United States

Background: Retinal vein occlusion (RVO) is the second most common cause of blindness among retinal vascular diseases. It consists of central retinal artery occlusion (CRAO), central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO). While the regional prevalence of RVO in the U.S. is 0.5 to 2 %, the national rate is still unknown. Therefore, we utilized a nationally representative sample collected by the National Health and Nutrition Examination Survey (NHANES) to better estimate the national prevalence and risk factors for
RVO.
Methods: The NHANES is a multi-ethnic study, which surveyed individuals from 30 different counties across the U.S. between 2005-2008. Besides demographic and medical diseases survey, participants underwent 45 degrees non-mydriatic retinal photography of both eyes. Out of 7081 cases, 1552 were excluded due to missing and ungradable images. For the remaining 5559 participants (2771 men and 2788 women), retinal scans were masked and evaluated by graders for the presence of RVO. We performed weighted analysis to estimate national prevalence rates and multivariate analysis to examine associated risk factors. 
Results: Out of 5559 subjects, 33 (20 men and 13 women, 0.59%) had RVO [27 (0.48%) BRVO, and 6 (0.11%) CRVO]. The overall national prevalence of BRVO, CRVO, and any RVO was 0.42% (95% CI = 0.23—0.60), 0.08% (95% CI = 0—0.18), and 0.50% (95% CI = 0.30—0.71), respectively. Multivariate analysis found that age, per 10-year increase (OR, 1.93; 95% CI = 1.31—2.92, P = 0.001) and elevated diastolic blood pressure, per 10 mm Hg increase (OR, 1.47; 95% CI = 1.10—2.12, P = 0.032) were significant risk factors for the prevalence of RVO. Race, gender, history of diabetes, stroke, and cardiovascular disease were not found to be significant risk factors. In univariate analysis glaucoma (P = 0.009) and total cholesterol (P =0.021) were significantly associated with RVO.
Conclusion: Our study found that the overall national prevalence of RVO was 0.50%. In addition, older age and elevated diastolic BP were strongly associated with RVO. We recommend that patients with these characteristics undergo regular comprehensive ocular examination.

2022 AMA Research Challenge

Prevalence of Retinal Vein Occlusion in the United States

ENDO 2021

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Charles Lopresto, DO

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Background
Glaucoma, the second leading cause of blindness, affects over 80 million patients worldwide, including 3 million patients in the USA. It is a progressive optic neuropathy affecting both the structure and vascular supply of the optic nerve and retina. Optical coherence tomography angiography (OCTA) is a new, noninvasive technique which excels at providing the vasculature and anatomy of these regions. Recent studies have demonstrated a possible link between vessel area density (VAD) and glaucoma progression. However, conflicting data indicates a need for more robust study of VAD and other quantitative parameters such as vessel length density (VLD) and branchpoint density (BPD). Therefore, our aim was to analyze and compare these three parameters in patients with primary open angle glaucoma (POAG) and healthy subjects using open-source ImageJ software.

Methods
This IRB-approved, retrospective study included 98 consecutive participants (49 healthy; 49 POAG) imaged at an academic center between January and May 2020. One eye was chosen at random from each subject. Exclusion criteria included OCTA scan quality < 6/10, significant artifacts, high myopia/hyperopia, and vitreoretinal diseases. We analyzed the superficial and deep plexuses of the retina as well as the radial peripapillary capillary (RPC) layer of the optic disc. VAD, VLD, and BPD were obtained for each layer using ImageJ and the relationship between healthy and glaucomatous eyes was analyzed via logistic regression. Diagnostic value
was determined using areas under receiver operating curves (AUC).

Results
VAD, VLD, and BPD were significantly reduced in glaucoma for all anatomical layers, with the greatest reduction occurring in the RPC layer (P < 0.001). The AUCs of the diagnostic models analyzing all parameters within the superficial, deep, and RPC layers were 0.883, 0.902, and 0.942, respectively. Combining all parameters from all layers into a single model yielded the best diagnostic performance (AUC = 0.974; p < 0.001).

Conclusion
Our study is among the first to quantitatively characterize OCTA scans of healthy and glaucomatous eyes using multiple parameters. Our combined model analyzing multiple ocular layers has shown excellent utility in the diagnosis of glaucoma.

Vascular Morphology of the Optic Nerve and Retina in Glaucoma

Background:
Acetabular fractures are highly complex injuries often resulting from high-energy trauma that orthopedic surgeons commonly address and treat. The use of open reduction internal fixation (ORIF) has increased in recent years and is highly technical, in that the quality of ORIF directly affects patient outcome. Studies have characterized multiple factors that contribute to post- operative quality of life. The purpose of this study is to further this understanding and investigate how (1) patient demographics and (2) patient-specific risk factors affect 90-day readmissions in patients.
Methods:
A retrospective, nationwide query of private insurance database from January 1st, 2010 to October 31st, 2020 was performed using ICD-9, ICD-10, and CPT codes. Patients who underwent acetabular fracture ORIF for acetabular fractures and were readmitted within 90 days following index procedure were included, while those patients who were not readmitted served as comparison controls, yielding a total of 3942 patients. Patients were divided by demographics (age and sex) and specific risk factors associated with readmission. A logistic regression model was used to identify the odds ratio (OR) and 95% confidence interval. Alpha-value of less than 0.002 was considered statistically significant.
Results:
The query yielded a total of 3,942 patients. Age and sex were found to be non-significant contributing risk factors to 90-day readmissions (p = 0.251 and p = 0.531, respectively). Data also showed that statistically significant co-morbidities included arrhythmia (OR:1.32, 1.16-1.78, p< 0.0001), cerebrovascular disease (OR: 1.43, OR: 1.43, CI: 1.16-1.78, p< 0.0001), coagulopathy (OR: 1.62, 1.30-2.02, p < 0.0001), fluid and electrolyte abnormalities (OR: 1.52, CI: 1.25-1.84, p< 0.0001), and pathologic weight loss (OR: 1.37, CI: 1.10-1.70, p< 0.0001). 
Conclusion:
This study illustrated how several patient-specific risk factors may contribute to increased 90-day readmission risk following acetabular ORIF. A heightened awareness of these comorbidities in patients requiring acetabular ORIF is required to improve patient outcomes and minimize rates of readmission. Further investigation is needed to optimize quality of ORIF in these patient populations, improve patient outcomes, and increase awareness of potential postoperative complications in these higher-risk patient populations.

Comparison of Patient Demographics and Patient Specific Risk Factors for Readmissions Following Open Reduction and Internal Fixation for Acetabular Fractures

Background: Although technology-assisted total knee arthroplasty (TKA) is becoming increasingly prevalent, insight into its reception by the public is limited. Here we evaluate the public’s perception of technology-assisted TKA compared to traditional TKA.

Methods: A prospective cohort study was performed utilizing a paid survey distributed via a validated online marketplace. Following baseline demographics, participants were queried whether they would prefer a computer-/robotic-assisted (technology) TKA or traditional TKA without additional information. Participants were separated into “Tech TKA” and “Traditional TKA” cohorts based on their responses. All respondents sequentially completed a pre-test, an evidence-based education table, and a post-test survey focused on the differences between technology versus traditional TKA. Upon completion, cohorts were again asked which TKA modality they would prefer. Statistical tests performed included Student’s t-tests and χ2 tests.

Results: 500 surveys were completed with 402 (80.4%) respondents in the tech TKA and 98 (19.6%) in the traditional TKA cohort. Tech TKA respondents were more educated (Bachelor’s degree: 46.88% vs 31.63%, p<.01), had higher incomes (>$75,000: 35.6% vs 18.4%), and more familiar with TKA (know of, very familiar, or underwent TKA: 93.2% vs 82.65%; p<.01;. Age, gender, race, ethnicity, and annual doctor visits were similar.

After reviewing the educational table, 33 (33.67%) of the traditional TKA respondents switched their preferences to technology TKA. Conversely, 95 (23.63%) Tech TKA switched to traditional TKA. Among post-test respondents interested in technology-assisted TKA, 75.00% were willing to switch their surgeons and 35.29% would pay an additional sum of moneys if not covered by insurance (35.29%). The most important information from the table for technology-assisted TKA respondents was length of stay, while traditional TKA was “who does the surgery.”

Conclusion: Technology-assisted TKA appears to be well-regarded and valued amongst the public. Educational material does not appear to dramatically change preferences.

Assessing Patient Preferences for Technology-Assisted versusTraditional Total Knee Arthroplasty Using a Validated Online SurveyMarketplace: Before and After Patient Education

Bridging Reconstruction and Reverse Total Shoulder Arthroplasty for Rotator Cuff Tear Management: Is there a Difference in Clinical Outcomes?

Objectives: Aseptic loosening is a feared complication following primary total elbow arthroplasty (TEA). Currently, the literature assessing patient-related variables that may be associated with this complication are limited. As such, the aims of this investigation were to: 1) compare baseline demographic profiles of patients who did and did not develop aseptic loosening following primary TEA; and 2) identify patient-specific risk factors associated with the development of aseptic loosening. 

Materials and Methods: A retrospective analysis using 100% Parts A and B portion of the Medicare claims was performed. The inclusion criteria for the study group consisted of all patients who underwent primary TEA and subsequently developed aseptic loosening within two years following the index procedures. Patients who did not develop mechanical loosening served as the comparison cohort. The final study yielded 11,048 patients within the study (n=307) and control cohorts (n=10,741). Baseline demographics were compared using Pearson’s chi-square analyses. A multivariate regression model was used to determine the odds ratio (OR), 95% confidence interval (95%CI), and p-value of various risk factors associated with development of aseptic loosening. A p-value less than 0.05 was considered statistically significant.

Results: Patients who developed aseptic loosening were found to have statistically significant differences in age (p=0.0001) and sex (p=0.0251). Study participants were also found to have significantly higher prevalence of various comorbid conditions compared to control subjects, including obesity (15.96% vs. 8.36%, p<0.0001). Risk factors associated with the greatest risk of aseptic loosening within two years were obesity (OR: 1.65, 95%CI: 1.18-2.28, p=0.002), male sex (OR: 1.51, 95%CI: 1.13-2.00, p=0.004), and opioid use disorder (OR: 1.58, 95%CI: 1.14-2.15, p=0.004). Other statistically significant risk factors included depression (OR: 1.41, 95%CI: 1.10-1.80, p=0.005), hypothyroidism (OR: 1.38, 95%CI: 1.08-1.75, p=0.009), and rheumatoid arthritis (OR: 1.29, 95%CI: 1.01-1.64, p=0.039).

Conclusion: The study is the first, to the best of the authors’ knowledge, to identify baseline demographic profiles and patient-related risk factors associated with aseptic loosening following primary TEA. This evidence provided can be applied to the clinical setting to both educate at-risk patients of this potential complication as well as potentially inform their clinical management.

Comparison of Baseline Demographics and Risk Factors for Aseptic Loosening Following Primary Total Elbow Arthroplasty

Introduction: Surgical site infections (SSIs) are a notable complication following open reduction and internal fixation (ORIF) for ankle fractures. Prior studies investigating risk factors of SSIs have been limited in their application to specific types of ankle fractures. The purpose of this study was to (1) compare baseline demographics of patients who did and did not develop SSIs within 90 days following ORIF for trimalleolar ankle fractures and (2) identify risk factors associated with developing SSIs in this setting.

Methods: A retrospective analysis from 2010 to 2020 was completed using a national administrative database. The study group consisted of patients who underwent ORIF for trimalleolar ankle fractures and developed SSIs within 90 days of their surgical fixation. Patients who did not develop SSIs in this setting served as the comparison cohort. The final study yielded 22,118 patients within the study (n = 1000) and control cohort (n = 21,118). Baseline demographics of the two cohorts were compared using Pearson’s Chi-Square Analyses. A multivariate binomial logistic regression model was constructed to determine the association of various comorbidities on developing SSIs in this setting. 

Results: The study demonstrated the SSI cohort to have a higher comorbidity burden, shown by statistically significant differences in several individual comorbidities and in mean Elixhauser-Comorbidity Indices (ECI) scores. The greatest risk factors for the development of SSIs following ORIF for trimalleolar ankle fractures were peripheral vascular disease (OR: 1.53, p<0.0001), diabetes mellitus (OR: 1.26, p=0.001), iron deficiency anemia (OR: 1.24, p=0.001), male sex (OR: 1.22, p=0.001), and tobacco use (OR: 1.15, p=0.001).

Conclusion: This study found significant baseline differences between the study and comparison cohorts and identified several risk factors associated with developing SSIs after ORIF for trimalleolar ankle fractures. This study recognizes the role of orthopaedic surgeons to develop patient-directed interventions to reduce the rate of SSIs in this setting.

Comparison of Patient Demographics and Risk of Surgical Site Infections Following Open Reduction and Internal Fixation of Trimalleolar Ankle Fractures: A Nationwide Analysis of a Private Payor

Introduction: Crohn’s Disease (CD) burdens a large percentage of Americans with rising prevalence in newly developed countries. Rates of primary total knee arthroplasty (TKA) have also increased in recent decades. While past studies have demonstrated a relationship between CD and outcomes and costs of TKA, there is still sparse evidence on specific postoperative complications. The purpose of this study is to reaffirm and further investigate the influence of CD on (1) in-hospital length of stay (LOS); (2) readmission rates; (3) implant-related complications; and (4) costs of care in patients undergoing primary TKA.

Methods: A retrospective query using the Medicare claims database was performed from January 1st, 2005 to March 31st, 2014 for patients undergoing primary TKA with and without CD using ICD-9 diagnoses codes. CD patients receiving primary TKA were matched to non-CD patients in a 1:5 ratio by age, sex, and medical comorbidities, yielding 96,229 patients (CD=16,039; non-CD=80,190). Primary endpoints were in-hospital LOS, readmission rates, implant-related complications, and day of surgery and 90-day costs of care. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using logistic regression analyses. A p-value less than 0.05 was considered statistically significant. 

Results: Patients with CD undergoing primary TKA experienced significantly longer in-hospital LOS (3- vs. 2- days, p<0.0001) in comparison to non-CD patients. In addition, patients with CD suffered significantly higher readmission rates (19.8% vs. 14.9%; OR, 1.40; 95% CI, 1.34-1.47; p<0.0001) compared to non-CD patients. Total implant-related complications following primary TKA were also significantly higher in CD patients (6.88% vs. 4.88%; OR, 1.43; 95% CI, 1.34-1.54; p<0.0001). CD patients incurred significantly higher day of surgery ($18,365.98 vs. $16,192.00; p<0.0001) and 90-day costs ($21,337.46 vs. $19,101.42; p<0.0001) compared to their counterparts.

Conclusion: This study demonstrated notably higher in-hospital LOS, readmission rates, implant-related complications, and costs of care in CD patients. Orthopedic surgeons may use this study to educate their higher-risk patients of potential postoperative complications.

Crohn’s Disease is Associated With Implant-Related Complications Following Primary Total Knee Arthroplasty: A Matched-Control Analysis

Background
Pedicle screw breach (PSB) is not uncommon following lumbar instrumentation, and in some instances, it may lead to vascular and/or neurologic complications. Previous literature suggested that screws crossing the vertebral midline on an anterior-posterior (AP) radiograph (or midsagittal on CT) are concerning for medial pedicle breach. 

Objective
Our primary aim was to map out the safe zones (SZ) of bilateral pedicle instrumentation and their relationship at each lumbar vertebral level. Our secondary aim was to evaluate the presence of SZs’ intersection at each lumbar level, denoting safe screw midline crossing not otherwise associated with medial pedicle breach.

Methodology
CT scans of 51 patients were randomly selected from “The Cancer Imaging Archive” (TCIA) online database for analysis. The Sectra 3D Spine software was used to create 3D renderings, place virtual screws, and make measurements. At each lumbar vertebra, the right and left pedicle corridors were mapped. At each pedicle, two screw positions were templated, the “medial limit screw” (MLS) and the “lateral limit screw” (LLS). Each limit screw was the most extreme position that the screw could exist in without causing a medial or lateral breach. The safe zone was defined as the zone between MLS and LLS (Figure 1). Measurements were taken for each level (between L1-L5) and side (Left, Right). 

Results
A total of 253 lumbar vertebrae from 51 patients (mean age 53.1, 56.9% male) were included. Two vertebrae from two patients were removed for poor image quality. Out of the 506 screw positions analyzed in our study, 97.4% had overlapping SZ and crossed the midplane without medial pedicle breach (Table 1). The significant factors (p < 0.01) for safe midplane-crossing screws included: the screw length (L1-L5); the laterality of the screw entry point (L1-L4); and the pedicle diameter (L2 and L5). 

Conclusion
A midline crossing pedicle screw on a lumbar AP radiograph is not necessarily indicative of a medial pedicle screw breach. Anatomical (i.e. larger pedicle diameter) and technical (i.e. longer screws, and lateral entry points) factors allow for safety zone intersections and indicate safe midline crossing by pedicle screws.

Prevalence of Retinal Vein Occlusion in the United States

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