Body morphometry did not affect the accuracy of a second-generation, miniature imageless navigation system for total hip arthroplasty (THA) using a posterior approach.

Introduction: Some modern imageless navigation platforms for total hip arthroplasty (THA) rely on virtual frontal and sagittal planes determined with the patient in the lateral decubitus position. Body morphometry that changes with gender, body mass index, and other demographic factors may affect accuracy in patient positioning and consequently, navigation accuracy. The objective of this study was to analyze the influence of patient factors on the intraoperative accuracy of a second-generation imageless computer-assisted surgery platform. Methods: 325 consecutive patients undergoing posterior approach, navigated THA arthroplasty for primary osteoarthritis by a single surgeon were retrospectively reviewed. An optic-based imageless navigation system referenced off a generic sagittal and coronal plane was used to determine acetabular inclination and anteversion. Acetabular accuracy was determined by assessing differences between intraoperative values and those obtained from measuring standardized 6-week follow-up radiographs. The effect of age, gender, BMI, race, ethnicity, and laterality on acetabular accuracy was assessed via t-tests, Pearson correlation and ANOVA. Results: Gender had a significant impact on raw inclination accuracy (females and males had an average error of 1.41° and -1.03°, respectively - p < 0.001). There was a weak correlation between acetabular accuracy and patient age and BMI as a continuous variable (both absolute γ < 0.2). No difference was found between acetabular accuracy and BMI groups. Conclusion: This second-generation imageless computer assisted device provided accurate cup positioning regardless of patient's BMI. Gender was the only factor impacting inclination accuracy.

Substantial Weight Loss May Not Improve Early Outcomes of Total Knee Arthroplasty in the Morbidly Obese.

INTRODUCTION: Body mass index (BMI) cutoffs for morbidly obese patients otherwise indicated for total knee arthroplasty (TKA) have been widely proposed and implemented, though they remain controversial. Previous studies suggested that a 5% reduction in BMI may be associated with fewer postoperative complications. Thus, the purpose of this study was to determine whether a substantial reduction in preoperative BMI in morbidly obese patients improved 90-day outcomes after TKA. METHODS: There were 1,270 patients who underwent primary TKA at a single institution and had a BMI > 40 recorded during the year prior to surgery. Patients were stratified into three cohorts based on whether their BMI within 3 months to 1 year preoperatively had decreased by ≥ 5% (228 patients [18%]); increased by ≥ 5% (310 [24%]); or remained unchanged (within 5%) (732 [58%]) on the day of surgery. There were several baseline differences between the cohorts with respect to medical comorbidities. The rate of 90-day complications and six-week patient-reported outcome measures were compared via univariate and multivariable analyses. RESULTS: On univariate analysis, individual and total complication rates were similar between the cohorts (P > 0.05). On multivariable logistic regression, the risk of complications was similar in patients who had decreased versus unchanged BMI (OR [odds ratio] 1.0; P = 0.898). However, there was a higher risk of complications in the increased BMI cohort compared to those patients who had an unchanged BMI (OR 1.5; P = 0.039). The six-week patient-reported outcome measures (PROMs) were similar between the cohorts. CONCLUSION: Patients who have a BMI > 40 who achieved a meaningful reduction in BMI prior to TKA did not have a lower rate of 90-day complications than those whose BMI remained unchanged. Furthermore, considering that nearly one in four patients experienced a significant increase in BMI while awaiting surgery, postponing TKA may actually be detrimental.

Obesity Severity Does Not Associate With Rate, Timing, or Invasiveness of Early Reinterventions After Total Knee Arthroplasty.

BACKGROUND: The use of body mass index (BMI) cutoff values has been suggested for proceeding with total knee arthroplasty (TKA) in obese patients. However, the relationship between obesity severity and early reoperations after TKA is poorly defined. This study evaluated whether increased World Health Organization (WHO) obesity class was associated with risk, severity, and timing of reintervention within one year after TKA. METHODS: There were 8,674 patients from our institution who had a BMI ≥ 30 and underwent unilateral TKA for primary osteoarthritis between 2016 and 2021. Patients were grouped by WHO obesity class: 4,456 class I (51.5%), 2,527 class II (29.2%), and 1,677 class III (19.4%). A chart review was performed to determine patient characteristics and identify patients who underwent any closed or open reintervention requiring anesthesia within the first postoperative year. Regression analyses were performed to identify variables associated with increased odds ratios (ORs) for requiring a reintervention, its timing, and invasiveness. RESULTS: There were 158 patients (1.8%) who required at least one reintervention, and 15 patients (0.2%) required at least 2 reinterventions. Reintervention rates for obesity classes I, II, and III were 1.8% (n = 81), 2.0% (n = 51), and 1.4% (n = 23), respectively. There were 65 closed procedures (41.1%), 47 minor procedures (29.7%), 34 open with or without liner exchange (21.5%), and 12 revisions with component exchange (7.6%). Obesity class was not associated with reintervention rate (P = .3), timing (P = .36), or invasiveness (P = .93). Diabetes (odds ratio [OR] = 2.47; P = .008) was associated with a need for reintervention. Non-Caucasian race (OR = 1.7; P = .01) and Charlson comorbidity index (OR = 2.1; P = .008) were associated with earlier reintervention. No factors were associated with the invasiveness of reintervention. CONCLUSIONS: The WHO obesity class did not associate with rate, timing, or invasiveness of reintervention after TKA in obese patients. These findings suggest that policies that restrict the indication for elective TKA based only on a BMI limit have limited efficacy in reducing early reintervention after TKA in obese patients. LEVEL OF EVIDENCE: III.

Defining the Learning Period of a Novel Imageless Navigation System for Posterior Approach Total Hip Arthroplasty: Analysis of Surgical Time and Accuracy.

Introduction: The use of imageless navigation in total hip arthroplasty (THA) is frequently associated with prolonged surgical times, predominantly during the learning period. The purpose of the present study was to characterize the learning period of a novel imageless navigation system, specifically as it related to surgical time and acetabular navigation accuracy. Materials and Methods: This was a retrospective observational study of a consecutive group of 158 patients who underwent primary unilateral THA for osteoarthritis by a team headed by a single surgeon. All procedures used an imageless navigation system to measure acetabular cup inclination and anteversion angles, referencing a generic sagittal and frontal plane. Navigation accuracy was determined by assessing differences between intraoperative inclination and anteversion values and those obtained from standardized 6-week follow-up radiographs. Operative time and navigation accuracy were assessed by plotting moving averages of 7 consecutive cases. The learning period was defined using Mann-Kendall trend analyses, student t-tests and nonlinear regression modeling based on surgical time and navigation accuracy. Alpha error was 0.05. Results: The average surgical time was 67.3 min (SD:9.2) (range 45-95). The average navigation accuracy for inclination was 0.01° (SD:4.2) (range - 10 to 10), and that for anteversion was - 4.9° (SD:3.8) (range - 14 to 5). Average surgical time and navigation accuracy were similar between the first and final cases in the series with no learning period detected. Conclusions: There was no discernible learning period effect on surgical time or system measurement accuracy during the early phases of adoption for this imageless navigation system.

The John N. Insall Award: Does Melatonin Improve Subjective Sleep Quality After Total Knee Arthroplasty? A Randomized, Placebo-Controlled Trial.

BACKGROUND: Sleep disturbance is a common problem following total knee arthroplasty (TKA). The objective of this study was to determine if exogenous melatonin improves sleep quality following primary TKA. METHODS: A randomized, double-blind, placebo-controlled trial was conducted. A total of 172 patients undergoing unilateral TKA for primary knee osteoarthritis were randomized to receive either 5 mg melatonin (n = 86) or 125 mg vitamin C placebo (n = 86) nightly for 6 weeks. The primary outcome was the Pittsburgh Sleep Quality Index (PSQI) at 6 weeks and 90 days postoperatively. Secondary outcomes included 6-week and 90-day patient-reported outcome measures (PROMs), morphine milligram equivalents prescribed, medication compliance, adverse events, and 90-day readmissions. RESULTS: Mean PSQI scores worsened at 6 weeks before returning to the preoperative baseline at 90 days in both groups. There were no differences in PSQI scores between melatonin and placebo groups at 6 weeks (10.2 ± 4.2 versus 10.5 ± 4.4, P = .66) or 90 days (8.1 ± 4.1 versus 7.5 ± 4.0, P = .43). Melatonin did not improve the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Lower Extremity Activity Scale, Visual Analog Scale for pain, or Veterans Rand 12 Physical Component Score or Mental Component Score at 6 weeks or 90 days. Poor sleep quality was associated with worse PROMs at 6 weeks and 90 days on univariate and multivariable analyses, but melatonin did not modify these associations. There were no differences in morphine milligram equivalents prescribed, medication compliances, adverse events, or 90-day readmissions between both groups. CONCLUSIONS: Exogenous melatonin did not improve subjective sleep quality or PROMs at 6 weeks or 90 days following TKA. Poor sleep quality was associated with worse patient-reported function and pain. Our results do not support the routine use of melatonin after TKA.

Directed Evolution of PD-L1-Targeted Affibodies by mRNA Display.

Therapeutic monoclonal antibodies directed against PD-L1 (e.g., atezolizumab) disrupt PD-L1:PD-1 signaling and reactivate exhausted cytotoxic T-cells in the tumor compartment. Although anti-PD-L1 antibodies are successful as immune checkpoint inhibitor (ICI) therapeutics, there is still a pressing need to develop high-affinity, low-molecular-weight ligands for molecular imaging and diagnostic applications. Affibodies are small polypeptides (∼60 amino acids) that provide a stable molecular scaffold from which to evolve high-affinity ligands. Despite its proven utility in the development of imaging probes, this scaffold has never been optimized for use in mRNA display, a powerful in vitro selection platform incorporating high library diversity, unnatural amino acids, and chemical modification. In this manuscript, we describe the selection of a PD-L1-binding affibody by mRNA display. Following randomization of the 13 amino acids that define the binding interface of the well-described Her2 affibody, the resulting library was selected against recombinant human PD-L1 (hPD-L1). After four rounds, the enriched library was split and selected against either hPD-L1 or the mouse ortholog (mPD-L1). The dual target selection resulted in the identification of a human/mouse cross-reactive PD-L1 affibody (M1) with low nanomolar affinity for both targets. The M1 affibody bound with similar affinity to mPD-L1 and hPD-L1 expressed on the cell surface and inhibited signaling through the PD-L1:PD-1 axis at low micromolar concentrations in a cell-based functional assay. In vivo optical imaging with M1-Cy5 in an immune-competent mouse model of lymphoma revealed significant tumor uptake relative to a Cy5-conjugated Her2 affibody.

How Does a "Dry Tap" Impact the Accuracy of Preoperative Aspiration Results in Predicting Chronic Periprosthetic Joint Infection?

BACKGROUND: Periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is challenging to diagnose. We aimed to evaluate the impact of dry taps requiring saline lavage during preoperative intra-articular hip aspiration on the accuracy of diagnosing PJI before revision surgery. METHODS: A retrospective review was conducted for THA patients with suspected PJI who received an image-guided hip aspiration from May 2016 to February 2020. Musculoskeletal Infection Society (MSIS) diagnostic criteria for PJI were compared between patients who had dry tap (DT) vs successful tap (ST). Sensitivity and specificity of synovial markers were compared between the DT and ST groups. Concordance between preoperative and intraoperative cultures was determined for the 2 groups. RESULTS: In total, 335 THA patients met inclusion criteria. A greater proportion of patients in the ST group met MSIS criteria preoperatively (30.2% vs 8.3%, P < .001). Patients in the ST group had higher rates of revision for PJI (28.4% vs 17.5%, P = .026) and for any indication (48.4% vs 36.7%, P = .039). MSIS synovial white blood cell count thresholds were more sensitive in the ST group (90.0% vs 66.7%). There was no difference in culture concordance (67.9% vs 65.9%, P = .709), though the DT group had a higher rate of negative preoperative cultures followed by positive intraoperative cultures (85.7% vs 41.1%, P = .047). CONCLUSION: Our results indicate that approximately one third of patients have dry hip aspiration, and in these patients cultures are less predictive of intraoperative findings. This suggests that surgeons considering potential PJI after THA should apply extra scrutiny when interpreting negative results in patients who require saline lavage for hip joint aspiration.

Factors predicting hip joint aspiration yield or "dry taps" in patients with total hip arthroplasty.

BACKGROUND: Image-guided joint aspirations used to assist the diagnosis of periprosthetic joint infection (PJI) may commonly result in a dry tap-or insufficient fluid for culture and cell count analysis. Dry tap aspirations are painful and invasive for patients and often utilize a subsequent saline lavage to obtain a microbiology sample. Currently, there is a paucity of the literature addressing predictors that could suggest whether a dry tap will occur. The purpose of this study was to examine the effects of various factors on "dry tap" occurrence in patients with suspected PJI following total hip arthroplasty (THA). METHODS: A retrospective review was performed among THA patients suspected for PJI who received image-guided joint aspiration procedures at our institution from May 2016 to February 2020. The procedural factors included the imaging modality used for aspiration, anatomic approach, needle gauge size used, and the presence of a trainee. The patient-specific factors included number of prior ipsilateral hip surgeries, femoral head size, ESR/CRP values, and BMI. RESULTS: In total, 336 patients met our inclusion criteria. One hundred and twenty hip aspirations resulted in a dry tap (35.7%) where the patients underwent a saline lavage. Among the procedural and patient-specific factors, none of the factors were found to be statistically different between the two cohorts nor conferred any greater odds of a dry tap occurring. CONCLUSION: No associations with dry tap occurrence were found among the procedural and patient-specific factors studied. Further research is needed to identify additional factors that may be more predictive of dry taps.

An international perspective of out-of-hospital cardiac arrest and cardiopulmonary resuscitation during the COVID-19 pandemic.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) accounts for a substantial proportion of sudden cardiac events globally, with hundreds of thousands of cases reported annually in the United States. The mortality rate of patients who suffer OHCA remains high despite extensive utilization of resources. OBJECTIVES: We aim to describe the current landscape of OHCA during the COVID-19 pandemic and provide an overview of the logistical challenges and resuscitation protocols amongst emergency medical service (EMS) personnel. DISCUSSION: Recent studies in Italy, New York City, and France characterized a significant increase in OHCA incidence in conjunction with the arrival of the 2019 coronavirus disease (COVID-19) pandemic. The presence of the pandemic challenged existing protocols for field resuscitation of cardiac arrest patients as the pandemic necessitated prioritization of EMS personnel and other healthcare providers' safety through stringent personal protective equipment (PPE) requirements. Studies also characterized difficulties encountered by the first responder system during COVID-19, such as dispatcher overload, increased response times, and adherence to PPE requirements, superimposed on PPE shortages. The lack of guidance by governmental agencies and specialty organizations to provide unified safety protocols for resuscitation led to the development of different resuscitative protocols globally. CONCLUSIONS: The ongoing COVID-19 pandemic modified the approach of first responders to OHCA. With the rise in OCHA during the pandemic in several geographic regions and the risks of disease transmission with superimposed equipment shortages, novel noninvasive, adjunct tools, such as point of care ultrasound, warrant consideration. Further prehospital studies should be considered to optimize OHCA and resource management while minimizing risk to personnel.

Resource utilisation among patients with syncope presenting to the emergency department.

BACKGROUND: Syncope is a common problem encountered in the emergency department (ED) and a significant source of ED resource utilisation, including advanced imaging modalities. Current guidelines do not recommend routine Computed Tomography (CT) imaging of the head for patients seen in the ED due to syncope. OBJECTIVE: In this study, we investigate resource allocation in the ED for syncope-related visits, including advanced imaging modalities using a large national database. OUTCOMES ANALYSIS: Data from the CDC's National Hospital Ambulatory Medical Care Survey (NHAMCS) for years 2008-2017 were compiled and analysed. Intrinsic survey and constructed variables were utilised to identify and investigate all syncope-related ED visits in the United States during the study period that met study criteria. Appropriate bivariate and multivariate statistical analyses were applied in order to identify and compare the resource utilisation, demographics, and ED visit dynamics of syncope and non-syncope-related ED visits. RESULTS: During the study period, there were over 15 million ED visits for syncope. A high percentage of syncope visits received head CT compared with non-syncope visits (34% vs. 4.5%, P > .001). When investigated by age-grouping utilisation of head CT ranged from 26.5 (95% CI 18.9-27.5) for ages 18-40 to as high as 40.2% (95% CI 33.8-47.1) for ages 80 and higher. Compared with non-syncope ED visits, syncope-related ED visits were older and more likely to have Medicare or private insurance. CONCLUSION: Syncope continues to be a large and growing share of visits to US EDs. Despite well-supported, evidence-based recommendations that do not recommend routine utilisation of head CT in syncope-related ED visits, these data suggest that emergency physicians routinely over-utilise this modality. More specific guidelines may be required to help reduce the use of imaging studies for patients who present to the ED with syncope.

Emergency department approach to gastric tube complications and review of the literature.

Nasogastric and orogastric tubes (NGT/OGT) are commonly used in emergency and critical care settings, with indications including medicinal administration, gastric decompression, and enteral feeding. Previous studies have highlighted a variety of complications associated with tube placement. These range from minor occurrences such as nose bleeds and sinusitis, to more severe cases highlighting tracheobronchial perforation, tube knotting, asphyxia, pulmonary aspiration, pneumothorax, and even intracranial insertion. Patients who suffer from these complications face additional obstacles including increased time spent in intensive care settings, healthcare associated costs, and nosocomial infections. Various bedside tests have been developed to reduce the risk of these complications, and current clinical protocol has characterized radiographic imaging as the gold standard. However, air insufflation, CO2 detection (capnography), aspirate pH testing, and point of care ultrasound (POCUS) have all been implemented with varying degrees of utility. Here we present a case involving a 60-year-old male who was brought to the ED and suffered a right sided pneumothorax (PTX) following improper OGT placement. In this case, air insufflation was utilized, but was ineffective in detecting the properly placed tube; leakage of an endotracheal tube cuff served as a lead for misplacement while imaging was conducted. The purpose of this study is not only to highlight the numerous complications that are possible with NGT and OGT placement, but also to propose the use of multiple bedside tests (pH testing, CO2 detection, POCUS) as an alternative to radiographic imaging to increase sensitivity and specificity for detection of improperly placed tubes.

mRNA Display Discovery of a Novel Programmed Death Ligand 1 (PD-L1) Binding Peptide (a Peptide Ligand for PD-L1).

Programmed death ligand 1 (PD-L1) is a critical immune checkpoint ligand whose overexpression on tumor cells provides a mechanism of escape from immune surveillance. The interaction between PD-L1 and PD-1 on T cell lymphocytes suppresses both T cell activation and effector function and is engaged by cancers to dampen antitumor immunity. Here, we used mRNA display to engineer an 18-residue linear peptide that binds to human PD-L1. This peptide, which we term SPAM (signal peptide-based affinity maturated ligand), is nonhomologous to known PD-L1 binding peptides and mAbs, with dissociation constants (KD) of 119 and 67 nM for unglycosylated and glycosylated human PD-L1, respectively. The SPAM peptide is highly selective for human PD-L1 and shows no significant binding to either mouse PD-L1 or human PD-L2. Competition binding assays indicate that the SPAM peptide binding site overlaps with the binding site of PD-1 as well as therapeutic anti-PD-L1 antibodies. Taken together, these results suggest that the SPAM peptide specifically binds to human PD-L1 and could potentially serve as a PD-L1 affinity agent and PD-L1/PD-1 pathway modulator.

The Effectiveness and Safety of Manual Therapy on Pain and Disability in Older Persons With Chronic Low Back Pain: A Systematic Review.

OBJECTIVES: The aim of this study was to perform a systematic review of the literature of the effectiveness and safety of manual therapy interventions on pain and disability in older persons with chronic low back pain (LBP). METHODS: A literature search of 4 electronic databases was performed (PubMed, EMBASE, OVID, and CINAHL). Inclusion criteria included randomized controlled trials of manual therapy interventions on older persons who had chronic LBP. Effectiveness was determined by extracting and examining outcomes for pain and disability, with safety determined by the report of adverse events. The PEDro scale was used for quality assessment of eligible studies. RESULTS: The search identified 405 articles, and 38 full-text articles were assessed. Four studies met the inclusion criteria. All trials were of good methodologic quality and had a low risk of bias. The included studies provided moderate evidence supporting the use of manual therapy to reduce pain levels and alleviate disability. CONCLUSIONS: A limited number of studies have investigated the effectiveness and safety of manual therapy in the management of older people with chronic LBP. The current evidence to make firm clinical recommendations is limited. Research with appropriately designed trials to investigate the effectiveness and safety of manual therapy interventions in older persons with chronic LBP is required.

Small intestinal adenocarcinoma: rarely considered, often missed?

Adenocarcinoma of the small intestine is rare in comparison with other gastrointestinal malignancies but its incidence is rising. It often presents at an advanced stage due to the non-specific symptomatology. More recent advances in small intestinal visualisation including video capsule endoscopy and double balloon enteroscopy may facilitate diagnosis in patients with suspected small intestinal neoplasia. At present aggressive surgical resection provides the best chance of cure of small intestinal adenocarcinoma. Despite apparent curative resection the long-term outlook remains poor. The role of adjuvant chemotherapy is not well defined due to the rarity of the disease and lack of randomised controlled trials; however, there appears to be a survival benefit in advanced disease with the use of oxaliplatin and 5-fluorouracil. We reviewed the clinical aspects of this aggressive condition focusing on the pathological associations, available diagnostic modalities and current management options. Three cases are included to illustrate the review.