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Increased prevalence of lower extremity soft tissue injuries and surgeries in patients with anorexia nervosa and bulimia nervosa. PHYSICIAN SPORTSMED 2024; 52:246-252. [PMID: 37462035 DOI: 10.1080/00913847.2023.2237988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023]
Abstract
PURPOSE An abundance of literature exists linking eating disorders and fracture risk. However, no studies, to our knowledge, have investigated the impact of eating disorders on lower extremity soft tissue injury or surgery risk. The purpose of this study was to determine if anorexia nervosa and bulimia nervosa are associated with prevalence of lower extremity soft tissue injuries and surgeries. METHODS Patients with anorexia nervosa or bulimia nervosa over 2010-2020 were identified through the International Classification of Diseases (ICD) codes in the PearlDiver Claims Database. Patients were matched by age, gender, comorbidities, record dates, and region to control groups without anorexia or bulimia. Soft tissue injuries were identified through ICD codes, and surgeries were identified through Current Procedural Terminology codes. Differences in relative prevalence were analyzed using chi-square analysis. RESULTS Patients with anorexia had a significantly increased prevalence of meniscus tears (RR = 1.57, CI 1.22-2.03, p = 0.001) or deltoid ligament sprains (RR = 1.83, CI 1.10-3.03, p = 0.025), and patients with bulimia had a significantly increased prevalence of meniscus tears (RR = 1.98, CI 1.56-2.51, p < 0.001), medial collateral ligament sprains (RR = 3.07, CI 1.72-5.48, p < 0.001), any cruciate ligament tears (RR = 2.14, CI 1.29-3.53, p = 0.004), unspecified ankle sprains (RR = 1.56, CI 1.22-1.99, p < 0.001), or any ankle ligament sprains (RR = 1.27, CI 1.07-1.52, p = 0.008). Patients with anorexia had a significantly increased prevalence of anterior cruciate ligament reconstructions (RR = 2.83, CI 1.12-7.17, p = 0.037) or any meniscus surgeries (RR = 1.54, CI 1.03-2.29, p = 0.042), and patients with bulimia had a significantly increased prevalence of partial meniscectomies (RR = 1.80, CI 1.26-2.58, p = 0.002) or any meniscus surgeries (RR = 1.83, CI 1.29-2.60, p < 0.001). CONCLUSIONS Anorexia and bulimia are associated with increased prevalence of soft tissue injuries and surgeries. Orthopedic surgeons should be aware of this risk, and patients presenting to clinics should be informed of the risks associated with these diagnoses and provided with resources promoting recovery to help prevent further injury or surgery.
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No Difference in 10-Year Survivorship of Total Shoulder Arthroplasty Versus Hemiarthroplasty for Avascular Necrosis of the Humeral Head. J Shoulder Elbow Surg 2024:S1058-2746(24)00324-0. [PMID: 38735634 DOI: 10.1016/j.jse.2024.03.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 03/02/2024] [Accepted: 03/23/2024] [Indexed: 05/14/2024]
Abstract
INTRODUCTION Avascular necrosis of the humeral head (AVN) is characterized by osteonecrosis secondary to disrupted blood flow to the glenohumeral joint. Following collapse of the humeral head, arthroplasty, namely total shoulder arthroplasty (TSA) or humeral head arthroplasty (hemiarthroplasty) is recommended standard of care. The literature is limited to underpowered and small sample sizes in comparing arthroplasty modalities. Therefore, the aims of this study were (1) to compare the 10-year survivorship of TSA and hemiarthroplasty in the treatment of AVN of the humeral head and (2) to identify differences in their revision etiologies. METHODS Patients who underwent primary TSA and hemiarthroplasty for AVN were identified using the PearlDiver database. TSA patients were matched by age, gender, and Charlson Comorbidity Index (CCI) to the hemiarthroplasty cohort in a 4:1 ratio since TSA patients were generally older, sicker, and more often female. The 10-year cumulative incidence rate of all-cause revision was determined using Kaplan-Meier survival analysis. Multivariable analysis was conducted using Cox Proportional Hazard modeling. Chi-squared analysis was conducted to compare the indications for revisions between matched cohorts including periprosthetic joint infection (PJI), dislocation, mechanical loosening, broken implants, periprosthetic fracture, and stiffness. RESULTS In total, 4,825 patients undergoing TSA and 1,969 patients undergoing hemiarthroplasty for AVN were included in this study. The unmatched 10-year cumulative incidence of revision for patients who underwent TSA and hemiarthroplasty was 7.0% and 7.7%, respectively. The matched 10-year cumulative incidence of revision for patients who underwent TSA and hemiarthroplasty was 6.7% and 8.0%, respectively. When comparing the unmatched cohorts, TSA patients were at significantly higher risk of 10-year all-cause revision (HR: 1.39; P = 0.017) when compared to hemiarthroplasty patients. After matching, there was no significant difference in risk of 10-year all-cause revision (HR: 1.29; P = 0.148) and no difference in the observed etiologies for revision (P > 0.05 for all). CONCLUSION After controlling for confounders, only 6.7% of TSA and 8.0% hemiarthroplasties for humeral head AVN were revised within 10-years of index surgery. The demonstrated high and comparable long-term survivorship for both modalities supports the utilization of either for the AVN induced humeral head collapse.
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Simultaneous Ipsilateral Anterior Cruciate Ligament and Proximal Hamstring Tendon Ruptures: A Case Report. J Orthop Case Rep 2024; 14:125-129. [PMID: 38681914 PMCID: PMC11043998 DOI: 10.13107/jocr.2024.v14.i04.4384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/23/2024] [Indexed: 05/01/2024] Open
Abstract
Introduction Simultaneous anterior cruciate ligament (ACL) and ipsilateral hamstring ruptures have never been reported in the literature. The purpose of this article is to describe a treatment approach for such a case. The principles in this case can help guide treatment for any patient with concomitant ACL and hamstring pathology. Case Report We describe the case of a 53-year-old male who presented with left ipsilateral simultaneous complete proximal hamstring tendon (HT) and ACL tears after an acute tennis injury. He was successfully treated with a staged procedure, first with a proximal HT repair and later with a delayed ACL reconstruction using a bone-patellar tendon-bone autograft. Conclusion Ipsilateral simultaneous complete proximal HT and ACL tears can be successfully treated with acute proximal HT repair and delayed ACL reconstruction after rehabilitation from the HT repair. The synergistic relationship between the ACL and hamstring muscles in preventing anterior translation of the tibia necessitates staged reconstruction in the setting of a simultaneous injury.
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Evaluation of Differences in Patellar Height After Patellar Stabilization Procedures Not Intended to Address Patella Alta: A Multicenter Study. Orthop J Sports Med 2024; 12:23259671241235597. [PMID: 38515605 PMCID: PMC10956155 DOI: 10.1177/23259671241235597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/08/2023] [Indexed: 03/23/2024] Open
Abstract
Background Recent studies have reported conflicting results as to whether isolated medial patellofemoral ligament reconstruction (MPFLr) leads to decreased patellar height. Purpose To investigate if patellar stabilization surgery not intended to address patella alta influences patellar height. Study Design Cohort study; Level of evidence, 3. Methods A multicenter retrospective chart review was conducted, and patients who underwent MPFLr, medializing tibial tuberosity osteotomy (TTO), and/or trochleoplasty between 2016 and 2020 were included. The Caton-Deschamps index (CDI) was calculated from radiographs obtained preoperatively, 2 weeks postoperatively, and 3 months postoperatively. The preoperative CDI value was compared with the 2-week postoperative and 3-month postoperative values according to stabilization procedure (isolated MPFLr, isolated TTO, MPFLr + TTO, MPFLr + trochleoplasty, and MPFLr + trochleoplasty + TTO) using the paired t test. Analyses of the 1-bundle versus 2-bundle MPFLr technique and the presence of lateral retinacular release or lateral retinacular lengthening were conducted on the isolated MPFLr and combined MPFLr + TTO cohorts. Results A total of 356 knees were included. Statistically significant pre- to postoperative decreases in CDI were seen in all stabilization procedures analyzed (P≤ .017 for all). Within the isolated MPFLr cohort, this significant decrease was seen at 2 weeks postoperatively with the 2-bundle technique (ΔCDI = -0.09; P < .001) but not with the 1-bundle technique (ΔCDI = -0.01; P = .621). Conclusion The different surgical techniques analyzed in the current study affected patellar height, even when a distalizing TTO was not performed. The decrease was dependent on surgical technique, with a 2-bundle MPFLr leading to a statistically significant decrease and a 1-bundle MPFLr effecting no change.
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Trends in utilization of meniscal allograft transplantation between 2010 and 2019. PHYSICIAN SPORTSMED 2023. [PMID: 38054215 DOI: 10.1080/00913847.2023.2292038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 12/04/2023] [Indexed: 12/07/2023]
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Graft failure within 2 years of isolated anterior cruciate ligament reconstruction is associated with increased risk of secondary meniscus tears. Knee Surg Sports Traumatol Arthrosc 2023; 31:5823-5829. [PMID: 37938327 DOI: 10.1007/s00167-023-07653-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 10/24/2023] [Indexed: 11/09/2023]
Abstract
PURPOSE A debilitating complication following anterior cruciate ligament reconstruction is a secondary meniscus tear. Currently, the literature is mixed regarding the risk factors associated with the incidence of secondary meniscus tears. The aim of this study was to investigate risk factors associated with meniscus tears following an isolated primary anterior cruciate ligament reconstruction. ACL graft failure was hypothesized to be the strongest risk factor for secondary meniscal injury occurrence. METHODS A retrospective cohort analysis was performed using the PearlDiver Database. Patients with a primary anterior cruciate ligament reconstruction were identified in the database. Patients with concomitant knee ligament injury or meniscus injury present at the time the index procedure were excluded. Patients were grouped to those who had a secondary meniscus tear within 2 years following anterior cruciate ligament reconstruction and those who did not. Univariate analysis and multivariable regression analysis was conducted to identify significant risk factors for a secondary meniscus tear. RESULTS There were 25,622 patients meeting criteria for inclusion in this study. Within 2 years from the primary anterior cruciate ligament reconstruction, there were 1,781 patients (7.0%) that experienced a meniscus tear. Graft failure had the highest odds of having a postoperative meniscus tear within 2 years (OR: 4.1; CI 3.5-4.8; p < 0.002). Additional significant risk factors included tobacco use (OR: 2.0; CI 1.0-3.1; p < 0.001), increased Charlson Comorbidity Index (OR: 1.2; CI 1.1-1.4), male gender (OR: 1.1; CI 1.1-1.2; p < 0.001), obesity (OR: 1.1; CI 1.1-1.2; p < 0.001), delayed surgery (OR:1.1; CI 1.1-1.2; p < 0.002), and patients age 30 and older (OR: 1.0; CI 1.0-1.0; p < 0.001). CONCLUSIONS This study found that anterior cruciate ligament graft failure is the strongest predictor of post-operative meniscus tears. Other risk factors, including tobacco use, increased CCI, male gender, obesity, delayed surgery, and age 30 and older, were established, with several being modifiable. Therefore, targeted preoperative optimization of modifiable risk factors and postoperative protocols may reduce the risk of secondary meniscus tears. LEVEL OF EVIDENCE Level III, prognostic trial.
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Higher revision rates in patients with preoperative contralateral pes planovalgus deformity following total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2023; 31:4920-4926. [PMID: 37596366 DOI: 10.1007/s00167-023-07520-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/23/2023] [Indexed: 08/20/2023]
Abstract
PURPOSE The purpose of this study was to compare the incidence of revision in those with pes planovalgus deformity to those without using a large national database. Given the reciprocal changes in lower extremity alignment associated with planovalgus foot deformity, it has been suggested that patients with this deformity has worse outcomes following total knee arthroplasty (TKA). METHODS A retrospective cohort analysis of patients undergoing elective TKA was conducted using the PearlDiver database. Patients were stratified into three cohorts: those without pes planovalgus, patients with ipsilateral or bilateral pes planovalgus relative to the TKA, and patients with contralateral pes planovalgus. Patients with prior foot reconstructive surgery were excluded. The cohorts were each matched to those without pes planovalgus. Bivariate analysis was performed comparing 90-day medical complications and 2- and 4-year revisions following TKA. An adjusted number needed to be exposed for one additional person to be harmed (NNEH) was calculated using the adjusted odds ratio (OR) and unexposed event rate. RESULTS Following matched analysis, those with contralateral pes planovalgus had similar odds (OR 3.41; 95% CI 0.93-12.54; p = n.s.) for aseptic revision within 2 years but significantly higher odds (OR 3.35; 95% CI 1.08-10.41; p = 0.03) within 4 years when compared to those without a pes planovalgus deformity. Within 4 years, there was no significant difference in the incidence of aseptic revision (p = n.s.) in patients with ipsilateral/bilateral pes planovalgus. No patients in any cohort underwent septic revision within 4 years of TKA. CONCLUSION This study found that patients with contralateral pes planovalgus deformity had higher odds of aseptic revision within 4 years following primary TKA in a national database, suggesting that the change in gait kinematics associated with this deformity could possibly be associated with increased revision rates. LEVEL OF EVIDENCE Level III.
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The influence of elevated international normalized ratio on complications following total shoulder arthroplasty. Shoulder Elbow 2023; 15:53-64. [PMID: 37692874 PMCID: PMC10492533 DOI: 10.1177/17585732221088974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 01/16/2022] [Accepted: 02/21/2022] [Indexed: 09/12/2023]
Abstract
Background Identifying preoperative risk factors for complications following total shoulder arthroplasty (TSA) has both clinical and financial implications. The purpose of this study was to determine the influence of different degrees of preoperative INR elevation on complications following TSA. Methods Patients undergoing primary TSA from 2007 to 2018 were identified in a national database. Patients were stratified into 4 cohorts: INR of <1.0, INR of >1.0 to 1.25, INR of >1.25 to 1.5, and INR of >1.5. Postoperative complications were assessed. Multivariate logistic regressions were performed to adjust for differences in demographics and comorbidities among the INR groups. Results Following adjustment and relative to patients with an INR of <1.0, those with INR of >1.0-1.25, >1.25-1.5, and >1.5 had 1.6-times, 2.4-times, and 2.8-times higher odds of having postoperative bleeding requiring transfusion, respectively (p < 0.05 for all). Relative to patients with INR <1.0, those with INR of > 1.25-1.5 and INR of >1.5 had 7.8-times and 7.0-times higher odds of having pulmonary complications, respectively (p < 0.05 for both). Discussion With increasing INR levels, there is an independent and step-wise increase in odd ratios for postoperative complications. Current guidelines for preoperative INR thresholds may need to be adjusted for more predictive risk-stratification for TSA. Level of Evidence III.
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Epidemiology of shoulder instability procedures: A comprehensive analysis of complications and costs. Shoulder Elbow 2023; 15:398-404. [PMID: 37538528 PMCID: PMC10395401 DOI: 10.1177/17585732221116814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/24/2022] [Accepted: 07/12/2022] [Indexed: 08/05/2023]
Abstract
Background Recurrent shoulder instability is a debilitating condition that can lead to chronic pain, decreased function, and inability to return to activities or sport. This retrospective epidemiology study was performed to report 90-day postoperative complications and costs of Latarjet, anterior bone block reconstruction, arthroscopic, and open Bankart repair for shoulder instability. Methods Patients 18 years and older who underwent four primary shoulder surgeries from 2010 to 2019 were identified using national claims data. Patient demographics, comorbidities, and 90-day postoperative complications were analyzed using univariate analysis and multivariable logistic regression. Total and itemized 90-day reimbursements were determined for each procedure. Results The 90-day medical and surgery-specific complication rates were highest for anterior bone block reconstruction, followed by Latarjet. Arthroscopic Bankart repair had the highest 90-day costs and primary procedure costs compared to other procedures. Conclusion Anterior bone block reconstruction and Latarjet procedures were associated with the highest rates of 90-day medical and surgery-specific complications, while arthroscopic Bankart repair was associated with the highest costs.
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SLAP repair and bicep tenodesis: a comparison of utilization and revision rates for SLAP tears. JSES Int 2023; 7:290-295. [PMID: 36911775 PMCID: PMC9998736 DOI: 10.1016/j.jseint.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hypothesis The management of superior labrum anterior to posterior (SLAP) tears typically consists of either repair or biceps tenodesis (BT). While repair is more frequently recommended in younger patients, patients older than 40 years are often treated with BT. The purpose of this study is to determine whether there has been a change in utilization of these procedures over the past decade with respect to patient age as well as compare reoperation rates between the two procedures. Methods The Pearldiver database was queried to identify BT and SLAP repairs indicated for SLAP tears performed from 2010 to 2019. The primary outcome was utilization rate, stratified by age. A secondary outcome was 2-year shoulder reoperation rates. Trends were reported in terms of compounded annual growth rate. Outcome analysis was conducted using univariate and multivariable analysis. Results From 2010 to 2019, SLAP repair was the most common procedure performed for SLAP tears. Regardless of age, BT performed for SLAP tear had a significantly increased utilization rate; whereas, SLAP repair had a significantly decreased utilization rate. SLAP repair was more commonly performed in younger patients compared to BT. Following multivariable analysis, patients who underwent SLAP repair had significantly higher odds (odds ratio (OR): 1.453; 95% confidence interval (CI): 1.26-1.68; P < .001) of requiring an arthroscopic reoperation within 2 years when compared to those who underwent BT with no significant difference with respect to 2-year open reoperation. Conclusion Although SLAP repair is still more commonly used to treat SLAP tears than BT, especially for younger patients, the utilization of SLAP repair is decreasing while BT is increasing. The increased utilization of BT may be associated with lower rates of shoulder reoperation for problematic SLAP tears.
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Delay of Timing of Anterior Cruciate Ligament Reconstruction Is Associated With Lower Risk of Arthrofibrosis Requiring Intervention. Arthroscopy 2023:S0749-8063(23)00161-5. [PMID: 36774969 DOI: 10.1016/j.arthro.2023.01.102] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 01/09/2023] [Accepted: 01/25/2023] [Indexed: 02/14/2023]
Abstract
PURPOSE To conduct 2 separate stratum-specific likelihood ratio analyses in patients younger than 40 year of age (<40 years) and those aged 40 and older (40+ years) at time of anterior cruciate ligament (ACL) reconstruction to define data-driven strata between ACL tear and primary isolated ACL reconstruction in which the risk of arthrofibrosis, using manipulation under anesthesia and arthroscopic lysis of adhesions as surrogates, is significantly different. METHODS A retrospective cohort analysis was conducted using the PearlDiver Database. Patients who underwent ACL reconstruction were identified using the Current Procedure Terminology code 29888. Patients were stratified to those aged younger than 40 (<40) and those 40 and older (40+) at time of ACL reconstruction. The incidence of 2-year arthrofibrosis was calculated for weekly intervals from initial ACL injury to reconstruction. Stratum specific likelihood ratio analysis was conducted to determine data-driven intervals from initial ACL tear to reconstruction that optimize differences in 2-year arthrofibrosis. Following the identification of these intervals for both those <40 and 40+, multivariable analysis was conducted. RESULTS For those <40, stratum-specific likelihood ratio analysis identified only 2 data-driven timing strata: 0-5 and 6-26 weeks. For those 40+, stratum-specific likelihood ratio analysis also only identified 2 data-driven strata: 0-9 and 10-26 weeks. A delay in ACL reconstruction from initial injury by at least 6 weeks in patients younger than 40 and at least 10 weeks in patients older than 40 years is associated with a 65% and 35% reduction of 2-year manipulation under anesthesia and arthroscopic lysis of adhesions, respectively. CONCLUSIONS Our analysis showed a delay in ACLR of at least 6 weeks in patients younger than 40 years to be associated with a 65% reduction in the risk of surgical intervention for arthrofibrosis and a delay of at least 10 weeks in patients 40 years and older to be associated with only a 35% reduction in the risk of surgical intervention for arthrofibrosis. The authors propose this difference in reduction to be multifactorial and potentially associated with mechanism of injury, activity level, and preoperative factors such as amount of physical therapy, rather than solely timing. LEVEL OF EVIDENCE III, retrospective comparative prognostic study.
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The Effect of Intra-articular Corticosteroid Injections on Vaccine Efficacy: A Current Concepts Review. THE ARCHIVES OF BONE AND JOINT SURGERY 2023; 11:306-312. [PMID: 37265524 PMCID: PMC10231920 DOI: 10.22038/abjs.2023.68418.3263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 01/22/2023] [Indexed: 06/03/2023]
Abstract
Orthopedic surgeons commonly perform corticosteroid injections. These injections have systemic side effects, including suppression of the hypothalamic-pituitary adrenal axis. Due to this suppression, there is a theoretical risk of corticosteroid injections affecting the efficacy of the novel COVID-19 vaccines. This potential interaction led the American Academy of Orthopedic Surgeons to recommend, "avoiding musculoskeletal corticosteroid injections for two weeks before and one week after COVID vaccine administration." This review examines the literature underlying this recommendation. An extensive literature review was performed through PubMed, MEDLINE, and Google Scholar from database inception to May 2022. Keywords searched were COVID, coronavirus, vaccine, vaccination, steroids, and corticosteroids. Search results included articles written in the English language and encompassed reviews, case series, empirical studies, and basic science articles. There is no definitive evidence that corticosteroid injections affect COVID-19 vaccine efficacy or increase the risk of contracting COVID. The authors recommend orthopedic surgeons follow the AAOS guidelines, which recommend avoiding injections two weeks before and one week following COVID vaccine administration. Additional research is needed to better define this theoretical risk, especially since there is good evidence that injections suppress the hypothalamic-pituitary-adrenal-axis.
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Increased Incidence of Upper Extremity Soft Tissue Injuries and Orthopaedic Surgeries in Patients with Eating Disorders. THE IOWA ORTHOPAEDIC JOURNAL 2023; 43:101-110. [PMID: 37383874 PMCID: PMC10296453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
Background Despite an established increased fracture risk in eating disorder patients, no studies, to our knowledge, have investigated the association between eating disorders and upper extremity soft tissue injury or surgery incidence. Given the association of eating disorders with nutritional deficiency and musculoskeletal sequelae, we hypothesized that patients with eating disorders would have an increased risk of soft tissue injury and surgery. The aim of this study was to elucidate this link and investigate if these incidences are increased in patients with eating disorders. Methods Cohorts of patients with anorexia ner-vosa or bulimia nervosa, identified using International Classification of Diseases (ICD) -9 and -10 codes, were identified in a large national claims database over 2010-2021. Control groups without these respective diagnoses were constructed, matched by age, sex, Charlson Comorbidity Index, record date, and geographical region. Upper extremity soft tissue injuries were identified using ICD-9 and -10 codes and surgeries using Current Procedural Terminology codes. Differences in incidence were analyzed using chi-square tests. Results Patients with anorexia and bulimia were significantly more likely to sustain a shoulder sprain (RR=1.77; RR=2.01, respectively), rotator cuff tear (RR=1.39; RR=1.62), elbow sprain (RR=1.85; RR=1.95), hand/wrist sprain (RR=1.73; RR=16.0), hand/wrist ligament rupture (RR=3.33; RR=1.85), any upper extremity sprain (RR=1.72; RR=1.85), or any upper extremity tendon rupture (RR=1.41; RR=1.65). Patients with bulimia were also more likely to sustain any upper extremity ligament rupture (RR=2.88). Patients with anorexia and bulimia were significantly more likely to undergo SLAP repair (RR=2.37; RR=2.03, respectively), rotator cuff repair (RR=1.77; RR=2.10), biceps tenodesis (RR=2.73; RR=2.58), any shoulder surgery (RR=2.02; RR=2.25), hand tendon repair (RR=2.09; RR=2.12), any hand surgery (RR=2.14; RR=2.22), or any hand/wrist surgery (RR=1.87; RR=2.06). Conclusion Eating disorders are associated with an increased incidence of numerous upper extremity soft tissue injuries and orthopaedic surgeries. Further work should be undertaken to elucidate the drivers of this increased risk. Level of Evidence: III.
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Height Gain After Spinal Fusion for Idiopathic Scoliosis: Which Model Fits Best? J Pediatr Orthop 2022; 42:457-461. [PMID: 35948528 DOI: 10.1097/bpo.0000000000002225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Patients will often inquire about the magnitude of height gain after scoliosis surgery. Several published models have attempted to predict height gain using preoperative variables. Many of these models reported good internal validity but have not been validated against an external cohort. We attempted to test the validity of 5 published models against an external cohort from our institution. Models included were Hwang, Van Popta, Spencer, Watanabe, and Sarlak models. METHODS We retrospectively queried our institution's records from 2006 to 2019 for patients with adolescent idiopathic scoliosis treated with posterior spinal fusion. We recorded preoperative and postoperative variables including clinical height measurements. We also performed radiographic measurements on preoperative and postoperative radiographic studies. We then tested the ability of the models to predict height gain by evaluating Pearson correlation coefficient, root mean square error, Akaike Information Criterion for each model. RESULTS A total of 387 patients were included. Mean clinical height gain was 3.1 (±1.7) cm.All models demonstrated a moderate positive Pearson correlation coefficient, except the Hwang model, which demonstrated a weak correlation. The Spencer model was the only model with acceptable root mean square error (≤0.5) and was also the best fitting with the lowest Akaike Information Criterion (-308). The mean differences in height gain predictions between all models except the Hwang model was ≤1 cm. CONCLUSIONS Four of the 5 models demonstrated moderate correlation and had good external validity compared with their development cohorts. Although the Spencer model was the best fitting, the clinical significance of the difference in height predictions compared with other models was low. The Watanabe model was the second best fitting and had the simplest formula, making it the most convenient to use in a clinical setting. We offer a simplified equation to use in a preoperative clinical setting based on this data-ΔHeight (mm)=0.77*(preoperative coronal angle-postoperative coronal angle). LEVEL OF EVIDENCE Not Applicable.
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A Novel and Simple Method for stabilizing a Transverse Segment in a Posterior Wall Acetabular Fracture: Continuous Compression Staples, A Report of three Cases. J Orthop Case Rep 2022; 12:102-106. [PMID: 36659886 PMCID: PMC9826688 DOI: 10.13107/jocr.2022.v12.i07.2936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/28/2022] [Indexed: 01/22/2023] Open
Abstract
Introduction Continuous compression implants (CCI) are a fixation device formed from nitinol, a shape memory alloy. This alloy is durable enough to augment fixation and combined with its small footprint, versatile enough to insert into areas that are too small for K wires or lag screws to hold a provisional fixation. Case Report We used CCIs to successfully stabilize the transverse segments in three posterior column with posterior wall fractures. Conclusion CCIs can be used to provisionally reduce posterior column with posterior wall acetabular fractures and stabilize small pelvic bone fragments that may be difficult to hold with lag screws. These cases highlight a novel augmentation of the surgical treatment of posterior column with posterior wall fractures.
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Abstract
The incidence of anterior cruciate ligament (ACL) reconstruction is increasing in the United States, particularly in the older athlete. Patients who undergo ACL reconstruction are at higher risk for undergoing total knee arthroplasty (TKA) later in life. TKA in patients with prior ACL reconstruction has been associated with longer operative time due in-part to difficulty with exposure and retained hardware. Outcomes after TKA in patients with prior ACL reconstruction are not well defined, with some reports showing increased rate of complications and higher risk of reoperation compared with routine primary TKA, but these results are based on small and nonrandomized cohorts. Future research is needed to determine whether graft choice or fixation technique for ACL reconstruction influences outcomes after subsequent TKA. Furthermore, whether outcomes are affected by choice of TKA implant design for patients with prior ACL reconstruction warrants further study. This review analyzes the epidemiology, operative considerations, and outcomes of TKA following ACL reconstruction.
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Abstract
INTRODUCTION Relative value units (RVUs) are integral to the U.S. physician compensation system used by the Centers for Medicare & Medicaid Services. The use of 'work RVUs' (herein, wRVUs) is intended to reimburse physicians according to the amount of expertise and effort needed to safely and effectively perform a procedure. Our purpose was to determine: 1) the number of wRVUs/hour generated by common sports medicine surgical procedures; and 2) how patient characteristics, surgical approach, and practice setting are associated with the number of wRVUs/hour. This analysis was performed to infer whether wRVUs are assigned appropriately according to the factors on which they are purported to be based. METHODS We queried the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database for common sports medicine surgical procedures performed in 2018. Data from 19,877 patients (8,258 women) with a mean age of 48 years (range, 18-90) who underwent a surgical sports medicine procedure were analyzed. Work RVUs and operative time were used to calculate work RVUs/hour for each surgical procedure. Univariate and multivariate analyses were used to assess correlations between patient characteristics and wRVUs/hour. RESULTS Knee chondroplasty generated the most mean (± standard deviation) wRVUs/hour at 22 ± 0.5, whereas 'open tenodesis of biceps tendon, long head' generated the least at 9.6 ± 0.25 wRVUs/hour. Factors associated with a greater mean number of wRVUs/hour were younger patient age, female sex, arthroscopic approach, and outpatient setting. Arthroscopic procedures also generated more wRVUs/hour than the same procedures performed through an open approach. wRVUs were not correlated with case complexity or surgical time. CONCLUSION wRVUs/hour in surgical sports medicine procedures vary widely depending on the procedure type, patient characteristics, surgical approach, and practice setting.
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Evidence-Based Musculoskeletal Care for Swimmers: A Critical Analysis Review. JBJS Rev 2022; 10:01874474-202204000-00002. [PMID: 35385413 DOI: 10.2106/jbjs.rvw.21.00200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
» Swimming is a popular activity with numerous health benefits. » Swimming involves complex biomechanical movements that, especially if performed incorrectly, can lead to musculoskeletal injuries. » The shoulder is the most commonly affected joint, although lower-extremity and spine injuries have also been reported.
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Sarcoma Happens: A Reminder for Arthroscopic Surgeons. Cureus 2022; 14:e24457. [PMID: 35651443 PMCID: PMC9132742 DOI: 10.7759/cureus.24457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2022] [Indexed: 11/26/2022] Open
Abstract
Primary intra-articular sarcomas are rare and present with nonspecific symptoms such as pain or swelling. Due to nonspecific symptoms, patients may undergo routine diagnostic arthroscopy, which ultimately leads to sarcoma diagnosis. Here we present four patients with intra-articular sarcomas of the knee diagnosed after arthroscopy. The goal of this study is to highlight the importance of including malignant bone and soft-tissue sarcomas in the differential diagnosis of patients with nonspecific knee symptoms. A case series was developed from a retrospective review of prospectively collected data from our institution's orthopedic oncology database. Patients who underwent arthroscopic procedures on the knee and who were diagnosed with intra-articular sarcomas postoperatively from 2014 to 2019 were identified. All patients underwent diagnosis, staging, and multidisciplinary evaluation and treatment. Clinical characteristics, oncologic considerations, and surgical outcomes are described. Four patients with intra-articular sarcomas of the knee diagnosed after arthroscopy for non-oncologic concerns were identified: two synovial sarcomas, one Ewing sarcoma of bone, and one osteosarcoma. All surgical plans and treatment options were significantly affected by the previous arthroscopic procedures. One patient underwent above-the-knee amputation; one patient underwent extra-articular wide resection of the knee, including portal sites with distal femur/total knee reconstruction; one patient underwent rotationplasty, and one patient was treated with therapeutic radiation (no surgery). All patients received chemotherapy. Although intra-articular sarcomas are rare, orthopaedic surgeons must remain vigilant when proceeding with arthroscopic procedures if the clinical history, physical exam, and imaging findings are not perfectly aligned.
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Increased Risk of Surgical-Site Infection and Need for Manipulation Under Anesthesia for Those Who Undergo Open Versus Arthroscopic Rotator Cuff Repair. Arthrosc Sports Med Rehabil 2022; 4:e527-e533. [PMID: 35494279 PMCID: PMC9042754 DOI: 10.1016/j.asmr.2021.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 11/13/2021] [Indexed: 11/19/2022] Open
Abstract
Purpose Methods Results Conclusions Level of Evidence
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21
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Are We Working Harder for Less Pay? A Survey of Medicare Reimbursement for Hand and Upper Extremity Surgery. Plast Reconstr Surg 2022; 149:711e-719e. [PMID: 35157616 DOI: 10.1097/prs.0000000000008906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Ongoing concern for declining Medicare payment to surgeons may incentivize surgeons to perform more cases to maintain productivity goals. The authors evaluated trends in physician payment, patient charges, and reimbursement ratios for the most common hand and upper extremity surgical procedures. METHODS The authors examined Medicare surgeon payment, patient charges, and surgical volume from 2012 to 2017 for 83 common surgical procedures, incorporating the year-to-year Consumer Price Index to adjust for inflation. The reimbursement ratio was calculated by dividing payment by charge. Weighted (by surgery type and volume) averages were calculated. RESULTS Total Medicare surgeon payment increased 5.6 percent to $272 million for the studied procedures. Patient charges were seven times greater than payment, growing 24 percent to $1.9 billion. Despite growth of total payment, the average overall weighted payment for a single surgery decreased 3.5 percent. The average weighted patient charge increased 8 percent, whereas the reimbursement ratio decreased 13 percent. A hand surgeon would need to perform three more cases per 100 in 2017 to maintain the same reimbursement received in 2012. After categorizing these 83 surgical procedures, distal radius fixation (>3 parts, 21 percent increase; >2-part intra-articular, extra-articular, and percutaneous pinning, 17 percent increase), bony trauma proximal to the distal radius (10 percent increase), and upper extremity flap (5 percent increase) were subject to the greatest increases in payment. Payment for forearm fasciotomy (39 percent decrease), endoscopic carpal tunnel release (30 percent decrease), and mass excisions proximal to the wrist (18 percent decrease) decreased the most. CONCLUSIONS From 2012 to 2017, despite a disproportionate increase in procedure charges, Medicare surgeon payment has not decreased substantially; however, total reimbursement is multifactorial and involves multiple sources of revenue and cost.
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Advanced Imaging of Ulnar Wrist Pain. Hand Clin 2021; 37:477-486. [PMID: 34602127 DOI: 10.1016/j.hcl.2021.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Ulnar-sided wrist pain can be a diagnostic challenge for clinicians and radiologists. The ulnar wrist has complex morphology and is composed of many small bone and soft tissue structures. Within these structures, a wide variety of pathologic conditions can occur. To successfully diagnose and treat these pathologic conditions, clinicians and radiologists must have a strong understanding of the advanced imaging techniques available to them. In this review, the authors present a brief review of the normal ulnar wrist anatomy, discuss the differential diagnosis of ulnar-sided wrist pain, and examine the indications for different advanced imaging modalities.
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Abstract
OBJECTIVES Chronic steroid use has been associated with poor healing and worse long-term outcomes in patients undergoing orthopedic surgery, but the specific risk profile and short-term complications related to chronic steroids in patients undergoing outpatient shoulder surgery are inadequately defined. The purpose of this study is to characterize the effects of chronic steroids on 30-day post-operative complications following arthroscopic and open shoulder surgery. METHODS The American College of Surgeons National Surgical Quality Improvement Program was used to identify patients who underwent arthroscopic and open rotator cuff repair, shoulder stabilization, and associated procedures from 2011 to 2018. Patients on chronic steroids were compared with patients not on chronic steroids. Demographic data and 30-day postoperative complications were analyzed. Multivariable logistic regression was used to isolate the effects of chronic steroid use on postoperative complications. RESULTS We identified 99,970 patients who underwent shoulder surgery during this period, of which 1.7% (1,662 patients) were on chronic steroids. Patients on chronic steroids were older (58.3 ± 0.30vs52.1 ± 0.05 years, p < 0.01), had higher average BMI (30.6 vs 30.1, p = 0.02), and were more likely to be female (54.9%vs38.0%, p < 0.01) and white (76.2%vs73.1%, p < 0.01). Patients on steroids had a higher American Society of Anesthesiologists class, and higher rates of diabetes, CHF, COPD, hypertension, bleeding disorders, and functionally dependency (all P < 0.01). Patients on chronic steroids were less likely to smoke (P < 0.01). Multivariable logistic regression revealed that chronic steroid use was an independent risk factor for major (OR 2.20[1.51-3.21], p < 0.001), minor (OR 2.32[1.13-3.2], p < 0.001), and infectious complications (OR 1.90[1.13-3.2], p = 0.01). CONCLUSIONS Preoperative chronic steroid use is independently associated with increased odds of major, minor, and infectious complications after open and arthroscopic rotator cuff repair, shoulder stabilization, and associated procedures. Patients on chronic steroids should be counseled about their increased risk for these complications, and both preoperative risk stratification and optimization should be employed to minimize perioperative risk.
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High-Grade Sarcoma Arising in Association With an Intraosseous Lipoma: A Case Report. JBJS Case Connect 2021; 10:e1900577. [PMID: 32910603 DOI: 10.2106/jbjs.cc.19.00577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CASE A 78-year-old man was followed for an incidentally found, asymptomatic lesion in his right proximal femur that was unchanged radiographically for 11 years. He developed pain and was believed to have experienced a stress fracture through the lesion. The lesion was biopsied, showing a high-grade pleomorphic sarcoma with an underlying senescent intraosseous lipoma. He was ultimately treated with wide excision and reconstruction of the proximal femur. CONCLUSION This case highlights the importance of obtaining a tissue diagnosis for lesions that become symptomatic.
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Biomechanical Evaluation of a New Suture Button Technique for Reduction and Stabilization of the Distal Tibiofibular Syndesmosis. FOOT & ANKLE ORTHOPAEDICS 2020; 5:2473011420969140. [PMID: 35097415 PMCID: PMC8564924 DOI: 10.1177/2473011420969140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: Stabilization methods for distal tibiofibular syndesmotic injuries present risk of malreduction. We compared reduction accuracy and biomechanical properties of a new syndesmotic reduction and stabilization technique using 2 suture buttons placed through a sagittal tunnel in the fibula and across the tibia just proximal to the incisura with those of the conventional method. Methods: Syndesmotic injury was created in 18 fresh-frozen cadaveric lower leg specimens. Nine ankles were repaired with the conventional method and 9 with the new technique. Reduction for the conventional method was performed using thumb pressure under direct visualization and for the new method by tightening both suture buttons passed through the fibular and tibial tunnels. Computed tomography was used to assess reduction accuracy. Torsional resistance, fibular rotation, and fibular translation were evaluated during biomechanical testing. Results: The new technique showed less lateral translation of the fibula on CT measurements after reduction (0.06 ± 0.06 mm) than the conventional method (0.26 ± 0.31 mm), P = .02. The new technique produced less fibular rotation during internal rotation after 0 cycles (new –2.4 ± 1.4 degrees; conventional –5.0 ± 1.2 degrees, P = .001), 100 cycles (new –2.1 ± 1.9 degrees; conventional –4.6 ± 1.4 degrees, P = .01), and 500 cycles (new –2.2 ± 1.6 degrees; conventional –5.3 ± 2.5 degrees, P = .01) and during external rotation after 100 cycles (new 3.9 ± 3.3 degrees; conventional 5.9 ± 3.5 degrees, P = .02) and 500 cycles (new 3.3 ± 3.2 degrees; conventional 6.3 ± 2.6 degrees, P = .03). Fixation failed in 3 specimens. Conclusion: The new syndesmotic reduction and fixation technique resulted in more accurate reduction of the fibula in the tibial incisura in the coronal plane and better rotational stability compared with the conventional method. Clinical Relevance: This new technique of syndesmosis reduction and stabilization may be a reliable alternative to current methods.
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Intramedullary Cage Removal for a Consolidated Proximal Humerus Fracture: A Case Report. JBJS Case Connect 2020; 10:e19.00565. [PMID: 32773713 DOI: 10.2106/jbjs.cc.19.00565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
CASE The expandable intramedullary cage (Conventus Orthopaedics) may treat 3- and 4-part proximal humerus fractures. Cage removal for symptomatic avascular necrosis with humeral head collapse requiring conversion to arthroplasty can be challenging because the cage's collapsing mechanism becomes inoperable after fracture consolidation. We present cage explantation followed by reverse total shoulder prosthesis placement in a 54-year-old man who underwent plate/cage fixation for a 3-part proximal humerus fracture 10 months earlier. CONCLUSION The proximal humeral cage can be extracted safely while preserving adequate bone stock for subsequent arthroplasty. Additional time and exposure are necessary compared with removing a locking plate alone.
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E-Cadherin Represses Anchorage-Independent Growth in Sarcomas through Both Signaling and Mechanical Mechanisms. Mol Cancer Res 2019; 17:1391-1402. [PMID: 30862685 DOI: 10.1158/1541-7786.mcr-18-0763] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/16/2018] [Accepted: 03/08/2019] [Indexed: 12/19/2022]
Abstract
CDH1 (also known as E-cadherin), an epithelial-specific cell-cell adhesion molecule, plays multiple roles in maintaining adherens junctions, regulating migration and invasion, and mediating intracellular signaling. Downregulation of E-cadherin is a hallmark of epithelial-to-mesenchymal transition (EMT) and correlates with poor prognosis in multiple carcinomas. Conversely, upregulation of E-cadherin is prognostic for improved survival in sarcomas. Yet, despite the prognostic benefit of E-cadherin expression in sarcoma, the mechanistic significance of E-cadherin in sarcomas remains poorly understood. Here, by combining mathematical models with wet-bench experiments, we identify the core regulatory networks mediated by E-cadherin in sarcomas, and decipher their functional consequences. Unlike carcinomas, E-cadherin overexpression in sarcomas does not induce a mesenchymal-to-epithelial transition (MET). However, E-cadherin acts to reduce both anchorage-independent growth and spheroid formation of sarcoma cells. Ectopic E-cadherin expression acts to downregulate phosphorylated CREB1 (p-CREB) and the transcription factor, TBX2, to inhibit anchorage-independent growth. RNAi-mediated knockdown of TBX2 phenocopies the effect of E-cadherin on CREB levels and restores sensitivity to anchorage-independent growth in sarcoma cells. Beyond its signaling role, E-cadherin expression in sarcoma cells can also strengthen cell-cell adhesion and restricts spheroid growth through mechanical action. Together, our results demonstrate that E-cadherin inhibits sarcoma aggressiveness by preventing anchorage-independent growth. IMPLICATIONS: We highlight how E-cadherin can restrict aggressive behavior in sarcomas through both biochemical signaling and biomechanical effects.
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Abstract
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Bordetella pertussis is the causative
agent of whooping cough. This pathogenic bacterium can obtain the
essential nutrient iron using its native alcaligin siderophore and
by utilizing xeno-siderophores such as desferrioxamine B, ferrichrome,
and enterobactin. Previous genome-wide expression profiling identified
an iron repressible B. pertussis gene
encoding a periplasmic protein (FbpABp). A previously reported
crystal structure shows significant similarity between FbpABp and previously characterized bacterial iron binding proteins, and
established its iron-binding ability. Bordetella growth studies determined that FbpABp was required for
utilization of not only unchelated iron, but also utilization of iron
bound to both native and xeno-siderophores. In this in vitro solution study, we quantified the binding of unchelated ferric iron
to FbpABp in the presence of various anions and importantly,
we demonstrated that FbpABp binds all the ferric siderophores
tested (native and xeno) with μM affinity. In silico modeling augmented solution data. FbpABp was incapable
of iron removal from ferric xeno-siderophores in vitro. However, when FbpABp was reacted with native ferric-alcaligin,
it elicited a pronounced change in the iron coordination environment,
which may signify an early step in FbpABp-mediated iron
removal from the native siderophore. To our knowledge, this is the
first time the periplasmic component of an iron uptake system has
been shown to bind iron directly as Fe3+ and indirectly
as a ferric siderophore complex.
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Redox properties of human hemoglobin in complex with fractionated dimeric and polymeric human haptoglobin. Free Radic Biol Med 2014; 69:265-77. [PMID: 24486321 PMCID: PMC4104362 DOI: 10.1016/j.freeradbiomed.2014.01.030] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 01/22/2014] [Accepted: 01/23/2014] [Indexed: 12/30/2022]
Abstract
Haptoglobin (Hp) is an abundant and conserved plasma glycoprotein, which binds acellular adult hemoglobin (Hb) dimers with high affinity and facilitates their rapid clearance from circulation after hemolysis. Humans possess three main phenotypes of Hp, designated Hp 1-1, Hp 2-1, and Hp 2-2. These variants exhibit diverse structural configurations and have been reported to be functionally nonequivalent. We have investigated the functional and redox properties of Hb-Hp complexes prepared using commercially fractionated Hp and found that all forms exhibit similar behavior. The rate of Hb dimer binding to Hp occurs with bimolecular rate constants of ~0.9 μM(-1) s(-1), irrespective of the type of Hp assayed. Although Hp binding does accelerate the observed rate of HbO2 autoxidation by dissociating Hb tetramers into dimers, the rate observed for these bound dimers is three- to fourfold slower than that of Hb dimers free in solution. Co-incubation of ferric Hb with any form of Hp inhibits heme loss to below detectable levels. Intrinsic redox potentials (E1/2) of the ferric/ferrous pair of each Hb-Hp complex are similar, varying from +54 to +59 mV (vs NHE), and are essentially the same as reported by us previously for Hb-Hp complexes prepared from unfractionated Hp. All Hb-Hp complexes generate similar high amounts of ferryl Hb after exposure to hydrogen peroxide. Electron paramagnetic resonance data indicate that the yields of protein-based radicals during this process are approximately 4 to 5% and are unaffected by the variant of Hp assayed. These data indicate that the Hp fractions examined are equivalent to one another with respect to Hb binding and associated stability and redox properties and that this result should be taken into account in the design of phenotype-specific Hp therapeutics aimed at countering Hb-mediated vascular disease.
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