 2 to 3 positive specimens yielding indistinguishable microorganisms has been recommended to improve sensitivity. Acute inflammation, evidenced by neutrophilic infiltrate on fixed or frozen tissue, is suggestive of PPI and is defined as the presence of at least 5 neutrophils per high-powered field, in at least 5 separate microscopic fields. Sonication of removed prosthetic components is used to dislodge the biofilm and the associated bacteria from the surface of the implant. The fluid surrounding the implant can be used for culture or analysis. PCR testing: Synovial fluid aspirate, periprosthetic tissue or sonicate fluid may be subject to molecular diagnosis to amplify genetic material and improve microbiological diagnosis of PPI. This technique has shown increased sensitivity in patients who had received antibiotics within 14 days before implant removal. Results have to carefully interpreted with due consideration for possibility of false positive results

Purpose and Introduction. The burden of Tuberculosis (TB) in South Africa is significant with recent reports showing an increase in the incidence of multi-drug resistant (MDR) TB. Little is known of the incidence and epidemiology, especially of MDR Tuberculous arthritis in children in the South African setting. The purpose of this study is to identify the number of TB cases identified with positive histology, culture and sensitivity. Methods. A retrospective review of laboratory results of children under the age of 14 years with Tuberculous arthritis at a South African Hospital between January 2008 and December 2012 was performed. The data was extracted from the NHLS data base for all synovium, bone or joint fluid collected for TB culture, sensitivity and histology. Results. Over a five year period positive cultures were found in ten patients. Of these ten patients five were sensitive and two were resistant to Isoniazid and Rifampicin using polymerase chain reaction (PCR) testing. Three had no sensitivity requested. Positive histology was found in nine of these patients consisting of chronic granulomata. The mean white cell count was 9 X ?10?∘9cells/l (Range 5–20), mean C reactive protein was 22 mg/l (Range 2–57) and mean erythrocyte sedimentation rate was 36 mm/hr (Range 8–70). Four of the ten patients had HIV testing – they were all negative. Conclusions. This study shows good correlation between positive TB culture and histology. The high prevalence of MDR TB (20%) in these patients is of major concern with further alarm regarding the appropriate treatment of these patients if sensitivities are not routinely checked. Emphasis must be placed on requesting and following up sensitivity testing in these patients. NO DISCLOSURES

Salmonella osteomyelitis occurs infrequently in children without a sickle cell disease, and its subacute form is rare. Diagnosis is often delayed because its slow onset, intermittent pain and it can be confused with bone tumors. An otherwise healthy 13-year-old boy was admitted from another center in order to discard bone tumor in proximal tibia, with compatible radiologic findings. There was no history of trauma or previous illness. Twenty days ago, he had flu symptoms and myalgia. On the physical examination the child was feverless, showed increased heat over his left knee, considerable effusion and painful restriction of movement. Inflammatory laboratory results revealed erythrocyte sedimentation rate 46mm/h and C-Reactive protein, 11,2 mg/L. Radiographs revealed a lytic lesion localized in the proximal metaphysis and epiphysis. The MRI showed an area of edema around the lytic lesion and surrounding soft tissues. Images supported the diagnosis of subacute osteomyelitis, (Brodie abscess). Empirically, intravenous cefuroxime was started. Forty-eight hours post admission, the patient underwent abscess surgical debridement, washout and cavity curettage. Samples were sent for cytology, culture and sensitivity and acid fast bacilli culture and sensitivity. Collection´s count cell was 173.000/ L white cells. Collection´s culture revealed Salmonella B sensitive to ciprofloxacin. Stool culture did not yield any growth. Intravenous cefuroxime was administered during 10 days. The patient responded well as evidenced by clinical and laboratory improvement He was discharged with his left leg immobilized in a cast during 1 month and treatment was completed with oral ciprofloxacin 500mg /12 h during 2 months. The patient had full range of knee motion after 2 months. Last reviewed, after two years of the income, he was completed recovered, and the radiograph showed bone healing without physeal neither damage nor limb leg discrepancy. The most effective therapy of a confirmed salmonella osteomyelitis is a combination of radical operative intervention and targeted intravenous antibiotics as in our case. Faced with a subacute osteomyelitis, we have to remember that it may mimic bone tumors. We highlight the isolation of Salmonella B in a patient without sickle cell disease

Background. The diagnosis of Periprosthetic Joint Infection (PJI) is a considerable challenge in total joint arthroplasty. The mainstay for diagnosis of PJI is a combination of serological markers, including C-reactive protein (CRP), along with joint aspirate for white cell count, differential and culture. The aim of this study was to examine the use of synovial fluid CRP in the diagnosis of PJI. Material & Methods. Synovial fluid samples were collected prospectively from patients undergoing primary and revision knee arthroplasty. Samples were assessed for CRP, cell count and differential. Three groups were analyzed; those undergoing primary knee arthroplasty, aseptic knee arthroplasties and infected arthroplasties. Demographic data, along with associated medical co-morbidities, were collected,. Statistical analysis was performed. Synovial fluid CRP was correlated with serum CRP values. Sensitivity and specificity were calculated. Results. 50 synovial fluid samples were collected from 50 patients. Synovial fluid CRP was 0.3 +/− 0.4 in native knees, 0.2 +/− 0.5 in aseptic knee arthroplasties, 4.3+/−4.1 in patients with infected knee arthroplasties. Synovial fluid CRP was significantly higher in septic total knee arthroplasties by comparison to both aseptic total knees (p< 0.001) and native knees (p=0.006). The specificity was 100% and the sensitivity was 89% at a CRP of 1. Conclusion. While this is preliminary data, synovial fluid CRP was found to be significantly elevated in patients with infected total knee arthroplasties. This test is easily performed under routine hospital laboratory conditions without specific, expensive assays. We believe synovial CRP assay holds great promise as a new, potentially low-cost, diagnostic marker for PJI

Background. Osteomyelitis can be difficult to diagnose. Unlike septic arthritis no defined diagnostic criteria exist as a guide. Inflammatory markers are frequently utilized at initial presentation, (in addition to white cell count). Methods. All radiologically confirmed cases of long bone osteomyelitis without septic arthritis, joint effusion or abscess, in paediatric patients, presenting to one hospital over an eighteen-month period were included. These patients were compared with all culture positive septic arthrides presenting to the same hospital within the same time period. Inflammatory markers taken on the day of admission were studied. Results. Thirty-seven patients with long bone osteomyelitis and thirteen with culture positive septic arthritis were identified. The two groups were comparable with regards to age and gender. At presentation 65% of the osteomyelitis patients had an ESR less than 40mm/hour, 48% below 20mm/hour and 19% within the normal range. 23% of the septic arthritis patients had an ESR below 40mm/hour, and none had an ESR below 20mm/hour or in the normal range. The CRP was in the normal range in 46% of the osteomyelitis patients and none of the septic arthritis patients. The average ESR and CRP in the osteomyelitis patients were 47mm/hour and 35mg/L respectively, while in the septic arthritis group these were 72mm/hour, (P< 0.021), and 107mg/L, (P< 0.028). Conclusions. The initial rise in inflammatory markers due to long bone osteomyelitis is significantly less than that in septic arthritis. A proportion of patients presenting with osteomyelitis have normal inflammatory markers at presentation. A high index of suspicion is required in diagnosing osteomyelitis, and inflammatory markers, while a useful adjunct to monitoring treatment, may offer false reassurance regarding the initial diagnosis

A randomised controlled pre-clinical trial utilising an existing extremity war wound model compared the efficacy of saline soaked gauze to commercial dressings. The Flexor Carpi Ulnaris of anaesthetised New Zealand rabbits was exposed to high-energy trauma using computer-controlled jig and inoculated with 10. 6. Staphylococcus aureus 3 hours prior to application of dressing. After 7 days the animals were culled. Quantitative microbiological assessment of post-mortem specimens demonstrated statistically significantly reduced S aureus counts in groups treated with iodine or silver based dressings (2-way ANOVA p< 0.05). Clinical observations and haematology were performed during the study. Histopathological assessment of post-mortem muscle specimens included image analysis of digitally scanned haematoxylin and eosin stained tissue sections and subjective semi-quantitative assessment of pathology severity using light microscopy to grade muscle injury and lymph node activation. Tissue samples were also examined using scanning electron microscopy to determine the presence of bacteria and biofilm formation within the injured muscle. Non-parametric data were compared using Kruskal-Wallis. There were no bacteraemias, significantly raised white cell counts, abscesses, purulent discharge or evidence of contralateral axillary lymph node activation. All injured muscle specimens showed evidence of haemorrhage, inflammatory cell infiltration and fibrosis. All ipsilateral axillary lymph nodes were activated. There were no significant differences in the amount of muscle loss, size of the activated lymph nodes or in subjective semi-quantitative scoring criteria for muscle injury or lymph node activation. There was no evidence of bacterial penetration or biofilm formation. This study demonstrated statistically significant reductions in Staphylococcus aureus counts associated with iodine and silver dressings, and no evidence that these dressings cause harm. This was a time-limited study which was primarily powered to detect reduction in bacterial counts; however, there was no significant variation in secondary outcome measures of local or systemic infection over 7 days