Branching topology of the human embryo transcriptome revealed by entropy sort feature weighting.

Analysis of single cell transcriptomics (scRNA-seq) data is typically performed after sub-setting to highly variable genes (HVGs). Here we show that Entropy Sorting provides an alternative mathematical framework for feature selection. On synthetic datasets, continuous entropy sort feature weighting (cESFW) outperforms HVG selection in distinguishing cell state specific genes. We apply cESFW to six merged scRNA-seq datasets spanning human early embryo development. Without smoothing or augmenting the raw counts matrices, cESFW generates a high-resolution embedding displaying coherent developmental progression from 8-cell to post-implantation stages and delineating 15 distinct cell states. The embedding highlights sequential lineage decisions during blastocyst development while unsupervised clustering identifies branch point populations obscured in previous analyses. The first branching region, where morula cells become specified for inner cell mass or trophectoderm, includes cells previously asserted to lack a developmental trajectory. We quantify the relatedness of different pluripotent stem cell cultures to distinct embryo cell types and identify marker genes of naïve and primed pluripotency. Finally, by revealing genes with dynamic lineage-specific expression we provide markers for staging progression from morula to blastocyst.

A feasibility cadaver study for placing screws in various pelvic osseous fracture pathways using a robotic arm.

INTRODUCTION: The use of a robotic system for the placement of pedicle screws in spine surgeries is well documented in the literature. However, there is only a single report in the United States describing the use of a robotic system to place two screws in osseous fixation pathways (OFPs) commonly used in the treatment of pelvic and acetabular fractures in a simulated bone model. The purpose of this study was to demonstrate the use of a robotic system to place screws in multiple, clinically relevant OFPs in a cadaveric model and to quantitatively measure accuracy of screw placement relative to the preoperative plan. METHODS: A single cadaveric specimen was obtained for the purpose of this study. All surrounding soft tissues were left intact. Screws were placed in OFPs, namely iliosacral (IS), trans-sacral (TS), Lateral Compression-II (LC-II), antegrade anterior column (AC) and antegrade posterior column (PC) of the right hemipelvis using standard, fluoroscopically assisted percutaneous or mini-open technique. Following the placement of screws into the right hemipelvis using standard techniques, screws were planned and placed in the same OFPs of the contralateral hemipelvis using the commercially available ExcelsiusGPS® robotic system (Globus Medical Inc., Audubon, PA). After robotic-assisted screw placement, a post-procedure CT scan was obtained to evaluate actual screw placement against the pre-procedure plan. A custom-made image analysis program was devised to measure screw tip/tail offset and angular offset on axial and sagittal planes. RESULTS: For different OFPs, the mean tip offset, tail offset and angular offsets were 1.6 ± 0.9 mm (Range 0.0-3.6 mm), 1.4 ± 0.4 mm (Range 0.3-2.5 mm) and 1.1 ± 0.4° (Range 0.5-2.1), respectively. CONCLUSION: In this feasibility study, surgeons were able to place screws into the clinically relevant fracture pathways of the pelvis using ExcelsiusGPS® for robotic-assisted surgery. The measured accuracy was encouraging; however, further investigation is needed to demonstrate that robotic-assisted surgery can be used to successfully place the screws in the bony corridors of the pelvis to treat traumatic pelvic injuries.

Differential chromatin accessibility and transcriptional dynamics define breast cancer subtypes and their lineages.

Breast cancer is a heterogeneous disease, and treatment is guided by biomarker profiles representing distinct molecular subtypes. Breast cancer arises from the breast ductal epithelium, and experimental data suggests breast cancer subtypes have different cells of origin within that lineage. The precise cells of origin for each subtype and the transcriptional networks that characterize these tumor-normal lineages are not established. In this work, we applied bulk, single-cell (sc), and single-nucleus (sn) multi-omic techniques as well as spatial transcriptomics and multiplex imaging on 61 samples from 37 breast cancer patients to show characteristic links in gene expression and chromatin accessibility between breast cancer subtypes and their putative cells of origin. We applied the PAM50 subtyping algorithm in tandem with bulk RNA-seq and snRNA-seq to reliably subtype even low-purity tumor samples and confirm promoter accessibility using snATAC. Trajectory analysis of chromatin accessibility and differentially accessible motifs clearly connected progenitor populations with breast cancer subtypes supporting the cell of origin for basal-like and luminal A and B tumors. Regulatory network analysis of transcription factors underscored the importance of BHLHE40 in luminal breast cancer and luminal mature cells, and KLF5 in basal-like tumors and luminal progenitor cells. Furthermore, we identify key genes defining the basal-like ( PRKCA , SOX6 , RGS6 , KCNQ3 ) and luminal A/B ( FAM155A , LRP1B ) lineages, with expression in both precursor and cancer cells and further upregulation in tumors. Exhausted CTLA4-expressing CD8+ T cells were enriched in basal-like breast cancer, suggesting altered means of immune dysfunction among breast cancer subtypes. We used spatial transcriptomics and multiplex imaging to provide spatial detail for key markers of benign and malignant cell types and immune cell colocation. These findings demonstrate analysis of paired transcription and chromatin accessibility at the single cell level is a powerful tool for investigating breast cancer lineage development and highlight transcriptional networks that define basal and luminal breast cancer lineages.

Epigenetic regulation during cancer transitions across 11 tumour types.

Chromatin accessibility is essential in regulating gene expression and cellular identity, and alterations in accessibility have been implicated in driving cancer initiation, progression and metastasis1-4. Although the genetic contributions to oncogenic transitions have been investigated, epigenetic drivers remain less understood. Here we constructed a pan-cancer epigenetic and transcriptomic atlas using single-nucleus chromatin accessibility data (using single-nucleus assay for transposase-accessible chromatin) from 225 samples and matched single-cell or single-nucleus RNA-sequencing expression data from 206 samples. With over 1 million cells from each platform analysed through the enrichment of accessible chromatin regions, transcription factor motifs and regulons, we identified epigenetic drivers associated with cancer transitions. Some epigenetic drivers appeared in multiple cancers (for example, regulatory regions of ABCC1 and VEGFA; GATA6 and FOX-family motifs), whereas others were cancer specific (for example, regulatory regions of FGF19, ASAP2 and EN1, and the PBX3 motif). Among epigenetically altered pathways, TP53, hypoxia and TNF signalling were linked to cancer initiation, whereas oestrogen response, epithelial-mesenchymal transition and apical junction were tied to metastatic transition. Furthermore, we revealed a marked correlation between enhancer accessibility and gene expression and uncovered cooperation between epigenetic and genetic drivers. This atlas provides a foundation for further investigation of epigenetic dynamics in cancer transitions.

Epigenetic dynamics during capacitation of naïve human pluripotent stem cells.

Human pluripotent stem cells (hPSCs) are of fundamental relevance in regenerative medicine. Naïve hPSCs hold promise to overcome some of the limitations of conventional (primed) hPSCs, including recurrent epigenetic anomalies. Naïve-to-primed transition (capacitation) follows transcriptional dynamics of human embryonic epiblast and is necessary for somatic differentiation from naïve hPSCs. We found that capacitated hPSCs are transcriptionally closer to postimplantation epiblast than conventional hPSCs. This prompted us to comprehensively study epigenetic and related transcriptional changes during capacitation. Our results show that CpG islands, gene regulatory elements, and retrotransposons are hotspots of epigenetic dynamics during capacitation and indicate possible distinct roles of specific epigenetic modifications in gene expression control between naïve and primed hPSCs. Unexpectedly, PRC2 activity appeared to be dispensable for the capacitation. We find that capacitated hPSCs acquire an epigenetic state similar to conventional hPSCs. Significantly, however, the X chromosome erosion frequently observed in conventional female hPSCs is reversed by resetting and subsequent capacitation.

Glenoid-based reference system to differentiate shoulder pathologies on plain radiographs.

BACKGROUND: Shoulder radiographs are used for evaluation and the planning of treatment of various pathologies. Making a diagnosis of these pathologies on plain radiographs occurs by recognizing the relationship of the humeral head on the registry of the glenoid. Quantification of these changes in registry does not currently exist. We hypothesize that a geometric relationship of the humeral head and the glenoid exists that is defined on an anteroposterior Grashey view radiograph by the relationship of the best-fit circle of the humeral head relative to the best-fit circle of the glenoid such that relative measurements will define the normal shoulder and the pathologic shoulder. METHODS: One hundred fifty-six shoulders were included: 53 normal shoulders, 51 with primary glenohumeral osteoarthritis (GHOA), and 52 with cuff tear arthropathy (CTA). Humeral head best-fit circle was used to define the circle of the humeral head (cHH). A glenoid best-fit circle (cG) was defined by the following rules: (1) best fit of the glenoid articular surface and (2) was limited by the acromion such that either (a) it reaches maximal interaction with the inferior surface of the acromion or (b) the perimeter of the circle is at the lateralmost point of the acromion. The relationship between cHH and cG is defined by measurement of cHH in horizontal and vertical planes relative to the glenoid circle reference. The horizontal displacement angle (HDA) measures the horizontal position of cHH relative to cG, representing the degree of medialization toward the glenoid. The vertical displacement angle (VDA) measures the vertical position of cHH relative to cG, representing the degree of superiorization toward the acromion. Angles were compared by diagnosis and sex. RESULTS: The mean HDA was 61.0° (95% confidence interval [CI] 60.3°-61.7°) in normal shoulders, 79.9° (95% CI 76.9°-82.9°) in GHOA, and 63.4° (95% CI 61.7°-65.1°) in CTA (P < .001). The mean VDA was 43.1° (95% CI 42.2°-44.0°) in normal shoulders, 40.9° (95% CI 39.9°-42.0°) in GHOA, and 59.7° (95% CI 57.6°-61.7°) in CTA (P < .001). Interobserver reliability was 0.991 (95% CI 0.94-1.0) and intraobserver reliability was 0.998 (95% CI 0.99-1.0). The geometric relationship of cHH to the glenoid circle reference was plotted for each group. CONCLUSION: A geometric relationship exists of the humeral head in reference to the glenoid circle. Together, the HDA and the VDA distinguish between a normal shoulder and those with GHOA or CTA. This suggests that this novel methodology may provide a preoperative planning tool that is easily accessible.

ISSCR standards for the use of human stem cells in basic research.

The laboratory culture of human stem cells seeks to capture a cellular state as an in vitro surrogate of a biological system. For the results and outputs from this research to be accurate, meaningful, and durable, standards that ensure reproducibility and reliability of the data should be applied. Although such standards have been previously proposed for repositories and distribution centers, no widely accepted best practices exist for laboratory research with human pluripotent and tissue stem cells. To fill that void, the International Society for Stem Cell Research has developed a set of recommendations, including reporting criteria, for scientists in basic research laboratories. These criteria are designed to be technically and financially feasible and, when implemented, enhance the reproducibility and rigor of stem cell research.

A contamination focused approach for optimizing the single-cell RNA-seq experiment.

Droplet-based single-cell RNA-seq (scRNA-seq) data are plagued by ambient contaminations caused by nucleic acid material released by dead and dying cells. This material is mixed into the buffer and is co-encapsulated with cells, leading to a lower signal-to-noise ratio. Although there exist computational methods to remove ambient contaminations post-hoc, the reliability of algorithms in generating high-quality data from low-quality sources remains uncertain. Here, we assess data quality before data filtering by a set of quantitative, contamination-based metrics that assess data quality more effectively than standard metrics. Through a series of controlled experiments, we report improvements that can minimize ambient contamination outside of tissue dissociation, via cell fixation, improved cell loading, microfluidic dilution, and nuclei versus cell preparation; many of these parameters are inaccessible on commercial platforms. We provide end-users with insights on factors that can guide their decision-making regarding optimizations that minimize ambient contamination, and metrics to assess data quality.

Robotic-assisted percutaneous pelvis fixation: A case report.

Key Clinical Message: It may be possible to extend the use of the robotic arm to pelvic and acetabular surgery leading to safe, repeatable screw placement, and less radiation exposure for patients, surgeons and OR staff. Abstract: In this case, a novel, robotic-assisted technique was used to place a sacroiliac screw in a patient with unstable injuries of the pelvic ring. Intraoperative and postoperative fluoroscopic, radiographic, and CT imaging demonstrated a safely positioned 6.5 mm cannulated screw without unplanned cortical violation or impingement on neurovascular structures. To our knowledge, this is the first such reported case using a robot widely available in the Americas or Europe.

Impact of a Dedicated Orthopaedic Trauma Room on Elective Arthroplasty Case Volume.

OBJECTIVE: To examine the effects of implementing a dedicated orthopaedic trauma room (DOTR) on elective arthroplasty volume. DESIGN: Retrospective cohort study. SETTING: Level I academic trauma center. INTERVENTION: A retrospective analysis was performed for two 3-year intervals before and after DOTR introduction on January 20, 2013, at a Level I trauma center. Surgeons were included if they performed elective primary total hip arthroplasty (THA), total knee arthroplasty (TKA), total shoulder arthroplasty (TSA), or reverse total shoulder arthroplasty (RTSA) regularly from 2010 to 2015. MAIN OUTCOME MEASURES: Change in elective arthroplasty volume after the implementation of a DOTR. RESULTS: A total of 2339 cases were performed by surgeons A-E, with an average of 303.3 cases per year pre-DOTR and an average of 476.3 cases per year post-DOTR. On average, within our institution, there were 75.79 per 10,000 cases/year in Michigan pre-DOTR and 104.2 per 10,000 cases/year in Michigan post-DOTR. Surgeons A-E averaged 173.0 more cases per year and increased their average proportion of elective arthroplasty case volume in Michigan. There was a statistically significant market share increase of 9.8 per 10,000 cases/year in Michigan, at our hospital in the post-DOTR periods ( P = 0.039) (CI [0.5442, 19.21], SE = 4.523). This market share increase of 9.8 cases/10,000 cases was the yearly increase in market share that our average surgeons saw after the DOTR implementation, this took into account the observed annual increase in arthroplasty volume statewide during those years. CONCLUSION: Implementation of a DOTR was associated with increases in the total number, annual mean, and annual proportion of elective arthroplasty cases performed in Michigan for both elective surgeons and the institution as a whole. These findings reveal a benefit of DOTR implementation to elective arthroplasty surgeons and health systems on a larger scale, in the form of increased arthroplasty case volume.

The Integrin Pathway Partially Mediates Stretch-Induced Deficits in Primary Rat Microglia.

Stretch-injured microglia display significantly altered morphology, function and inflammatory-associated gene expression when cultured on a synthetic fibronectin substrate. However, the mechanism by which stretch induces these changes is unknown. Integrins, such as α5ß1, mediate microglial attachment to fibronectin via the RGD binding peptide; following integrin ligation the integrin-associated signaling enzyme, focal adhesion kinase (FAK), autophosphorylates tyrosine residue 397 and mediates multiple downstream cellular processes. We therefore hypothesize that blocking the RGD binding/integrin pathway with a commercially available RGD peptide will mimic the stretch-induced morphological alterations and functional deficits in microglia. Further, we hypothesize that upregulation of stretch-inhibited downstream integrin signaling will reverse these effects. Using primary rat microglia, we tested the effects of RGD binding peptide and a FAK activator on cellular function and structure and response to stretch-injury. Similar to injured cells, RGD peptide administration significantly decreases media nitric oxide (NO) levels and iNOS expression and induced morphological alterations and migratory deficits. While stretch-injury and RGD peptide administration decreased phosphorylation of the tyrosine 397 residue on FAK, 20 nM of ZINC 40099027, an activator specific to the tyrosine 397 residue, rescued the stretch-induced decrease in FAK phosphorylation and ameliorated the injury-induced decrease in media NO levels, iNOS expression and inflammatory associated gene expression. Additionally, treatment alleviated morphological changes observed after stretch-injury and restored normal migratory behavior to control levels. Taken together, these data suggest that the integrin/FAK pathway partially mediates the stretch-injured phenotype in microglia, and may serve as a pathway to modulate microglial responses.

Cell state transitions: catch them if you can.

The Company of Biologists' 2022 workshop on 'Cell State Transitions: Approaches, Experimental Systems and Models' brought together an international and interdisciplinary team of investigators spanning the fields of cell and developmental biology, stem cell biology, physics, mathematics and engineering to tackle the question of how cells precisely navigate between distinct identities and do so in a dynamic manner. This second edition of the workshop was organized after a successful virtual workshop on the same topic that took place in 2021.

Muscle disuse as hindlimb unloading in early postnatal mice negatively impacts grip strength in adult mice: a pilot study.

Physical inactivity has many detrimental effects on health, yet the impact of physical inactivity in early life on muscle health in adulthood remains unknown. Early postnatal malnutrition has prolonged effects into adulthood and we propose that early postnatal (P) physical inactivity would have similar negative effects. To test this hypothesis, we exposed postnatal mice (∼P28, C57BL/6J) to 14 days of physical inactivity (shortly after weaning, from ∼P28 to P42 days of age) in the form of muscle disuse with hindlimb unloading (HU). After this early-life physical inactivity, they were allowed to normally ambulate until 5 mo of age (P140, adulthood) when they underwent 14 days of HU with and without 7-day recovery. They were then tested for physical function (grip strength) and muscles were extracted and weighed. Immunofluorescence was carried out on these muscle cross sections for analysis of myofiber cross-sectional area (fCSA), macrophage density (CD68+ cells), and extracellular matrix (ECM) area. Muscle weights and fCSA and myofiber diameter were used to quantify changes in muscle and fiber size. Compared with age-matched controls, no notable effects of early-life physical inactivity (HU) on skeletal muscle and myofiber size were observed. However, a significant reduction in adult grip strength was observed in those exposed to HU early in life. This was associated with reduced muscle macrophages and increased ECM area. Exposure to a short period of early life disuse has negative enduring effects into adulthood impacting grip strength, muscle macrophages, and muscle composition as low muscle quality.NEW & NOTEWORTHY We demonstrate that early life disuse resulted in less grip strength in adulthood. Analysis of muscle composition demonstrated no loss of whole muscle or myofiber size indicating lower muscle quality akin to premature aging. This poor muscle quality was characterized by altered muscle macrophages and extracellular matrix area. We demonstrate intriguing correlations between this loss of grip strength and muscle macrophages and also area of noncontractile tissue in the muscle.

Biophysical models of early mammalian embryogenesis.

Embryo development is a critical and fascinating stage in the life cycle of many organisms. Despite decades of research, the earliest stages of mammalian embryogenesis are still poorly understood, caused by a scarcity of high-resolution spatial and temporal data, the use of only a few model organisms, and a paucity of truly multidisciplinary approaches that combine biological research with biophysical modeling and computational simulation. Here, we explain the theoretical frameworks and biophysical processes that are best suited to modeling the early mammalian embryo, review a comprehensive list of previous models, and discuss the most promising avenues for future work.

Entropy sorting of single-cell RNA sequencing data reveals the inner cell mass in the human pre-implantation embryo.

A major challenge in single-cell gene expression analysis is to discern meaningful cellular heterogeneity from technical or biological noise. To address this challenge, we present entropy sorting (ES), a mathematical framework that distinguishes genes indicative of cell identity. ES achieves this in an unsupervised manner by quantifying if observed correlations between features are more likely to have occurred due to random chance versus a dependent relationship, without the need for any user-defined significance threshold. On synthetic data, we demonstrate the removal of noisy signals to reveal a higher resolution of gene expression patterns than commonly used feature selection methods. We then apply ES to human pre-implantation embryo single-cell RNA sequencing (scRNA-seq) data. Previous studies failed to unambiguously identify early inner cell mass (ICM), suggesting that the human embryo may diverge from the mouse paradigm. In contrast, ES resolves the ICM and reveals sequential lineage bifurcations as in the classical model. ES thus provides a powerful approach for maximizing information extraction from high-dimensional datasets such as scRNA-seq data.

Liposomal bupivacaine nerve block provides better pain control post-total shoulder arthroplasty than continuous indwelling catheter.

BACKGROUND: Pain control is essential to successful total shoulder arthroplasty (TSA). MATERIALS AND METHODS: This non-blinded, randomized clinical trial compared shoulder pain, narcotic use, interscalene (IS) block application time, and costs in 76 subjects who were randomly assigned to receive either a single injection IS nerve block of 10 cc (133 mg) liposomal bupivacaine mixed with 10 cc of 0.5% bupivacaine (Group 1), or 20 cc of 0.5% ropivacaine direct injection combined with an indwelling IS nerve block catheter delivering 0.2% ropivacaine at a continual 4 cc/h infusion for the initial 3 post-operative days (Group 2). Surgical time, local anesthesia duration, hospital stay length, morphine milligram equivalents (MME) consumed, worst shoulder pain at 24, 48 and 72 h, and complications were recorded. Patient reported function, pain and activity level surveys were completed before, and 6-week post-TSA (P < 0.05). RESULTS: Group 1 had less pain 24-h (0.72 ± 0.8 vs. 3.4 ± 2.9, p < 0.0001) and 48-h (2.5 ± 2.2 vs. 4.8 ± 2.6, p = 0.005) post-TSA. At 24-h post-TSA, MME consumption was similar (Group 1 = 4.5 ± 6.4 vs. Group 2 = 3.7 ± 3.8, p = 0.54), but was lower for Group 1 at 48 h (0.0 ± 0.0 vs. 0.64 ± 0.99, p = 0.001). Group 2 had longer IS block application time (10.00 ± 4.6 min vs. 4.84 ± 2.7 min, p < 0.0001). Only group 2 had a strong relationship between MME consumption over the first 24-h post-TSA and pain 24-h post-TSA (r = 0.76, p < 0.0001), a moderate relationship with pain 48-h post-TSA (r = 0.59, P = 0.001), and a weak relationship with pain 72-h post-TSA (r = 0.44, P = 0.02). Significant relationships for these variables were not observed for Group 1 (r ≤ 0.30, p ≥ 0.23). Group 1 IS block costs were less/patient than Group 2 ($190.17 vs. $357.12 USD). CONCLUSION: A single shot, liposomal bupivacaine interscalene nerve block provided better post-TSA pain control with less narcotic consumption, less time for administration and less healthcare system cost compared to interscalene nerve block using a continuous indwelling catheter. LEVEL OF EVIDENCE: Level I, Prospective, Randomized.

Matrix stiffness enhances cancer-macrophage interactions and M2-like macrophage accumulation in the breast tumor microenvironment.

The role of intratumor heterogeneity is becoming increasingly apparent in part due to expansion in single cell technologies. Clinically, tumor heterogeneity poses several obstacles to effective cancer therapy dealing with biomarker variability and treatment responses. Matrix stiffening is known to occur during tumor progression and contribute to pathogenesis in several cancer hallmarks, including tumor angiogenesis and metastasis. However, the effects of matrix stiffening on intratumor heterogeneity have not been thoroughly studied. In this study, we applied single-cell RNA sequencing to investigate the differences in the transcriptional landscapes between stiff and compliant MMTV-PyMT mouse mammary tumors. We found similar compositions of cancer and stromal subpopulations in compliant and stiff tumors but differential intercellular communication and a significantly higher concentration of tumor-promoting, M2-like macrophages in the stiffer tumor microenvironments. Interestingly, we found that cancer cells seeded on stiffer substrates recruited more macrophages. Furthermore, elevated matrix stiffness increased Colony Stimulating Factor 1 (CSF-1) expression in breast cancer cells and reduction of CSF-1 expression on stiffer substrates reduced macrophage recruitment. Thus, our results demonstrate that tissue phenotypes were conserved between stiff and compliant tumors but matrix stiffening altered cell-cell interactions which may be responsible for shifting the phenotypic balance of macrophages residing in the tumor microenvironment towards a pro-tumor progression M2 phenotype. STATEMENT OF SIGNIFICANCE: Cells within tumors are highly heterogeneous, posing challenges with treatment and recurrence. While increased tissue stiffness can promote several hallmarks of cancer, its effects on tumor heterogeneity are unclear. We used single-cell RNA sequencing to investigate the differences in the transcriptional landscapes between stiff and compliant MMTV-PyMT mouse mammary tumors. We found similar compositions of cancer and stromal subpopulations in compliant and stiff tumors but differential intercellular communication and a significantly higher concentration of tumor-promoting, M2-like macrophages in the stiffer tumor microenvironments. Using a biomaterial-based platform, we found that cancer cells seeded on stiffer substrates recruited more macrophages, supporting our in vivo findings. Together, our results demonstrate a key role of matrix stiffness in affecting cell-cell communication and macrophage recruitment.

Does Preoperative Opioid Consumption Influence Patient Satisfaction following Total Knee Arthroplasty?

Chronic opioid use prior to total knee arthroplasty (TKA) has been implicated in adverse outcomes. The purpose of this study was to evaluate clinical outcome measures and patient satisfaction in patients with a history of preoperative chronic opioid use undergoing primary TKA. A retrospective cohort study was performed on 296 consecutive patients undergoing primary TKA. Seventy-four (25%) patients were identified with chronic preoperative opioid use (study group; 22 males, 52 females). A 3:1 matched cohort ratio of control versus study group was utilized resulting in a control group consisting of 222 patients (97 males, 125 females) without chronic opioid use prior to surgery. There was no statistically significant difference in age, BMI, or follow-up. Average follow-up was 23.4 months in the control group and 23.6 months in the study group (p = 0.87). Clinical data including patient satisfaction (Likert score), Knee Society (KS) Knee scores, KS Function scores, Forgotten Joint Score (FJS), length of stay (LOS), and complications were evaluated. Patient satisfaction at the most recent visit was 92.8% in the control group versus 83.8% in the chronic opioid group (p = 0.0016). Differences in patient-reported outcomes measures comparing the control and study cohorts included KS Function Score of 83.23 versus 75.31 (p = 0.0034). The FJS of 63.7 versus 58 (p = 0.1883) and the KS Knee Score of 89.5 versus 88.1 (p = 0.4075) were not significant. Postoperative opioid usage for the control versus the study group was 62/222 (27.9%) versus 56/74 (75.7%) at 4 to 8 weeks (p <0.0001), and 4/222 (1.80%) versus 27/74 (36.5%) at 12 months (p <0.0001). Overall complication occurrence was 18.9% in the study group versus 11.3% in the control group (p = 0.11). Patients with history of chronic preoperative opioid use had significantly lower patient satisfaction and KS Function scores and increased postoperative opioid usage at 12 months compared with patients without a history of opioid use prior to TKA.

Absent Pulmonary Artery Presenting as High-Altitude Pulmonary Edema.

CASE PRESENTATION: A 22-year-old male with no known past medical history presented to our emergency department complaining of difficulty breathing. A plain film chest radiograph revealed findings consistent with a tension pneumothorax. DISCUSSION: However, due to physical examination findings inconsistent with the imaging report, a computed tomography of the chest was ordered which revealed an absent right pulmonary artery.The patient was ultimately treated for high altitude pulmonary edema and discharged on nifedipine and supplementary oxygen.