Preoperative Corticosteroid Injections Within 4 Weeks of Arthroscopic Shoulder Procedures Are Associated With Increased Postoperative Infection Rates.

PURPOSE: To refine the understanding of the effect of timing of corticosteroid injections (CSIs) and shoulder arthroscopy on postoperative infection. METHODS: An insurance database was used to determine all patients who underwent shoulder arthroscopy for a 5-year period with an associated preoperative ipsilateral corticosteroid injection. Patients were stratified into cohorts based on timing of preoperative CSI: (1) 0-<2 weeks, (2) 2-<4 weeks, (3) 4-<6 weeks, and (4) 6-<8 weeks. Patients were pooled to include all patients who had a CSI less than 4 weeks and those longer than 4 weeks. A cohort of patients who never had a corticosteroid injection before undergoing arthroscopy were used as a control. All patients had a follow-up of 2 years. Multivariable regression analyses were performed using R Studio with significance defined as P < .05. RESULTS: Multivariate logistic regression showed a greater odds ratio (OR) for postoperative infection in patients who received CSI 0-<2 weeks before shoulder arthroscopy at 90 days (3.10, 95% confidence interval [CI] 1.62-5.57, P < .001), 1 year (2.51, 95% CI 1.46-4.12, P < .001), and 2 years (2.08, 95% CI 1.27-3.28, P = .002) compared with the control group. Patients who received CSI 2-<4 weeks before shoulder arthroscopy had greater OR for infection at 90 days (2.26, 95% CI 1.28-3.83, P = .03), 1 year (1.82, 95% CI 1.13-2,82, P = .01), and 2 years (1.62, 95% CI 1.10-2.47, P = .012). Patients who received CSI after 4 weeks had similar ORs of infection at 90 days (OR 1.15, 95% CI 0.78-1.69, P = .48) 1 year (OR 1.18, 95% CI 0.85-1.63 P = .33), and 2 years (OR 1.09, 95% CI 0.83-1.42, P = .54), compared with the control cohort. CONCLUSIONS: The present study shows the postoperative infection risk is greatest when CSIs are given within 2 weeks of shoulder arthroscopy, whereas CSIs given within 2-<4 weeks also portend increased risk, albeit to a lesser degree. The risk of postoperative infection is not significantly increased when CSIs are given more than 1 month before surgery. LEVEL OF EVIDENCE: Level III, retrospective comparative, prognosis study.

Current Concepts in Management of Lateral Epicondylosis.

Lateral epicondylosis is a common cause of lateral elbow pain and can lead to disability and overall diminished quality of life. Repetitive gripping and wrist extension is thought to lead to microtearing and degeneration of the extensor tendons. In general, patients with symptoms of lateral epicondylosis experience relief of symptoms with non-operative management alone. However, controversy remains concerning the role of non-surgical management and which modality facilitates the quickest recovery. Moreover, debate remains throughout the literature regarding surgical intervention and other treatment options for refractory cases. This article serves to provide an updated review of the various treatment options and management for treating lateral epicondylosis.

Curtailing infection risks in hepatitis C patients: the effect of antiviral treatment in revision shoulder arthroplasty.

BACKGROUND: Revision shoulder arthroplasty (RevSA) is a complex procedure that can result in various postoperative complications. However, the impact of hepatitis C virus (HCV) on postoperative complications after RevSA remains unclear because of limited and inconsistent evidence. This study aims (1) to investigate the incidence of postoperative complications in patients with HCV undergoing RevSA and (2) to evaluate the impact of HCV treatment on complication rates at different time points after the revision procedure, specifically at 90 days, 1 year, and 2 years. METHODS: We queried a national, all-payer database to investigate recent trends in the use of RevSA among HCV patients to assess postoperative complication rates, including venous thromboembolism (VTE), wound complication, transfusion, and periprosthetic joint infection (PJI). Statistical analyses involved propensity score matching to create balanced cohorts and logistic regression to determine the relative risk of postoperative complications. Data were analyzed with SPSS software (version 24.0 for Windows). The study included patients who underwent partial or total RevSA procedures between January 1, 2010, and December 31, 2020. Patients were identified based on medical claims that included procedural codes for RevSA and associated diagnosis codes for PJI or insertion/removal of an antibiotic spacer. A Bonferroni correction was used because many tests were performed and statistical significance was set at P = .0125. RESULTS: The HCV cohort demonstrated higher PJI rates at 1-year (5.5% vs. 3.9%, P = .006) and 2-year follow-ups (6.7% vs. 4.6%, P = .006). However, no significant differences emerged in VTE and wound complication rates between the HCV and non-HCV cohorts. Comparing untreated and treated HCV patients, the former showed significantly higher PJI rates at 2 years (P = .010), whereas the treated group had significantly lower odds ratios for PJI. When comparing treated HCV patients with the non-HCV cohort, minimal differences were found in postoperative outcomes, indicating no significant difference in the risk of complications between the groups. CONCLUSION: Our study observed an association between HCV patients who received antiviral treatment prior to RevSA and a reduced incidence of PJI compared to untreated HCV patients. When comparing this group to the non-HCV controls, there was no significant difference in the incidence of PJI, suggesting a potential association between antiviral treatment and the observed risk patterns in HCV patients. Proper management of HCV-positive patients during RevSA is crucial for improving outcomes and reducing complications.

Trends in Deep Vein Thrombosis Prophylaxis After Total Knee Arthroplasty: 2016 to 2021.

BACKGROUND: In 2011, the American Academy of Orthopaedic Surgeons released a consensus recommending venous thromboembolism (VTE) prophylaxis after total knee arthroplasty (TKA). The purpose of our study was to examine (1) incidences of postoperative complications, including pulmonary embolism (PE), deep vein thrombosis (DVT), and transfusion rates; (2) trends from 2016 to 2021 in VTE prophylaxis; and (3) independent risk factors for 90-day total complications following TKA between aspirin, enoxaparin, rivaroxaban, and warfarin. METHODS: Using a national, all-payer database from 2016 to 2021, we identified all patients who underwent primary TKA. Exclusions included all patients who had prescribed anticoagulants within 1 year prior to TKA, hypercoagulable states, and cancer. Data were collected on baseline demographics, including age, sex, diabetes, and a comorbidity index, in each of the VTE prophylaxis cohorts. Postoperative outcomes included rates of PE, DVT, and transfusion. Multivariable regressions were performed to determine independent risk factors for total complications at 90 days following TKA. RESULTS: From 2016 to 2021, aspirin was the most used anticoagulant (n = 62,054), followed by rivaroxaban (n = 26,426), enoxaparin (n = 20,980), and warfarin (n = 13,305). The cohort using warfarin had the highest incidences of PE (1.8%) and DVT (5.7%), while the cohort using aspirin had the lowest incidences of PE (0.6%) and DVT (1.6%). The rates of aspirin use increased the most from 2016 to 2021 (32.1% to 70.8%), while the rates of warfarin decreased the most (19.3% to 3.0%). Enoxaparin, rivaroxaban, and warfarin were independent risk factors for total complications at 90 days. CONCLUSIONS: An epidemiological analysis of VTE prophylaxis use from 2016 to 2021 shows an increase in aspirin following TKA compared to other anticoagulant cohorts in a nationally representative population. This approach provides more insight and a better understanding of anticoagulation trends over this time period in a nationally representative sample.

Elevated risk of prosthetic infections in cannabis users after shoulder arthroplasty.

INTRODUCTION: An increasing number of states are beginning to legalize recreational cannabis use, and as such, more patients using cannabis are undergoing shoulder arthroplasty procedures. The present study sought to examine the impact of cannabis use on post-operative outcomes. The primary outcomes of interest were postoperative complications, which included infection, periprosthetic fractures, periprosthetic joint infections (PJI), dislocations, and aseptic loosening as well as medical complications. Secondary outcomes were risk factors for PJI and aseptic loosening at two-years. METHODS: A private, nationwide, all-payer database (Pearldiver Technologies) was queried to identify shoulder arthroplasty patients from 2010 to 2020. Those not using tobacco or cannabis ("control", n = 10,000), tobacco users (n = 10,000), cannabis users (n = 155), and concurrent tobacco and cannabis users (n = 9,842) were identified. Risk factors for PJI and aseptic loosening at two-years were further quantified utilizing multivariable logistic regression analysis. RESULTS: Compared to non-users, cannabis users experienced the highest odds for PJI and aseptic revisions, which were followed by concurrent cannabis and tobacco users and tobacco-only users. Concurrent users, as well as tobacco users were at higher risk for dislocation. Cannabis use was the most significant risk factor for PJI, followed by concurrent use and male sex. CONCLUSIONS: Our study found cannabis use to cause greater risk for superficial and deep infection. More research involving randomized trials are needed to fully elucidate the impact of cannabis use on shoulder arthroplasty procedures. Clinically, these findings can appropriately guide surgeons and patients alike regarding expectations prior to undergoing TSA.

Open versus arthroscopic treatment of the rheumatoid elbow arthritis: a comparison of complications at two years utilizing a nationally representative database.

PURPOSE: Symptomatic rheumatoid arthritis (RA) can be addressed surgically with open procedures or elbow arthroscopy. Previous studies comparing outcomes of open to arthroscopic arthrolysis for the management of RA did not utilize a large database study. The aim was to compare demographics and two-year complications, in RA patients undergoing open or arthroscopic elbow arthrolysis. METHODS: A retrospective, cohort study was performed utilizing a private, nationwide, all-payer database. We queried the database to identify patients undergoing open (n = 578) or arthroscopic (n = 379) arthrolysis for elbow RA. The primary goal of the study was to compare complications at two-years. Categorical variables were assessed utilizing the chi-squared test; while, continuous variables were analyzed using the Student's t-test. Multivariable logistic regression was performed to assess risk factors for infection following open or arthroscopic arthrolysis. RESULTS: RA patients undergoing open elbow arthrolysis were older (55 vs. 49 years, p < 0.001), predominately female (61.6% vs 60.9%, p = 0.895), and likely to have chronic kidney disease (20.4 vs. 12.9%), and DM (45.2 vs. 32.2%) (both p < 0.005). Open elbow arthrolysis was also associated with higher rates of infection (31.7 vs. 4.7%) and wound complications (26.8 vs. 3.4%) (both p = 0.001). Nerve injury rates were found to be similar (8.3 vs. 9.0%, p = 0.81). On multivariable logistic regression, open elbow procedures were associated with the highest risk for infection (OR: 8.43). CONCLUSIONS: Patients undergoing open arthrolysis for RA were at a higher risk of infection and wound complications compared to arthroscopic arthrolysis utilizing a nationally representative database. While there appears to be a difference in outcomes following these two procedures, higher level evidence is needed to draw more definitive conclusions. LEVEL OF EVIDENCE: Retrospective, Level III.

Does needle penetration of the shoulder joint prior to arthroscopy increase infection risk? The effect of preoperative magnetic resonance arthrogram or corticosteroid injection.

BACKGROUND: Prior literature has associated preoperative corticosteroid shoulder injection (CSI) with infection following shoulder surgery. A recent study found an equally elevated risk of total knee arthroplasty infection with preoperative injection of either CSI or hyaluronic acid. The implication is that violation of a joint prior to surgery, even in the absence of corticosteroid, may pose an elevated risk of infection following orthopedic surgery. The aim of the present study was to determine whether violation of the shoulder joint for magnetic resonance arthrogram (MRA) poses an elevated risk of infection following shoulder arthroscopy, and to compare this risk to that introduced by preoperative CSI. METHODS: A national, all-payer database was queried to identify patients undergoing shoulder arthroscopy between January 2015 and October 2020. Patients were stratified into the following groups: (1) no CSI or MRA within 6 months of surgery (n = 5000), (2) CSI within 2 weeks of surgery (n = 1055), (3) CSI between 2 and 4 weeks prior to surgery (n = 2575), (4) MRA within 2 weeks of surgery (n = 414), and (5) MRA between 2 and 4 weeks prior to surgery (n = 1138). Postoperative infection (septic shoulder or surgical site infection) was analyzed at 90 days, 1 year, and 2 years, postoperatively. Multivariable logistic regression analysis controlled for differences among groups. RESULTS: MRA within 2 weeks prior to shoulder surgery was associated with an increased risk of infection at 1 year (odds ratio [OR], 2.17; P = .007), while MRA 2-4 weeks preceding surgery was not associated with an increased risk of postoperative infection at any time point. By comparison, CSI within 2 weeks prior to surgery was associated with an increased risk of postoperative infection at 90 days (OR, 1.72; P = .022), 1 year (OR, 1.65; P = .005), and 2 years (OR, 1.63; P = .002) following surgery. Similarly, CSI 2-4 weeks prior to surgery was associated with an increased risk of postoperative infection at 90 days (OR, 1.83; P < .001), 1 year (OR, 1.62; P < .001), and 2 years (OR, 1.79; P < .001). CONCLUSION: Preoperative CSI within 4 weeks of shoulder arthroscopy elevates the risk of postoperative infection. Needle arthrotomy for shoulder MRA elevates the risk of infection in a more limited fashion. Avoidance of MRA within 2 weeks of shoulder arthroscopy may mitigate postoperative infection risk. Additionally, the association between preoperative CSI and postoperative infection may be more attributed to medication profile than to needle arthrotomy.

Does timing matter? The effect of preoperative smoking cessation on the risk of infection or revision following rotator cuff repair.

BACKGROUND: Nicotine in tobacco products is known to impair bone and tendon healing, and smoking has been associated with an increased rate of retear and reoperation following rotator cuff repair (RCR). Although smoking is known to increase the risk of failure following RCR, former smoking status and the timing of preoperative smoking cessation have not previously been investigated. METHODS: A national all-payer database was queried for patients undergoing RCR between 2010 and 2020. Patients were stratified into 5 mutually exclusive groups according to smoking history: (1) never smokers (n = 50,000), (2) current smokers (n = 28,291), (3) former smokers with smoking cessation 3-6 months preoperatively (n = 34,513), (4) former smokers with smoking cessation 6-12 months preoperatively (n = 786), and (5) former smokers with smoking cessation >12 months preoperatively (n = 1399). The risks of postoperative infection and revision surgery were assessed at 90 days, 1 year, and 2 years following surgery. Multivariate logistic regressions were used to isolate and evaluate risk factors for postoperative complications. RESULTS: The 90-day rate of infection following RCR was 0.28% in never smokers compared with 0.51% in current smokers and 0.52% in former smokers who quit smoking 3-6 months prior to surgery (P < .001). Multivariate logistic regression identified smoking (odds ratio [OR], 1.49; P < .001) and smoking cessation 3-6 months prior to surgery (OR, 1.56; P < .001) as risk factors for 90-day infection. The elevated risk in these groups persisted at 1 and 2 years postoperatively. However, smoking cessation >6 months prior to surgery was not associated with a significant elevation in infection risk. In addition, smoking was associated with an elevated 90-day revision risk (OR, 1.22; P = .038), as was smoking cessation between 3 and 6 months prior to surgery (OR, 1.19; P = .048). The elevated risk in these groups persisted at 1 and 2 years postoperatively. Smoking cessation >6 months prior to surgery was not associated with a statistically significant elevation in revision risk. CONCLUSION: Current smokers and former smokers who quit smoking within 6 months of RCR are at an elevated risk of postoperative infection and revision surgery at 90 days, 1 year, and 2 years postoperatively compared with never smokers. Former smokers who quit >6 months prior to RCR are not at a detectably elevated risk of infection or revision surgery compared with those who have never smoked.

THAs Performed Within 6 Months of Clostridioides difficile Infection Are Associated with Increased Risk of 90-Day Complications.

BACKGROUND: Clostridioides difficile infection (CDI) may be a surrogate for poor patient health. As such, a history of CDI before THA may be used to identify patients at higher risk for postoperative CDI and complications after THA. Investigations into the associations between CDI before THA and postoperative CDI and complications are lacking. QUESTIONS/PURPOSES: We compared the (1) frequency and potential risk factors for CDI after THA, (2) the frequency of 90-day complications after THA in patients with and without a history of CDI, and (3) the length of stay and frequency of readmissions in patients experiencing CDIs more than 6 months before THA, patients experiencing CDIs in the 6 months before THA, and patients without a history of CDI. METHODS: Patients undergoing primary THA from 2010 to 2019 were identified in the PearlDiver database using ICD and Current Procedural Terminology codes (n = 714,185). This analysis included Medicare, Medicaid, and private insurance claims across the United States with the ability to perform longitudinal and costs analysis using large patient samples to improve generalizability and reduce error rates. Patients with a history of CDI before THA (n = 5196) were stratified into two groups: those with CDIs that occurred more than 6 months before THA (n = 4003, median 2.2 years [interquartile range 1.2 to 3.6]) and those experiencing CDIs within the 6 months before THA (n = 1193). These patients were compared with the remaining 708,989 patients without a history of CDI before THA. Multivariable logistic regression was used to evaluate the association of risk factors and incidence of 90-day postoperative CDI in patients with a history of CDI. Variables such as antibiotic use, proton pump inhibitor use, chemotherapy, and inflammatory bowel disease were included in the models. Chi-square and unadjusted odds ratios with 95% confidence intervals were used to compare complication frequencies. A Bonferroni correction adjusted the p value significance threshold to < 0.003. RESULTS: Prior CDI during either timespan was associated with higher unadjusted odds for postoperative CDI (CDI > 6 months before THA: OR 8.44 [95% CI 6.95 to 10.14]; p < 0.001; CDI ≤ 6 months before THA: OR 49.92 [95% CI 42.26 to 58.54]; p < 0.001). None of the risk factors included in the regression were associated with increased odds for postoperative CDI in patients with preoperative history of CDI. Patients with a history of CDI before THA were associated with higher unadjusted odds for every 90-day complication compared with patients without a history of CDI before THA. CDI during either timespan was associated with longer lengths of stay (no CDI before THA: 3.8 days; CDI > 6 months before THA: 4.5 days; CDI ≤ 6 months before THA: 5.3 days; p < 0.001) and 90-day readmissions (CDI > 6 months before THA: OR 2.21 [95% CI 1.98 to 2.47]; p < 0.001; CDI ≤ 6 months before THA: OR 3.39 [95% CI 2.85 to 4.02]; p < 0.001). CONCLUSION: Having CDI before THA was associated with higher odds of postoperative CDI compared with patients without a history of CDI. A history of CDI within the 6 months before THA was associated with the greatest odds for postoperative complications and readmissions. Providers should strongly consider delaying THA until 6 months after CDI, if possible, to provide adequate time for patient recovery and eradication of infection. LEVEL OF EVIDENCE: Level III, therapeutic study.

How Does Conversion Total Hip Arthroplasty Compare to Primary?

BACKGROUND: Recent institutional evidence suggests that conversion total hip arthroplasty (THA) incurs higher complication rates and costs when compared to primary THA. These findings contrast with the current reimbursement system as conversion and primary THAs are classified under the same diagnosis-related group. Thus, a national all-payer database was utilized to compare complication rates up to 2 years, 30-day readmission rates, and 90-day costs between conversion THA and matched primary THA patients. METHODS: A retrospective review of the PearlDiver database between 2010 and second quarter of 2018 was performed using Current Procedural Terminology (CPT) codes to compare conversion THA (CPT 27132) to primary THA (CPT 27130). Patients were matched at a 1:3 ratio based on age, gender, Charlson Comorbidity Index, body mass index, tobacco use, and diabetes (conversion = 8369; primary = 25,081 patients). RESULTS: Conversion THA had higher rates of periprosthetic joint infections (conversion: 7.7% vs primary: 1.4%), hip dislocations (4.5% vs 2.0%), blood transfusions (2.0% vs 1.0%), mechanical complications (5.5% vs 1.0%), and revision surgeries (4.0% vs 1.5%) (P < .001 for all) by 90 days. The 30-day readmission rate for conversion THA was significantly higher compared to the primary group (7.3% vs 3.3%) (P < .001). Median cost at 90 days for conversion THA was significantly higher compared to primary THA ($18,800 vs $13,611, P < .001). CONCLUSION: This study revealed increased complication rates, revisions, readmissions, and costs among conversion THA patients compared to matched primary THA patients. These results support the reclassification of conversion into a diagnosis-related group separate from primary THA.

Osteoarthritis and Osteonecrosis in Total Hip Arthroplasty: 90-Day Postoperative Costs and Outcomes.

BACKGROUND: Two common diagnoses for patients undergoing total hip arthroplasty (THA) are osteoarthritis (OA) and osteonecrosis (ON), pathologically different diseases that affect postoperative complication rates. The underlying pathology of ON may predispose patients to a higher rate of certain complications. Previous research has linked ON with higher mortality and revisions, but a comparison of costs and complication rates may help elucidate further risks. This study reports 90-day costs, lengths of stay (LOS), readmission rates, and complication rates between patients undergoing THA for OA and ON. METHODS: The Nationwide Readmissions Database was retrospectively reviewed for primary THAs, with 90-day readmissions assessed from the index procedure. Patients diagnosed with OA (n = 1,577,991) and ON (n = 55,034) were identified. Costs, LOS, and any readmission within 90 days for complications were recorded and analyzed with the chi-square and t-tests. RESULTS: Patients with ON had higher 90-day costs ($20,110.80 vs. 22,462.79, P < .01) and longer average LOS (3.48 vs. 4.49 days, P < .01). Readmission rates within 90 days of index THA were significantly higher among patients with ON (7.7% vs. 13.1%, P < .01). Patients with OA had a lower incidence of 90-day overall complications (4.1 vs. 6.4%, P < .01). CONCLUSIONS: Patients undergoing THA for ON incur higher readmission-related costs and complication rates. Understanding the predisposing factors for increased complications in ON may improve patient outcomes.

The Affordable Care Act and Global Budget Revenue: The Impact on Total Hip Arthroplasties.

BACKGROUND: Maryland possesses a unique, population-based alternative payment model named Global Budget Revenue (GBR). This study evaluated the effects of GBR on demographics and outcomes for patients who underwent primary total hip arthroplasty (THA) by comparing Maryland to the United States (U.S.). METHODS: We identified primary THA patients in the Maryland State Inpatient Database (n = 35,925) and the National Inpatient Sample (n = 2,155,703) between 2011 and 2016 utilizing International Classification of Diseases 9 and 10 diagnosis codes. Qualitative analysis was used to report trends. Multiple regressions were used for difference-in-difference (DID) analyses to compare Maryland to the U.S. between pre-GBR (2011-2013) and post-GBR (2014-2016) periods. RESULTS: After GBR implementation, there were proportionally more patients who were obese (Maryland: +5.1% vs U.S.: +3.0%), used Medicare (+1.6% vs +0.7%), used Medicaid (+2.4% vs +1.3%) while less used private insurance (-4.2% vs -1.8%) (all P < .001). There were proportionally less home health care patients in Maryland, but more in the U.S. (-3.5% vs +1.6%; both P < .001). The mean costs decreased for both cohorts (-$1780.80 vs -$209.40; both P < .001). The DID found Maryland saw more Medicaid and less private insurance patients under GBR (both P ≤ .001). Maryland saw more obese patients than would be expected (P = .001). The DID also found decreased costs for patients under GBR (P < .001 for both). CONCLUSION: Maryland has benefitted from GBR with decreased cost and an increase in Medicaid patients. Maryland may provide a viable model for future healthcare policies that incorporate global budgets.

Antibiotic Choice: The Synergistic Effect of Single vs Dual Antibiotics.

INTRODUCTION: This review summarizes single vs dual antibiotic cement literature, evaluating for synergistic activity with dual antibiotics. METHODS: A systematic review was performed for literature regarding dual antibiotics in cement, identifying 13 studies to include for review. RESULTS: Many in vitro studies reported higher elution from cement and/or improved bacteria inhibition with dual antibiotics, typically at higher dosages with a manual mixing technique. Limited clinical data from hip hemiarthroplasties and spacers demonstrated that dual antibiotics were associated with improved infection prevention and higher intra-articular antibiotic concentrations. CONCLUSION: In addition to broader pathogen coverage, several studies document synergy of elution and increased antibacterial activity when dual antibiotics are added to cement. Limited clinical evidence suggests that dual antibiotic cement may be associated with reduced infection rates.

Total Hip Arthroplasty: National Bearing Surface Trends for 20- to 50-Year-Old Patients.

INTRODUCTION: Total hip arthroplasty (THA) is reaching a broader spectrum of younger patients who struggle with incapacitating hip disease. This study aimed to explore national bearing surface trends for young THA recipients. Specifically, we evaluated bearing surface utilization, patient demographics, and hospital demographics in 20- to 50-year-old THA recipients in the United States from 2009 to 2016. MATERIALS AND METHODS: The National Inpatient Sample database was queried for patients aged 20 to 50 who underwent primary THA from 2009-2016 (n=279,190). Patients were grouped according to bearing surface type (metal-on-polyethylene [MOP], metal-on-metal [MOM], ceramic-on-ceramic [COC], and ceramic-on-polyethylene [COP]). Demographics included sex, age, race, obesity status, age-adjusted Charlson Comorbidity Index (CCI), primary payer, median household income, region, and teaching status. Chi-square analyses were employed for categorical variables, while independent t-tests were utilized for continuous variables. RESULTS: The incidence of THA for patients aged 20 to 50 increased slightly from 33,003 in 2009 to 33,545 in 2016 (p<0.001). Overall, bearing surface type was reported in 46.8% (n=127,876) of THAs. Of the THAs with bearing surface codes, the use of MOP (29.6 to 18.7%) and MOM (39.6 to 4.4%) decreased, while COC (9.0 to 14.3%) and COP (21.8 to 62.6%) utilization increased (p<0.001 for all). Those receiving COC implants had the youngest average age (42 years) (p<0.001). Females were more likely to receive COC (44.2%) or COP (43.6%) implants (p<0.001). Obese individuals were more likely to receive MOP (21.3%) or COP (21.2%) (p<0.001). CONCLUSION: Over an 8-year period, considerable shifts in bearing surface trends have occurred across the United States among 20 to 50-year-old patients. Advantages of ceramic femoral heads, along with increased acceptance of highly cross-linked polyethylene, appear to be reasons for the selection of COP over other bearing surfaces.

Mid-Term Follow Up of Newer-Generation Morphometric Wedge Stems for Total Hip Arthroplasty (THA).

INTRODUCTION: Proximally coated, morphometric wedge femoral stems illustrated excellent survivorship and clinical outcomes at a minimum five-year postoperative follow up. MATERIALS AND METHODS: We completed a retrospective review of 186 THA patients from three high-volume surgeons to assess clinical- and patient-reported outcomes five years after implantation with a cementless, proximally coated morphometric wedge femoral stem. We reviewed Gruen zones on early postoperative and mid-term radiographs for signs of osteolysis, loosening, and wear. Clinical- and patient-reported outcomes were compared with previously published two-year outcomes for these femoral stems. RESULTS: No progression of radiolucencies or loosening was observed radiographically when comparing minimum one-year and five-year follow up. Reactive radiodense lines were observed in 23 cases (12.64%), and 13 cases (7.14%) exhibited true radiolucencies of 1-3mm, and all remained unchanged between follow ups or were no longer present on the five-year film. Cortical hypertrophy was noted in Gruen zones 3 and/or 5 in 11 cases (6.04%). No stems were revised for mechanical loosening or for periprosthetic fracture. Nine (9) patients (4.87%) underwent revisions during the follow-up period for periprosthetic infection, femoral head and/or acetabular component revisions, and impingement requiring release and femoral head change. Average Harris Hip Scores were excellent at five years and improved slightly when compared to a two-year follow up; however, this change was not statistically significant. Health-related quality of life mental component and physical component scores were a mean of 48.45 and 43.10 at 5 years, respectively. All cause Kaplan-Meier survivorship of the femoral stem was calculated at 98.4% at an average 65.7 months post implantation. Additionally, this cohort exhibited 100% aseptic survivorship during the follow-up period. CONCLUSION: Newer-generation morphometric wedge femoral stems for THA exhibit excellent radiographic stability, patient satisfaction, and clinical outcomes five years post implantation.

NaV1.9 channels in muscle afferent neurons and axons.

The exercise pressor reflex (EPR) is activated by muscle contractions to increase heart rate and blood pressure during exercise. While this reflex is beneficial in healthy individuals, the reflex activity is exaggerated in patients with cardiovascular disease, which is associated with increased mortality. Group III and IV afferents mediate the EPR and have been shown to express both tetrodotoxin-sensitive (TTX-S, NaV1.6, and NaV1.7) and -resistant (TTX-R, NaV1.8, and NaV1.9) voltage-gated sodium (NaV) channels, but NaV1.9 current has not yet been demonstrated. Using a F--containing internal solution, we found a NaV current in muscle afferent neurons that activates at around -70 mV with slow activation and inactivation kinetics, as expected from NaV1.9 current. However, this current ran down with time, which resulted, at least in part, from increased steady-state inactivation since it was slowed by both holding potential hyperpolarization and a depolarized shift of the gating properties. We further show that, following NaV1.9 current rundown (internal F-), application of the NaV1.8 channel blocker A803467 inhibited significantly more TTX-R current than we had previously observed (internal Cl-), which suggests that NaV1.9 current did not rundown with that internal solution. Using immunohistochemistry, we found that the majority of group IV somata and axons were NaV1.9 positive. The majority of small diameter myelinated afferent somata (putative group III) were also NaV1.9 positive, but myelinated muscle afferent axons were rarely labeled. The presence of NaV1.9 channels in muscle afferents supports a role for these channels in activation and maintenance of the EPR. NEW & NOTEWORTHY Small diameter muscle afferents signal pain and muscle activity levels. The muscle activity signals drive the cardiovascular system to increase muscle blood flow, but these signals can become exaggerated in cardiovascular disease to exacerbate cardiac damage. The voltage-dependent sodium channel NaV1.9 plays a unique role in controlling afferent excitability. We show that NaV1.9 channels are expressed in muscle afferents, which supports these channels as a target for drug development to control hyperactivity of these neurons.

The effects of exogenous cortisol on myostatin transcription in rainbow trout, Oncorhynchus mykiss.

Glucocorticoids (GCs) strongly regulate myostatin expression in mammals via glucocorticoid response elements (GREs), and bioinformatics methods suggest that this regulatory mechanism is conserved among many vertebrates. However, the multiple myostatin genes found in some fishes may be an exception. In silico promoter analyses of the three putative rainbow trout (Oncorhynchus mykiss) myostatin promoters have failed to identify putative GREs, suggesting a divergence in myostatin function. Therefore, we hypothesized that myostatin mRNA expression is not regulated by glucocorticoids in rainbow trout. In this study, both juvenile rainbow trout and primary trout myoblasts were treated with cortisol to examine the effects on myostatin mRNA expression. Results suggest that exogenous cortisol does not regulate myostatin-1a and -1b expression in vivo, as myostatin mRNA levels were not significantly affected by cortisol treatment in either red or white muscle tissue. In red muscle, myostatin-2a levels were significantly elevated in the cortisol treatment group relative to the control, but not the vehicle control, at both 12 h and 24 h post-injection. As such, it is unclear if cortisol was acting alone or in combination with the vehicle. Cortisol increased myostatin-1b expression in a dose-dependent manner in vitro. Further work is needed to determine if this response is the direct result of cortisol acting on the myostatin-1b promoter or through an alternative mechanism. These results suggest that regulation of myostatin by cortisol may not be as highly conserved as previously thought and support previous work that describes potential functional divergence of the multiple myostatin genes in fishes.

C. Difficile Infection within 6 Months before TKA Is Associated with Increased Short-Term Complications.

A history of Clostridium difficile infection (CDI) before total knee arthroplasty (TKA) may be a marker for poor patient health and could be used to identify patients with higher risks for complications after TKA. We compared the frequency of 90-day postoperative CDI, complications, readmissions, and associated risk factors in (1) patients experiencing CDIs more than 6 months before TKA, (2) patients experiencing CDIs in the 6 months before TKA, and (3) patients without a history of CDI. We identified patients who underwent primary TKAs from 2010 to 2019 and had a history of CDI before TKA (n = 7,195) using a national, all-payer database. Patients were stratified into two groups: those with CDIs > 6 months before TKA (n = 6,027) and those experiencing CDIs ≤ 6 months before TKA (n = 1,168). These patients were compared with the remaining 1.4 million patients without a history of CDI before TKA. Chi-square and unadjusted odds ratios (ORs) with 95% confidence intervals (CI) were used to compare complication frequencies. Prior CDI during either timespan was associated with higher unadjusted odds for postoperative CDI (CDI > 6 months before TKA: OR 8.03 [95% CI 6.68-9.63]; p < 0.001; CDI ≤ 6 months before TKA: OR 59.05 [95% CI 49.66-70.21]; p < 0.001). Patients with a history of CDI before TKA were associated with higher unadjusted odds for 90-day complications and readmission compared with patients without a history of CDI before TKA. Other comorbidities and health metrics were not found to be associated with postoperative CDI (i.e., age, obesity, smoking, antibiotic use, etc.). CONCLUSION: CDI before TKA was associated with higher odds of postoperative CDI compared with patients without a history of CDI. CDI ≤ 6 months before TKA was associated with the highest odds for postoperative complications and readmissions. Providers should consider delaying TKA after CDI, if possible, to allow for patient recovery and eradication of infection.

An anatomic study of the morphologic characteristics of the dorsal capitolunate ligament.

PURPOSE: There is consensus in favor of a description of the dorsal ligaments of the carpus as not including a direct ligament between the lunate and capitate. On the other hand, there is an anatomical formation which, according to the currently accepted description, corresponds to the dorsal midcarpal capsule, itself thickened by the dorsal intercarpal ligament. The question is whether the capsule at this point deserves to be called an individualizable ligament. In our operative experience of the dorsal carpus, we have encountered a stout structure adherent to the lunate and capitate. In this article, we present the anatomic evidence of this structure's existence. METHODS: Seven adult fresh frozen upper extremities were dissected. Three wrists were longitudinally sectioned in line with the middle finger metacarpal. The remaining 4 were dissected dorsally. Two representative samples of the stout structure connecting the lunate to the capitate were sent to pathology for histologic analysis and staining. RESULTS: In all 3 of the longitudinally sectioned wrists, a thick band of tissue could clearly be seen, originating on the lunate, spanning the dorsal interval between the lunate and the capitate, and inserting on the capitate. With this structure intact, dorsal dislocation of the capitate was not possible, but preliminary sectioning of the structure allowed dislocation. In the 4 dorsally dissected wrists, the same connection was observed, palmar to the dorsal intercarpal ligament, in every specimen. The average dimensions of the dorsal capitolunate were: 15.25 ± 1 mm long, 8.75 ± 1 mm wide at the midpoint, and 1.75 ± 1 mm thick. The two specimens sent to pathology after sectioning showed longitudinally oriented collagen fibers. This structure also stained positive for elastin and contained intrasubstance vascular structures. CONCLUSION: There is a stout ligamentous structure connecting the lunate to the capitate, palmar to the dorsal intercarpal ligament. Disruption of this structure appears to be necessary for dorsal dislocation of the capitate. Clinical studies are needed to gain better understanding of the exact function and importance of this structure.

Comparative analysis of open versus endoscopic carpal tunnel release in a comprehensive national database.

PURPOSE: Carpal tunnel syndrome is the most common compressive neuropathy. There is limited evidence to support endoscopic compared to open carpal tunnel release according to the 2016 American Academy of Orthopaedic Surgeons Clinical Practice Guideline on carpal tunnel syndrome. The purpose of the present study was to assess differences between the two procedures by comparing 30- and 90-day complications and mean hospital costs in a large patient population. METHODS: Using the national Mariner15 Database by PearlDiver Technologies, we retrospectively studied 27,192 carpal tunnel syndrome patients who received carpal tunnel release using an endoscopic or open surgical approach from 2010 to 2019. Patients who met the inclusion criteria were grouped and case-matched at a 1:1 ratio through the corresponding International Classification of Diseases codes (n = 13,596) and assessed for 30- and 90-day complications such as median nerve injury, superficial palmar arch injury, and revision carpal tunnel release surgery. Univariate analysis was used to compare outcomes and a multivariate regression was performed to identify risk factors associated with each outcome. RESULTS: Endoscopic carpal tunnel release was associated with a higher rate of median nerve injury than open release at 30 days (0.3% vs. 0.1% odds ratio, 2.21; 95% confidence interval, 1.29-3.81; p < 0.05) and 90 days (0.4% vs. 0.3%; odds ratio, 1.77; 95% confidence interval, 1.16-2.70; p < 0.05). Endoscopic release was also associated with a higher rate of superficial palmar arch injury (0.1% vs. 0%; odds ratio, 25.02; 95% confidence interval, 1.48-423.0; p < 0.05). CONCLUSIONS: In the present study, risk of median nerve injury and vascular injury was higher after endoscopic than open carpal tunnel release. At 90 days, all-cause revision rates were similar between techniques. Surgeons should understand these differences, to optimize surgical decision-making. LEVEL OF EVIDENCE: Therapeutic, IIIa.