Interval Time of at Least 6 Weeks Between Bilateral Total Knee Arthroplasties is Associated With Decreased Postoperative Complications.

BACKGROUND: Staged, bilateral total knee arthroplasty (TKA) has an increased risk of complications if the second procedure is performed before physiologic recovery from the first. The aims of this study were to 1) determine whether there is a time-dependent relationship between TKA staging and rates of revisions and complications and 2) identify data-driven time intervals that reduce risk of revisions and complications. METHODS: Data were collected from a national insurance database from 2015 to 2018. Staged intervals were initially assessed using fixed 6-week intervals. Stratum-specific likelihood ratio analyses were subsequently conducted to observe data-driven staging thresholds. Bivariate and multivariable regression analyses were conducted to determine the associations between the time intervals and 2-year rates of revision surgery and 90-day major complications. We included 25,527 patients undergoing staged bilateral TKA. RESULTS: In comparison to the shortest fixed time interval (1-6 weeks), as the staging interval increased the odds of 2-year all-cause revision and 90-day major complications significantly decreased (P < .05 for all). Stratum-specific likelihood ratio analysis identified 3 data-driven staging categories 1-5, 6-17, and 18-24 weeks that maximized the difference in both 2-year rates of revision and 90-day major complications. CONCLUSION: Our data showed a time-dependent relationship between the timing of TKA stages and complications. If staging is considered, a delayed interval of at least 6 weeks between procedures may significantly reduce revision and major complications. LEVEL OF EVIDENCE: Level III Therapeutic Study.

Extended length of stay in diabetic octogenarians following revision total hip arthroplasty.

PURPOSE: Past research has shown diabetic patients, including those of geriatric age, to be at an increased risk of postoperative complications following various surgeries, including revision total hip arthroplasty (rTHA). However, whether these risks are disproportionately greater in octogenarian patients has not been well investigated. This study aimed to determine whether diabetic octogenarians are at an increased risk of postoperative complications following rTHA. METHODS: The national surgical quality improvement program database was used to identify all diabetic patients who underwent rTHA from 2007 to 2018. Patients were divided into two groups: an aged 65 to 79 cohort and an aged 80 to 89 cohort. Patient demographics, comorbidities, and postoperative complications were assessed and compared between the two aged cohorts, with the utilization of bivariate and multivariate analyses. RESULTS: Of the 1184 diabetic patients who underwent rTHA, 906 (76.5%) patients were in the aged 65 to 79 cohort and 278 (23.5%) patients were in the aged 80 to 89 cohort. After adjusting for patient demographics and medical comorbidities, compared to patients in the aged 65 to 79 group, diabetic patients who were 80 to 89 years old were found to have an increased risk of extended length of hospital stay (OR 1.67; p = 0.017). CONCLUSION: Diabetic octogenarian patients have an increased risk for a prolonged hospital stay following rTHA relative to their younger diabetic geriatric counterparts. Orthopedic surgeons should be aware of these increased risks to properly educate diabetic octogenarians and assist in surgical management decision making in these patients considering rTHA.

Does Symptomatic Benign Prostatic Hyperplasia Increase the Risk of Periprosthetic Joint Infection After Primary Total Joint Arthroplasty?

BACKGROUND: Periprosthetic joint infection (PJI) is among the leading causes of failure in total joint arthroplasty. A recently proposed risk factor for PJI is symptomatic benign prostatic hyperplasia (sBPH). This study aims to determine if sBPH is associated with PJI following primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: Using the Mariner all-payer claims database, 1745 patients with sBPH undergoing primary THA were propensity-matched with 3490 controls, and 3053 patients with sBPH undergoing primary TKA were propensity-matched with 6106 controls. Additionally, the same 1745 patients with sBPH undergoing THA were compared to 317,360 prematched controls, and the same 3053 patients with sBPH undergoing TKA were compared to 557,730 prematched controls. Univariate analysis was conducted using chi-squared or ANOVA where appropriate. RESULTS: At two years postoperatively, patients with sBPH were not at significantly increased risk for PJI following primary THA (1.54% vs 1.43%; P = .745) and TKA (1.99% vs 2.14%; P = .642) relative to postmatch controls. Compared to matched controls, THA patients with sBPH had an increased 90-day incidence of anemia (P < .001), blood transfusion (P < .001), and urinary tract infection (UTI; P < .001). Total knee arthroplasty patients with sBPH had an increased 90-day incidence of anemia (P < .001), blood transfusion (P < .001), cellulitis (P = .023), renal failure (P = .030), heart failure (P = .029), and UTI (P < .001) relative to matched controls. CONCLUSION: In primary THA and TKA, sBPH does not appear to be an independent risk factor for PJI within two years postoperatively. However, clinicians should be cognizant of the significantly increased risk for postoperative UTI in this patient population.

Preoperative Anemia Independently Predicts Significantly Increased Odds of Short-Term Complications Following Aseptic Revision Hip and Knee Arthroplasty.

BACKGROUND: Preoperative anemia is an important risk factor for developing complications following revision hip (rTHA) and knee (rTKA) arthroplasty. We aim to determine the effect of anemia severity on 30-day postoperative complications following revision hip and knee arthroplasty. METHODS: A retrospective cohort study was conducted using the American College of Surgeons National Quality Improvement Program Database. All patients who underwent revision joint arthroplasty (rTJA) between 2006 to 2017 were identified and grouped based upon the hematocrit (Hct) level. Anemia was defined as Hct <36% for women and <39% for men, and further stratified into mild anemia (Hct 33% to 36% for women, Hct 33% to 39% for men), and moderate to severe anemia (Hct <33% for both men and women). Univariate and multivariate analysis were used to evaluate the incidence of multiple adverse events within 30 days after TJA. RESULTS: A total of 8932 patients undergoing rTHA and 13,313 patients undergoing rTKA were included for analysis. On multivariate adjustment, patients undergoing rTHA with moderate to severe anemia had an increased odds of 5.437 (95% Confidence Interval (CI) 4.604 to 6.421; P < .001) of developing any postoperative complication. On multivariate adjustment, patients undergoing rTKA with moderate to severe anemia had increased odds of 6.731 (95% Confidence Interval (CI) 5.540 to 8.179; P < .001) of developing any postoperative complication. CONCLUSION: The increasing severity of anemia was associated with an increasing risk of developing any postoperative complication and death following revision hip and knee arthroplasty. There is a significant trend between diminishing preoperative hematocrit levels and increasing odds of postoperative complication.

Balancing Thromboprophylaxis and Bleeding in Total Joint Arthroplasty: Impact of Eliminating Enoxaparin and Predonation and Implementing Pneumatic Compression and Tranexamic Acid.

BACKGROUND: Venous thromboembolic disease (VTED) after total hip arthroplasty (THA) and total knee arthroplasty (TKA) poses substantial risk. Pharmacologic prophylaxis against VTED can cause bleeding, transfusion, and associated complications. The ActiveCare+SFT is a portable, intermittent pneumatic compression device (IPCD), providing equivalent VTED prophylaxis to pharmacologic agents without associated bleeding. Tranexamic acid (TXA) is an antifibrinolytic that reduces blood loss after THA and TKA. Our objective was to measure blood transfusion and VTED after eliminating enoxaparin, introducing an IPCD, eliminating autologous blood transfusion, and administering TXA during primary TKA and THA. METHODS: Four consecutive cohorts of THA and TKA patients were studied. Group A, the historical control, received enoxaparin VTED prophylaxis. Group B received IPCD VTED prophylaxis. Group C received IPCD VTED prophylaxis along with TXA (1 g intravenous at incision and closure). Groups A, B, and C predonated 1 unit of autologous blood. Group D received IPCD VTED prophylaxis, TXA as above, but did not donate blood preoperatively. RESULTS: Seventeen of 50 patients (34%) in Group A, 7 of 47 (14.9%) patients in Group B, 4 of 43 (9.3%) patients in Group C, and 0 of 46 patients in Group D received transfusions. There were no major symptomatic VTED events. CONCLUSION: Using an IPCD and TXA and discontinuing enoxaparin and preoperative autologous blood donation eliminated blood transfusion in primary THA and TKA without any increase in VTED. Using an IPCD instead of enoxaparin, adding TXA, and eliminating preoperative autologous donation each had an incremental dose response effect. This protocol provides effective VTED prophylaxis equivalent to pharmacologic methods and eliminates transfusion risk in the primary THA and TKA population.

Trends of Venous Thromboembolism After Total Hip Arthroplasty in the United States: Analysis From 2011 to 2019.

BACKGROUND: In 2011, the American Academy of Orthopaedic Surgeons released a Clinical Practice Guideline` that recommended routine venous thromboembolism (VTE) prophylaxis after total joint arthroplasty. The purpose of this study was to examine (1) the change in the incidence of 90-day VTE, deep vein thrombosis, and pulmonary embolism, (2) the change in the utilization of antithrombotic agents; and (3) the change in the economic burden associated with VTE after total hip arthroplasty (THA) from 2011 to 2019. METHODS: National, administrative claims data from 2011 to 2019 were used to identify patients who underwent primary THA for osteoarthritis. Exclusions entailed liver pathology, coagulopathy, malignancy, or those on prior prescribed blood thinners before THA. Multivariable regression was used, controlling for age and Charlson Comorbidity Index for all years, with 2011 as the reference year. RESULTS: From 2011 to 2019, there was a significant reduction in 90-day VTE rates after THA, with a significant reduction in deep vein thrombosis and pulmonary embolism during this time frame as well. Of the antithrombotic agents prescribed after THA, the utilization of prescribed aspirin significantly increased and that of nonaspirin anticoagulants significantly decreased. Among nonaspirin anticoagulants, the utilization of direct factor Xa inhibitors and direct thrombin inhibitors significantly increased. The added reimbursements associated with VTE after THA significantly decreased during this period. CONCLUSION: Since 2011, the incidence and economic burden associated with VTE after THA have significantly declined. In addition, there has been an increase in prescription aspirin and direct oral anticoagulants. LEVEL OF EVIDENCE: Therapeutic, III.

Revision Total Knee Arthroplasty for Ballistic Component Damage From an Intra-articular Missile.

Gunshot wounds (GSWs) and total knee arthroplasty (TKA) are increasingly common, yet a GSW to a TKA is a rare injury. A 60-year-old man sustained an intra-articular GSW to a prior TKA. The patient was scheduled for irrigation and debridement with polyethylene liner exchange. Intraoperatively, the new polyethylene liner was unable to engage the tibial tray. Damage to the locking mechanism on the tibial tray was suspected so total revision proceeded. Upon inspection of the explanted components, it was noted that a bullet fragment offline from the missile trajectory had blocked the locking of the polyethylene liner in the tibial tray. Expeditious antibiotics should be given and meticulous debridement should be performed to avoid unnecessary total component revision.

Impact of sickle cell disease on postoperative outcomes following total hip arthroplasty.

INTRODUCTION: Osteonecrosis (ON) of the femoral head is a common complication of sickle cell disease (SCD), frequently necessitating total hip arthroplasty (THA). Although THA is a common procedure with few complications when indicated for osteoarthritis (OA), patients with SCD have increased rates of complications. The purpose of this study is to determine the impact of SCD on outcomes and complications following THA. METHODS: Subjects were retrospectively identified using a national insurance claims database (PearlDiver Technologies) using CPT and ICD-9/10. Patients were included if they underwent THA with at least 2-year follow-up and were diagnosed with SCD and ON, ON without SCD, or OA without SCD. The SCD cohort was matched based on age, gender, Charlson Comorbidity Index, and obesity to the other 2 cohorts. 2-year revision rate and 90-day complication rates were analyzed using chi-square tests. RESULTS: Each cohort had 881 patients. The SCD cohort had significantly higher 90-day medical complications when compared to the ON without SCD and OA cohorts (p < 0.001). The SCD cohort had a higher rate of 2-year revision for PJI (5.0%) compared to the ON without SCD (2.8%) and OA (2.5%) groups (p = 0.019 and 0.005 respectively) and a higher rate of aseptic loosening (1.94%) compared to the ON without SCD cohort (0.68%; p = 0.021). CONCLUSIONS: Patients with SCD who undergo THA have an increased risk for short-term postoperative medical complications and 2-year aseptic loosening and PJI compared to ON patients without SCD and patients with OA. Given the magnitude of these risks, patient counseling and optimised perioperative care are essential.

Increased Complications in Octogenarians Undergoing Same-Day Discharge following Total Knee Arthroplasty: A Matched Cohort Analysis.

Same-day discharge pathways in total knee arthroplasty (TKA) are gaining popularity as a means to increase patient satisfaction and reduce overall costs, but these pathways have not been thoroughly evaluated in potentially at-risk populations, such as in patients ≥80 years old. The purpose of this study was to compare 90-day complications and mortality following same-day discharge after primary TKA in patients ≥80 years old and those <80 years old. Patients who underwent unilateral primary TKA, were discharged on postoperative day 0, and had a minimum 90-day follow-up were identified in a national insurance claims database (PearlDiver Technologies) using Current Procedural Terminology code 27447. These patients were stratified into two cohorts based upon age: (1) nonoctogenarians (<80 years old) and (2) octogenarians (≥80 years old). These cohorts were propensity matched based upon sex, Charlson comorbidity index, and obesity status. Univariate analysis was performed to determine differences in 90-day complications and mortality between the two cohorts. In total, 1,111 patients were included in each cohort. Both cohorts were successfully matched, with no observed differences in matched parameters for demographics or comorbidities. There was no significant difference in 90-day mortality between the two cohorts (p = 0.896). However, octogenarians were at significantly increased risk of postoperative atrial fibrillation (20.8 vs. 10.4%; p < 0.001), nonatrial fibrillation arrhythmias (8.4 vs. 5.6%; p = 0.009), pneumonia (4.5 vs. 2.2%; p = 0.002), stroke (3.1 vs. 1.7%; p = 0.037), heart failure (10.5 vs. 7.5%; p = 0.012), and urinary tract infection (UTI; 14.3 vs. 9.4%; p < 0.001) compared with the nonoctogenarian cohort. Relative to matched controls, octogenarians were at significantly increased risk of numerous 90-day medical complications following same-day primary TKA, including cardiopulmonary complications, stroke, and UTI. Clinicians should be cognizant of these complications and counsel patients appropriately when electing to perform same-day TKA in the octogenarian population.

Impact of Large Database Studies on Orthopedic Surgery Literature: Are We Advancing the Field?

Background: While database studies have become more prevalent in the literature, there is concern over their value. In addition, the questions they are suitable to answer are limited. Questions/Purposes: We sought to determine the incidence of database studies in the orthopedic literature and in each subspecialty. In addition, we wanted to assess the impact of database studies on the literature by determining whether citations and Altmetric Attention Scores (AAS) varied by study type (studies using internal or external databases and those not using databases). Methods: We searched PubMed for articles published in impactful orthopedic surgery journals in the year 2018. All articles were discoverable on the Altmetric explorer portal database. Impact was determined by journal impact factor. Study design, subspecialty, number of citations, and AAS were obtained. Univariable analyses were conducted between study type, demographic variables, and the outcome of either citation count or AAS. Multivariable analyses were performed to identify independent predictors of the primary outcomes. Subgroup analyses were performed to differentiate the impact of external and internal database studies compared with non-database studies. Results: A total of 2684 total articles were eligible for inclusion. Of these, 366 studies (13.6%) were database studies. Hip and knee articles had the greatest incidence of database studies. Database studies had significantly more citations (5.9 vs 4.0) and significantly higher AAS (12.8 vs 11.3) compared with non-database studies. External database studies had significantly more citations (6.7 vs 4.8) and significantly higher AAS (14.0 vs 10.7) than internal database studies. Internal database studies had higher traditional citation counts but similar AAS to non-database studies. Conclusions: In 2018, database studies in well-reputed orthopedic journals had a greater number of citations but similar AAS compared with non-database studies. Further studies are warranted.

Core Decompression and Bone Marrow Aspiration Concentrate Grafting for Osteonecrosis of the Femoral Head.

BACKGROUND: Core decompression (CD) with bone marrow aspiration concentrate (BMAC) is a technique that may improve outcomes in osteonecrosis of the femoral head (ONFH). The primary aim of this study was to evaluate the radiographic progression free survival (PFS) of CD augmented with BMAC. Secondary aims were to determine the survivorship with conversion (CFS) to total hip arthroplasty (THA) as an endpoint, determine prognostic factors, and characterize the cellular quality of the BMAC. METHODS: A retrospective cohort study of 61 femoral heads (40 patients) was performed. Patient demographics, comorbidities, BMI, smoking status, etiology, location and extent of ONFH were recorded. The primary endpoint was radiographic progression of ONFH and secondarily, conversion to THA. Additional aims were to determine predictive factors for progression and report the cellular characteristics of the BMAC. Data obtained were compared to the results of a prior randomized controlled trial comparing CD alone versus CD with polymethylmethacrylate cement (PMMA) augmentation. RESULTS: Radiographic PFS of CD with BMAC at 2 and 5 years was 78.3% and 53.3%, respectively. The risk of progression was lower in the CD with BMAC group compared to CD alone (HR0.45, p = 0.03), however this difference no longer remained statistically significant on multivariate analysis. Conversion to total hip arthroplasty free survival (CFS) of CD with BMAC at both 2 and 5 years was 72.1% and 54.6%, respectively with no differences compared to the control groups (CD alone, CD and PMMA). The predictive factors for progression were obesity (BMI ≥ 30) and the extent of the disease as quantified by either percentage involvement, necrotic index or modified necrotic index. CONCLUSIONS: No differences in PFS or CFS between CD with BMAC compared to CD alone or CD with PMMA were identified. Independent statistically significant predictors of progression-free survival or conversion to THA are BMI ≥ 30 and the extent of ONFH. Further research with an adequately powered randomized controlled trial is needed. LEVEL OF EVIDENCE: 3.

Extended length of stay and postoperative complications in octogenarians with hypertension following revision total knee arthroplasty.

BACKGROUND: Prior studies have shown hypertensive patients to be at an increased risk of postoperative complications following various surgeries, including revision total knee arthroplasty (rTKA). However, whether these risks are compounded in octogenarian patients has not yet been well explored. The purpose of this study was to analyze whether hypertensive octogenarians, aged 80 to 89, undergoing rTKA are at an increased risk of postoperative complications relative to the younger hypertensive geriatric population aged 65 to 79. METHODS: A national database was used to collect data for all hypertensive patients who underwent rTKA from 2006 to 2018. Patients were stratified into an aged 65 to 79 cohort and an aged 80 to 89 cohort. Demographics, medical comorbidities, and postoperative complications were compared between the two cohorts. Bivariate and multivariate analyses were performed. RESULTS: Of the 6,599 hypertensive patients who underwent rTKA, 5,477 (83.0%) patients were in the aged 65 to 79 group and 1,122 (17.0%) patients were in the aged 80 to 89 group. Following adjustment to control for demographic and comorbidity data, relative to patients in the 65 to 79 age group, hypertensive patients who were 80-89 years old had an increased risk of unplanned reintubation (OR 3.52; p = 0.008), urinary tract infection (OR 2.08; p = 0.011), postoperative transfusion (OR 1.90; p < 0.001), myocardial infarction (OR 2.55; p = 0.017), and extended length of hospital stay (OR 1.77; p < 0.001). CONCLUSION: Hypertensive octogenarian patients undergoing rTKA have an increased risk of an extended length of stay and other postoperative complications relative to their younger hypertensive geriatric counterparts. Orthopaedic surgeons should consider a multi-disciplinary approach to managing hypertension in these octogenarian patients prior to surgery to minimize this risk. However, even with this risk, an octogenarian age should not be used independently in evaluating if a hypertensive geriatric patient is a safe rTKA candidate.

An Analysis of Underrepresented in Medicine Away Rotation Scholarships in Surgical Specialties.

Background: Underrepresented in medicine (UIM) visiting student clerkship scholarships provide an opportunity for supporting diversity. Although these scholarships have become a popular initiative to recruit diverse surgical applicants, they have not been thoroughly analyzed regarding which programs offer scholarships and the characteristics of the scholarships. UIM scholarship opportunity disparities may exist depending on location, funding, reputation, and program size among different specialties. Objective: To describe the characteristics and prevalence of UIM visiting student scholarships by examining institutional and program websites for the surgical specialties. Methods: Using the Accreditation Council for Graduate Medical Education (ACGME) Accreditation Data System for 2021, residency training and diversity websites were identified and evaluated for the availability of UIM visiting student scholarships in July 2021. Eight surgical specialties were examined. Scholarships were categorized by how UIM was defined, the funding amount provided, and scholarship application requirements. We analyzed the association of the program's National Institutes of Health funding, size, type, region, reputation, and population density of the program's area via Doximity on scholarship availability using chi-square and multivariate analysis. Results: Of the 1058 analyzed programs, 314 (29.7%) had a UIM visiting student scholarship. There were 4 different definitions of UIM used among the analyzed programs. The average scholarship amount offered was $1,852.25 ($500-$4,000). Depending on the specialty, different variables were associated with whether a program had a UIM scholarship. Conclusions: Currently, UIM scholarship offerings were variable between programs and surgical specialties.

Do Orthopedic Surgery Residency Program Web Sites Address Diversity and Inclusion?

Background: Orthopedic surgery is one of the least diverse medical specialties. Other medical specialties have employed diversity-related initiatives to increase the number of students underrepresented in medicine (URM). Furthermore, with the suspension of visiting student rotations during the COVID-19 pandemic, medical students used residency program Web sites as a main source of program-specific information. Aims/Purpose: The purpose of this study was to measure the extent to which orthopedic surgery residency program Web sites describe diversity and inclusion initiatives. Methods: The Electronic Residency Application Service (ERAS) was used to identify U.S. orthopedic surgery residency programs. The programs' Web sites were reviewed, and data on commitments to diversity and inclusion were collected. Descriptive statistics of these data were generated. Results: There were 192 residency programs identified and 3 were excluded from the analysis due to lack of Web sites. Of the remaining 189 residency program Web sites, only 55 (29.10%) contained information on diversity and inclusion. Information on a commitment to improving diversity and inclusion was the most prevalent data point found among program Web sites, although it was found on only 15% of program Web sites. Conclusion: Orthopedic surgery residency programs rarely address topics related to diversity and inclusion on their program Web sites. An emphasis on opportunities for URM students and initiatives related to diversity and inclusion on program Web sites may improve URM outreach and serve as one method for increasing URM matriculation into orthopedic surgery.

Total Knee Arthroplasty After Genicular Nerve Radiofrequency Ablation: Reduction in Prolonged Opioid Use Without Increased Postsurgical Complications.

INTRODUCTION: Genicular nerve radiofrequency ablation (GNRFA) is an increasingly used nonsurgical treatment modality for patients with advanced knee osteoarthritis. Previous studies have demonstrated this to be an effective and safe method to decrease pain and increase functionality in this patient population. The purpose of this study was to compare 2-year postoperative complication rates and rates of prolonged postoperative opioid usage between patients undergoing total knee arthroplasty (TKA) after previous GNRFA and those undergoing TKA alone. METHODS: Patients who underwent primary TKA after prior GNRFA (GNRFA-TKA) of the ipsilateral knee were identified in a national all-payer claims database from 2010 to 2019. Univariate and multivariable analyses were conducted comparing those with prior GNRFA and those without. Outcomes of interest included prolonged postoperative opioid usage, 2-year revision rates, and 90-day medical complications. Statistical analysis was conducted using R software provided by the PearlDiver Database. RESULTS: In total, 675 patients in the GNRFA-TKA cohort were compared with a control cohort of 255,351 patients. Genicular nerve radiofrequency ablation-total knee arthroplasty patientshad lower odds of prolonged opioid use postoperatively (OR: 0.478; 95%: 0.409 to 0.559; P < 0.001). No notable difference was observed in the 2-year surgical outcomes between cohorts. Patients in the GNRFA-TKA cohort had lower odds of requiring a blood transfusion and having postoperative anemia, all arrhythmias, and urinary infections compared with primary TKA control patients. CONCLUSION: Preoperative GNRFA leads to a lower rate of prolonged postoperative opioid use in patients undergoing TKA, without an increased risk of complications. Future prospective studies are needed to validate the findings of this database study.

Conversion total knee arthroplasty: A case complexity between primary and revision total knee arthroplasty.

BACKGROUND: Conversion total knee arthroplasty (TKA) may represent a more complex procedure compared with primary TKA. The purpose of this study was to compare 30-day complications between conversion TKA and primary, non-conversion TKA as well as between conversion TKA and revision TKA on a national scale using a multi-center surgical registry. METHODS: Adult patients undergoing conversion TKA from 2006 to 2018 were identified in the National Surgical Quality Improvement Program database and were compared with patients who underwent primary TKA and aseptic revision TKA. In this analysis, 30-day complications were assessed. Bivariate analyses, including chi-squared and analysis of variance, and multivariate logistic regressions were performed. RESULTS: Of 299,065 total patients undergoing knee arthroplasty, 1,310 (0.4%) underwent conversion TKA, 275,470 (92.1%) underwent primary TKA, and 22,285 (7.5%) underwent revision TKA. Following adjustment, patients who underwent conversion TKA were more likely to have increased risks of any complications (P < 0.001), mortality (P = 0.021), wound complications (P < 0.001), cardiac issues (P = 0.018), bleeding requiring transfusion (P < 0.001), and reoperation (P = 0.002) relative to primary TKA patients. Compared with patients who underwent revision TKA, conversion TKA patients were less likely to have septic complications (P = 0.009). CONCLUSION: Conversion TKA is associated with significantly higher rates of complications compared with primary, non-conversion TKA, but less risk of sepsis compared with revision TKA. Because current reimbursement classifications do not account for the case complexity of a conversion TKA, new classifications should be implemented with reimbursements for conversion TKA approximating reimbursements for revision TKA.

Neural network prediction of 30-day mortality following primary total hip arthroplasty.

PURPOSE: The purpose is to utilize an artificial neural network (ANN) model to determine the most important variables in predicting mortality following total hip arthroplasty (THA). METHODS: Patients that underwent primary THA were included from a national database. Demographic, preoperative, and intraoperative variables were analyzed based on their contribution to 30-day mortality with the use of an ANN model. RESULTS: The five most important factors in predicting mortality following THA were preoperative international normalized ratio, age, body mass index, operative time, and preoperative hematocrit. CONCLUSION: ANN modeling represents a novel approach to determining perioperative factors that predict mortality following THA.

Increasing Burden of Total Hip Arthroplasty Revisions in Patients Between 45 and 64 Years of Age.

BACKGROUND: This study provides a comprehensive analysis of total hip arthroplasty (THA) revisions in the U.S. from 2007 to 2013. METHODS: International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes were used to identify all THA revisions in the Nationwide Inpatient Sample (NIS) from 2007 to 2013. The diagnoses leading to the revisions, types of revisions, major inpatient complications, and hospital and patient characteristics were compared between 2007 and 2013. Multivariable logistic regression models were used to calculate adjusted odds ratios (ORs) for complications in 2013 versus 2007. RESULTS: This study identified 320,496 THA revisions performed between 2007 and 2013. From 2007 to 2013, the THA revision rate adjusted for U.S. population growth increased by 30.4% in patients between 45 and 64 years of age and decreased in all other age groups. The rate of surgically treated THA dislocations decreased by 14.3% from 2007 to 2013 (p < 0.0001). The mean length of the hospital stay and hospital costs for THA revision were significantly lower in 2013 than in 2007 (4.6 versus 5.8 days and $20,463 versus $25,401 both p < 0.0001). A multivariable model showed that the odds of a patient undergoing THA revision having the following inpatient complications were significantly lower in 2013 than in 2007: deep vein thrombosis (OR = 0.57, p = 0.004), pulmonary embolism (OR = 0.45, p = 0.047), myocardial infarction (OR = 0.52, p = 0.003), transfusion (OR = 0.64, p < 0.0001), pneumonia (OR = 0.56, p < 0.0001), urinary tract infection (OR = 0.66, p < 0.0001), and mortality (OR = 0.50, p = 0.0009). Notably, the odds of being discharged to a skilled nursing facility were also lower in 2013 than in 2007 (OR = 0.71, p < 0.0001). CONCLUSIONS: The THA revision rate has significantly increased in patients between 45 and 64 years of age. However, the rate of surgically treated THA dislocations has decreased significantly. This may indicate that evolving techniques and implants are improving stability. The rate of inpatient complications following THA revision also decreased significantly from 2007 to 2013. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Costs of pair-bonding and paternal care in male prairie voles (Microtus ochrogaster).

The direct costs of paternal care are relatively well documented in primates, however little research has explored these effects in monogamous rodents. The present study examines the long-term effects that pairing and parenting have on male prairie voles. We hypothesized that there would be a significant weight loss over the course of pairing and parenting, presumably from the energetic demands that accompany these changes in social condition. In a longitudinal study, we followed ten male prairie voles through being housed with their brother; paired with a female; and caring for three consecutive litters. We found a significant drop in bodyweight across time, with maximum weight loss near the weaning of the first litter. At that same time, feeding increased, leading to possible recovery in weight; however, leptin levels dropped precipitously across time and did not recover. Corticosterone did not change significantly across time points, and overall activity levels also did not vary significantly over the course of the study. In addition, newly paired males showed a significant increase in preference for a 2% sucrose solution during a three-hour test, indicating a metabolic need for more calories. A cross-sectional study confirmed leptin and corticosterone findings, and showed significant loss of subcutaneous (inguinal) fat in males that had cared for a litter of pups, when compared to males housed with their brothers or newly paired males. These results suggest that cohabitation with a female, and caring for pups, all have costs for male prairie voles.