Acute kidney injury in the context of staged revision arthroplasty and the use of antibiotic-laden cement spacers: a systematic review

BACKGROUND

The most common cause of revision arthroplasty is prosthetic joint infection (PJI). Chronic PJI is commonly treated with two-stage exchange arthroplasty involving the placement of antibiotic-laden cement spacers (ACS) in the first stage, often containing nephrotoxic antibiotics. These patients often have significant comorbidity burdens and have higher rates of acute kidney injury (AKI). This systematic review aims to assess the current literature to identify (1) AKI incidence, (2) associated risk factors, and (3) antibiotic concentration thresholds in ACS that increase AKI risk following first-stage revision arthroplasty.

METHODS

An electronic search was performed of the PubMed database of all studies involving patients undergoing ACS placement for chronic PJI. Studies assessing AKI rates and risk factors were screened by two authors independently. Data synthesis was performed when possible. Significant heterogeneity prevented meta-analysis.

RESULTS

Eight observational studies consisting of 540 knee PJIs and 943 hip PJIs met inclusion criteria. There were 309 (21%) cases involving AKI. The most commonly reported risk factors included perfusion-related factors (lower preoperative hemoglobin, transfusion requirement, or hypovolemia), older age, increased comorbidity burden, and nonsteroidal anti-inflammatory drug consumption. Only two studies found increased risk with greater ACS antibiotic concentration (> 4 g vancomycin and > 4.8 g tobramycin per spacer in one study, > 3.6 g of vancomycin per batch or > 3.6 g of aminoglycosides per batch in the other); however, these were reported from univariate analyses not accounting for other potential risk factors.

DISCUSSION

Patients undergoing ACS placement for chronic PJI are at an increased risk for AKI. Understanding the risk factors may lead to better multidisciplinary care and safer outcomes for chronic PJI patients.

LEVEL OF EVIDENCE III

Comparing five equations to calculate estimated glomerular filtration rate to predict acute kidney injury following total joint arthroplasty

BACKGROUND

Acute kidney injury (AKI) following total joint arthroplasty (TJA) is associated with increased morbidity and mortality. Estimated glomerular filtration rate (eGFR) is used as an indicator of renal function. The purpose of this study was (1) to assess each of the five equations that are used in calculating eGFR, and (2) to evaluate which equation may best predict AKI in patients following TJA.

METHODS

The National Surgical Quality Improvement Program (NSQIP) was queried for all 497,261 cases of TJA performed from 2012 to 2019 with complete data. The Modification of Diet in Renal Disease (MDRD) II, re-expressed MDRD II, Cockcroft-Gault, Mayo quadratic, and Chronic Kidney Disease Epidemiology Collaboration equations were used to calculate preoperative eGFR. Two cohorts were created based on the development of postoperative AKI and were compared based on demographic and preoperative factors. Multivariate regression analysis was used to assess for independent associations between preoperative eGFR and postoperative renal failure for each equation. The Akaike information criterion (AIC) was used to evaluate predictive ability of the five equations.

RESULTS

Seven hundred seventy-seven (0.16%) patients experienced AKI after TJA. The Cockcroft-Gault equation yielded the highest mean eGFR (98.6 ± 32.7), while the Re-expressed MDRD II equation yielded the lowest mean eGFR (75.1 ± 28.8). Multivariate regression analysis demonstrated that a decrease in preoperative eGFR was independently associated with an increased risk of developing postoperative AKI in all five equations. The AIC was the lowest in the Mayo equation.

CONCLUSIONS

Preoperative decrease in eGFR was independently associated with increased risk of postoperative AKI in all five equations. The Mayo equation was most predictive of the development of postoperative AKI following TJA. The mayo equation best identified patients with the highest risk of postoperative AKI, which may help providers make decisions on perioperative management in these patients.

Transfusion Rates in the Operative Treatment of Prosthetic Hip and Knee Infection

Surgery for prosthetic joint infection (PJI) can often lead to significant blood loss, necessitating allogeneic blood transfusion (ABT). The use of ABT is associated with higher rates of morbidity and death in revision total joint arthroplasty, particularly in the treatment of PJI. We compared ABT rates by procedure type among patients treated for PJI. We retrospectively reviewed 143 operative cases of hip and knee PJI performed at our institution between 2016 and 2018. Procedures were categorized as irrigation and debridement (I&D) with modular component exchange (modular component exchange), explantation with I&D and placement of an antibiotic spacer (explantation), I&D with antibiotic spacer exchange (spacer exchange), or antibiotic spacer removal and prosthetic reimplantation (reimplantation). Rates of ABT and the number of units transfused were assessed. Factors associated with ABT were assessed with a multilevel mixed-effects regression model. Of the cases, 77 (54%) required ABT. The highest rates of ABT occurred during explantation (74%) and spacer exchange (72%), followed by reimplantation (36%) and modular component exchange (33%). A lower preoperative hemoglobin level was associated with higher odds of ABT. Explantation, reimplantation, and spacer exchange were associated with greater odds of ABT. Antibiotic spacer exchange and explantation were associated with greater odds of multiple-unit transfusion. Rates of ABT remain high in the surgical treatment of PJI. Antibiotic spacer exchange and explantation procedures had high rates of multiple-unit transfusions, and additional units of blood should be made available. Preoperative anemia should be treated when possible, and further refinement of blood management protocols for prosthetic joint infection is necessary. [Orthopedics. 2022;45(6):353-359.].

A Novel Method for Stratification of Major Complication Risk Using Body Mass Index Thresholds for Patients Undergoing Total Hip Arthroplasty: A National Cohort of 224,413 Patients

INTRODUCTION

Elevated body mass index (BMI) is associated with complications following Total Hip Arthroplasty (THA). Since obese individuals are almost 10 times more likely to require THA compared to non-obese individuals, we need to understand the risk-benefit continuum while considering THA in obese patients. We aimed to determine data-driven thresholds for BMI at which the risk of major complications following THA increases significantly.

METHODS

Patients were identified in a national database who underwent primary THA from 2010 to 2020. BMI thresholds were identified using the stratum-specific likelihood ratio (SSLR) methodology, which is an adaptive technique that allows for identification of BMI cut-offs, at which the risk of major complications is increased significantly . BMI cutoffs identified using SSLR were used to create a logistic regression model.

RESULTS

A total of 224,413 patients were identified with a mean age of 66 ± 10, BMI 32 ± 6.7, and 7,186 (3%) sustained a major complication. BMI thresholds were defined as 19-31, 32-37, 38-49 and 50+. Overall, the absolute risk of major complications increased from 2.9% in the lowest BMI strata to 7.5% in the highest BMI strata. Compared to patients with a BMI between 19-31, the odds of sustaining a major complication sequentially increased by 1.2, 1.6, and 2.5-times for patients in each higher BMI strata (all, P < .05).

CONCLUSIONS

We have identified BMI cutoffs using SSLR that categorizes patients into four categories of risk for major complications in a nationally representative patient sample. These thresholds can be used in the surgical decision-making process between patients and surgeons.

Preoperative Hypoalbuminemia Is Associated With Early Morbidity and Mortality After Revision Total Hip Arthroplasty

Hypoalbuminemia is associated with early morbidity and mortality in revision total knee arthroplasty. We evaluated the effect of preoperative hypoalbuminemia on 30-day morbidity and mortality in revision total hip arthroplasty (THA). The National Surgical Quality Improvement Program (NSQIP) database was queried from 2015 to 2018 to identify patients who underwent revision THA. Patients were stratified based on the presence or absence of preoperative hypoalbuminemia and their odds of a major complication or death within 30 days of revision THA with multivariate logistic regression. After Bonferroni correction for these 2 primary outcomes, statistical significance was defined as P<.025. A total of 2492 revision THAs with complete data were identified, of which 486 (20%) had preoperative hypoalbuminemia. Preoperative hypoalbuminemia increased the absolute risk of a major complication by 15.3% compared with patients with revision THA without hypoalbuminemia (30% vs 14.7%, P<.001). Patients with preoperative hypoalbuminemia also had nearly a 7-fold higher incidence of death (3.3%) compared with those with revision THA without preoperative hypoalbuminemia (0.5%, P<.001). After logistic regression, the odds of having a major complication after revision THA with preoperative hypoalbuminemia within 30 days were increased by 80% (odds ratio, 1.8; 95% CI, 1.4-2.3; P<.001), and the odds of death within 30 days were increased by 210% (odds ratio, 3.1; 95% CI, 1.2-7.8; P=.020). Hypoalbuminemia is associated with early morbidity and mortality after revision THA. [Orthopedics. 2022;45(5):281-286.].

Extremity fasciotomy for patients on extracorporeal membrane oxygenation is independently associated with inpatient mortality

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) maintains end-organ perfusion in critically ill patients with cardiac or respiratory failure; however, ECMO cannulation in the extremities has been associated with significant limb ischemia and risk of compartment syndrome. Current literature on ECMO and fasciotomies is limited to small single-center retrospective studies. This study aimed to (1) compare the incidence of postoperative outcomes and mortality in patients undergoing fasciotomy while on ECMO to those of non-fasciotomy ECMO patients, and (2) assess the difference in adjusted mortality risk between the two groups.

HYPOTHESIS

We hypothesized that patients undergoing fasciotomy while on ECMO would have significantly higher odds of in-hospital mortality than non-fasciotomy ECMO patients after adjustment for perioperative variables.

METHODS

We conducted a retrospective review of NIS from January 1st, 2012-September 30, 2015 for all hospitalizations involving ECMO and stratified them into two cohorts based on whether they underwent fasciotomy after ECMO. Patient baseline characteristics, in-hospital procedures, and postoperative outcomes were compared between the two cohorts. Logistic regression was used to assess in-hospital mortality risk between the two cohorts adjusting for age, sex, Elixhauser score, and perioperative procedures and non-fasciotomy perioperative morbidity.

RESULTS

There were 7,085 estimated eligible discharges between 2012 and 2015 identified, 149 (2.1%) of which underwent fasciotomy following ECMO. One hundred and thirteen of the 149 hospitalizations (77%) in the fasciotomy cohort resulted in in-hospital mortality, compared to 3,805 of the 6,936 (55%) in the non-fasciotomy cohort. There were no differences in rates of transfusion (p=0.290), length of stay (p=0.282), or discharge disposition (p=0.126) between the two cohorts. In the logistic regression model, the fasciotomy cohort had a higher odds of in-hospital mortality than non-fasciotomy cohort (OR, 2.5; 95% CI, 1.1-5.6).

DISCUSSION

Operative treatment of acute compartment syndrome for patients on ECMO therapy is associated with significantly increased mortality and morbidity. Whether fasciotomy is a marker of sickness or represents a cause-and-effect relationship is unknown and future should investigate the role of non-operative treatment of compartment syndrome on mortality in this population.

LEVEL OF EVIDENCE

III; Prognostic.

Preoperative Patient Optimization in Total Joint Arthroplasty-The Paradigm Shift from Preoperative Clearance: A Narrative Review

Background: Total joint arthroplasty (TJA) is one of the most common procedures performed in the United States. Outcomes of this elective procedure may be improved via preoperative optimization of modifiable risk factors. Purposes: We sought to summarize the literature on the clinical implications of preoperative risk factors in TJA and to develop recommendations regarding preoperative optimization of these risk factors. Methods: We searched PubMed in August 2019 with an update in September 2020 for English-language, peer-reviewed publications assessing the influence on outcomes in total hip and knee replacement of 7 preoperative risk factors-obesity, malnutrition, hypoalbuminemia, diabetes, anemia, smoking, and opioid use-and recommendations to mitigate them. Results: Sixty-nine studies were identified, including 3 randomized controlled trials, 8 prospective cohort studies, 42 retrospective studies, 6 systematic reviews, 3 narrative reviews, and 7 consensus guidelines. These studies described worse outcomes associated with these 7 risk factors, including increased rates of in-hospital complications, transfusions, periprosthetic joint infections, revisions, and deaths. Recommendations for strategies to screen and address these risk factors are provided. Conclusions: Risk factors can be optimized, with evidence suggesting the following thresholds prior to surgery: a body mass index <40 kg/m², serum albumin ≥3.5 g/dL, hemoglobin A1C ≤7.5%, hemoglobin >12.0 g/dL in women and >13.0 g/dL in men, and smoking cessation and ≥50% decrease in opioid use by 4 weeks prior to surgery. Surgery should be delayed until these risk factors are adequately optimized.

Predictors and Outcomes of Postoperative Hemoglobin of <8 g/dL in Total Joint Arthroplasty

BACKGROUND

Restrictive transfusion practices have decreased transfusions in total joint arthroplasty (TJA). A hemoglobin threshold of <8 g/dL is commonly used. Predictors of this degree of postoperative anemia in TJA and its association with postoperative outcomes, independent of transfusions, remain unclear. We identified predictors of postoperative hemoglobin of <8 g/dL and outcomes with and without transfusion in TJA.

METHODS

Primary elective TJA cases performed with a multimodal blood management protocol from 2017 to 2018 were reviewed, identifying 1,583 cases. Preoperative and postoperative variables were compared between patients with postoperative hemoglobin of <8 and ≥8 g/dL. Logistic regression and receiver operating characteristic curves were used to assess predictors of postoperative hemoglobin of <8 g/dL.

RESULTS

Positive predictors of postoperative hemoglobin of <8 g/dL were preoperative hemoglobin level (odds ratio [OR] per 1.0-g/dL decrease, 3.0 [95% confidence interval (CI), 2.4 to 3.7]), total hip arthroplasty (OR compared with total knee arthroplasty, 2.1 [95% CI, 1.3 to 3.4]), and operative time (OR per 30-minute increase, 2.0 [95% CI, 1.6 to 2.6]). Negative predictors of postoperative hemoglobin of <8 g/dL were tranexamic acid use (OR, 0.42 [95% CI, 0.20 to 0.85]) and body mass index (OR per 1 kg/m2 above normal, 0.90 [95% CI, 0.86 to 0.94]). Preoperative hemoglobin levels of <12.4 g/dL in women and <13.4 g/dL in men best predicted postoperative hemoglobin of <8 g/dL. Overall, 5.2% of patients with postoperative hemoglobin of 7 to 8 g/dL and 95% of patients with postoperative hemoglobin of <7 g/dL received transfusions. Patients with postoperative hemoglobin of <8 g/dL had longer hospital stays (p < 0.001) and greater rates of emergency department visits or readmissions (p = 0.001) and acute kidney injury (p < 0.001). Among patients with postoperative hemoglobin of <8 g/dL, patients who received transfusions had a lower postoperative hemoglobin nadir (p < 0.001) and a longer hospital stay (p = 0.035) than patients who did not receive transfusions.

CONCLUSIONS

Postoperative hemoglobin of <8 g/dL after TJA was associated with worse outcomes, even for patients who do not receive transfusions. Optimizing preoperative hemoglobin levels may mitigate postoperative anemia and adverse outcomes.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Iatrogenic Metastasis of Soft-tissue Sarcoma at the Donor Flap Site: Case Report and Proposed Surgical Oncologic Techniques

An 81-year-old woman with multiply recurrent undifferentiated pleomorphic sarcoma of the foot underwent wide excision and reconstruction with an anterolateral thigh free flap. Six years postoperatively, she developed biopsy-proven recurrence within the harvest site. No other sites of disease were detected on staging workup. The flap site recurrence was attributed to iatrogenic implantation at the time of harvesting. Iatrogenic metastases are thought to be caused by tumor implantation, which may be attributable to cross-contamination from instrumentation and surgical techniques. In the present article, we highlight preventive techniques and oncologic surgical principles intended to reduce the likelihood of iatrogenic metastasis. Increased awareness by all members of the surgical team may prevent this unfortunate complication.

Survival bias may explain the appearance of the obesity paradox in hip fracture patients

Patients with low-energy hip fractures do not follow the obesity paradox as previously reported. In datasets where injury mechanism is not available, the use of age >50 years (as opposed to commonly used >65 years) as a surrogate for a low-energy hip fracture patients may be a more robust inclusion criterion.  PURPOSE: In elderly patients with a hip fracture, limited data suggests that obese patients counterintuitively have improved survival compared to normal-weight patients. This "obesity paradox" may be the byproduct of selection bias. We hypothesized that the obesity paradox would not apply to elderly hip fracture patients.

METHODS

The National Surgical Quality Improvement Project dataset identified 71,685 hip fracture patients ≥50 years-of-age with complete body mass index (BMI) data that underwent surgery. Patients were stratified into under and over 75-year-old cohorts (n=18,956 and 52,729, respectively). Within each age group, patients were stratified by BMI class and compared with respect to preoperative characteristics and 30-day mortality. Significant univariate characteristics (p<0.1) were included in multivariate analysis to determine the independent effect of obesity class on 30-day mortality (p<0.05).

RESULTS

Multivariate analysis of <75-year-old patients with class-III obesity were more likely to die within 30-days than similarly aged normal-weight patients (OR 1.91, CI 1.06-3.42, p=0.030). Multivariate analysis of ≥75-year-old overweight (OR 0.69, CI 0.62-0.77, p<0.001), class-I obese (OR 0.62, CI 0.51-0.74, p<0.001), or class-II obese (OR=0.69, CI 0.50-0.95, p=0.022) patients were less likely to die within 30-days when compared to similarly aged normal-weight patients.

CONCLUSIONS

Our data suggest that obesity is a risk factor for mortality in low-energy hip fracture patients, but the appearance of the "obesity paradox" in elderly hip fracture patients results from statistical bias that is only evident upon subgroup analysis.

Septic Arthritis Among Users of Injection Drugs: Clinical Course and Microbial Characteristics

Injection drug use (IDU) is a risk factor for septic arthritis (SA) of native joints. Amid the opioid crisis, IDU rates have increased. This study assessed differences in pre-operative characteristics, microbial characteristics, and postoperative outcomes of 177 cases of SA treated operatively from 2015 to 2019 at 3 US hospitals, by self-reported IDU status. Forty cases (23%) involved patients who reported IDU. Patient characteristics, comorbidities, microbial characteristics, duration of hospital stay, discharge destination, follow-up rates, and rates of persistent/secondary infection were compared by self-reported IDU status. Compared with non-IDU-associated SA (non-IDU-SA), IDU-associated SA (IDU-SA) was associated with female sex (P=.001), younger age (P<.001), lower body mass index (P<.001), tobacco use (P<.001), and psychiatric diagnosis (P=.04) and was more likely to involve methicillin-resistant Staphylococcus aureus (P<.001). The IDU-SA was associated with discharge to a skilled nursing facility or against medical advice (P<.001) and with loss to follow-up (P=.01). The 2 groups did not differ in terms of American Society of Anesthesiologists classification, joint involved, Gram stain positivity, presence of bacteremia, peripherally inserted central catheter placement, return to hospital within 3 months, or persistent/secondary positive results on culture within 3 months. Patients with IDU-SA were younger, were more likely to be female, had lower body mass index, and had fewer medical comorbidities but were more likely to use tobacco and to have a psychiatric diagnosis compared with patients with non-IDU-SA. Methicillin-resistant S aureus was more common in the IDU-SA group, as was discharge to a skilled nursing facility or against medical advice. Patients with IDU-SA were less likely to return for follow-up than patients with non-IDU-SA. [Orthopedics. 2021;44(6):e747-e752.].

Incidence, mortality, and complications of acute myocardial infarction with and without percutaneous coronary intervention in hip fracture patients

INTRODUCTION

Acute myocardial infarction (AMI) is a common cause of death following hip fracture surgery. This study aimed to determine the incidence and timing of perioperative AMI treated with percutaneous coronary intervention (PCI) in hip fracture patients, and to compare in-hospital mortality and complications between hip fracture patients who did not have an AMI, those who sustained a perioperative AMI and did not undergo PCI, and those who sustained an AMI and underwent PCI.

METHODS

The National Inpatient Sample (NIS) was queried from 2010 through the third quarter of 2015 to identify all patients undergoing hip fracture surgery. Patients were stratified into three cohorts: perioperative AMI but no PCI (no PCI cohort), perioperative AMI with PCI (PCI cohort), and no perioperative AMI or PCI (no AMI cohort). Patient demographics, comorbidities, in-hospital mortality, and complications were compared between cohorts. Multivariable logistic regression adjusting for age, sex, procedure, and Elixhauser score was used to assess the relative odds of in-hospital mortality for each cohort.

RESULTS

A total of 1,535,917 hip fracture cases were identified, with 1.9% in the no PCI cohort, 0.01% in the PCI cohort, and 98.0% in the no AMI cohort. In-hospital mortality was lower in the PCI cohort than in the no PCI cohort (8.8% vs. 14%), and was greater for both than in the no AMI cohort (1.6%, p < 0.001 for all). Both the no PCI cohort (OR, 6.1; 95% CI, 5.6-6.6) and PCI cohort (OR, 4.1; 95% CI, 2.8-6.0) had increased adjusted odds of in-hospital mortality compared to the no AMI cohort. The PCI cohort had a higher rate of bleeding complications than both other cohorts, and the no PCI cohort had a higher rate of transfusion than both other cohorts.

CONCLUSIONS

Perioperative AMI both with and without PCI independently increases the risk of mortality in hip fracture patients, with the highest risk of mortality in those with AMI without PCI. Providers should understand the increased morbidity and mortality associated with AMI in hip fracture patients, as well as the risks and benefits of perioperative PCI, in order to better counsel and manage these patients.

LEVEL OF EVIDENCE

III.

Complications and 30-Day Mortality Rate After Hip Fracture Surgery in Superobese Patients

OBJECTIVE

Paradoxically, overweight and obesity are associated with lower odds of complications and death after hip fracture surgery. Our objective was to determine whether this "obesity paradox" extends to patients with "superobesity." In this study, we compared rates of complications and death among superobese patients with those of patients in other body mass index (BMI) categories.

METHODS

Using the National Surgical Quality Improvement Program database, we identified >100,000 hip fracture surgeries performed from 2012 to 2018. Patients were categorized as underweight (BMI <18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9), obese (BMI 30-39.9), morbidly obese (BMI 40-49.9), or superobese (BMI ≥50). We analyzed patient characteristics, surgical characteristics, and 30-day outcomes. Using multivariate regression with normal-weight patients as the referent, we determined odds of major complications, minor complications, and death within 30 days by BMI category.

RESULTS

Of 440 superobese patients, 20% had major complications, 33% had minor complications, and 5.2% died within 30 days after surgery. When comparing patients in other BMI categories with normal-weight patients, superobese patients had the highest odds of major complications [odds ratio (OR): 1.6, 95% confidence interval (CI), 1.2-2.0] but did not have significantly different odds of death (OR: 0.91, 95% CI, 0.59-1.4) or minor complications (OR: 1.2, 95% CI, 0.94-1.4).

CONCLUSION

Superobese patients had significantly higher odds of major complications within 30 days after hip fracture surgery compared with all other patients. This "obesity paradox" did not apply to superobese patients.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a Complete Description of Levels of Evidence.

Reducing unnecessary crossmatching for hip fracture patients by accounting for preoperative hemoglobin concentration

BACKGROUND

Maximum surgical blood order schedules were designed to eliminate unnecessary preoperative crossmatching prior to surgery in order to conserve blood bank resources. Most protocols recommend type and cross of 2 red blood cell (RBC) units for patients undergoing surgery for treatment of hip fracture. Preoperative hemoglobin has been identified as the strongest predictor of inpatient transfusion, but current maximum surgical blood order schedules do not consider preoperative hemoglobin values to determine the number of RBC units to prepare prior to surgery.

AIM

To determine the preoperative hemoglobin level resulting in the optimal 2:1 crossmatch-to-transfusion (C:T) ratio in hip fracture surgery patients.

METHODS

In 2015 a patient blood management (PBM) program was implemented at our institution mandating a single unit-per-occurrence transfusion policy and a restrictive transfusion threshold of < 7 g/dL hemoglobin in asymptomatic patients and < 8 g/dL in those with refractory symptomatic anemia or history of coronary artery disease. We identified all hip fracture patients between 2013 and 2017 and compared the preoperative hemoglobin which would predict a 2:1 C:T ratio in the pre PBM and post PBM cohorts. Prediction profiling and sensitivity analysis were performed with statistical significance set at P < 0.05.

RESULTS

Four hundred and ninety-eight patients who underwent hip fracture surgery between 2013 and 2017 were identified, 291 in the post PBM cohort. Transfusion requirements in the post PBM cohort were lower (51% vs 33%, P < 0.0001) than in the pre PBM cohort. The mean RBC units transfused per patient was 1.15 in the pre PBM cohort, compared to 0.66 in the post PBM cohort (P < 0.001). The 2:1 C:T ratio (inpatient transfusion probability of 50%) was predicted by a preoperative hemoglobin of 12.3 g/dL [area under the curve (AUC) 0.78 (95% confidence interval (CI), 0.72-0.83), Sensitivity 0.66] in the pre PBM cohort and 10.7 g/dL [AUC 0.78 (95%CI, 0.73-0.83), Sensitivity 0.88] in the post PBM cohort. A 50% probability of requiring > 1 RBC unit was predicted by 11.2g/dL [AUC 0.80 (95%CI, 0.74-0.85), Sensitivity 0.87] in the pre PBM cohort and 8.7g/dL [AUC 0.78 (95%CI, 0.73-0.83), Sensitivity 0.84] in the post-PBM cohort.

CONCLUSION

The hip fracture maximum surgical blood order schedule should consider preoperative hemoglobin in determining the number of units to type and cross prior to surgery.

Compensated Cirrhosis Is Associated With Increased Risk of Complications Following Total Hip Arthroplasty in a Large Medicare Database

BACKGROUND

The aim of this study is to evaluate medical and surgical complications of liver cirrhosis patients following total hip arthroplasty (THA), with attention to different etiologies of cirrhosis and their financial burden following THA.

METHODS

In total, 18,321 cirrhotics and 722,757 non-cirrhotics who underwent primary elective THA between 2006 and 2013 were identified from a retrospective database review. This cohort was further subdivided into 2 major etiologies of cirrhosis (viral and alcoholic cirrhosis) and other cirrhotic etiology. Cirrhotics were compared to non-cirrhotics for hospital length of stay, 90-day mean total charges and reimbursement, hospital readmission, and major medical and arthroplasty-specific complications.

RESULTS

Cirrhosis was associated with increased rates of major medical complications (4.3% vs 2.4%; odds ratio [OR] 1.20, P < .001), minor medical complications, transfusion (3.4% vs 2.1%; OR 1.16, P = .001), encephalopathy, disseminated intravascular coagulation, and readmission (13.5% vs 8.6%; OR 1.18, P < .001) within 90 days. Cirrhosis was associated with increased rates of revision, periprosthetic joint infection, hardware failure, and dislocation within 1 year postoperatively (3.1% vs 1.6%; OR 1.37, P < .001). Cirrhosis independently increased hospital length of stay by 0.14 days (P < .001), and it independently increased 90-day charges and reimbursements by $13,791 (P < .001) and $1707 (P < .001), respectively. Viral and alcoholic cirrhotics had higher rates of 90-day and 1-year complications compared to controls-other causes only had higher rates of 90-day medical complications, encephalopathy, readmission, and 1-year revision, hardware failure, and dislocation compared to controls.

CONCLUSION

Cirrhosis, especially viral and alcoholic etiologies, is associated with higher risk of early postoperative complications and healthcare utilization following elective THA.

Free Falling: Declining Inflation-Adjusted Payment for Arthroplasty Surgeons

BACKGROUND

Over the past decade, there have been ongoing concerns over declining surgeon compensation for lower extremity arthroplasty. We aimed to determine changes in surgeon payment, patient charges, and overall reimbursement rates for patients undergoing unicompartmental arthroplasty (UKA) and both primary and revision total knee (TKA) and hip (THA) arthroplasty.

METHODS

Using Medicare data from 2012 to 2017, we determined inflation-adjusted changes in annual surgeon payment (professional fee), patient charges, and reimbursement rate (payment-to-charge ratio) for UKA and primary/revision TKA and THA. Both nonweighted and weighted (by procedure frequency/volume) means were calculated.

RESULTS

Inflation-adjusted surgeon payment decreased for all procedures analyzed, with primary TKA (-17%) and THA (-11%) falling the most. Payment for UKA increased the most (+30%). There was a small increase in charges for THA revision (+2.2%, +2.1%, and +3.2% for acetabulum only, femur only, and both components, respectively). Charges for primary TKA (-3.7%) and THA (-1.5%) decreased slightly. The reimbursement rate for all procedures fell with UKA (-15%), TKA (-14%), and THA (-10%) falling the most. After weighting by procedure frequency/volume and combining all surgeries, average charges fell slightly (-0.7%), whereas surgeon payment (-13%) and reimbursement rate (-12%) fell more sharply.

CONCLUSION

Although patient charges have grown in pace with the inflationary rate for primary and revision TKA and THA, surgeon payment and reimbursement rates have fallen sharply. The orthopedic community needs to be aware of these financial trends to communicate to payers and health care policy makers the importance of protecting a sustainable payment infrastructure.

Routine Basic Metabolic Panels Are Not Needed in All Patients After Primary Total Joint Arthroplasty: An Opportunity for Cost Reduction

BACKGROUND

As the incidence of total joint arthroplasty (TJA) increases, identifying methods for cost reduction is essential. Basic metabolic panels (BMPs) are obtained routinely after TJA. We aimed at assessing the prevalence of intervention secondary to abnormal BMPs after primary TJA and at identifying predictors of the need for postoperative BMPs.

METHODS

We reviewed 802 cases (758 patients) of primary lower-extremity TJA performed from January 1 through December 31, 2018, at our tertiary care medical center. Patient characteristics, preoperative and postoperative BMPs, comorbidities, current medications, and in-hospital interventions were recorded. Age-adjusted Charlson Comorbidity Index (AA-CCI) values were calculated. Institutional costs of 1 BMP and of all BMPs not prompting intervention were calculated. We used multiple regression to identify independent predictors of in-hospital interventions secondary to abnormal postoperative BMPs.

RESULTS

Our institutional BMP cost was $36. A total of 1032 postoperative BMPs were ordered; 958 (93%) prompted no intervention. This equated to $34,488 of avoidable BMP costs. We identified 27 cases (3.4%) requiring intervention secondary to abnormal BMPs. Independent predictors of intervention were preoperative renal dysfunction (ie, abnormal creatinine or glomerular filtration rate <60 mL/min) (odds ratio [OR], 7.8; 95% confidence interval [CI], 2.8-22), number of current nephrotoxic medications (OR, 1.9; 95% CI, 1.3-2.9), and AA-CCI value (OR, 1.2; 95% CI, 1.0-1.5).

CONCLUSION

Routine postoperative BMPs are unwarranted for most patients undergoing primary TJA. Testing may be reserved for those with renal dysfunction, those taking multiple nephrotoxic medications, or those with a high AA-CCI value.

Impact of Compensated Cirrhosis Etiology on Postoperative Outcomes Following Total Knee Arthroplasty

BACKGROUND

Cirrhotics often demonstrate worse outcomes than their non-cirrhotic counterparts following orthopedic surgery; however, there are limited arthroplasty-focused data on this occurrence. Additionally, variances in postoperative outcomes among the different etiologies of cirrhosis have not been well described. The aim of this study is to evaluate the effect compensated cirrhosis had on postoperative outcomes following elective total knee arthroplasty (TKA).

METHODS

In total, 1,734,568 patients who underwent primary TKA from 2006 to 2013 were identified using the Medicare Claims Database. Patients were divided into those with a history of compensated cirrhosis and those with no history of liver disease. Subgroup analysis was performed based on the etiology of cirrhosis. Multivariate logistic regression was used to evaluate postsurgical outcomes of interest.

RESULTS

Cirrhotic patients had higher risk of developing disseminated intravascular coagulation (odds ratio [OR] 2.76, P = .003), encephalopathy (OR 3.00, P < .001), and periprosthetic infection (OR 1.79, P < .001) compared to controls. Following subgroup analysis, alcoholic cirrhotics had high risk of periprosthetic infection (OR 2.12, P < .001), fracture (OR 3.28, P < .001), transfusion (OR 2.45, P < .001), and encephalopathy (OR 7.34, P < .001) compared to controls. Viral cirrhosis was associated with an increase in 90-day charges ($14,941, P < .001) compared to controls, while cirrhosis secondary to other causes was associated with few adverse outcomes compared to controls.

CONCLUSION

Liver cirrhosis is an independent risk factor for increased perioperative morbidity and financial burden following TKA. Cirrhosis due to etiologies other than viral infections and alcoholism are associated with few adverse outcomes. Surgeons should be aware of these complications to properly optimize postoperative management.

Routine Preoperative Nutritional Screening in All Primary Total Joint Arthroplasty Patients Has Little Utility

BACKGROUND

Nutritional optimization before total joint arthroplasty (TJA) may improve patient outcomes and decrease costs. However, the utility of serologic laboratory markers, including albumin, transferrin, and total lymphocyte count (TLC), as primary indicators of nutrition is unclear. We analyzed the prevalence of abnormal nutritional values before TJA and identified factors associated with them.

METHODS

We retrospectively reviewed 819 primary cases of TJA performed at 1 institution from January to December 2018. Patient demographic characteristics were assessed for associations with abnormal preoperative nutritional values (albumin <3.5 g/dL, transferrin <200 mg/dL, and TLC <1.5 cells/μL³). Associations of comorbidities, American Society of Anesthesiologists Physical Status classification, and age-adjusted Charlson Comorbidity Index (CCI) with abnormal values were assessed with logistic regression.

RESULTS

Values were abnormal for albumin in 21 cases (2.6%), transferrin in 26 cases (5.6%), and TLC in 185 cases (25%). Thirteen cases (1.7%) had abnormal values for 2 markers. Age was associated with abnormal albumin and TLC, and race with abnormal transferrin. Congestive heart failure, chronic kidney disease, pancreatic insufficiency, gastroesophageal reflux disease, osteoporosis, dementia, and CCI were associated with abnormal albumin; Parkinson disease and American Society of Anesthesiologists Physical Status with abnormal transferrin; and dementia, body mass index, cancer history, and CCI with abnormal TLC.

CONCLUSION

We report low prevalence of and a low concordance rate among abnormal nutritional values before primary TJA. Our results suggest that routine testing of all healthy patients is not warranted before TJA.

Musculoskeletal Effects of Cancer and Cancer Treatment

Improvements in cancer treatment have led to prolonged survival and increased rates of cure. An estimated 14 million cancer survivors live in the United States. The cornerstones of cancer treatment, including radiation, chemotherapy, and surgery, give rise to a host of chronic health conditions, some of which affect the musculoskeletal system. As survivorship continues to improve, orthopaedic surgeons across all subspecialties will be tasked with managing these complications of treatment. This article reviews orthopaedic health concerns secondary to cancer treatment that are likely to present to orthopaedic surgeons for evaluation, such as osteoporosis, osteonecrosis, secondary malignancies, radiation-associated fractures, exercise tolerance, and perioperative evaluation.

Does Polycythemia Vera Increase Risk of Postoperative Complications Following Primary Total Joint Arthroplasty? A Retrospective Matched Control Cohort Study of 6932 Polycythemia Vera Patients

BACKGROUND

There is sparsity of data on outcomes following joint arthroplasty among polycythemia vera (PV) patients. The aim of this study is to evaluate postoperative outcomes following primary total knee (TKA) and hip (THA) arthroplasty among PV patients.

METHODS

A retrospective Medicare database review identified 6932 PV patients who underwent a primary total joint arthroplasty (4643 TKAs and 2289 THAs) from 2006 to 2013. A comparison of hospital length of stay, mortality, and the diagnosis of surgical site infections (SSIs), stroke, myocardial infarction, acute pulmonary embolism (PE), deep vein thrombosis (DVT), and other postoperative complications was made between PV patients undergoing TKA and THA and their respective matched control groups.

RESULTS

PV was significantly associated with increased rates of acute PE (2.3% vs 1.6%; odds ratio [OR] 1.44, 95% confidence interval [CI] 1.17-1.75), DVT (4.2% vs 3.6%; OR 1.40, 95% CI 1.20-1.61, P < .001), postoperative hematoma (0.6% vs 0.4%; OR 1.57, 95% CI 1.03-2.28), and SSI (4.5% vs 3.6%; OR 1.25, 95% CI 1.08-1.44, P = .002) following TKA. Among PV patients who underwent a primary THA, PV was significantly associated with increased rate of acute PE (1.9% vs 1.4%; OR 1.40, 95% CI 1.01-1.88, P = .035), DVT (3.5% vs 2.6%; OR 1.32, 95% CI 1.04-1.66, P = .035), postoperative hematoma (1.1% vs 0.6%; OR 1.86, 95% CI 1.22-2.80), and 1-year mortality (2.2% vs 1.6%; OR 1.43, 95% CI 1.06-1.89, P = .016).

CONCLUSION

PV was significantly associated with increased risk for DVT, PE, postoperative hematoma, SSI (TKA only), and 1-year mortality (THA only) following primary total joint arthroplasty.

Establishing Telemedicine in an Academic Total Joint Arthroplasty Practice: Needs and Opportunities Highlighted by the COVID-19 Pandemic

The coronavirus disease 2019 (COVID-19) pandemic has prompted rapid restructuring of the health-care system in an effort to stop the spread of the virus and to treat patients who are acutely ill with COVID-19, while continuing to provide outpatient care for the remainder of patients. To help control spread of this pandemic, many centers, including total joint arthroplasty clinics, have boosted telemedicine capability to care for patients who would typically be seen in person in outpatient settings. We review key components relevant to the establishment and effective use of telemedicine, focused on patient education, practice logistics, technological considerations, and sensitive patient health information–associated compliance factors, which are necessary to provide care remotely for total joint arthroplasty patients.

Revision Joint Arthroplasty and Renal Transplant: A Matched Control Cohort Study

BACKGROUND

There is little literature concerning clinical outcomes following revision joint arthroplasty in solid organ transplant recipients. The aims of this study are to (1) analyze postoperative outcomes and mortality following revision hip and knee arthroplasty in renal transplant recipients (RTRs) compared to non-RTRs and (2) characterize common indications and types of revision procedures among RTRs.

METHODS

A retrospective Medicare database review identified 1020 RTRs who underwent revision joint arthroplasty (359 revision total knee arthroplasty [TKA] and 661 revision total hip arthroplasty [THA]) from 2005 to 2014. RTRs were compared to their respective matched control groups of nontransplant revision arthroplasty patients for hospital length of stay, readmission, major medical complications, infections, septicemia, and mortality following revision.

RESULTS

Renal transplantation was significantly associated with increased length of stay (6.12 ± 7.86 vs 4.33 ± 4.29, P < .001), septicemia (odds ratio [OR], 2.52; 95% confidence interval [CI], 1.83-3.46; P < .001), and 1-year mortality (OR, 2.71; 95% CI, 1.51-4.53; P < .001) following revision TKA. Among revision THA patients, RTR status was associated with increased hospital readmission (OR, 1.23; 95% CI, 1.03-1.47; P = .023), septicemia (OR, 1.82; 95% CI, 1.41-2.34; P < .001), and 1-year mortality (OR, 2.65; 95% CI, 1.88-3.66; P < .001). The most frequent primary diagnoses associated with revision TKA and THA among RTRs were mechanical complications of prosthetic implant.

CONCLUSION

Prior renal transplantation among revision joint arthroplasty patients is associated with increased morbidity and mortality when compared to nontransplant recipients.

Healing of Pathologic Humeral Fractures in Patients with Metastatic Disease: Consideration for Operative Fixation in Patients

We compared short-term outcomes after operative versus nonoperative treatment of pathologic humeral fractures. We hypothesized that patients who underwent operative fixation would heal faster and have better pain control. A retrospective review was conducted of 25 patients who underwent operative fixation and 6 who received nonoperative treatment from 2005-2017. Operative patients healed significantly earlier than nonoperative patients (p = 0.02). At 16-week follow-up, radiographs showed evidence of healing in 24 of 25 operatively treated patients and 2 of 6 nonoperatively treated patients (p < 0.01). Pain improved during the inpatient stay in 24 of 25 operatively treated patients and none of the nonoperatively treated patients (p < 0.01). All operatively treated patients returned to self-reported baseline motor function by final follow-up, whereas none of the nonoperatively treated patients returned to baseline (p = 0.01). Operative treatment was associated with earlier healing, pain control and return to function compared with nonoperative treatment of pathologic humeral fractures. Level of Evidence: 3. (Journal of Surgical Orthopaedic Advances 29(3):177-181, 2020).

Recent Preoperative Lumbar Epidural Steroid Injection Is an Independent Risk Factor for Incidental Durotomy During Lumbar Discectomy

STUDY DESIGN

Retrospective review.

OBJECTIVE

To investigate the association between lumbar epidural steroid injection (LESI) and incidental durotomy (ID) in patients with a diagnosis of disc herniation undergoing a primary discectomy.

METHODS

A Medicare patient database was queried for patients between the ages of 65 and 85 years who underwent a primary lumbar discectomy for a diagnosis of lumbar disc herniation or degeneration from 2008 to 2014. Our main cohort of 64 849 patients was then divided into 2 groups: patients who experienced a dural tear (N = 2369) and our matched (age, gender, and history of diabetes) control cohort of patients who did not (N = 62 480). All patients who had a history of LESI were further identified and stratified into 4 subgroups by duration between LESI and discectomy (<3 months, 3-6 months, 6 months to 1 year, and overall), and a comparison of the relative incidence of ID was made among these subgroups. A multivariate logistic regression analysis was employed to determine the relationship between LESI and ID.

RESULTS

Overall incidence of ID was 3.7%. There was a significant difference in incidence of LESI (27.1% vs 35.0%, P < .001) between our control and ID groups. An adjusted odds ratio (OR) showed that prior LESI within 3 to 6 months (OR 1.47, 95% CI 1.20-1.81, P < .001) and within less than 3 months (OR 1.46, 95% CI 1.24-1.72, P < .001) of surgery were significantly associated with ID.

CONCLUSION

LESI increases the risk of ID in patients who undergo a subsequent lumbar discectomy within 6 months of injection.

Opioid-related compartment syndrome and associated morbidity

INTRODUCTION

Opioid-related compartment syndrome (ORCS) is an understudied complication related to opioid overdose. We hypothesized that ORCS would be associated with worse clinical outcomes, including higher amputation rates, need for multiple surgical procedures, and rhabdomyolysis on admission, compared with nonopioid-related compartment syndrome (NORCS).

METHODS

We used Current Procedural Terminology codes for fasciotomy as a proxy marker for cases of compartment syndrome treated at 1 health system from January 1, 2016, to December 21, 2018. We excluded patients younger than 18 years, those treated for exertional compartment syndrome, and those who underwent elective fasciotomies. Seventy-four patients met our inclusion criteria. Data reviewed included patient characteristics, cause of compartment syndrome, time until evaluation for compartment syndrome, peak creatinine kinase levels, number of surgical procedures required, duration of hospital stay, and postoperative inpatient morbidity and death. Patients were categorized as having ORCS (n = 8) or NORCS (n = 66). Alpha = .05.

RESULTS

All cases of ORCS occurred in men. Opioid use was the third most common cause of compartment syndrome. Two patients underwent amputation, both in the ORCS group (p <  0.01). The median number of debridements was significantly higher for the ORCS group (median, 4; interquartile range [IQR]: 3-6) than for the NORCS group (median, 3; IQR 2-4) (p =  0.03). Duration of hospital stay was longer for the ORCS group (median, 27 days; IQR 16-38) compared with the NORCS group (median, 9 days; IQR: 5-13) (p <  0.001). Mean (± standard deviation) peak creatinine kinase level was significantly higher in the ORCS group (224,000 ± 225,052 U/L) compared with the NORCS group (7550 ± 32,500) (p <  0.001). The proportion of patients who underwent hemodialysis was higher in the ORCS group (88%) than in the NORCS group (35%) (p <  0.001). All ORCS patients presented >8 h after immobilization in a dependent position.

CONCLUSION

Patients in the ORCS group had delayed presentations and significantly more morbidity compared with patients in the NORCS group.

Cross-country transport and isolation and identification of Streptococcus pneumoniae by use of alternate sources of blood supplemented media among laboratories in India

Background

The isolation of S. pneumoniae (Sp) depends on specimen integrity / transport, media and expertise. The non-availability of sheep blood agar poses a challenge in identification of colonial morphology and identification in India.

Methods

Laboratories processed swabs containing either pure Sp or Sp in mixed cultures with a second (confounding) bacterium shipped across the country in cold conditions. Duplicate set of swabs was shipped back to the central laboratory to assess the impact of shipping on culture viability. The identical swab was cultured on sheep, human blood and one additional agar plate used in the laboratory.

Results

46/60(77%) of cultures containing only Sp were correctly identified. In specimens where Sp was present in mixed culture, the proportion of isolates in which Sp was correctly identified varied, with most variability attributed to the particular confounding organism rather than the media. There was no discernible impact of temperature-controlled (4-6°C) transport on the isolation of Sp from culture swabs.

Conclusions

The study clearly elucidates the ability of laboratories for isolation of S. pneumoniae on human blood agar in resource limited settings. The results highlight the difficulties inherent in correctly identifying pathogens in mixed cultures in needs improvement using standardized tests across the study centers. The study also reaffirms the ability to transport biological specimens over long geographical distances without loss.

Extremity gossypiboma mimicking sarcoma: case report and review

A 70-year-old man with a history of bladder and colon cancer presented with an enlarging mass in his right lower extremity. Forty years before presentation, he had injured his right lower extremity in a motor vehicle accident. Imaging findings indicated suspected sarcoma, which led to biopsy. Biopsy and further surgical exploration revealed the presence of a surgical sponge and surrounding local inflammatory reaction. No neoplasm was found, and the sponge and involved tissues were removed. Gossypiboma is exceedingly rare in the extremities. Imaging of retained foreign material can appear suggestive of sarcoma because of strong inflammatory responses and local tissue mass-like derangement resulting in heterogeneous signal changes. Ultimately, biopsy must be performed to ensure that no oncological pathological condition is present.

A Road Map for Important Centers of Growth in the Pediatric Skeleton to Consider During Radiation Therapy and Associated Clinical Correlates of Radiation-Induced Growth Toxicity

With the increasing use of advanced radiation techniques such as intensity modulated radiation therapy, stereotactic radiation therapy, and proton therapy, radiation oncologists now have the tools to mitigate radiation-associated toxicities. This is of utmost importance in the treatment of a pediatric patient. To best use these advanced techniques to mitigate radiation-induced growth abnormalities, the radiation oncologist should be equipped with a nuanced understanding of the anatomy of centers of growth. This article aims to enable the radiation oncologist to better understand, predict, and minimize radiation-mediated toxicities on growth. We review the process of bone development and radiation-induced growth abnormalities and provide an atlas for contouring important growth plates to guide radiation treatment planning. A more detailed recognition of important centers of growth may improve future treatment outcomes in children receiving radiation therapy.

A high-resolution anorectal manometry parameter based on integrated pressurized volume: A study based on 204 male patients with constipation and 26 controls

BACKGROUND

Conventional anorectal manometric parameters based on linear waves cannot properly predict balloon expulsion (BE) time. We aimed to determine the correlation between integrated pressurized volume (IPV) parameters during simulated evacuation (SE) and BE time in healthy individuals and constipated patients and to assess the correlation between each parameter and symptoms.

METHODS

A total of 230 male participants (including 26 healthy volunteers and 204 chronically constipated patients) underwent high-resolution anorectal manometry (HRAM) and BE tests. The IPV was calculated by multiplying the amplitude, distance, and time from the HRAM profile. Receiver operating characteristic curve (ROC) analysis and partial least square regression (PLSR) were performed.

KEY RESULTS

ROC analysis indicated that the IPV ratio between the upper 1 cm and lower 4 cm of the anal canal was more effective for predicting BE time (area under the curve [AUC]: 0.74, 95% confidence interval [CI]: 0.67-0.80, P < .01) than the conventional anorectal parameters, including defecation index and rectoanal gradient (AUC: 0.60, 95% CI: 0.52-0.67, P = .01). PLSR analysis of a linear combination of IPV parameters yielded an AUC of 0.79. Moreover, the IPV ratio showed a greater clinical correlation with patient symptoms than conventional parameters.

CONCLUSIONS AND INFERENCES

The IPV parameters and the combination of IPV parameters via PLSR were more significantly correlated with BE time than the conventional parameters. Thus, this study presents a useful diagnostic tool for the evaluation of pathophysiologic abnormalities in dyssynergic defecation using IPV and BE time.

Determinants of perioperative transfusion risk in patients with adult spinal deformity

OBJECTIVE

To determine predictors of perioperative allogeneic packed red blood cell (pRBC) transfusion requirement (total units transfused) in patients with adult spinal deformity (ASD).

METHODS

The authors retrospectively analyzed records of patients aged 18 years or older who underwent surgical correction of ASD that involved 4 or more spinal levels by the same spine surgeon between 2010 and 2016. Data regarding patient characteristics, comorbidities, surgical factors, and perioperative transfusions (up to 10 days after surgery) were analyzed using a linear regression model. Significance was set at p < 0.05.

RESULTS

The authors analyzed 165 patients (118 women) with a mean (± SD) age of 61 ± 12 years. Three-column osteotomies were associated with a mean intraoperative transfusion volume of 1.74 additional units of pRBCs. Each unit of intraoperatively salvaged blood used was associated with a mean 0.39-U increase in postoperative transfusion volume (p = 0.031). Every unit of allogeneic blood transfused intraoperatively was associated with a mean 0.23-U decrease in postoperative transfusion volume (p = 0.001). A preoperative hemoglobin concentration of 11.5 g/dl or more was associated with significantly fewer units transfused intraoperatively; a preoperative hemoglobin concentration of 14.0 g/dl or more was associated with fewer units transfused postoperatively. A history of smoking and intraoperative antifibrinolytic use were associated with increased and decreased numbers of units transfused postoperatively, respectively.

CONCLUSIONS

Effective blood management is key to perioperative care of patients with ASD. Three-column osteotomies were associated with a greater number of units of blood transfused. When considering postoperative transfusion requirements, surgeons should note that intraoperative blood salvage might be inferior to intraoperative allogeneic blood transfusion. Using antifibrinolytics and increasing the preoperative hemoglobin concentration to 11.5 g/dl or more are strategies for decreasing the need for perioperative transfusion. A history of smoking is a risk factor for postoperative transfusion requirement (total units transfused).

Development, content validity, and cross-cultural adaptation of a patient-reported outcome measure for real-time symptom assessment in irritable bowel syndrome

BACKGROUND

End-of-day questionnaires, which are considered the gold standard for assessing abdominal pain and other gastrointestinal (GI) symptoms in irritable bowel syndrome (IBS), are influenced by recall and ecological bias. The experience sampling method (ESM) is characterized by random and repeated assessments in the natural state and environment of a subject, and herewith overcomes these limitations. This report describes the development of a patient-reported outcome measure (PROM) based on the ESM principle, taking into account content validity and cross-cultural adaptation.

METHODS

Focus group interviews with IBS patients and expert meetings with international experts in the fields of neurogastroenterology & motility and pain were performed in order to select the items for the PROM. Forward-and-back translation and cognitive interviews were performed to adapt the instrument for the use in different countries and to assure on patients' understanding with the final items.

KEY RESULTS

Focus group interviews revealed 42 items, categorized into five domains: physical status, defecation, mood and psychological factors, context and environment, and nutrition and drug use. Experts reduced the number of items to 32 and cognitive interviewing after translation resulted in a few slight adjustments regarding linguistic issues, but not regarding content of the items.

CONCLUSIONS AND INFERENCES

An ESM-based PROM, suitable for momentary assessment of IBS symptom patterns was developed, taking into account content validity and cross-cultural adaptation. This PROM will be implemented in a specifically designed smartphone application and further validation in a multicenter setting will follow.

Cellulase production through solid-state tray fermentation, and its use for bioethanol from sorghum stover

The production of cellulase by Trichoderma reesei RUT C-30 under solid-state fermentation (SSF) on wheat bran and cellulose was optimized employing a two stage statistical design of experiments. Optimization of process parameters resulted in a 3.2-fold increase in CMCase production to 959.53IU/gDS. The process was evaluated at pilot scale in tray fermenters and yielded 457IU/gDS using the lab conditions and indicating possibility for further improvement. The cellulase could effectively hydrolyze alkali pretreated sorghum stover and addition of Aspergillus niger β-glucosidase improved the hydrolytic efficiency 174%, indicating the potential to use this blend for effective saccharification of sorghum stover biomass. The enzymatic hydrolysate of sorghum stover was fermented to ethanol with ∼80% efficiency.

Methods of anorectal manometry vary widely in clinical practice: Results from an international survey

BACKGROUND

Ano-rectal manometry (ARM) is the most commonly performed investigation for assessment of anorectal dysfunction. Its use is supported by expert consensus documents and international guidelines. Variation in technology, data acquisition, and analysis affect results and clinical interpretation. This study examined variation in ARM between institutions to establish the status of current practice.

METHODS

A 50-item web-based questionnaire assessing analysis and interpretation of ARM was distributed by the International Anorectal Physiology Working Group via societies representing practitioners that perform ARM. Study methodology and performance characteristics between institutions were compared.

KEY RESULTS

One hundred and seven complete responses were included from 30 countries. Seventy-nine (74%) institutions performed at least two studies per week. Forty-nine centers (47%) applied conventional ARM (≤8 pressure sensors) and 57 (53%) high-resolution ARM (HR-ARM). Specialist centers were most likely to use HR-ARM compared to regional hospitals and office-based practice (63% vs 37%). Most conventional ARM systems used water-perfused technology (34/49); solid-state hardware was more frequently used in centers performing HR-ARM (44/57). All centers evaluated rest and squeeze. There was marked variation in the methods used to report results of maneuvers. No two centers had identical protocols for patient preparation, setup, study, and data interpretation, and no center fully complied with published guidelines.

CONCLUSIONS & INFERENCES

There is significant discrepancy in methods for data acquisition, analysis, and interpretation of ARM. This is likely to impact clinical interpretation, transfer of data between institutions, and research collaboration. There is a need for expert international co-operation to standardize ARM.

Quantifying Health Status and Function in Marfan Syndrome

Two hundred thirty patients were prospectively enrolled in this study and completed various portions of the Short Form 36 and a study-specific questionnaire (visual analog scale 1 to 10, comprising three separate questionnaires) to evaluate quality of life and function in patients with Marfan syndrome. The greatest health concern was cardiac problems (high in 70% of patients), followed by spine issues and generalized fatigue (both high, in 53%). The most severe reported pain involved the back: 105 patients (46%) rated pain as 6 to 10 on the visual analog scale. Among the 72 patients who responded to work life questions, work hours were reduced because of treatment in 59 (82%) or directly because of Marfan syndrome in 29 (40%). Across all Short Form 36 domains, patients scored significantly lower than United States population norms (p<.05); physical health scores were considerably lower than mental health scores.

Regional gastrointestinal transit and pH studied in 215 healthy volunteers using the wireless motility capsule: influence of age, gender, study country and testing protocol

BACKGROUND

The wireless motility capsule (WMC) offers the ability to investigate luminal gastrointestinal (GI) physiology in a minimally invasive manner.

AIM

To investigate the effect of testing protocol, gender, age and study country on regional GI transit times and associated pH values using the WMC.

METHODS

Regional GI transit times and pH values were determined in 215 healthy volunteers from USA and Sweden studied using the WMC over a 6.5-year period. The effects of test protocol, gender, age and study country were examined.

RESULTS

For GI transit times, testing protocol was associated with differences in gastric emptying time (GET; shorter with protocol 2 (motility capsule ingested immediately after meal) vs. protocol 1 (motility capsule immediately before): median difference: 52 min, P = 0.0063) and colonic transit time (CTT; longer with protocol 2: median 140 min, P = 0.0189), but had no overall effect on whole gut transit time. Females had longer GET (by median 17 min, P = 0.0307), and also longer CTT by (104 min, P = 0.0285) and whole gut transit time by (263 min, P = 0.0077). Increasing age was associated with shorter small bowel transit time (P = 0.002), and study country also influenced small bowel and CTTs. Whole gut and CTTs showed clustering of data at values separated by 24 h, suggesting that describing these measures as continuous variables is invalid. Testing protocol, gender and study country also significantly influenced pH values.

CONCLUSIONS

Regional GI transit times and pH values, delineated using the wireless motility capsule (WMC), vary based on testing protocol, gender, age and country. Standardisation of testing is crucial for cross-referencing in clinical practice and future research.

Cervical fractures with associated spinal cord injury in children and adolescents: epidemiology, costs, and in-hospital mortality rates in 4418 patients

BACKGROUND

Cervical spine fractures with spinal cord injury (CFSCI) can be devastating. We describe the epidemiology of children and adolescents with CFSCI.

METHODS

Using the Nationwide Inpatient Sample (NIS) database, we identified 4418 patients (≤18 years old) who had CFSCI from 2000 through 2010. Outcomes of interest were patient characteristics (age, sex), injury characteristics [fracture location, spinal cord injury (SCI) pattern], economic variables (duration of hospital stay, total hospital charges), and mortality.

RESULTS

Upper cervical fractures (UCFs) occurred half as often (31.4 %) as lower cervical fractures (LCFs; 68.8 %). Among patients <8 years old, 73.6 % had UCFs; among patients ≥8 years old, 72.3 % had LCFs. Overall, 68.7 % had incomplete SCI, 22.4 % had complete SCI, 6.6 % had central cord syndrome, and 2.3 % had anterior cord syndrome. Patients with complete SCI had the longest hospital stays and highest hospital charges. The overall in-hospital mortality rate was 7.3 %, with a sixfold higher rate in patients <8 (30.6 %) vs. those ≥8 (5.1 %) years old (p < 0.001). There was a threefold higher mortality rate in patients with upper (13.5 %) vs. lower (4.3 %) cervical fractures (p < 0.001). Patients with complete SCI had a 1.85-fold higher mortality rate than patients with other cord syndromes (p < 0.001).

CONCLUSIONS

Patients <8 years old were more likely than older patients to sustain UCFs. Patients with UCFs had a significantly higher mortality rate than those with LCFs. Patients with complete SCI had the longest duration of hospital stay and highest hospital charges and in-hospital mortality rate.

Dilute acid pretreatment and enzymatic hydrolysis of sorghum biomass for sugar recovery--a statistical approach

Sorghum is one of the commercially feasible lignocellulosic biomass and has a great potential of being sustainable feedstock for renewable energy. As with any lignocellulosic biomass, sorghum also requires pretreatment which increases its susceptibility to hydrolysis by enzymes for generating sugars which can be further fermented to alcohol. In the present study, sorghum biomass was evaluated for deriving maximum fermentable sugars by optimizing various pretreatment parameters using statistical optimization methods. Pretreatment studies were done with H2SO4, followed by enzymatic saccharification. The efficiency of the process was evaluated on the basis of production of the total reducing sugars released during the process. Compositional analysis was done for native as well as pretreated biomass and compared. The biomass pretreated with the optimized conditions could yield 0.408 g of reducing sugars /g of pretreated biomass upon enzymatic hydrolysis. The cellulose content in the solid portion obtained after pretreatment using optimised conditions was found to be increased by 43.37% with lesser production of inhibitors in acid pretreated liquor.

Phase I study of weekly nab-paclitaxel + weekly cetuximab + intensity-modulated radiation therapy (IMRT) in patients with stage III-IVB head and neck squamous cell carcinoma (HNSCC)

BACKGROUND

There is a clinical need to improve the efficacy of standard cetuximab + concurrent intensity-modulated radiation therapy (IMRT) for patients with locally and/or regionally advanced HNSCC. Taxanes have radiosensitizing activity against HNSCC, and nab-paclitaxel may offer therapeutic advantage in comparison with other taxanes.

PATIENTS AND METHODS

This was a single-institution phase I study with a modified 3 + 3 design. Four dose levels (DLs) of weekly nab-paclitaxel were explored (30, 45, 60, and 80 mg/m(2)), given with standard weekly cetuximab (450 mg/m(2) loading dose followed by 250 mg/m(2) weekly) and concurrent IMRT (total dose, 70 Gy).

RESULTS

Twenty-five eligible patients (20 M, 5 F) enrolled, with median age 58 years (range, 46-84 years). Primary tumor sites were oropharynx, 19 (10 human papillomavirus [HPV] pos, 8 HPV neg, 1 not done); neck node with unknown primary, 2; larynx 2; and oral cavity and maxillary sinus, 1 each. Seven patients had received prior induction chemotherapy. Maximum tolerated dose (MTD) was exceeded at DL4 (nab-paclitaxel, 80 mg/m(2)) with three dose-limiting toxicities (DLTs) (grade 3 neuropathy, grade 3 dehydration, with grade 3 mucositis grade 3 anemia) among five assessable patients. There was only one DLT (grade 3 supraventricular tachycardia) among six patients at DL3 (nab-paclitaxel, 60 mg/m(2)), and this was deemed the MTD. Among 23 assessable patients, the most common ≥ g3 AEs were lymphopenia 100%, functional mucositis 65%, and pain in throat/oral cavity 52%. At a median follow-up of 33 months, 2-year failure-free survival (FFS) is 65% [95% confidence interval (CI) 42% to 81%] and 2-year overall survival (OS) is 91% (95% CI 69-97).

CONCLUSION

The recommended phase II dose for nab-paclitaxel is 60 mg/m(2) weekly when given standard weekly cetuximab and concurrent IMRT. This regimen merits further study as a nonplatinum alternative to IMRT + cetuximab alone.

CLINICALTRIALSGOV ID

NCT00736619.

Interface magnetism in epitaxial BiFeO3-La0.7Sr0.3MnO3 heterostructures integrated on Si(100)

We report on the heteroepitaxial growth of ferroelectric (FE)-antiferromagnetic (AFM) BiFeO3 (BFO) on ferromagnetic La0.7Sr0.3MnO3 (LSMO), integrated on Si(100) using pulsed laser deposition via the domain matching epitaxy paradigm. The BFO/LSMO films were epitaxially grown on Si(100) by introducing epitaxial layers of SrTiO3/MgO/TiN. X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photo absorption spectroscopy, and atomic force microscopy were employed to fully characterize the samples. Furthermore, we have investigated the magnetic behavior of this five layer heterostructure, in which a d(5) system (Fe(3+)) manifested in FE-AFM BFO is epitaxially conjoined at the interface to a multivalent transition metal ion such as Mn(3+)/Mn(4+) in LSMO. The temperature- and magnetic field-dependent magnetization measurements reveal an unexpected enhancement in magnetic moment and improved magnetic hysteresis squareness originating from the BFO/LSMO interface. We observe a stronger temperature dependence of HEB when the polarity of field cooling is negative as compared to positive field cooling. We believe such an enhancement in magnetic moment and magnetic coupling is likely directly related to an electronic orbital reconstruction at the interface and complex interplay between orbital and spin degrees of freedom, similar to what has previously been reported in the literature. Future work will involve the linearly polarized X-ray absorption measurements to prove this hypothesis. This work represents a starting step toward the realization of magneto-electronic devices integrated with Si(100).

Validated Stability-indicating High-performance Liquid Chromatographic Method for Estimation of Degradation Behaviour of Eberconazole Nitrate and Mometasone Furoate in Cream Formulation

The objective of current investigation was to study the degradation behaviour of eberconazole nitrate and mometasone furoate under different International Conference on harmonisation recommended stress condition using reverse phase high performance liquid chromatographic method and to establish validated stability-indicating high performance liquid chromatographic method to determine purity of eberconazole nitrate and mometasone furoate in presence of its impurities, forced degradation products and placebo in pharmaceutical dosage forms. The method was developed using Hypersil BDS, C18, 150Χ4.6 mm, 5 μ as stationary phase with mobile phase containing a gradient mixture of solvent A and B. 0.01 M phosphate buffer with 0.1% triethyl amine, adjusted pH 7.0 with phosphoric acid was used as buffer. Buffer pH 7.0 was used as solvent A and methanol:acetonitrile in 150:850 v/v ratios were used as solvent B. The eluted compounds were monitored at 240 nm. The run time was 50 min. The developed method was validated as per international conference on harmonization guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness.

Randomised clinical trials: linaclotide phase 3 studies in IBS-C - a prespecified further analysis based on European Medicines Agency-specified endpoints

BACKGROUND

Treatment options that improve overall symptoms of irritable bowel syndrome with constipation (IBS-C) are lacking.

AIM

A prespecified further analysis to evaluate the efficacy and safety of linaclotide, a guanylate cyclase C agonist, in patients with IBS-C, based on efficacy parameters prespecified for European Medicines Agency (EMA) submission.

METHODS

Two randomised, double-blind, multicentre Phase 3 trials investigated once-daily linaclotide (290 μg) for 12 weeks (Trial 31) or 26 weeks (Trial 302) in patients with IBS-C. Prespecified primary endpoints were the EMA-recommended co-primary endpoints: (i) 12-week abdominal pain/discomfort responders [≥30% reduction in mean abdominal pain and/or discomfort score (11-point scales), with neither worsening from baseline, for ≥6 weeks] and (ii) 12-week IBS degree-of-relief responders (symptoms 'considerably' or 'completely' relieved for ≥6 weeks).

RESULTS

Overall, 803 (Trial 31) and 805 patients (Trial 302) were randomised. A significantly greater proportion of linaclotide-treated vs. placebo-treated patients were 12-week abdominal pain/discomfort responders (Trial 31: 54.8% vs. 41.8%; Trial 302: 54.1% vs. 38.5%; P < 0.001) and IBS degree-of-relief responders (Trial 31: 37.0% vs. 18.5%; Trial 302: 39.4% vs. 16.6%; P < 0.0001). Similarly, significantly more linaclotide- vs. placebo-treated patients were responders for ≥13 weeks in Trial 302 (abdominal pain/discomfort: 53.6% vs. 36.0%; IBS degree-of-relief: 37.2% vs. 16.9%; P < 0.0001). The proportion of sustained responders (co-primary endpoint responders plus responders for ≥2 of the last 4 weeks of treatment) was also significantly greater with linaclotide vs. placebo in both trials (P < 0.001).

CONCLUSION

Linaclotide treatment significantly improved abdominal pain/discomfort and degree-of-relief of IBS-C symptoms compared with placebo over 12 and 26 weeks.

TRIAL REGISTRATION

ClinicalTrials.gov (identifiers: NCT00948818 and NCT00938717).

Ferromagnetism in graphene nanoribbons: split versus oxidative unzipped ribbons

Two types of graphene nanoribbons: (a) potassium-split graphene nanoribbons (GNRs), and (b) oxidative unzipped and chemically converted graphene nanoribbons (CCGNRs) were investigated for their magnetic properties using the combination of static magnetization and electron spin resonance measurements. The two types of ribbons possess remarkably different magnetic properties. While a low-temperature ferromagnet-like feature is observed in both types of ribbons, such room-temperature feature persists only in potassium-split ribbons. The GNRs show negative exchange bias, but the CCGNRs exhibit a "positive exchange bias". Electron spin resonance measurements suggest that the carbon-related defects may be responsible for the observed magnetic behavior in both types of ribbons. Furthermore, information on the proton hyperfine coupling strength has been obtained from hyperfine sublevel correlation experiments performed on the GNRs. Electron spin resonance finds no evidence for the presence of potassium (cluster) related signals, pointing to the intrinsic magnetic nature of the ribbons. Our combined experimental results may indicate the coexistence of ferromagnetic clusters with antiferromagnetic regions leading to disordered magnetic phase. We discuss the possible origin of the observed contrast in the magnetic behaviors of the two types of ribbons studied.

Electron spin resonance investigation of ultra-small double walled carbon nanotubes embedded in zeolite nanochannels

We report on the low temperature electron spin resonance (ESR) properties of ultra-small (0.45 nm) double walled carbon nanotubes (DWCNTs) embedded in zeolite nanochannels. An isotropic ESR signal is observed at g(c) = 2.002 77 with the spin density (S = 1/2) ∼ 10(19) g(-1), which is suggested to originate from the carbon related point defects in the DWCNTs. Measurements of the ESR line width and signal intensity as a function of temperature indicate that the spins are of a localized nature as opposed to the conduction type electrons observed in large diameter CNTs. The results are consistent with the suggestion that electrons are trapped at interstitial defects. The observed linear frequency dependence of the ESR line width of embedded DWCNTs points to 'strain' as the prime source of broadening. By contrast, the study of free standing DWCNTs shows the presence of a distinctly superlinear frequency dependence of the signal width at low temperatures. The possible origin of the frequency dependence is discussed.

Probing the existing magnetic phases in Pr0.5Ca0.5MnO3 (PCMO) nanowires and nanoparticles: magnetization and magneto-transport investigations

We show from conventional magnetization measurements that the charge order (CO) is completely suppressed in 10 nm Pr(0.5)Ca(0.5)MnO(3)(PCMO 10) nanoparticles. Novel magnetization measurements, designed by a special high field measurement protocol, show that the dominant ground state magnetic phase is ferromagnetic-metallic (FM-M), which is an equilibrium phase, which coexists with the residual charge ordered anti-ferromagnetic phase (CO AFM) (an arrested phase) and exhibits the characteristic features of a 'magnetic glassy state' at low temperatures. It is observed that there is a drastic reduction in the field required to induce the AFM to FM transition (∼5-6 T) compared to their bulk counterpart (∼27 T); this phase transition is of first order in nature, broad, irreversible and the coexisting phases are tunable with the cooling field. Temperature-dependent magneto-transport data indicate the occurrence of a size-induced insulator-metal transition (T(M-I)) and anomalous resistive hysteresis (R-H) loops, pointing out the presence of a mixture of the FM-M phase and AFM-I phase.

Pathophysiology of evacuation disorders

This review details our contemporary knowledge of the mechanisms underlying evacuatory disorders. There is confusion concerning terminology and classification, which is based upon both an incomplete understanding of the multiple mechanisms involved in evacuation, and that current tests to investigate it are not physiological. Nevertheless, despite the need for more research, significant advances have been made and current assessments can direct therapy.

Chronic constipation: overview and challenges

Despite its high prevalence and cost implications, our understanding of the pathophysiology of constipation remains primitive, and available therapies have limited efficacy. The purpose of this supplement is to address critically the reasons for the current lack of understanding and to propose avenues of future research to address these deficiencies.

Conservative and behavioural management of constipation

This article deals with psychological contributions, such as stool withholding or responses to abuse experiences, to the aetiology of evacuation disorders (with a focus on dyssynergic defecation), and with education and behavioural approaches to treatment.

Realizing the 'hindered charge ordered phase' in nanoscale charge ordered manganites: magnetization, magneto-transport and EPR investigations

We report three prominent observations made on the nanoscale charge ordered (CO) manganites RE(1-x)AE(x)MnO(3) (RE = Nd,Pr; AE = Ca; x = 0.5) probed by temperature dependent magnetization and magneto-transport, coupled with electron magnetic/paramagnetic resonance spectroscopy (EMR/EPR). First, evidence is presented to show that the predominant ground state magnetic phase in nanoscale CO manganites is ferromagnetic and it coexists with a residual anti-ferromagnetic phase. Secondly, the shallow minimum in the temperature dependence of the EPR linewidth shows the presence of a charge ordered phase in nanoscale manganites which was shown to be absent from the DC static magnetization and transport measurements. Thirdly, the EPR linewidth, reflective of spin dynamics, increases significantly with a decrease of particle size in CO manganites. We discuss the interesting observations made on various samples of different particle sizes and give possible explanations. We have shown that EMR spectroscopy is a highly useful technique to probe the 'hindered charge ordered phase' in nanoscale CO manganites, which is not possible by static DC magnetization and transport measurements.