Rapid Osteoarthritis and Femoral Head Collapse: A Case Series.

Introduction: Rapidly progressive hip osteoarthritis (OA) leading to femoral head collapse (FHC) following intra-articular (IA) corticosteroid injections is a perplexing variant of OA. We explored eight cases of chronic joint pain treated with IA corticosteroid injections. Subsequently, they experienced swift deterioration of the femoral head integrity within as little as 10 weeks. These cases underscore the need for a comprehensive assessment of risk factors versus benefits in this patient population. Case Report: The study reveals a complex interplay between comorbidities, treatments, and outcomes. Patients exhibited various health factors, including obesity, smoking history, cancer treatment, and deficiencies in Vitamin D levels, which have been found to increase the risk of FHC. Furthermore, the study explores the chondrotoxicity of corticosteroids and local anesthetics used in IA injections. In vitro studies show complete loss of chondrocyte viability after a single dose of corticosteroids, potentially leading to cartilage degradation. In addition, local anesthetics may induce cellular demise and structural alterations in the articular cartilage. These factors highlight various influences affecting treatment outcomes in patients with OA. Conclusion: In conclusion, this case series highlights the rare adverse outcome of rapidly progressive hip OA and FHC following IA corticosteroid injections and possible risk factors. While a definitive etiology remains unclear, the study provides valuable conclusions to aid in future treatment decision-making.

Managing an epidemic within a pandemic: orthopedic opioid prescribing trends during COVID-19.

INTRODUCTION: In response to the opioid epidemic, a multitude of policy and clinical-guideline based interventions were launched to combat physician overprescribing. However, the sudden rise of the Covid-19 pandemic disrupted all aspects of healthcare delivery. The purpose of this study was to evaluate how opioid prescribing patterns changed during the Covid-19 pandemic within a large multispecialty orthopedic practice. MATERIALS AND METHODS: A retrospective review of 1,048,559 patient encounters from January 1, 2015 to December 31, 2022 at a single orthopedic practice was performed. Primary outcomes were the percent of encounters with opioids prescribed and total morphine milligram equivalents (MMEs) per opioid prescription. Differences in outcomes were assessed by calendar year. Encounters were then divided into two groups: pre-Covid (1/1/2019-2/29/2020) and Covid (3/1/2020-12/31/2022). Univariate analyses were used to evaluate differences in diagnoses and outcomes between periods. Multivariate analysis was performed to assess changes in outcomes during Covid after controlling for differences in diagnoses. Statistical significance was assessed at p < 0.05. RESULTS: The percentage of encounters with opioids prescribed decreased from a high of 4.0% in 2015 to a low of 1.6% in 2021 and 2022 (p < 0.001). MMEs per prescription decreased from 283.6 ± 213.2 in 2015 to a low of 138.6 ± 100.4 in 2019 (p < 0.001). After adjusting for diagnoses, no significant differences in either opioid prescribing rates (post-COVID OR = 0.997, p = 0.893) or MMEs (post-COVID ß = 2.726, p = 0.206) were observed between the pre- and post-COVID periods. CONCLUSION: During the Covid-19 pandemic opioid prescribing levels remained below historical averages. While continued efforts are needed to minimize opioid overprescribing, it appears that the significant progress made toward this goal was not lost during the pandemic era.

Properties of the iron-sulfur cluster electron transfer relay in an [FeFe]-hydrogenase that is tuned for H2 oxidation catalysis.

[FeFe]-hydrogenases catalyze the reversible oxidation of H2 from electrons and protons at an organometallic active site cofactor named the H-cluster. In addition to the H-cluster, most [FeFe]-hydrogenases possess accessory FeS cluster (F-cluster) relays that function in mediating electron transfer with catalysis. There is significant variation in the structural properties of F-cluster relays among the [FeFe]-hydrogenases; however, it is unknown how this variation relates to the electronic and thermodynamic properties, and thus the electron transfer properties, of enzymes. Clostridium pasteurianum [FeFe]-hydrogenase II (CpII) exhibits a large catalytic bias for H2 oxidation (compared to H2 production), making it a notable system for examining if F-cluster properties contribute to the overall function and efficiency of the enzyme. By applying a combination of multifrequency and potentiometric electron paramagnetic resonance, we resolved two electron paramagnetic resonance signals with distinct power- and temperature-dependent properties at g = 2.058 1.931 1.891 (F2.058) and g = 2.061 1.920 1.887 (F2.061), with assigned midpoint potentials of -140 ± 18 mV and -406 ± 12 mV versus normal hydrogen electrode, respectively. Spectral analysis revealed features consistent with spin-spin coupling between the two [4Fe-4S] F-clusters, and possible functional models are discussed that account for the contribution of coupling to the electron transfer landscape. The results signify the interplay of electronic coupling and free energy properties and parameters of the FeS clusters to the electron transfer mechanism through the relay and provide new insight as to how relays functionally complement the catalytic directionality of active sites to achieve highly efficient catalysis.

Neutrophil Extracellular Traps and Respiratory Disease.

Extracellular traps made by neutrophils (NETs) and other leukocytes such as macrophages and eosinophils have a key role in the initial immune response to infection but are highly inflammatory and may contribute to tissue damage. They are particularly relevant to lung disease, with the pulmonary anatomy facilitating their ability to fully extend into the airways/alveolar space. There has been a rapid expansion in the number of published studies demonstrating their role in a variety of important respiratory diseases including chronic obstructive pulmonary disease, cystic fibrosis, bronchiectasis, asthma, pneumonia, COVID-19, rhinosinusitis, interstitial lung disease and lung cancer. The expression of NETs and other traps is a specific process, and diagnostic tests need to differentiate them from other inflammatory pathways/causes of cell death that are also characterised by the presence of extracellular DNA. The specific targeting of this pathway by relevant therapeutics may have significant clinical benefit; however, current clinical trials/evidence are at a very early stage. This review will provide a broad overview of the role of NETs and their possible treatment in respiratory disease.

The association between losartan potassium prescription and postoperative outcomes following total knee arthroplasty: A TriNetX analysis.

BACKGROUND: Total knee arthroplasty (TKA) is a common surgical procedure performed to alleviate pain and improve functional outcomes in patients with knee osteoarthritis and rheumatoid arthritis who have failed conservative treatments. Arthrofibrosis has been extensively studied due to its negative impact on TKA outcomes. Losartan, an angiotensin receptor blocker (ARB), has the potential to improve TKA outcomes by inhibiting TGF-ß and decreasing fibrosis. This study aims to analyze a large-scale, real-world healthcare database to investigate the association between losartan potassium prescription and postoperative outcomes such as readmissions, ED visits, and the need for MUA or revision TKA. HYPOTHESIS: Based on previous literature and the nature of ARBs, it is expected that the addition of losartan will aid in better outcomes for patients following a primary TKA. PATIENTS AND METHODS: In this retrospective observational study, the TriNetX Research Network (TriNetX) database was queried as of June 21, 2023. All patients who underwent a primary total knee arthroplasty (TKA) prior to June 21, 2022 were included. Patients were then divided into two cohorts by whether they had an active losartan potassium prescription within the year prior to their surgery to within 90days postoperatively. Patients were then propensity-matched to eliminate differences in demographics and comorbidities. RESULTS: Losartan TKA patients were 1.18 [OR: 0.85 (95% CI: 0.79-0.90), p<0.001] times less likely to be readmitted within 90days and were 1.15 (OR: 0.87 (95% CI: 0.79-0.96); p=0.009) times less likely to undergo a manipulation under anesthesia (MUA) within the 1-year postoperative period. There were no statistically significant differences in rates of emergency department (ED) visits at 90days postoperatively or revision TKAs at 1year postoperatively. DISCUSSION: In conclusion, patients with an active losartan prescription prior to TKA had a significantly lower likelihood of readmission within 90days and a lower likelihood of undergoing MUA within the 1-year postoperative period compared to patients not taking losartan. This presents an opportunity for further clinical investigation to explore the value of losartan in TKA. LEVEL OF EVIDENCE: III; an observational cohort study.

The Inhibition of Serine Proteases by Serpins Is Augmented by Negatively Charged Heparin: A Concise Review of Some Clinically Relevant Interactions.

Serine proteases are members of a large family of hydrolytic enzymes in which a particular serine residue in the active site performs an essential role as a nucleophile, which is required for their proteolytic cleavage function. The array of functions performed by serine proteases is vast and includes, among others, the following: (i) the ability to fight infections; (ii) the activation of blood coagulation or blood clot lysis systems; (iii) the activation of digestive enzymes; and (iv) reproduction. Serine protease activity is highly regulated by multiple families of protease inhibitors, known collectively as the SERine Protease INhibitor (SERPIN). The serpins use a conformational change mechanism to inhibit proteases in an irreversible way. The unusual conformational change required for serpin function provides an elegant opportunity for allosteric regulation by the binding of cofactors, of which the most well-studied is heparin. The goal of this review is to discuss some of the clinically relevant serine protease-serpin interactions that may be enhanced by heparin or other negatively charged polysaccharides. The paired serine protease-serpin in the framework of heparin that we review includes the following: thrombin-antithrombin III, plasmin-anti-plasmin, C1 esterase/kallikrein-C1 esterase inhibitor, and furin/TMPRSS2 (serine protease Transmembrane Protease 2)-alpha-1-antitrypsin, with the latter in the context of COVID-19 and prostate cancer.

Social vulnerability adversely affects emergency-department utilization but not patient-reported outcomes after total joint arthroplasty.

INTRODUCTION: Multiple studies demonstrate social deprivation is associated with inferior outcomes after total hip (THA) and total knee (TKA) arthroplasty; its effect on patient-reported outcomes is debated. The primary objective of this study evaluated the relationship between social vulnerability and the PROMIS-PF measure in patients undergoing THA and TKA. A secondary aim compared social vulnerability between patients who required increased resource utilization or experienced complications and those who didn't. MATERIALS AND METHODS: A retrospective review of 537 patients from March 2020 to February 2022 was performed. The Centers for Disease Control Social Vulnerability Index (SVI) were used to quantify socioeconomic disadvantage. The cohort was split into THA and TKA populations; univariate and multivariate analyses were performed to evaluate primary and secondary outcomes. Statistical significance was assessed at p < 0.05. RESULTS: 48.6% of patients achieved PROMIS-PF MCID at 1-year postoperatively. Higher levels of overall social vulnerability (0.40 vs. 0.28, p = 0.03) were observed in TKA patients returning to the ED within 90-days of discharge. Increased overall SVI (OR = 9.18, p = 0.027) and household characteristics SVI (OR = 9.57, p = 0.015) were independent risk factors for 90-day ED returns after TKA. In THA patients, increased vulnerability in the household type and transportation dimension was observed in patients requiring 90-day ED returns (0.51 vs. 0.37, p = 0.04). CONCLUSION: Despite an increased risk for 90-day ED returns, patients with increased social vulnerability still obtain good 1-year functional outcomes. Initiatives seeking to mitigate the effect of social deprivation on TJA outcomes should aim to provide safe alternatives to ED care during early recovery.

Non-White Race and Concomitant Orthopedic Conditions Are Risk Factors for Failure to Achieve Clinically Relevant Improvement After Total Knee Arthroplasty.

BACKGROUND: Data from the American Joint Replacement Registry demonstrate that 1-year minimal clinically important difference (MCID) achievement rates after total knee arthroplasty (TKA) are substantially lower when using general patient reported outcome measures, such as Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), than joint specific measures. The purpose of this study was to evaluate patient characteristics and outcomes associated with MCID achievement after TKA using the PROMIS-PF measure. METHODS: A retrospective review of 263 patients undergoing TKA with preoperative and 1-year postoperative PROMIS-PF scores from March 12, 2020 to February 8, 2022 was performed. Three multivariate models were built to evaluate predictors of MCID achievement. Preoperative predictors evaluated included demographics, comorbidities, history of spine and knee surgery, and baseline PROMIS-PF. Postoperative clinical outcomes evaluated included lengths of stay, discharge statuses, complications, and utilizations of other orthopaedic services. RESULTS: There were 109 patients (41%) who achieved an MCID at 1-year postoperatively. Non-white patients had 2.17 times lower odds of achieving MCID. No clinical outcomes assessed were independently predictive of MCID achievement. During the 1-year postoperative period, 63% of patients sought care for another orthopaedic condition. Patients requiring postoperative injections on another joint had a 2.27 times lower odds of achieving MCID. Those seen for spine conditions postoperatively had a 2.44 lower odds of achieving MCID. CONCLUSIONS: Race, postoperative injections, and treatment for spine conditions after TKA were independent predictors of failure to achieve MCID. These results may guide preoperative patient consultation and risk-adjustment in future studies using PROMIS-PF as an endpoint for evaluation of TKA outcomes.

Effect of Lower Extremity Osteoarthritis on Outcomes of Lumbar Decompression.

BACKGROUND: The purpose of this study is to evaluate how hip or knee osteoarthritis (OA) and total joint arthroplasty impact the outcomes of patients undergoing lumbar decompression. METHODS: A retrospective review of 342 patients undergoing lumbar decompression without fusion from January 2019 and June 2021 at a single institution was performed. Univariate and multivariate analyses were used to compare outcomes between patients with and without concomitant hip or knee OA. RESULTS: Forty-six percent of patients had a hip or knee OA diagnosis and were higher risk as they were older, had higher BMIs, were more likely to be former smokers, had higher ASA scores, and were more likely to undergo 3+ level surgery. Postoperatively, after adjusting for differences between groups, hip or knee OA patients were more likely to be readmitted (OR=12.45, p=0.026) or have a complication (OR=13.77, p=0.031). However, patient reported outcomes as measured by Patient Reported Outcomes Measurement Information System-physical function. were similar at 1-3 months and 3-6 months. Higher levels of physical function were observed at 3-6 months postoperatively in hip OA patients with a history of THA. CONCLUSION: Patients with concomitant hip or knee OA are at higher risk for readmission and postoperative complications but may achieve similar levels of physical function as those without OA.

Outpatient parenteral antibiotic therapy (OPAT) for the management of bronchiectasis.

Background: Patients with bronchiectasis often require hospitalisation for the administration of intravenous antibiotics for the management of acute exacerbations. Increasingly, Outpatient Parenteral Antibiotic Therapy (OPAT) services have become available as a potential alternative for domiciliary management. Aims: This study assessed outcomes in both cystic fibrosis (CF) and non-CF bronchiectasis patients who received OPAT for the management of an acute exacerbation of bronchiectasis. Methods: A retrospective study of consecutive subjects was done in both CF and non-CF groups in a large metropolitan Health Service in Australia from 2016 to 2022. Results: There were 51 episodes of care in the non-CF group (22 subjects) and 73 episodes in the CF group (13 subjects). The non-CF group were nearly all treated with once daily domiciliary intravenous (IV) ceftriaxone (49/51 episodes) for a duration of 9.1 ± 3.0 days (mean and standard deviation (SD)) via a peripherally inserted venous canula (84% of episodes). In contrast, the CF group generally received dual IV antibiotics (64% of episodes), with an average duration of 16.8 ± 6.3 days via central venous access (100%). In the non-CF group, the admission rate to hospital after 1 month was 9.6% and in the CF group was 0%. At 3 and 6 months the readmission rate for the non-CF group was 15.7% and 19.6% and CF group was 21.9% and 31.5%. There was a low rate of complications for the OPAT admissions (2% for the non-CF group and 7% for CF group). Conclusions: OPAT is a viable alternative for the management of bronchiectasis exacerbations.

Leveraging Integrated Primary Care to Enhance the Health System Response to IPV: Moving toward Primary Prevention Primary Care.

Intimate partner violence (IPV) is a prominent public health problem in the United States, with significant health impacts that are often severe and persistent. Healthcare systems have been called upon to improve both the systematic identification and treatment of IPV largely by adopting secondary and tertiary prevention efforts. Research to date demonstrates both benefits and challenges with the current strategies employed. In this paper, we summarize current knowledge about the healthcare system's response to IPV and evaluate the strengths, limitations, and opportunities. We offer recommendations to broaden the continuum of healthcare resources to address IPV, which include a population health approach to primary prevention.

Thoracic Society of Australia and New Zealand (TSANZ) position statement on chronic suppurative lung disease and bronchiectasis in children, adolescents and adults in Australia and New Zealand.

This position statement, updated from the 2015 guidelines for managing Australian and New Zealand children/adolescents and adults with chronic suppurative lung disease (CSLD) and bronchiectasis, resulted from systematic literature searches by a multi-disciplinary team that included consumers. The main statements are: Diagnose CSLD and bronchiectasis early; this requires awareness of bronchiectasis symptoms and its co-existence with other respiratory diseases (e.g., asthma, chronic obstructive pulmonary disease). Confirm bronchiectasis with a chest computed-tomography scan, using age-appropriate protocols and criteria in children. Undertake a baseline panel of investigations. Assess baseline severity, and health impact, and develop individualized management plans that include a multi-disciplinary approach and coordinated care between healthcare providers. Employ intensive treatment to improve symptom control, reduce exacerbation frequency, preserve lung function, optimize quality-of-life and enhance survival. In children, treatment also aims to optimize lung growth and, when possible, reverse bronchiectasis. Individualize airway clearance techniques (ACTs) taught by respiratory physiotherapists, encourage regular exercise, optimize nutrition, avoid air pollutants and administer vaccines following national schedules. Treat exacerbations with 14-day antibiotic courses based upon lower airway culture results, local antibiotic susceptibility patterns, clinical severity and patient tolerance. Patients with severe exacerbations and/or not responding to outpatient therapy are hospitalized for further treatments, including intravenous antibiotics and intensive ACTs. Eradicate Pseudomonas aeruginosa when newly detected in lower airway cultures. Individualize therapy for long-term antibiotics, inhaled corticosteroids, bronchodilators and mucoactive agents. Ensure ongoing care with 6-monthly monitoring for complications and co-morbidities. Undertake optimal care of under-served peoples, and despite its challenges, delivering best-practice treatment remains the overriding aim.

The effects of hypoalbuminemia in obese patients undergoing total joint arthroplasty.

INTRODUCTION: Total joint arthroplasty (TJA) is a highly effective surgery. However, poor nutritional status has been associated with worse outcomes. In orthopedics, nutrition status is commonly evaluated using serum albumin. When albumin levels fall below 3.0 g/dL, wound healing ability becomes impaired. Typically, malnutrition is associated with low BMI, but malnourished patients can also be obese. The goals of this study were to investigate the relationship between malnourishment represented through albumin levels of obese patients and likelihood of postoperative complications. METHODS: A retrospective review of patients undergoing primary TJA from 2016 to 2020 in the American College of Surgeons National Surgical Quality Improvement Program national database was performed. Patients with an albumin of < 3.5 g/dL were considered to have hypoalbuminemia and those with ≥ 3.5 g/dL were considered normal albumin. Univariate analysis was used to determine demographic and comorbidity differences between those with and without hypoalbuminemia. Outcomes of interest included length of stay, resource utilization, discharge disposition, and unplanned readmissions. Multivariate logistic regression examined albumin as a predictor of increased resource utilization and complications after controlling for possible confounding variables. RESULTS: Of the 79,784 patients, 4.96% of patients had low albumin. Those with hypoalbuminemia were nearly 1.5 years older than those with normal albumin, were more likely to be black, female, and had an overall increased comorbidity burden as shown by percent of patients with ASA > 3 (all p < 0.001). After risk adjustment, those with hypoalbuminemia and a BMI of 35 + had greater risk of complications and increased resource utilization. CONCLUSION: Our results demonstrated the prevalence of malnutrition increases as a patient's BMI increases. Further, hypoalbuminemia was associated with increased resource utilization and increased complication rates in all obese patients. We suggest screening albumin levels in obese patients preoperatively to give surgeons the best opportunity to optimize patient nutrition before undergoing surgery.

Acetabular Total Hip Arthroplasty Revision: A Summary of Operative Factors, Outcomes, and Comparison of Approaches.

BACKGROUND: Revision total hip arthroplasty (THA) presents a greater risk to patients than primary THA, and surgical approach may impact outcomes. This study aimed to summarize acetabular revisions at our institution and to compare outcomes between direct anterior and posterior revision THA. METHODS: A series of 379 acetabular revision THAs performed from January 2010 through August 2022 was retrospectively reviewed. Preoperative, perioperative, and postoperative factors were summarized for all revisions and compared between direct anterior and posterior revision THA. RESULTS: The average time to acetabular revision THA was 10 years (range, 0.04 to 44.1), with mechanical failure (36.7%) and metallosis (25.6%) being the most prevalent reasons for revision. No differences in age, body mass index, or sex were noted between groups. Anterior revision patients had a significantly shorter length of stay (2.2 versus 3.2 days, P = .003) and rate of discharge to a skilled nursing facility (7.5 versus 25.2%, P = .008). In the 90-day postoperative period, 9.2% of patients returned to the emergency department (n = 35) and twelve patients (3.2%) experienced a dislocation. There were 13.2% (n = 50) of patients having a rerevision during the follow-up period with a significant difference between anterior and posterior approaches (3.8 versus 14.7%, respectively, P = .049). CONCLUSION: This study provides some evidence that the anterior approach may be protective against skilled nursing facility discharge and rerevision and contributes to decreased lengths of stay. We recommend surgeons select the surgical approach for revision THA based on clinical preferences and patient factors.

The Efficacy of Telemedicine Versus In-Person Education for High-Risk Patients Undergoing Primary Total Joint Arthroplasty.

BACKGROUND: While multiple studies have demonstrated the positive impact of preoperative education on total joint arthroplasty (TJA) outcomes, the traditional method of conducting in-person individualized counseling or group education may limit access to these resources for a subset of the population. This study aimed to evaluate the use of preoperative telemedicine and in-person educational programs for primary TJA patients to determine if the utilization of telemedicine is inferior to in-person education in high-risk populations. METHODS: A retrospective chart review of all "high-risk" patients undergoing primary unilateral TKA or THA by 1 of 10 board-certified surgeons at a single institution over 1 year was performed. Patients were prospectively classified as high-risk based on race/ethnicity, comorbidities, and socioeconomic and psychosocial factors. Demographics, comorbidities, and hospital outcomes were compared between patients receiving preoperative nurse navigator education via telemedicine versus those receiving face-to-face education. RESULTS: When comparing the interventions, telemedicine education was noninferior to face-to-face visits. No significant differences between postoperative length of stay, discharge home, 30-day emergency department return, or 30-day readmission rates were noted. Within the telemedicine group, patients who received video consultations were found to be 6 times more likely to be discharged home after surgery (odds ratio (OR): 5.95, 95% confidence interval (CI): 2.00 to 25.49; P = .004) and less likely to have a 30-day readmission than the phone consultations (OR: 0.36, 95% CI: 0.12 to 0.94: P = .050). CONCLUSION: This study demonstrates that telemedicine is not inferior to in-person preoperative education for patients undergoing unilateral TJA, although video-based consultation may improve outcomes over phone-only education.

'Teach me how to look after myself': What people with bronchiectasis want from education in a pulmonary rehabilitation setting.

INTRODUCTION: Pulmonary rehabilitation is recommended for people with bronchiectasis. Various education topics are included in these programmes, but the content is largely guided by the needs of people with other respiratory conditions. OBJECTIVES: With the education topics applicable to people with bronchiectasis unclear, we aimed to explore the perspective of adults with this condition on relevant educational topics in a pulmonary rehabilitation context. METHODS: Participants from the Australian Bronchiectasis Registry were invited to undertake a semi-structured interview. Interview transcripts were coded independently, with themes established by consensus (two researchers). RESULTS: Twenty-one people participated. The major themes were greater clarity on the underlying cause of bronchiectasis and prognosis. Most sought knowledge about self-management strategies and treatments to address extra-pulmonary symptoms. Participants requested more information on physiotherapy options and the role of exercise and physical activity outside of pulmonary rehabilitation. Preferences were mixed for the education delivery model. CONCLUSIONS: We have identified unmet educational topics of interest for people with bronchiectasis. Our study provides a framework for education topics desired by adults with bronchiectasis within a pulmonary rehabilitation setting. The topics identified will guide development of an education curriculum for pulmonary rehabilitation that is more fit-for-purpose for people with bronchiectasis.

Postoperative Outcomes in Patients Undergoing Orthopaedic Surgery Within 90 Days of Coronavirus Disease 2019.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) has resulted in a global pandemic with several hundred million infections worldwide. COVID-19 causes systemic complications that last beyond the initial infection. It is not known whether patients who undergo elective orthopaedic surgeries after COVID-19 are at increased risk of complications. The purpose of this study was to evaluate whether patients who undergo orthopaedic procedures after recent COVID-19 diagnosis are at increased risk of complications compared with those who have not had a recent COVID-19 diagnosis. METHODS: The TriNetX Research Network database was queried for patients undergoing elective orthopaedic surgeries from April 2020 to January 2022 in the following subspecialties: arthroscopic surgery, total joint arthroplasty, lumbar fusion, upper extremity surgery, foot and ankle (FA) surgery. Cohorts were defined by patients undergoing surgery with a diagnosis of COVID-19 from 7 to 90 days before surgery and those with no COVID-19 diagnosis 0 to 90 days before surgery. These cohorts were propensity-score matched based on differences in demographics and comorbidities. The matched cohorts were evaluated using measures of association analysis for complications, emergency department (ER) visits, and readmissions occurring 90 days postoperatively. RESULTS: Patients undergoing arthroscopic surgery were more likely to experience venous thromboembolism (VTE) ( P = 0.006), myocardial infarction ( P = 0.001), and ER visits ( P = 0.001). Patients undergoing total joint arthroplasty were more likely to experience VTE ( P < 0.001), myocardial infarction ( P < 0.001), pneumonia ( P < 0.001), and ER visits ( P = 0.037). Patients undergoing lumbar fusion were more likely to experience VTE ( P = 0.016), infection ( P < 0.001), pneumonia ( P < 0.001), and readmission ( P = 0.006). Patients undergoing upper extremity surgery were more likely to experience VTE ( P = 0.001) and pneumonia ( P = 0.015). Patients undergoing foot and ankle surgery were more likely to experience VTE ( P < 0.001) and pneumonia ( P < 0.001). CONCLUSION: There is an increased risk of complications in patients undergoing orthopaedic surgery after COVID-19 infection; all cohorts were at increased risk of VTE and most at increased risk of pneumonia. Additional investigation is needed to stratify the risk for individual patients.

Pain After Preoperative Ultrasound Guided Hip Injections for Total Hip Arthroplasty: A Pilot Randomized Controlled Trial.

Introduction. Hip replacement is a frequently performed and highly successful treatment for patients with end stage osteoarthritis. Advances in technique and pain management have allowed for rapid mobilization and early discharge after surgery. We hypothesize that pre-incision intra-articular injection of local anesthetic with epinephrine under image guidance combined with post incision peri-articular injection (PAI) may be more effective than PAI alone. Methods. A prospective, randomized, controlled, comparative investigation at a single institution of 41 patients undergoing THA who received standard 30 mL post-arthrotomy, PAI of ropivacaine with epinephrine under direct visualization after prosthesis implantation before closure or an equivalent dose divided into a 10 mL pre-incision, ultrasound guided intra-articular injection and a 20 mL post-arthrotomy PAI. Results. 42 patients were included in this study before its early conclusion with 22 patients in the treatment group and 20 in the control group. There were no significant differences in age, BMI or ASA scores. Additionally, there were no significant differences noted when comparing groups by postoperative outcome measures including OMME, EBL, OR time, PACU minutes, and first and last PACU pain score. Furthermore, there were no significant differences in the PROMs evaluated. Discussion. The addition of ultrasound guided pre-incision intra-articular injection to the standard PAI had no benefit when compared with standard PAI during a THA. Portable mobile phone based ultrasound devices provide a cost effective way to perform musculoskeletal blocks, and further studies on their use and comparative accuracy is warranted. A novel technique for confirmation of injection location is described.

The Contribution of Proton-Donor pKa on Reactivity Profiles of [FeFe]-hydrogenases.

The [FeFe]-hydrogenases are enzymes that catalyze the reversible activation of H2 coupled to the reduction-oxidation of electron carriers. Members of the different taxonomic groups of [FeFe]-hydrogenases display a wide range of preference, or bias, for H2 oxidation or H2 production reactions, despite sharing a common catalytic cofactor, or H-cluster. Identifying the properties that control reactivity remains an active area of investigation, and models have emerged that include diversity in the catalytic site coordination environments and compositions of electron transfer chains. The kinetics of proton-coupled electron transfer at the H-cluster might be expected to be a point of control of reactivity. To test this hypothesis, systematic changes were made to the conserved cysteine residue that functions in proton exchange with the H-cluster in the three model enzymes: CaI, CpII, and CrHydA1. CaI and CpII both employ electron transfer accessory clusters but differ in bias, whereas CrHydA1 lacks accessory clusters having only the H-cluster. Changing from cysteine to either serine (more basic) or aspartate (more acidic) modifies the sidechain pKa and thus the barrier for the proton exchange step. The reaction rates for H2 oxidation or H2 evolution were surveyed and measured for model [FeFe]-hydrogenases, and the results show that the initial proton-transfer step in [FeFe]-hydrogenase is tightly coupled to the control of reactivity; a change from cysteine to more basic serine favored H2 oxidation in all enzymes, whereas a change to more acidic aspartate caused a shift in preference toward H2 evolution. Overall, the changes in reactivity profiles were profound, spanning 105 in ratio of the H2 oxidation-to-H2 evolution rates. The fact that the change in reactivity follows a common trend implies that the effect of changing the proton-transfer residue pKa may also be framed as an effect on the scaling relationship between the H-cluster di(thiolmethyl)amine (DTMA) ligand pKa and E m values of the H-cluster. Experimental observations that support this relationship, and how it relates to catalytic function in [FeFe]-hydrogenases, are discussed.