United States

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&lt;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. 


2022 AMA Research Challenge

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

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Jessica Li, MD/PhD Candidate
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Charles Lopresto, DO

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Welcome to the largest national, multi-specialty research event featuring research from 750 medical students, residents and fellows, and international medical graduates.


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.

poster

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.

Evaluating the Safe Zone for Lumbar Pedicle Screws: Are Midline Crossing Screws Indicative of Pedicle Screw Breach?

Fibular Displacement Predicts Tibial Malrotation in Simulated Tibia-Fibula Fractures

Gray Scale and Power Doppler Ultrasound Findings Predictive of Cubital Tunnel Syndrome Severity

Background Context: In the United States, the prevalence of inflammatory bowel disease (IBD) has increased concurrently with an aging population with degenerative disc changes. In these patients, primary 1- to 2-lumbar fusion (1-2LF) is a common procedure to resolve serious complications of the spine. Studies comparing these patient demographics to hospital lengths of stay, post-operative complications, readmission rates, and costs of care is limited in the literature.

Purpose: The purpose of this study was to determine whether IBD in patients with degenerative disc changes undergoing primary 1-2LF is associated with higher rates of: 1) in-hospital length of stay; 2) medical complications; 3) readmissions; and 4) costs of care.

Study Design/Setting: Retrospective Cohort Study

Patient Sample: The PearlDiver database was queried from 2010 to 2022 to identify patients who underwent primary 1- to 2- level lumbar fusion operations using International Classification of Diseases, Ninth and Tenth Revision, Clinical Modification (ICD-9-CM, ICD-10-CM) coding. Current Procedural Terminology (CPT) codes were also utilized to identify the patient cohort isolated.

Methods: A retrospective study using the PearlDiver database from the years 2010 to 2020 was performed to isolate IBD patients with degenerative disc disease undergoing primary 1-2LF. The inclusion criteria consisted of patients with IBD who underwent 1-2LF, using a 90-day surveillance period, post-operatively. This 90-day surveillance period was used to measure length of hospital stay, rates of medical complications, rates of readmissions, and overall costs of care. The IBD cohort was matched against a case-matched cohort group. The study yielded 20,640 patients, overall, with 3,446 IBD patients and 17,194 non-IBD patients. Baseline demographics were compared. Chi-Square Analyses were performed to properly match the two cohorts. Welch’s t-tests were used to test for significance for the length of stay and reimbursement data between both groups. Logistic regression analyses were utilized to calculate the odds-ratios (OR) and 95% confidence intervals (95%CI) to further analyze the association between IBD on post-operative outcomes after 1-2LF. Bonferroni adjustments were made and yielded an alpha value less than 0.001 as statistically significant. Finally, a p-value less than 0.05 was considered statistically significant.

Results: Patients in the study group had significantly longer in-hospital lengths of stay (4- vs. 3-days, p < 0.001). Additionally, patients in the study group had significantly higher incidence and odds of developing post-operative medical complications within 90 days (42.3% vs. 25.7%; OR: 1.73, p < 0.0001). Also, study group patients had significantly higher readmission rates (11.32% vs. 9.44%; OR: 1.22, p = 0.0007). Finally, patients in the study group had significantly higher costs of care than their case-matched cohort ($60,412.83 vs. $59,331.94, p < 0.0001).

Conclusions: This study demonstrated that patients with IBD and degenerative disc disease are burdened with longer in-hospital lengths of stay, rates of post-operative medical complications, rates of readmission, and costs of care after undergoing primary 1-2LF. Spine surgeons and other orthopaedic professionals would benefit from providing adequate counseling to this patient demographic so patients are fully aware of the potential post-operative burdens they may accrue.

Keywords: Lumbar Fusion; Inflammatory Bowel Disease; Degenerative Disc Disease

How Does Inflammatory Bowel Disease Impact Outcomes and Costs of CareFollowing Primary 1- to 2- Level Lumbar Fusion for Degenerative Disc Disease?

How Has COVID-19 Affected Rates of Musculoskeletal Pain and Digital Media Use in Children?

Amnion epithelial and mesenchymal cells have been shown in vitro to contain a variety of regulatory mediators that result in the promotion of cellular proliferation, differentiation, epithelialization, and the inhibition of fibrosis, immune rejection, inflammation, and bacterial invasion. Amniotic membrane products are approved for use as human cells, tissues, and cellular and tissue-based products (HCT/Ps) under the 361 or 351 pathways of the Food and Drug Administration (FDA). Previously reported clinical applications of human amniotic membrane (hAM) include nerve repair, tendon injury, joint and cartilage damage, and wound management. Although there is some evidence regarding the use of amniotic allografts in animals, there is a paucity of literature regarding their use to treat pathology of the hand and wrist. Further investigation is necessary to determine their effectiveness and therapeutic value in the upper extremity.

Human Amniotic Allograft in Hand Surgery

Abstract Title: In vitro Murine Bioassay of IL-12-loaded PLGA Nanoparticles

Background: The cytokine Interleukin (IL)-12 has been shown to have significant anti-tumor effects through its impact on the differentiation of T helper cells and M1 activation of macrophages. While intravenous (i.v.) IL-12 has shown anti-tumor effects in murine models, in human clinical trials, research has been halted due to limited efficacy and serious side effects. These side effects are believed to be due to peripheral immune exhaustion associated i.v. IL-12 delivery. Nanoparticle encapsulation of IL-12 (nIL- 12) with Poly(D,L-lactide-co-glycolide) acid (PLGA) shows the potential to retain anti-tumor effects while mitigating dose-limiting toxicity. After injection, these PLGA nanospheres distribute systemically, deposit into tissues (limiting immune stimulation in the peripheral blood), and then slowly release encapsulated IL-12. Development of an in vitro bioassay is particularly important to ensure that the bioactivity of IL-12 is not altered following nanoparticle synthesis and encapsulation.

Methods: Following an in vitro study of nIL-12 elution, nIL-12 was used to stimulate male C57BL/6 murine splenocytes. Cultured splenocytes were exposed to five 10-fold serial dilutions of nIL-12, concentration-matched stock (unencapsulated) IL-12 (sIL-12), or unloaded nanoparticles. Production of IFN-γ was evaluated via ELISA; an ED-50 curve (IL-12 concentration vs IFN-γ production) was generated.

Results: nIL-12 and sIL-12 were diluted to an average of 18257.93, 1825.79, 182.57, 18.25, and 1.82 pg of IL-12. nIL-12 produced an average of 32652.26, 98022.06, 52440.92, 17883.45, and 991.26 pg of IFN- γ, respectively, yielding an ED50 of 40.4 ± 16.45 pg/mL. sIL-12 produced an average of 59404.67, 101668.97, 67137.01, 23587.61, and 7255.68 pg of IFN-γ, respectively, yielding an ED50 of 119.0±35.04 pg/mL. There was no statistically significant difference in ED50 between nIL-12 and sIL-12 (p = 0.1477). Thus, PLGA encapsulation was not found to alter cytokine bioactivity.

Conclusion: Successful validation of IL-12 bioactivity post-encapsulation is a critical quality control measure that shows IL-12 can be loaded into PLGA nanoparticles. These results support an in vitro dose- dependent IFN-γ response to nIL-12. Further experiments will evaluate in vivo immunological response in a murine model of metastatic osteosarcoma.

In vitro Murine Bioassay of IL-12-loaded PLGA Nanoparticles

Intraoperative Full-Length Radiographs after Long Bone Nailing Increase Anesthesia Time and Costs, But Do Not Lead to Revision
Patrick Ryan, M21, Michael Beltran, MD2, Nihar Shah, MD2
1: University of Cincinnati College of Medicine, Cincinnati, Ohio
2: Department of Orthopaedic Surgery, University of Cincinnati College of Medicine

Background:
The treatment of long bone fractures places a large socioeconomic burden on the workforce of the USA. Plate fixation, external fixation, and intramedullary nailing are the most common treatment options for these fractures. Surgeons performing intramedullary nailing of lone bone fractures often employ intraoperative full-length radiographs prior to reversal of general anesthesia—even after utilizing intraoperative fluoroscopy, but it is unknown if this alters patient care. The purpose of this study is to determine if intraoperative full-length ‘check radiographs’ alter patient care. We theorized that these radiographs rarely alter care and are associated with increased costs and anesthesia time.
Methods:
Medical records of patients undergoing fluoroscopy-guided tibial and femoral nailing operations at the University of Cincinnati Medical Center between June 2018 and June 2021 were reviewed. Data about the patient demographics, fracture characteristics, operative details, and reintervention status were collected from 734 procedures. Standard statistical techniques were utilized to compare reintervention rates.
Results:
Of the 734 procedures reviewed, five were excluded because the status of intraoperative check radiograph imaging was not included in the chart. The remaining 729 procedures included 673 cases where check radiographs were taken (with a median of four images captured per procedure) and 56 cases where surgeons used only intraoperative fluoroscopic images to assess for proper nail placement. Only two of the 673 check radiographs (0.29% [0%, 0.7%]) led to intraoperative revision nailing during the same anesthetic event, and 36 check radiographs (5.3% [3.6%, 7.0%]) resulted in reintervention surgeries at later dates. In the cohort not receiving check radiographs, five patients (8.9% [1.5%, 16.4%]) required reintervention surgery at a later date. No significant difference in overall reintervention rate was found between procedures which did not use check radiographs and those procedures which did (odds ratio = 1.64 [0.62, 4.34]; p=0.317).
Conclusion:
Intraoperative full-length radiographs after tibial and femoral nailing rarely lead to revision surgery during the same anesthetic event. We found no difference in reintervention for tibial and femoral nailing procedures with and without check radiographs. The increased anesthesia time, costs, and surgical delays associated with obtaining these radiographs do not appear to be justified.


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

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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

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