Aim. Differentiation of infected (INF) nonunion from aseptic (AS) nonunion is crucial for the choice of intra- and postoperative treatment. Preoperative diagnosis of infected nonunion is challenging, especially in case of low-grade infection lacking clinical signs of infection. Standard blood markers such as C-reactive protein or leucocyte count do not aid in preoperative diagnosis. Proteomic profiling has shown promising results for differentiation of numerous chronic disease states, and in this study was applied to preoperative blood samples of patients with nonunion in an attempt to identify potential biomarkers. Method. This prospective multicenter study enrolled patients undergoing revision surgery of femur or tibia nonunion. Patients with implant removal after regular fracture healing (HEAL) were included as a control-group. Preoperative blood samples, intraoperative tissue samples, sonication of osteosynthesis material and 1-year-follow-up questionnaire were taken. Nonunion patients were grouped into INF or AS after assessing bacterial culture and histopathology of retrieved samples. Diagnosis of infection followed the fracture related infection consensus group criteria, with additional consideration of healing one year after revision surgery. Targeted proteomics was used to investigate a predefined panel of 45 cytokines in preoperative blood samples. Statistical differences were calculated with Kruskal Wallis and Dunn's post hoc test. Cytokines with less than 80% of samples being above the lower limit of detection range (LLDR) were excluded for this study. Results. We recruited 62 AS, 43 INF and 32 HEAL patients. Patients in the two nonunion groups (INF and AS) did not differ concerning smoking, diabetes or initial open or closed fracture. Thirty-two cytokines were above LLDR in >80% of patients. INF patients showed a significant difference in expression of 8 cytokines compared to AS, with greatest differences observed for Macrophage Colony Stimulating Factor 1 (MCSF-1) and Hepatocyte Growth Factor (HGF) (p<0.01). In comparing AS with HEAL patients, 9 cytokines displayed significant differences, including interleukin (IL)-6, Vascular Endothelial Growth Factor A (VEGFA), Matrix Metalloproteinase 1 (MMP-1). Comparison of INF with HEAL patients revealed significantly different expression of 20 cytokines, including. IL-6, IL-18, VEGFA or MMP-1. Conclusions. Our study revealed differences in plasma cytokine profile of blood samples from INF and AS patients. Although no single biomarker is sufficient to differentiate these patients preoperatively in isolation, future multivariant analysis of this cytokine data in combination with clinical characteristics may provide valuable diagnostic insights. Funded by German Social Accident Insurance (FF-FR 0276) and AO Trauma (AR2021_04)

Routine post-operative bloods following all elective arthroplasty may be unnecessary. This retrospective cohort study aims to define the proportion of post-operative tests altering clinical management. Clinical coding identified all elective hip or knee joint replacement under Hawkes Bay District Health Board contract between September 2019-December 2020 (N=373). Uni-compartmental and bilateral replacements, procedures performed for cancer, and those with insufficient data were excluded. Demographics, perioperative technique, and medical complication data was collected. Pre- and post-operative blood tests were assessed. Outcome measures included clinical intervention for abnormal post-operative sodium (Na), creatinine (Cr), haemoglobin (Hb), or potassium (K) levels. A cost-benefit analysis assessed unnecessary testing. 350 patients were Included. Median age was 71 (range 34-92), with 46.9% male. Only 26 abnormal post-operative results required intervention (7.1%). 11 interventions were for low Na, 4 for low K, and 4 for elevated Cr. Only 7 patients were transfused blood products. Older age (p=0.009) and higher ASA (p=0.02) were associated with intervention of any kind. Abnormal preoperative results significantly predicted intervention for Na (p<0.05) and Cr (p<0.05). All patients requiring treatment for K used diuretic medication. Preoperative Hb level was not associated with need for transfusion. Overall, there were 1027 unnecessary investigations resulting in $18,307 excess expenditure. Our study identified that the majority of elective arthroplasty patients do not require routine postoperative blood testing. We recommend investigations for patients with preoperative electrolyte abnormality, those taking diuretics, and patients with significant blood loss noted intra-operatively. In future, a larger, randomised controlled trial would be useful to confirm these factors

Abstract. Background. Blood transfusion requirement after primary total hip replacements (THR) and total knee replacements (TKR) was found to be related to increased post-operative complications rate and length of hospital stay. Pre-operative haemoglobin level remains the single most important factor determining the requirement for post-operative blood transfusion. Methods. We carried out a local retrospective audit of 977 THRs and TKRs in 2019. Pre-operative and pre-transfusion haemoglobin levels for transfused group of patients were recorded. Results. A total of 977 patients had THRs and TKRs of which 34 (3.5%) had blood transfusions. From the 437 THRs, 24(5.5%) had bloods transfusions of which 19 were female. From the 540 TKRs 10(1.8%) were transfused, 9 were female. The average length of stay (LOS) for those transfused was 6.8 days and the average LOS for our trust is 3.2 days. Conclusion. The incidence of blood transfusion after primary THR or TKR was 3.5% in 2019. The majority of patients who received post-operative blood transfusion were found to have pre-operative haemoglobin level below 12 g/dl representing 61.7% of all the transfused patients. Transfused patients had more than double the average expected length of stay. The incidence of blood transfusion and associated risks can be improved by early detection and proper management of pre-op anaemia. Pre-assessment clinic has got a pivotal role but needs reminding of pre-op haemoglobin management strategies. Pre-operative optimisation of patients using either oral, intravenous iron supplements or erythropoietin according to the blood management protocol by the Royal College of Surgeons

BACKGROUND. Theatre-listed trauma patients routinely require two ‘group and save’ blood-bank samples, in case they need perioperative transfusion. The Welsh Blood Service (WBS) need patients to have one recorded sample from any time in the last 10 years. A second sample, to permit cross-matching and blood issuing, must be within 7 days of transfusion (or within 48 hours if the patient is pregnant, or has been transfused within the last 3 months). The approximate cost of processing a sample is £15.00. AIM. To investigate whether routine pretransfusion blood sampling for trauma admissions exceeds requirements. METHODS. Electronic records were used to collect pretransfusion sampling data for all adult non-elective trauma patients listed for theatre under a trauma and orthopaedics consultant between 1/1/2023-31/1/2023. Data were collected on unnecessary samples, rejected samples and total excess samples. RESULTS. 113 patients (mean age[±SD] 64.09[±19.96]) underwent 132 procedures. On average, unnecessary sampling occurred at a rate of 0.48 samples per operation, equating to a cost of £945.00/month. Samples were rejected by the laboratory at a rate of 0.25 samples per operation. Common reasons for rejection were ‘patient date of birth discrepancy’ (between sample and request form), ‘patient address discrepancy’ and ‘signature discrepancy’. Overall, total excessive sampling occurred at a rate of 0.60 samples per operation. CONCLUSION. Nearly half of trauma patients undergo unnecessary blood testing in anticipation of potential perioperative transfusion. This has implications for sustainability, financial cost and patient welfare. This signals poor understanding of WBS requirements and is an area that requires improvement

Tranexamic acid is a potent antifibrinolytic which has shown efficacy in reducing blood loss in total knee arthroplasty when administered intravenously. We performed a randomised controlled trial of oral tranexamic acid in total knee arthroplasty in order to assess the blood sparing effect of this preparation. We investigated the effects of oral tranexamic acid on blood loss in 50 patients (25 treatment arm and 25 placebo) undergoing unilateral total knee replacement in a two year period starting January 2007. The treatment arm received 1500 mg of encapsulated oral tranexamic acid TDS pre-operatively, with the third dose occurring within two hours of surgery, and a fourth dose six hours post surgery. The control arm received an identically encapsulated non-active formulation at the same dosing intervals. Baseline pre-operative haemoglobin and heamatocrit measures were collected. Outcome measures were post-operative haemoglobin and haematocrit taken 12 to 24 hours post operatively and total blood loss in wound drains at 24 hours. Results showed a non-clinically significant trend towards decreased blood loss and transfusion rates in the treatment arm when compared to placebo. No significant adverse events occurred in relation to the use of oral Tranexamic acid in this study. The perioperative use of oral tranexamic acid in conjuntion with elective total knee arthroplasty appears safe; however, its efficacy as a blood sparing medication is less than that which has been recorded with intravenous dosing. The study supports further consideration of the availability of intravenous tranexamic acid for decreasing blood loss in orthopaedic arthroplasty

Aims. Orthopaedic surgeries are complex, frequently performed procedures associated with significant haemorrhage and perioperative blood transfusion. Given refinements in surgical techniques and changes to transfusion practices, we aim to describe contemporary transfusion practices in orthopaedic surgery in order to inform perioperative planning and blood banking requirements. Methods. We performed a retrospective cohort study of adult patients who underwent orthopaedic surgery at four Canadian hospitals between 2014 and 2016. We studied all patients admitted to hospital for nonarthroscopic joint surgeries, amputations, and fracture surgeries. For each surgery and surgical subgroup, we characterized the proportion of patients who received red blood cell (RBC) transfusion, the mean/median number of RBC units transfused, and exposure to platelets and plasma. Results. Of the 14,584 included patients, the most commonly performed surgeries were knee arthroplasty (24.8%), hip arthroplasty (24.6%), and hip fracture surgery (17.4%). A total of 10.3% of patients received RBC transfusion; the proportion of patients receiving RBC transfusions varied widely based on the surgical subgroup (0.0% to 33.1%). Primary knee arthroplasty and hip arthroplasty, the two most common surgeries, were associated with in-hospital transfusion frequencies of 2.8% and 4.5%, respectively. RBC transfusion occurred in 25.0% of hip fracture surgeries, accounting for the greatest total number of RBC units transfused in our cohort (38.0% of all transfused RBC units). Platelet and plasma transfusions were uncommon. Conclusion. Orthopaedic surgeries were associated with variable rates of transfusion. The rate of RBC transfusion is highly dependent on the surgery type. Identifying surgeries with the highest transfusion rates, and further evaluation of factors that contribute to transfusion in identified at-risk populations, can serve to inform perioperative planning and blood bank requirements, and facilitate pre-emptive transfusion mitigation strategies. Cite this article: Bone Jt Open 2021;2(10):850–857

A concern of metal on metal hip resurfacing arthroplasty is long term exposure to Cobalt (Co) and Chromium (CR) wear debris from the bearing. This study compares whole blood metal ion levels from patients drawn at one-year following Birmingham Hip Resurfacing (BHR) to levels taken at a minimum 10-year follow-up. A retrospective chart review was conducted to identify all patients who underwent a BHR for osteoarthritis with a minimum 10-year follow-up. Whole blood metal ion levels were drawn at final follow-up in June 2019. These results were compared to values from patients with one-year metal ion levels. Of the 211 patients who received a BHR, 71 patients (54 males and 17 females) had long term metal ion levels assessed (mean follow-up 12.7 +/− 1.4 years). The mean Co and Cr levels for patients with unilateral BHRs (43 males and 13 females) were 3.12 ± 6.31 ug/L and 2.62 ± 2.69 ug/L, respectively, and 2.78 ± 1.02 ug/L and 1.83 ± 0.65 ug/L for patients with bilateral BHRs (11 males and 4 females). Thirty-five patients (27 male and 8 female) had metal-ion levels tested at one-year postoperatively. The mean changes in Co and Cr levels were 2.29 ug/l (p = 0.0919) and 0.57 (p = 0.1612), respectively, at one year compared to long-term. These changes were not statistically significant. This study reveals that whole blood metal ion levels do not change significantly when comparing one-year and ten-year Co and Cr levels. These ion levels appear to reach a steady state at one year. Our results also suggest that regular metal-ion testing as per current Medicines and Healthcare products Regulatory Agency (MHRA) guidelines may be impractical for asymptomatic patients. Metal-ion levels, in and of themselves, may in fact possess little utility in determining the risk of failure and should be paired with radiographic and clinical findings to determine the need for revision

This study aimed to identify factors associated with increased rates of blood transfusion in patients with adolescent idiopathic scoliosis (AIS) treated with posterior spinal fusion (PSF). A retrospective case-control study was performed for AIS patients treated at a large children's hospital between August 2018 and December 2020. All patients with a diagnosis of AIS were evaluated. Data on patient demographics, AIS, and transfusion parameters were collected. Univariate regression and multivariate logistic modeling were utilized to assess risk factors associated with requiring transfusion. Odds ratios (OR) and 95% confidence interval (CI) were calculated. Surgeries were done by three surgeons and thirty anesthesiologists. To quantify the influence of anesthesia practice preferences a categorical variable was defined as “higher-transfusion practice preference”, for the provider with the highest rate of transfusion. A total of 157 AIS patients were included, of whom 56 were transfused RBC units (cases), and 101 did not receive any RBC transfusion (controls). On univariate analysis, the following variables were significantly correlated with receiving RBC transfusion: “higher-transfusion practice preference,” “administration of crystalloids,” “receiving fresh frozen plasma (FFP),” “receiving platelets,” “pre-operative hemoglobin,” “cell saver volume,” and “surgical time.” On multiple regression modeling, “pre-operative hemoglobin less than 120 g/L” (OR 14.05, 95% CI: 1.951 to 135.7) and “higher-transfusion practice preference” (OR 11.84, 95% CI: 2.505 to 63.65) were found to be meaningfully and significantly predictive of RBC transfusion. In this cohort, we identified pre-operative hemoglobin of 120 g/L as a critical threshold for requiring transfusion. In addition, we identified significant contribution from anesthesia transfusion practice preferences. Our multivariate model indicated that these two factors are the major significant contributors to allogenic blood transfusion. Although further studies are required to better understand factors contributing to transfusion in AIS patients, we suggest standardized, peri-operative evidence-based strategies to potentially help reduce variations due to individual provider preferences

Staphylococcus aureus osteo-articular infections (OAI) are frequently accompanied by blood stream infections (BSI) diagnosed by positive blood culture (BC). Microbiological protocols in adults advise prolonged intravenous antibiotics and repeat BC 48-hourly in the presence of a BSI, however evidence to support the systematic employment of these guidelines in paediatric patients is lacking. We aimed to determine whether there was an increased incidence of orthopaedic and systemic complications in patients with s aureus BSI, and whether a shorter duration of intravenous antibiotics was associated with the development of complications. Following ethical approval, the departmental surgical database was searched for patients that underwent surgery for acute OAI over a 5-year period. Patients with no sample taken for BC were excluded, as were those with other or no organisms identified from any site. Demographic and clinical data were captured, including duration of IV antibiotics and development of complications. Statistical significance was set at p<0.05. Following exclusions, 44 patients with a median age of 85 months remained to be analysed. Thirty patients (68%) had a positive BC. A positive BC was associated with a higher rate of systemic complications (p=0.026) but not orthopaedic complications (p=0.159). Patients who had developed any complication had a significantly longer duration of IV antibiotic treatment compared to those without complications (p<0.001). The presenting CRP levels were significantly higher in patients that developed complications (p=0.004). Patients with staphylococcal BSI in association with an OAI are at increased risk of developing systemic complications. In our cohort, a shorter duration of antibiotic use was not associated with the development of complications, which does not support the systematic use of long courses of IV antibiotics in s aureus BSI. Further research will be required to determine the ideal protocol for these patients

Total hip and knee arthroplasty is known to have a significant blood loss averaging 3–4 g/dL. Historically, transfusion rates have been as high as 70%. Despite years of work to optimise blood management, some published data suggests that transfusion rates (especially with allogeneic blood) are rising. There is wide variability between surgeons as well, suggesting that varying protocols can influence transfusion rates. Multiple studies now associate blood transfusions with negative outcomes including increased surgical site infection, costs, and length of stay. Preoperative measures can be employed. Identify patients that are at increased risk of blood transfusion. Smaller stature female patients, have pre-operative anemia (Hgb less than 13.0 gm/dl), or are undergoing revision or bilateral surgery are at high risk. We identify these patients and check a hemoglobin preoperatively, using a non-invasive finger monitor for screening. For anemic patients, iron administration (oral or IV) can be given, along with Procrit/Epogen in select cases. Insurance coverage for that medication has been challenging. Intraoperative measures that have been linked to reduced postoperative transfusions include regional anesthesia and intraoperative hypotension (mean arterial pressure <60mm/hg). Lowering the surgical time by practicing efficient, organised, and quality surgery, along with leaving a dry field at the completion of surgery can reduce blood loss. Tranexemic acid (TXA) is an antifibrinolytic agent that has been shown to be effective, reducing average blood loss by 300 cc per case. There are multiple different administration protocols: IV using either a weight-based dosing 10–20 mg/kg or standardised dosing for all patients. Our current regimen is 1 gm IV preoperatively, 1 gm IV in PACU. Topical TXA can be used, usually 2–3 gm mixed in 50–100 cc of saline, sprayed in wound and allow to soak for 3–5 minutes. Oral administration is attractive for ease of use and reduced cost, standard oral dosing is 1950 mg PO 2 hours prior to surgery. The American Association of Hip and Knee Surgeons, in collaboration with the American Association of Orthopedic Surgeons, American Society of Regional Anesthesiologists, and the Hip & Knee Society have developed a Clinical Practice Guideline with 8 recommendations for TXA as follows: All individual formulations are effective at reducing blood loss – strong; No method of administration is clearly superior at reducing blood loss and the risk of transfusion; The dose of IV or topical TXA does not significantly affect the drug's ability to reduce blood loss and risk of transfusion; Multiple doses of IV or oral TXA compared to a single dose does not significantly alter the risk of blood transfusion; Pre-incision IV TXA administration potentially reduces blood loss and risk of transfusion compared to post-incision administration; Administration of all TXA formulations in patients without history of VTE does not increase the risk of VTE; Administration of all TXA formulations in patients with a history of VTE, MI, CVA, TIA, or vascular stent does not appear to increase the risk of VTE; Administration of all TXA formulations does not appear to increase the risk of arterial thrombotic events; Postoperative measures to reduce transfusion rates include changing transfusion triggers. Instead of treating a “number”, use lower thresholds and employ safe algorithms established. In conclusion, a comprehensive blood management program can reduce transfusion rates to less than 3% for THA and 1% for TKA and facilitate outpatient total joint arthroplasty

Introduction and Aim. Quadriceps strength is crucial for physical function in patients with knee osteoarthritis (KOA). This study aimed to investigate the effect of combining blood flow restriction (BFR) with low-intensity training (LIT) on quadricep strength in patients with advanced KOA. Methods. Patients with advanced KOA were block randomized by gender into the control or BFR group. The control group received LIT with leg press (LP) and knee extension (KE) at 30% of 1-repetition maximum (1-RM), while the BFR group underwent the same training with 70% limb occlusion. Physical function and patient-reported outcomes were assessed up to 16 weeks. Results. A total of 42 patients were analyzed: 22 in the BFR group (9 males, 13 females) and 20 in the control group (8 males, 12 females). In the BFR group, males exhibited increased KE power from the 4th to the 16th week (p<0.05) and LP power from the 4th to the 12th week (p<0.05). Females in the BFR group showed increased KE power in the 4th and 12th weeks (p<0.05), and LP power increased from the 4th to the 16th week (p<0.05). Males also had improved TSS at the 12th week, while females had improved TSS from the 8th to the 16th week. In the control group, males did not experience an increase in quadricep power. Females, however, had increased KE power in the 4th, 12th, and 16th weeks (p<0.05), and LP power from the 4th to the 12th week (p<0.05). Females in the control group also had improved TSS at the 4th week. Patient-reported outcomes did not differ, and all patients tolerated the training without any dropouts or adverse events. Conclusion. Combining BFR with LIT significantly improved quadricep power and physical function in both genders of KOA patients without exacerbating symptoms

Abstract. Source of Study: London, United Kingdom. This intervention study was conducted to assess two developing protocols for quadriceps and hamstring rehabilitation: Blood Flow Restriction (BFR) and Neuromuscular Electrical Stimulation Training (NMES). BFR involves the application of an external compression cuff to the proximal thigh. In NMES training a portable electrical stimulation unit is connected to the limb via 4 electrodes. In both training modalities, following device application, a standardised set of exercises were performed by all participants. BFR and NMES have been developed to assist with rehabilitation following lower limb trauma and surgery. They offer an alternative for individuals who are unable to tolerate the high mechanical stresses associated with traditional rehabilitation programmes. The use of BFR and NMES in this study was compared across a total of 20 participants. Following allocation into one of the training programmes, the individuals completed training programmes across a 4-week period. Post-intervention outcomes were assessed using Surface Electromyography (EMG) which recorded EMG amplitude values for the following muscles: Vastus Medialis, Vastus Lateralis, Rectus Femoris and Semitendinosus. Increased Semitendinosus muscle activation was observed post intervention in both BFR and NMES training groups. Statistically significant differences between the two groups was not identified. Larger scale randomised-controlled trials are recommended to further assess for possible treatment effects in these promising training modalities

Introduction. The volume of intraoperative blood loss is measured and reported by OR nurses in many hospitals and doctors do not usually measure it by themselves. To measure intraoperative blood loss accurately is such a difficult task that many measurement errors occur due to various factors. However, it is important to obtain a more correct measurement for performing a safe operation and stable anesthesia control. Case report. In total hip arthroplasty (THA) we had experienced massive intraoperative blood loss errors and later identified the two major causes of these errors. One is the excess volume of infusions for irrigation infusions, and the other is the validity and reliability of the scales on infusion containers. To accurately measure intraoperative blood loss, we should know these two important factors of intraoperative blood loss errors. In arthroplasty we use many infusions for irrigation of the operative field. The labeled (nominal) volume of infusion containers do not accurately indicate the volume of infusions in the container. This is even defined by the WHO international pharmacopoeia (pharmaceutical laws), US, EU, and Japanese pharmacopoeia. According to these pharmacopoeia, the actual volume of infusions is (must be) not less than the labeled (nominal) volume. Moreover, the upper limit of excess volume is not regulated so far. This results in all parenteral infusions (i.e., I.V infusion bags, or bottles of saline) having excess volume compared to their respective labeled volumes. We also have verified the accuracy of volume scales on the infusions bags and bottles and found out some products have inaccuracies that we cannot ignore. After inquiring the pharmaceutical companies about the information concerning excess volume of infusions, we discovered that the excess volume is 2–5% higher than the labeled (nominal) volume depending on the product and company. (e.g., One product has around 3140ml in the container labeled 3000ml). Discussion. Detailed information about excess volume of infusions is neither well recognized so far nor is it open to the public. Knowledge about the excess volume of infusions is necessary to acquire the accurate volume of intraoperative blood loss when using large volume of infusions (i.e., above 3 liters) for irrigating the field of operation. In these cases, excess volume in infusions can be large and cannot be ignored. Further investigation revealed intraoperative blood loss errors tend to be greater when irrigating Total Hip Arthroplasty (THA) compared to the Total Knee Arthroplasty (TKA). A large error in the volume of intraoperative blood loss may affect the decision of whether or not to perform a blood transfusion. Conclusions. This presentation highlights two causes of intraoperative blood loss errors; excess volume of infusions and the validity and reliability of scales on infusion containers. This information has not been shared in any known medical publications and has not been written so far on package inserts (i.e. attached document, Labeling, SmPC, interview form)

Over 300,000 total hip arthroplasties (THA) are performed annually in the USA. Surgical Site Infections (SSI) are one of the most common complications and are associated with increased morbidity, mortality and cost. Risk factors for SSI include obesity, diabetes and smoking, but few studies have reported on the predictive value of pre-operative blood markers for SSI. The purpose of this study was to create a clinical prediction model for acute SSI (classified as either superficial, deep and overall) within 30 days of THA based on commonly ordered pre-operative lab markers and using data from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. All adult patients undergoing an elective unilateral THA for osteoarthritis from 2011–2016 were identified from the NSQIP database using Current Procedural Terminology (CPT) codes. Patients with active or chronic, local or systemic infection/sepsis or disseminated cancer were excluded. Multivariate logistic regression was used to determine coefficients, with manual stepwise reduction. Receiver Operating Characteristic (ROC) curves were also graphed. The SSI prediction model included the following covariates: body mass index (BMI) and sex, comorbidities such as congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), smoking, current/previous steroid use, as well as pre-operative blood markers, albumin, alkaline phosphate, blood urea nitrogen (BUN), creatinine, hematocrit, international normalized ratio (INR), platelets, prothrombin time (PT), sodium and white blood cell (WBC) levels. Since the data met logistic assumption requirements, bootstrap estimation was used to measure internal validity. The area under the ROC curve for final derivations along with McFadden's R-squared were utilized to compare prediction models. A total of 130,619 patients were included with the median age of patients at time of THA was 67 years (mean=66.6+11.6 years) with 44.8% (n=58,757) being male. A total of 1,561 (1.20%) patients had a superficial or deep SSI (overall SSI). Of all SSI, 45.1% (n=704) had a deep SSI and 55.4% (n=865) had a superficial SSI. The incidence of SSI occurring annually decreased from 1.44% in 2011 to 1.16% in 2016. Area under the ROC curve for the SSI prediction model was 0.79 and 0.78 for deep and superficial SSI, respectively and 0.71 for overall SSI. CHF had the largest effect size (Odds Ratio(OR)=2.88, 95% Confidence Interval (95%CI): 1.56 – 5.32) for overall SSI risk. Albumin (OR=0.44, 95% CI: 0.37 – 0.52, OR=0.31, 95% CI: 0.25 – 0.39, OR=0.48, 95% CI: 0.41 – 0.58) and sodium (OR=0.95, 95% CI: 0.93 – 0.97, OR=0.94, 95% CI: 0.91 – 0.97, OR=0.95, 95% CI: 0.93 – 0.98) levels were consistently significant in all clinical prediction models for superficial, deep and overall SSI, respectively. In terms of pre-operative blood markers, hypoalbuminemia and hyponatremia are both significant risk factors for superficial, deep and overall SSI. In this large NSQIP database study, we were able to create an SSI prediction model and identify risk factors for predicting acute superficial, deep and overall SSI after THA. To our knowledge, this is the first clinical model whereby pre-operative hyponatremia (in addition to hypoalbuminemia) levels have been predictive of SSI after THA. Although the model remains without external validation, it is a vital starting point for developing a risk prediction model for SSI and can help physicians mitigate risk factors for acute SSI post THA

Total knee arthroplasty (TKA) is the most commonly performed elective orthopaedic procedure. With an increasingly aging population, the number of TKAs performed is expected to be ∼2,900 per 100,000 by 2050. Surgical Site Infections (SSI) after TKA can have significant morbidity and mortality. The purpose of this study was to construct a risk prediction model for acute SSI (classified as either superficial, deep and overall) within 30 days of a TKA based on commonly ordered pre-operative blood markers and using audited administrative data from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. All adult patients undergoing an elective unilateral TKA for osteoarthritis from 2011–2016 were identified from the NSQIP database using Current Procedural Terminology (CPT) codes. Patients with active or chronic, local or systemic infection/sepsis or disseminated cancer were excluded. Multivariate logistic regression was conducted to estimate coefficients, with manual stepwise reduction to construct models. Bootstrap estimation was administered to measure internal validity. The SSI prediction model included the following co-variates: body mass index (BMI) and sex, comorbidities such as congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), smoking, current/previous steroid use, as well as pre-operative blood markers, albumin, alkaline phosphatase, blood urea nitrogen (BUN), creatinine, hematocrit, international normalized ratio (INR), platelets, prothrombin time (PT), sodium and white blood cell (WBC) levels. To compare clinical models, areas under the receiver operating characteristic (ROC) curves and McFadden's R-squared values were reported. The total number of patients undergoing TKA were 210,524 with a median age of 67 years (mean age of 66.6 + 9.6 years) and the majority being females (61.9%, N=130,314). A total of 1,674 patients (0.8%) had a SSI within 30 days of the index TKA, of which N=546 patients (33.2%) had a deep SSI and N=1,128 patients (67.4%) had a superficial SSI. The annual incidence rate of overall SSI decreased from 1.60% in 2011 to 0.68% in 2016. The final risk prediction model for SSI contained, smoking (OR=1.69, 95% CI: 1.31 – 2.18), previous/current steroid use (OR=1.66, 95% CI: 1.23 – 2.23), as well as the pre-operative lab markers, albumin (OR=0.46, 95% CI: 0.37 – 0.56), blood urea nitrogen (BUN, OR=1.01, 95% CI: 1 – 1.02), international normalized ratio (INR, OR=1.22, 95% CI:1.05 – 1.41), and sodium levels (OR=0.94, 95% CI: 0.91 – 0.98;). Area under the ROC curve for the final model of overall SSI was 0.64. Models for deep and superficial SSI had ROC areas of 0.68 and 0.63, respectively. Albumin (OR=0.46, 95% CI: 0.37 – 0.56, OR=0.33, 95% CI: 0.27 – 0.40, OR=0.75, 95% CI: 0.59 – 0.95) and sodium levels (OR=0.94, 95% CI: 0.91 – 0.98, OR=0.96, 95% CI: 0.93 – 0.99, OR=0.97, 95% CI: 0.96 – 0.99) levels were consistently significant in all prediction models for superficial, deep and overall SSI, respectively. Overall, hypoalbuminemia and hyponatremia are both significant risk factors for superficial, deep and overall SSI. To our knowledge, this is the first prediction model for acute SSI post TKA whereby hyponatremia (and hypoalbuminemia) are predictive of SSI. This prediction model can help fill an important gap for predicting risk factors for SSI after TKA and can help physicians better optimize patients prior to TKA

Perioperative blood conservation remains an important topic today in order to reduce complications, improve function, and facilitate recovery after a total knee replacement (TKR). Studies have shown that the degree of postoperative anemia is related to an increase in complications. A greater blood loss and need for transfusion is associated with a higher risk of infection, a slower recovery process, increased morbidity to patients, as well as an increased cost to the health care system. Typical blood loss estimates range from 800cc to over 1700cc, when accounting not only for intraoperative but postoperative blood loss. Several strategies have been developed to help mitigate the risk of perioperative blood loss and need for subsequent transfusion. Firstly, preoperative measures such as vitamin and mineral supplementation can ensure the starting hemoglobin and red cell count are maximised. Additionally, erythropoietin can be helpful in refractory cases of preoperative anemia. Preoperative autologous blood donation was used extensively in the past, but has fallen out of favor due to its inefficiency and cost. Intraoperatively, measures such as the use of a tourniquet, meticulous technique, and expeditious surgery can help reduce blood loss. The most effective method, however, has been the use of tranexamic acid (TXA). TXA, an antifibrinolytic compound, has been extremely effective at reducing perioperative blood loss without increasing the risk of thromboembolic events. TXA can be used topically or intravenously. Other methods that can reduce intraoperative blood loss include the use of fibrin sealants, applied to the soft tissues and bony surfaces around the knee. Postoperatively, the avoidance of wound drains is associated with a higher blood count and reduced transfusion risk. Alternatively, drainage reinfusion systems can be used to raise the postoperative blood count, particularly in cases of bilateral TKR

Aim. Diagnosis of periprosthetic joint infection (PJI) presents a real challenge in some patients. Batteries of tests are available to reach this diagnosis. It is unknown if blood cultures have any role in diagnosis of PJI. The objective of this study was to evaluate whether blood cultures, taken in a group of patients with PJI, was useful in identifying the infecting pathogen. Methods. The institutional database was used to identify all patients treated at our institution between 2000 – 2015 for PJI according to the latest MSIS criteria. There were a total of 864 patients with mean age of 68 years. Synovial fluid sample and/or deep tissue samples were analyzed and cultured in all of these patients. In 371 (42.9%) patients with PJI, blood cultures were also taken. Statistical analyses were performed for correlation purposes. Results. In 246 (66.3%) patients in whom an organism was isolated from joint fluid, blood cultures were negative. 32 (8.6%) patients had both negative blood and synovial joint tissue culture. Of the 93 (25%) patients with positive blood cultures, 77 (82.7%) patients had identical organism in the joint and 16 (17.2%) had different organisms. Interestingly one infection that was fungal in nature showed no growth on tissue/fluid culture, yet a fungal organism was isolated in blood culture. Additionally, of the 93 patients with positive blood cultures, 57 (61.2%) had signs of systemic sepsis with leukocytosis and increased PMN/left shift. Within the 57 patients, 50 (87.7%) had identical blood and joint culture and 7 (12.2%) were from different culture organisms. 36 (38.7%) patients had subclinical infection with no signs of systemic sepsis. Discussion. Although this study does not advocate the routine use of blood culture for diagnosis of PJI, the finding that blood culture is successful in isolating the infecting organism as the joint in a handful of cases is compelling. Thus, the result of blood culture when performed should be considered as representative of the infecting organism in PJI cases

Total knee replacement is a standard procedure for the end-staged knee joints. The main concerns at the perioperative period are infection prophylaxis, pain control, and blood loss management. Several interventions are designed to decrease the blood loss during and after the operation of total knee arthroplasty. In the recent meta-analysis showed that early tourniquet release of the tourniquet for hemostasis increased the total measured blood loss with primary TKR about 228.7 ml. So, Intra-operative blood loss for hemostasis can be saved by not to release the tourniquet after implants fixation, irrigation, closure of the wound and the application of compression dressing. Our study showed that most of the post-operative blood loss was collected during the first few postoperative hours: 37% in the first 2 hours and 55% in the first 4 hours and 82.1% in the first 24 hours. So, clamping the drainage for the first 4 postoperative hours would reduce blood loss after TKA (518 v.s. 843 mL). The fall in hemoglobin and Hct are also of significant difference (1.64 vs. 2.09 for Hb; 5.18 vs.7.69 for Hct). Appropriate clamping for an optimal time may be the most economical and simple, and the benefits of clamping also appear to outweigh its potential risks. NO DRAIN at all is able to reduce the post-operative blood loss. Our study showed that the decrease of postoperative hemoglobin was significantly less than that in no-drain group (1.45±0.72 vs 1.8±0.91). Shorter hospital stay was achieved in the no-drain group (8.3 ± 2.6 vs 10.7±3.2 days). All patients achieved good range of motion (flexion: 0 to >90 degree)by the five days after operation and no prosthetic infection was noted during follow-up. Thus, the routine use of closed suction drains for elective minimal-invasive total knee arthroplasty is not recommended

Tranexamic acid (TXA) is an effective medication to limit blood loss and transfusion requirements in association with contemporary total joint arthroplasty. TXA is in a class of medications termed anti-fibrinolytics due to their action to limit the breakdown of clot that has already been formed. It is useful to note that TXA does not promote the formation of clot, it simply limits the breakdown of already established clot. A recent systematic review and meta-analysis of randomised clinical trials of TXA use in total hip replacement demonstrated: 1) a substantial reduction in the proportion of patients who required transfusion and 2) no increase in DVT or PE. Similarly a recent Cochrane Database systematic review assessed Anti-fibrinolytic Use for Minimizing Perioperative Blood Transfusion and found tranexamic acid to be effective in reducing blood loss during and after surgery and to be free of serious adverse effects. In orthopaedic surgery varying doses have been used over time. A pragmatic dosing approach for Total Knee and Total Hip patients has been used at the Mayo Clinic over the past 16 years: 1 gram IV over 10 minutes prior to incision (delivered at same time as pre-op antibiotics) followed by 1 gram IV over 10 minutes at the time wound closure is initiated. Infusion rates greater than 100 mg/minute have been associated with hypotension and thus the recommendation for 1 gram over 10 minutes. A recent review of 1500 TKA patients at Mayo Clinic revealed a very low prevalence of clinically symptomatic DVT and PE when tranexamic acid was used with 3 different thromboembolic prophylaxis regimens (aspirin and foot pumps; coumadin; low molecular weight heparin). The safety of TXA for patients with coronary stents has not been fully clarified

Dysglycemia in the post-operative period has been associated with increased rates of infection following total joint arthroplasty. Additionally, patients without clinical diagnosis of diabetes with hemoglobin A1c% values between 5.7% and 6.4% have been shown to be dysglycemic in the peri-operative period. This study examines the influence of post-operative blood glucose management on rates of re-operation for infection in patients undergoing total joint arthroplasty in diabetic, and clinically non-diabetic patients. We performed a retrospective review of prospectively collected data, for all primary, elective total hip and total knee arthroplasties performed at The Ottawa Hospital between April 2010 and October 2017. Kaplan-Meier survivorship, and mutivarient regression analysis were used to determine predictors of infection based on pre-operative diabetes status, HbA1c%, and post-operative insulin management. 4159 joints met inclusion criteria. Patients with HbA1c 5.7–6.4% had lower rate of revision for infection if they received post-operative blood glucose management (0.80%), vs without glucose management (1.20%). Kaplan-Meier survivorship analysis showed this difference to be insignificant (p=0.23). Patients with DM1 had statistically worse survivorship when compared to other groups (p=0.010). Patients with undiagnosed perioperative dysglycemia may be at a greater predisposition for developing infection, requiring re-operation, following total joint arthroplasty. This study may be underpowered due to overall low rates of revision. More rigorous peri-operative glucose management strategies may be required for patients, who otherwise receive no glycemic management outside of hospital. This is more pertinent with trends towards decreasing post-operative lengths-of-stay