Comparison of Postoperative Outcomes of Patients Undergoing Total Hip and Total Knee Arthroplasty Following a Diagnosis of Dementia: A TriNetX Database Study

Background

As life expectancy improves for patients with dementia, the demand for mobility-improving surgeries such as total joint arthroplasty (TJA) will increase. There is little research on patients with dementia undergoing TJA, although dementia has been shown to be a risk factor for complications. The purpose of this study is to compare postoperative outcomes of patients with dementia undergoing TJA at 90 days, 2 years, and 5 years.

Methods

The TriNetX database was retrospectively queried for all patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). Patients were divided into cohorts by preoperative diagnosis of dementia and propensity score matched. The following outcomes were evaluated between groups at 90 days, 2 years, and 5 years postoperatively: revision, resection arthroplasty, closed reduction (THA only), femur fracture plating, and prosthetic joint infection. Readmission and manipulation under anesthesia (TKA only) were evaluated at 90 days postoperatively. Univariate and multivariate analyses were performed.

Results

After matching, there were no differences in demographics or comorbidities between groups. TKA (odds ratio [OR] = 1.75, 95% confidence interval [CI] 1.42-2.15, P < .001) and THA (OR = 2.17, 95% CI 1.92-2.45, P < .001) patients with dementia were more likely to be readmitted than patients without dementia. At 2 years (OR = 2.07, 95% CI 1.14-3.77, P = .015) and 5 years (OR = 2.14, 95% CI 1.32-3.48, P = .002) postoperatively, THA patients with dementia were more likely to have proximal femur fracture plating than patients without dementia.

Conclusions

Patients undergoing THA with dementia had worse outcomes than patients undergoing THA without dementia and TKA with dementia. The overall rate of complications was low, and a diagnosis of dementia should not be an absolute contraindication to proceeding with TJA.

Managing an epidemic within a pandemic: orthopedic opioid prescribing trends during COVID-19

INTRODUCTION

In response to the opioid epidemic, a multitude of policy and clinical-guideline based interventions were launched to combat physician overprescribing. However, the sudden rise of the Covid-19 pandemic disrupted all aspects of healthcare delivery. The purpose of this study was to evaluate how opioid prescribing patterns changed during the Covid-19 pandemic within a large multispecialty orthopedic practice.

MATERIALS AND METHODS

A retrospective review of 1,048,559 patient encounters from January 1, 2015 to December 31, 2022 at a single orthopedic practice was performed. Primary outcomes were the percent of encounters with opioids prescribed and total morphine milligram equivalents (MMEs) per opioid prescription. Differences in outcomes were assessed by calendar year. Encounters were then divided into two groups: pre-Covid (1/1/2019-2/29/2020) and Covid (3/1/2020-12/31/2022). Univariate analyses were used to evaluate differences in diagnoses and outcomes between periods. Multivariate analysis was performed to assess changes in outcomes during Covid after controlling for differences in diagnoses. Statistical significance was assessed at p < 0.05.

RESULTS

The percentage of encounters with opioids prescribed decreased from a high of 4.0% in 2015 to a low of 1.6% in 2021 and 2022 (p < 0.001). MMEs per prescription decreased from 283.6 ± 213.2 in 2015 to a low of 138.6 ± 100.4 in 2019 (p < 0.001). After adjusting for diagnoses, no significant differences in either opioid prescribing rates (post-COVID OR = 0.997, p = 0.893) or MMEs (post-COVID β = 2.726, p = 0.206) were observed between the pre- and post-COVID periods.

CONCLUSION

During the Covid-19 pandemic opioid prescribing levels remained below historical averages. While continued efforts are needed to minimize opioid overprescribing, it appears that the significant progress made toward this goal was not lost during the pandemic era.

Non-White Race and Concomitant Orthopedic Conditions Are Risk Factors for Failure to Achieve Clinically Relevant Improvement After Total Knee Arthroplasty

BACKGROUND

Data from the American Joint Replacement Registry demonstrate that 1-year minimal clinically important difference (MCID) achievement rates after total knee arthroplasty (TKA) are substantially lower when using general patient reported outcome measures, such as Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), than joint specific measures. The purpose of this study was to evaluate patient characteristics and outcomes associated with MCID achievement after TKA using the PROMIS-PF measure.

METHODS

A retrospective review of 263 patients undergoing TKA with preoperative and 1-year postoperative PROMIS-PF scores from March 12, 2020 to February 8, 2022 was performed. Three multivariate models were built to evaluate predictors of MCID achievement. Preoperative predictors evaluated included demographics, comorbidities, history of spine and knee surgery, and baseline PROMIS-PF. Postoperative clinical outcomes evaluated included lengths of stay, discharge statuses, complications, and utilizations of other orthopaedic services.

RESULTS

There were 109 patients (41%) who achieved an MCID at 1-year postoperatively. Non-white patients had 2.17 times lower odds of achieving MCID. No clinical outcomes assessed were independently predictive of MCID achievement. During the 1-year postoperative period, 63% of patients sought care for another orthopaedic condition. Patients requiring postoperative injections on another joint had a 2.27 times lower odds of achieving MCID. Those seen for spine conditions postoperatively had a 2.44 lower odds of achieving MCID.

CONCLUSIONS

Race, postoperative injections, and treatment for spine conditions after TKA were independent predictors of failure to achieve MCID. These results may guide preoperative patient consultation and risk-adjustment in future studies using PROMIS-PF as an endpoint for evaluation of TKA outcomes.

Social vulnerability adversely affects emergency-department utilization but not patient-reported outcomes after total joint arthroplasty

INTRODUCTION

Multiple studies demonstrate social deprivation is associated with inferior outcomes after total hip (THA) and total knee (TKA) arthroplasty; its effect on patient-reported outcomes is debated. The primary objective of this study evaluated the relationship between social vulnerability and the PROMIS-PF measure in patients undergoing THA and TKA. A secondary aim compared social vulnerability between patients who required increased resource utilization or experienced complications and those who didn't.

MATERIALS AND METHODS

A retrospective review of 537 patients from March 2020 to February 2022 was performed. The Centers for Disease Control Social Vulnerability Index (SVI) were used to quantify socioeconomic disadvantage. The cohort was split into THA and TKA populations; univariate and multivariate analyses were performed to evaluate primary and secondary outcomes. Statistical significance was assessed at p < 0.05.

RESULTS

48.6% of patients achieved PROMIS-PF MCID at 1-year postoperatively. Higher levels of overall social vulnerability (0.40 vs. 0.28, p = 0.03) were observed in TKA patients returning to the ED within 90-days of discharge. Increased overall SVI (OR = 9.18, p = 0.027) and household characteristics SVI (OR = 9.57, p = 0.015) were independent risk factors for 90-day ED returns after TKA. In THA patients, increased vulnerability in the household type and transportation dimension was observed in patients requiring 90-day ED returns (0.51 vs. 0.37, p = 0.04).

CONCLUSION

Despite an increased risk for 90-day ED returns, patients with increased social vulnerability still obtain good 1-year functional outcomes. Initiatives seeking to mitigate the effect of social deprivation on TJA outcomes should aim to provide safe alternatives to ED care during early recovery.

Effect of Lower Extremity Osteoarthritis on Outcomes of Lumbar Decompression

BACKGROUND

The purpose of this study is to evaluate how hip or knee osteoarthritis (OA) and total joint arthroplasty impact the outcomes of patients undergoing lumbar decompression.

METHODS

A retrospective review of 342 patients undergoing lumbar decompression without fusion from January 2019 and June 2021 at a single institution was performed. Univariate and multivariate analyses were used to compare outcomes between patients with and without concomitant hip or knee OA.

RESULTS

Forty-six percent of patients had a hip or knee OA diagnosis and were higher risk as they were older, had higher BMIs, were more likely to be former smokers, had higher ASA scores, and were more likely to undergo 3+ level surgery. Postoperatively, after adjusting for differences between groups, hip or knee OA patients were more likely to be readmitted (OR=12.45, p=0.026) or have a complication (OR=13.77, p=0.031). However, patient reported outcomes as measured by Patient Reported Outcomes Measurement Information System-physical function. were similar at 1-3 months and 3-6 months. Higher levels of physical function were observed at 3-6 months postoperatively in hip OA patients with a history of THA.

CONCLUSION

Patients with concomitant hip or knee OA are at higher risk for readmission and postoperative complications but may achieve similar levels of physical function as those without OA.

The Impact of Total Hip Arthroplasty Surgical Approach on Short-Term Postoperative and Patient-Reported Outcomes

Background While multiple studies have compared outcomes between the direct anterior approach (DAA) and posterolateral (PL) total hip arthroplasty (THA), the debate over the optimal approach remains. Proponents of the DAA suggest that its muscle-sparing properties and unrestricted rehabilitation facilitate a more rapid return to function. The majority of studies demonstrate that patient-reported outcomes (PROs) are similar between approaches beyond the one-year timeframe, but results are mixed when evaluating earlier time points. The purpose of this study was to compare clinical outcomes and PROs between DAA and PL THAs at six weeks postoperatively. Methods A retrospective review of 749 primary THAs (151 PL, 598 DAA) from March 2020 to November 2022 was performed. All surgeries were performed by one of the five board-certified and fellowship-trained orthopedic surgeons. All patients completed Patient Reported Outcomes Measurement Information System-Physical Function (PROMIS-PF) questionnaires preoperatively and at six weeks postoperatively. A univariate comparison of clinical outcomes (length of stay (LOS), home discharge rate, 90-day ED returns, and readmissions) and six-week PROMIS-PF scores between approaches was performed. Multivariate analysis was performed to evaluate the effect of the approach on outcomes after adjusting for baseline differences between groups. Results Patients undergoing DAA THA experienced significantly shorter average LOS (0.71 vs. 1.36 days, p<0.001), higher rates of home discharge (99.0 vs. 92.1%, p<0.001), and lower rates of 90-day readmissions (0.7 vs. 6.0%, p<0.001) than those undergoing the PL approach. At six weeks postoperatively, DAA patients achieved higher average PROMIS-PF scores (42.2 vs. 39.9, p=0.001). After adjusting for the Charlson Comorbidity Index and baseline physical function, the DAA was significantly associated with shorter LOS (β=-0.52, p<0.001), increased odds of home discharge (OR=5.70, p=0.001), reduced risk of 90-day readmission (OR=0.14, p=0.001), and higher PROMIS-PF scores at six weeks postoperatively (β=1.37, p=0.045). Conclusion In comparison to patients undergoing PL THA, those treated using the DAA experienced improved clinical and PROs over the six-week postoperative period. While both approaches resulted in satisfactory outcomes, these results support the assertion that DAA THA may result in more rapid recovery and return to function.

Outpatient physical therapy bundled payment models are feasible for total hip arthroplasty patients: an evaluation of utilization, cost and outcomes

BACKGROUND

Various episode-of-care bundled payment models for patients undergoing total joint arthroplasty have been implemented. However, participation in bundled payment programs has dropped given the challenges of meeting continually lower target prices. The purpose of our study is to investigate the cost of outpatient physical therapy (PT) and the potential for stand-alone outpatient PT bundled payments for patients undergoing total hip arthroplasty (THA).

METHODS

A retrospective review of 501 patients who underwent primary unilateral THA from November 2017 to February 2020 was performed. All patients included in this study received postoperative PT care at a single hospital-affiliated PT practice. Patients above the 75th percentile of therapy visits were then classified as high-PT utilizers and compared with the rest of the population using univariate statistics. Stepwise multivariate logistic regression was used to assess the predictors of high therapy utilization.

RESULTS

Patients averaged 65 ± 10 years of age and a BMI of 29 ± 5 kg/m². Overall, 80% of patients were white and 53% were female. The average patient had 11 ± 8 total therapy sessions in 42 days: one initial evaluation, one re-evaluation and 9 standard sessions. High-PT utilizers incurred estimated average costs of $1934 ± 431 per patient, compared to $783 ± 432 (P < 0.001) in the rest of the population. Further, no significant differences in 90-day outcomes including lower extremity functional scale scores, emergency department returns, readmissions, or returns to the operating room were observed between high utilizers and the rest of the population (all P > 0.08). In the multivariate analysis, women (OR = 1.68, P = 0.017) and those with sleep apnea (OR = 2.02, P = 0.012) were nearly twice as likely to be high utilizers, while white patients were 42% less likely to be high utilizers than patients of other races (OR = 0.58, P = 0.028).

CONCLUSIONS

Outpatient PT utilization is highly variable in patients undergoing THA. However, despite using more services and incurring increased cost, patients in the top quartile of utilization experienced similar outcomes to the rest of the population. If outpatient therapy bundles are to be developed, 16 visits appear to be a reasonable target for pricing, given this provides adequate coverage for 75% of THA patients.

The effects of hypoalbuminemia in obese patients undergoing total joint arthroplasty

INTRODUCTION

Total joint arthroplasty (TJA) is a highly effective surgery. However, poor nutritional status has been associated with worse outcomes. In orthopedics, nutrition status is commonly evaluated using serum albumin. When albumin levels fall below 3.0 g/dL, wound healing ability becomes impaired. Typically, malnutrition is associated with low BMI, but malnourished patients can also be obese. The goals of this study were to investigate the relationship between malnourishment represented through albumin levels of obese patients and likelihood of postoperative complications.

METHODS

A retrospective review of patients undergoing primary TJA from 2016 to 2020 in the American College of Surgeons National Surgical Quality Improvement Program national database was performed. Patients with an albumin of < 3.5 g/dL were considered to have hypoalbuminemia and those with ≥ 3.5 g/dL were considered normal albumin. Univariate analysis was used to determine demographic and comorbidity differences between those with and without hypoalbuminemia. Outcomes of interest included length of stay, resource utilization, discharge disposition, and unplanned readmissions. Multivariate logistic regression examined albumin as a predictor of increased resource utilization and complications after controlling for possible confounding variables.

RESULTS

Of the 79,784 patients, 4.96% of patients had low albumin. Those with hypoalbuminemia were nearly 1.5 years older than those with normal albumin, were more likely to be black, female, and had an overall increased comorbidity burden as shown by percent of patients with ASA > 3 (all p < 0.001). After risk adjustment, those with hypoalbuminemia and a BMI of 35 + had greater risk of complications and increased resource utilization.

CONCLUSION

Our results demonstrated the prevalence of malnutrition increases as a patient's BMI increases. Further, hypoalbuminemia was associated with increased resource utilization and increased complication rates in all obese patients. We suggest screening albumin levels in obese patients preoperatively to give surgeons the best opportunity to optimize patient nutrition before undergoing surgery.

Acetabular Total Hip Arthroplasty Revision: A Summary of Operative Factors, Outcomes, and Comparison of Approaches

BACKGROUND

Revision total hip arthroplasty (THA) presents a greater risk to patients than primary THA, and surgical approach may impact outcomes. This study aimed to summarize acetabular revisions at our institution and to compare outcomes between direct anterior and posterior revision THA.

METHODS

A series of 379 acetabular revision THAs performed from January 2010 through August 2022 was retrospectively reviewed. Preoperative, perioperative, and postoperative factors were summarized for all revisions and compared between direct anterior and posterior revision THA.

RESULTS

The average time to acetabular revision THA was 10 years (range, 0.04 to 44.1), with mechanical failure (36.7%) and metallosis (25.6%) being the most prevalent reasons for revision. No differences in age, body mass index, or sex were noted between groups. Anterior revision patients had a significantly shorter length of stay (2.2 versus 3.2 days, P = .003) and rate of discharge to a skilled nursing facility (7.5 versus 25.2%, P = .008). In the 90-day postoperative period, 9.2% of patients returned to the emergency department (n = 35) and twelve patients (3.2%) experienced a dislocation. There were 13.2% (n = 50) of patients having a rerevision during the follow-up period with a significant difference between anterior and posterior approaches (3.8 versus 14.7%, respectively, P = .049).

CONCLUSION

This study provides some evidence that the anterior approach may be protective against skilled nursing facility discharge and rerevision and contributes to decreased lengths of stay. We recommend surgeons select the surgical approach for revision THA based on clinical preferences and patient factors.

The Efficacy of Telemedicine Versus In-Person Education for High-Risk Patients Undergoing Primary Total Joint Arthroplasty

BACKGROUND

While multiple studies have demonstrated the positive impact of preoperative education on total joint arthroplasty (TJA) outcomes, the traditional method of conducting in-person individualized counseling or group education may limit access to these resources for a subset of the population. This study aimed to evaluate the use of preoperative telemedicine and in-person educational programs for primary TJA patients to determine if the utilization of telemedicine is inferior to in-person education in high-risk populations.

METHODS

A retrospective chart review of all "high-risk" patients undergoing primary unilateral TKA or THA by 1 of 10 board-certified surgeons at a single institution over 1 year was performed. Patients were prospectively classified as high-risk based on race/ethnicity, comorbidities, and socioeconomic and psychosocial factors. Demographics, comorbidities, and hospital outcomes were compared between patients receiving preoperative nurse navigator education via telemedicine versus those receiving face-to-face education.

RESULTS

When comparing the interventions, telemedicine education was noninferior to face-to-face visits. No significant differences between postoperative length of stay, discharge home, 30-day emergency department return, or 30-day readmission rates were noted. Within the telemedicine group, patients who received video consultations were found to be 6 times more likely to be discharged home after surgery (odds ratio (OR): 5.95, 95% confidence interval (CI): 2.00 to 25.49; P = .004) and less likely to have a 30-day readmission than the phone consultations (OR: 0.36, 95% CI: 0.12 to 0.94: P = .050).

CONCLUSION

This study demonstrates that telemedicine is not inferior to in-person preoperative education for patients undergoing unilateral TJA, although video-based consultation may improve outcomes over phone-only education.

Adductor Canal Blocks Are Not Associated With Improved Early Postoperative Outcomes in Patients Undergoing Total Knee Arthroplasty

Background: As length of stay after total knee arthroplasty (TKA) continues to shorten, interventions that may reduce early postoperative pain and complications must be studied. Peripheral nerve block is being explored as a potential means of improving pain management. The purpose of this study was to evaluate the impact of adductor canal block (ACB) on postoperative outcomes for patients undergoing TKA. Methods: We conducted a retrospective review of 565 patients who received unilateral TKA under spinal anesthesia with a periarticular anesthetic injection. Patients were divided by ACB status. Univariate comparisons and multivariate regression were used to compare outcomes for patients receiving ACBs vs those who did not. Results: Of the 565 patients, 167 received an ACB, and 398 did not. Patients who received an ACB were less likely to require nausea medication during the immediate postoperative period. Length of stay, narcotic consumption, rate of discharge to home, postanesthesia care unit recovery time, urinary retention, ability to complete physical therapy, and 30-day readmission rate did not differ significantly between groups. After risk adjustment, the only significant finding was decreased likelihood of nausea in patients receiving an ACB. Conclusion: ACBs appear to have little to no significant impact on early clinical outcomes in patients having TKA under spinal anesthesia with a periarticular anesthetic injection. Further study of larger patient cohorts is required to validate these findings.

Racial Disparities in Outcomes of Total Joint Arthroplasty at a Single Institution: Have We Made Progress?

Background

Health disparities disproportionately affect minority groups across the United States with respect to care access, quality, and outcomes. The aim of this study is to examine existing disparities between white and African American (AA) patients regarding postoperative outcomes following total joint arthroplasty and provide insight into disparity trends over a 9-year period.

Methods

A retrospective review of 16,779 total joint arthroplasty patients at a single institution between January 2013 and December 2021 was performed. Patients were grouped by race as AA or white. Outcomes of interest included length of stay (LOS), home discharge, 30-day emergency department return, and 30-day readmission. Univariate statistics and multivariate regressions were utilized to analyze results.

Results

Significant improvements in LOS and rates of home discharge occurred for both white and AA patients at our institution over a 9-year period, while rates of 30-day emergency department returns and readmissions demonstrated a downward but non-statistically significant trend. Despite these trends, AA patients continued to experience longer lengths of stay, less likelihood of 0- or 1-day LOS, and higher risk of nonhome discharge for most years examined. However, after controlling for demographic and comorbidity differences, the differences between groups narrowed over time resulting in no significant differences in the aforementioned 3 measures by 2021.

Conclusions

Although racial disparities in outcomes are still apparent, over time, the differences in resource utilization between AA and white patients have narrowed. Initiatives aimed at creating healthier communities with increased access to care and the ultimate goal of equitable care must continue to be pursued.

Postoperative outcomes of mepivacaine vs. bupivacaine in patients undergoing total joint arthroplasty with spinal anesthesia

Background

Spinal anesthesia (SA) has been previously associated with improved outcomes after total joint arthroplasty (TJA). The purpose of this study was to compare outcomes between various local anesthetics.

Methods

This was a retrospective study of 1,328 patients undergoing primary TJA with SA from September 2020–2021 at a single institution. Patients were grouped based on TKA or THA and further separated and analyzed in terms of anesthetic agents—mepivacaine (M), hyperbaric bupivacaine (HB), or isobaric bupivacaine (IB). Subgroup analysis of same-day-discharge (SDD) patients and low- (<11 mg) and high-dose bupivacaine was performed. Statistical significance was assessed at P<0.05.

Results

Mepivacaine use was associated with younger age, lower ASAs, and lower Charlson Comorbidity Index (CCI) scores in both THAs and TKAs. Postoperatively, significant differences were found between HB, IB, and M in LOS, the first PT ambulation distance and rates of SDD, and home discharge in both THAs and TKAs. No significant differences in outcomes were observed between high- and low-dose bupivacaine in THAs or TKAs. In SDD patients, a significant difference was found only in the first 6-clicks mobility scores. After controlling for age, BMI, sex, ASA, and procedure type, mepivacaine was found to be associated with shorter LOS, increased likelihood of SDD, home discharge, POD-0 ambulation, and, further, the first ambulation distance. No significant differences were observed in 6-clicks mobility scores, urinary retention, 30-day ED returns or 30-day readmissions.

Conclusions

Both bupivacaine and mepivacaine are safe and effective local anesthetics for patients undergoing TJA as evidenced by low, similar rates of urinary retention and 30-day ED returns and readmissions. Mepivacaine does appeared to facilitate early ambulation, shorter LOS and home discharge and should be considered as the local anesthetic of choice for patients undergoing rapid recovery TJA.

Effect of Weight Change on Patient-Reported Outcomes Following Total Joint Arthroplasty

BACKGROUND

Increased body mass index (BMI) has been previously described as a risk factor for complications after total joint arthroplasty (TJA); however, its effect on patient-reported outcomes has not been thoroughly investigated. This study examines the effect of postoperative weight change on the Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF) scores for total knee arthroplasty (TKA) and total hip arthroplasty (THA) patients.

METHODS

A retrospective review of 988 patients undergoing THA or TKA was performed. PROMIS-PF scores and BMI were recorded throughout the study duration. Patients were classified by a 5% change in BMI. A univariate analysis evaluated differences across groups. Mixed-effect models evaluated predictors of change in functional score over the postoperative follow-up time.

RESULTS

43.1% patients had a THA and 56.9% patients had a TKA. At 0 to 3 months, 92% of patients had no change in BMI, 3 to 6 months 82% had no change, and 6 to 12 months 80% had no change. There were no significant demographic or comorbidity differences across groups for both THA and TKA. Similar improvements in PROMIS-PF scores were observed across weight change groups. In the mixed-effect models, postoperative time was found to be a significant predictor of postoperative PF score. Both THA and TKA patients saw greater improvements in PROMIS-PF scores in patients with lower preoperative BMIs.

CONCLUSION

These results demonstrate most patients do not experience substantial changes in weight following TJA. However, lower BMIs at the time of surgery were associated with an increased functional improvement. Therefore, efforts to optimize BMI should be focused preoperatively to improve surgical outcomes.

Lower Extremity Osteoarthritis: A Risk Factor for Mental Health Disorders, Prolonged Opioid Use, and Increased Resource Utilization After Single-Level Lumbar Spinal Fusion

INTRODUCTION

Few studies have examined the effect of hip or knee osteoarthritis, together described as lower extremity osteoarthritis (LEOA) on patient outcomes after lumbar fusion. The purpose of this study was to evaluate the effect of LEOA on postoperative outcomes and resource utilization in patients undergoing single-level lumbar fusion.

METHODS

Using a national deidentified database, TriNetX, a retrospective observational study of 17,289 patients undergoing single-level lumbar fusion with or without a history of LEOA before September 1, 2019, was conducted. The no-LEOA and LEOA groups were propensity score matched, and 2-year outcomes were compared using univariate statistical analysis.

RESULTS

After propensity score matching, 2289 patients with no differences in demographics or comorbidities remained in each group. No differences in the rate of repeat lumbar surgery were observed between groups (all P > 0.30). In comparison with patients with no LEOA, patients with LEOA experienced higher rates of overall and new onset depression or anxiety, prolonged opioid use, hospitalizations, emergency department visits, and ambulatory visits over the 2-year postoperative period (all P < 0.02).

CONCLUSION

Patients with LEOA undergoing single-level lumbar fusion surgery are at higher risk for suboptimal outcomes and increased resource utilization postoperatively. This complex population may benefit from additional individualized education and multidisciplinary management.

Point Absorber Limits to Future Gravitational-Wave Detectors

High-quality optical resonant cavities require low optical loss, typically on the scale of parts per million. However, unintended micron-scale contaminants on the resonator mirrors that absorb the light circulating in the cavity can deform the surface thermoelastically and thus increase losses by scattering light out of the resonant mode. The point absorber effect is a limiting factor in some high-power cavity experiments, for example, the Advanced LIGO gravitational-wave detector. In this Letter, we present a general approach to the point absorber effect from first principles and simulate its contribution to the increased scattering. The achievable circulating power in current and future gravitational-wave detectors is calculated statistically given different point absorber configurations. Our formulation is further confirmed experimentally in comparison with the scattered power in the arm cavity of Advanced LIGO measured by in situ photodiodes. The understanding presented here provides an important tool in the global effort to design future gravitational-wave detectors that support high optical power and thus reduce quantum noise.

Postoperative outcomes of total knee arthroplasty across varying levels of multimodal pain management protocol adherence

We examined the effect of varying multimodal pain management (MMPM) combinations on oral morphine milligram equivalents (OMME) and length of stay (LOS) after total knee arthroplasty (TKA). Five groups were compared based on the combination of multimodal analgesics ranging from no MMPM to full MMPM with acetaminophen, gabapentinoids, and celecoxib. After risk adjustment, MMPM was associated with decreased odds of LOS ≥2 days and OMME ≥75th percentile. MMPM protocols are effective at reducing LOS and postoperative narcotic requirements post-TKA. Patients appear to derive similar benefit from receiving all three medications, as well as various combinations of these drugs.

Preoperative Education for Total Joint Arthroplasty: Does Reimbursement Reduction Threaten Improved Outcomes?

BACKGROUND

Nurse navigation programs have been previously shown to reduce cost and improve outcomes after total joint arthroplasty (TJA). Medicare has proposed a 13.7% reduction in professional fee reimbursement for TJA procedures that may adversely impact providers' and health systems' ability to fund ancillary support resources such as nurse navigators.

METHODS

A consecutive series of primary TJAs performed between April 2019 and February 2020 was retrospectively reviewed. Clinical and financial outcomes of patients attending a nurse navigator-led preoperative education class were compared with those who did not attend.

RESULTS

There were 2057 TJAs identified during the study period. Most patients attended the preoperative education class (82.7%) and were discharged home (92.8%). Controlling for significant differences between groups, class attendance was associated with reduced length of stay (LOS), increased chance of 0- or 1-day LOS, reduced chance of discharge to a skilled nursing facility, and reduced hospital charges. For this patient sample, a proposed 13.7% reduction in nurse navigator-led classes was modeled to increase overall cost to payers by >$400,000 annually. Complete elimination of this class was estimated to increase the total annual cost by >$5,700,000 and cost per TJA by >$2700.

CONCLUSION

The use of a nurse navigator-led preoperative education class was associated with shorter LOS, more frequent 0- and 1-day LOS, reduced discharge to skilled nursing facilities, and lower total hospital charges for those patients who attended. Potential reductions proposed by Medicare may interfere with the ability to support such services and negatively impact both clinical and financial outcomes.

Approaching the motional ground state of a 10-kg object

The motion of a mechanical object, even a human-sized object, should be governed by the rules of quantum mechanics. Coaxing them into a quantum state is, however, difficult because the thermal environment masks any quantum signature of the object's motion. The thermal environment also masks the effects of proposed modifications of quantum mechanics at large mass scales. We prepared the center-of-mass motion of a 10-kilogram mechanical oscillator in a state with an average phonon occupation of 10.8. The reduction in temperature, from room temperature to 77 nanokelvin, is commensurate with an 11 orders-of-magnitude suppression of quantum back-action by feedback and a 13 orders-of-magnitude increase in the mass of an object prepared close to its motional ground state. Our approach will enable the possibility of probing gravity on massive quantum systems.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

The Utility of Frozen Section Histology in Diagnosing Periprosthetic Joint Infection in Revision Total Joint Arthroplasty

BACKGROUND

Surgeons utilize a combination of preoperative tests and intraoperative findings to diagnose periprosthetic joint infection (PJI); however, there is currently no reliable diagnostic marker that can be used in isolation. The purpose of our study is to evaluate the utility of frozen section histology in diagnosis of PJI.

METHODS

Retrospective analysis of 614 patients undergoing revision total joint arthroplasty with frozen section histology from a single institution was performed. Discriminatory value of frozen section histology was assessed using univariate analysis and evaluation of area under the curve (AUC) of a receiver operating characteristic curve comparing frozen section histology results to the 2018 International Consensus Meeting (ICM) PJI criteria modified to exclude the histology component.

RESULTS

The sensitivity of the frozen section histology was 53.6% and the specificity was 95.2%. There was 99.2% concordance between the permanent section and frozen section results. The receiver operating characteristic curve for frozen section yielded an AUC of 0.744 (95% confidence interval 0.627-0.860) and the modified ICM score yielded an AUC of 0.912 (95% confidence interval 0.836-0.988) when compared to the full score. The addition of frozen section histology changed the decision to infected in 20% of "inconclusive" cases but less than 1% of total cases.

CONCLUSION

In comparison to the modified ICM criteria, intraoperative frozen section histology has poor sensitivity, strong specificity, and acceptable overall discrimination for diagnosing PJI. This test appears to be of particular value for patients deemed "inconclusive" for infection using the remaining ICM criteria.

General vs Neuraxial Anesthesia in Direct Anterior Approach Total Hip Arthroplasty: Effect on Length of Stay and Early Pain Control

BACKGROUND

Recent literature has suggested some benefits for neuraxial anesthesia (NA) as an alternative for general anesthesia (GA) for primary total hip arthroplasty patients. We examined the impact of NA vs GA on outcomes for patients undergoing direct anterior (DA) approach total hip arthroplasty (THA) in an institution with established rapid recovery protocols.

METHODS

A retrospective review was conducted for 500 consecutive THA patients from a single institution. Univariate analysis and multivariate linear regression were used to compare outcomes for THA patients receiving NA and GA.

RESULTS

There was a significant difference in length of stay with NA patients having a shorter length of stay (NA 32.7 hours vs GA 38.1 hours, P = .003). Patients receiving NA had significantly lower PACU morphine milligram equivalents (MME) (NA 10.2 MME vs GA 15.6 MME, P < .001) and reported a lower score on the PACU pain numeric rating scale (NA 2.1 vs GA 3.7, P < .001).

CONCLUSION

Neuraxial anesthesia is associated with decreased LOS, decreased PACU MME, and a lower PACU pain score for patients undergoing primary DA THA. These trends remained consistent when controlling for age, gender, BMI, and ASA.

Same-Day vs One-Day Discharge: Rates and Reasons for Emergency Department Return After Hospital-Based Total Joint Arthroplasty

BACKGROUND

As short stay and outpatient total joint arthroplasties (TJAs) are more widely adopted, it is important to assess whether reducing length of stay leads to increased emergency department (ED) visits or readmissions.

METHODS

This is a retrospective review of 1743 primary TJA patients with same-day discharge (SDD) or 1-day length of stay between January and December 2019. Patients who returned to the ED or were readmitted within 30 days of TJA were identified, and chart review was performed to identify their primary reason for revisit.

RESULTS

Patients discharged on the day of surgery (n = 203, 11.6%) were more likely to be younger (P < .001) and have a lower body mass index (total hip arthroplasty, P = .018; total knee arthroplasty, P < .001) and American Society of Anesthesiologists score (P < .001). The overall rate of return was 6.3%, and 1.3% of patients were readmitted. Controlling for age, gender, body mass index, surgery type, and American Society of Anesthesiologists, patients selected for SDD were not found to be at higher risk of return to the ED compared to 1-day length of stay patients (4.9% vs 6.4%, odds ratio 0.980, 95% confidence interval 0.484-1.984, P = .956).

CONCLUSION

SDD of eligible patients does not increase the risk of 30-day return to the ED. Continued analysis of risk factors for return and readmission will improve prospective identification of patients who can safely be discharged on the day of surgery, and future quality improvement initiatives should target the most common reasons for ED return.

Impact of Dexamethasone on Length of Stay and Early Pain Control in Direct Anterior Approach Total Hip Arthroplasty With Neuraxial Anesthesia

BACKGROUND

Dexamethasone has been shown to reduce postoperative pain and opioid consumption for total joint arthroplasty patients; however, its impact on patients who received neuraxial anesthesia (NA) is not well described. We examined the impact of perioperative dexamethasone on outcomes for patients undergoing direct anterior approach total hip arthroplasty (THA) under NA.

METHODS

A retrospective review was conducted for 376 THA patients from a single institution. Univariate analysis was used to compare postoperative outcomes for 164 THA patients receiving dexamethasone compared to 212 who did not receive dexamethasone.

RESULTS

No differences in age, gender, body mass index, or American Society of Anesthesiologists (ASA) Score were observed between the groups. Patients receiving perioperative dexamethasone reported statistically significantly lower postanesthesia care unit (PACU) pain numeric rating scale (Dexamethasone 1.6 vs No dexamethasone 2.3, P = .014) and received lower PACU morphine milligram equivalents (MME) (Dexamethasone 8.57 vs No dexamethasone 11.44, P < .001). Patients receiving dexamethasone had significantly shorter LOS (Dexamethasone 29.40 vs No dexamethasone 35.26 hrs., P < .001).

CONCLUSION

Perioperative dexamethasone is associated with decreased postoperative pain and narcotic consumption, and shorter length of stay for patients undergoing primary direct anterior approach THA with NA.

Risk factors for progression to total knee arthroplasty within two years of presentation for knee osteoarthritis

INTRODUCTION

Knee osteoarthritis (OA) is a leading cause of disability and functional limitations in aging adults. Total knee arthroplasty (TKA) is the gold standard treatment of this condition. The purpose of this study is to evaluate which patient characteristics are associated with proceeding to TKA.

METHODS

Retrospective review of patients with knee osteoarthritis at a single institution was conducted. Demographic, radiographic and clinical patient characteristics were analyzed. The primary outcome measure was whether patients underwent TKA over the study time-period. Univariate comparisons between patients not undergoing surgery and those undergoing TKA were performed. Multivariate logistic regression was performed to evaluate risk factors for undergoing TKA.

RESULTS

Two hundred seven patients were included in the study. One hundred eighty seven patients (90.3%) did not undergo surgery, while 20 (9.7%) underwent TKA. No statistically significant differences in demographics were observed between patients who underwent TKA and those who did not. On multivariate analysis, patients with Kellgren Lawrence grade 4 OA (OR: 20.793, p = 0.009) and varus alignment (OR: 13.044, p = 0.040) were at significantly increased risk of undergoing TKA. Using only these two variables, the area under the curve for predicting which patients would undergo TKA was 0.846, indicating excellent discrimination.

CONCLUSION

In patients diagnosed with knee OA, Kellgren Lawrence grade 4 classification and varus knee alignment are significant risk factors for undergoing TKA, and are associated with a decreased time from initial presentation to surgery. These findings may be used to counsel patients, aid triage decisions, and inform the development of future predictive models.

Preoperative Predictors of Same-Day Discharge After Total Knee Arthroplasty

Background

In January 2020, The Centers for Medicare and Medicaid Services approved total knee arthroplasty (TKA) to be performed in ambulatory surgery centers (ASCs). This study aims to develop a predictive model for targeting appropriate patients for ASC-based TKA.

Methods

A retrospective review of 2266 patients (205 same-day discharge [SDD; 9.0%] and 2061 one-day length of stay [91.0%]) undergoing TKA at a regional medical center between July 2016 and September 2020 was conducted. Multiple logistic regression was used to evaluate predictors of SDD, as these patients represent those most likely to safely undergo TKA in an ASC.

Results

Controlling for other demographics and comorbidities, patients with the following characteristics were at reduced odds of SDD: increased age (odds ratio [OR] = 0.935, P < .001), body mass index ≥35 (OR = 0.491, P = .002), female (OR = 0.535, P < .001), nonwhite race (OR = 0.456, P = .003), primary hypertension (OR = 0.710, P = .032), ≥3 comorbidities (OR = 0.507, P = .002), American Society of Anesthesiologists score ≥3 (OR = 0.378, P < .001). The model was deemed to be of adequate fit using the Hosmer and Lemeshow test (χ² = 12.437, P = .112), and the area under the curve was found to be 0.773 indicating acceptable discrimination.

Conclusion

For patients undergoing primary TKA, increased age, body mass index ≥35, female gender, nonwhite race, primary hypertension, ≥3 comorbidities, and American Society of Anesthesiologists score ≥3 decrease the likelihood of SDD. A predictive model based on readily available patient presentation and comorbidity characteristics may aid surgeons in identifying patients that are candidates for SDD or ASC-based TKA.

GW190521: A Binary Black Hole Merger with a Total Mass of 150 M_{⊙}

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21}  M_{⊙} and 66_{-18}^{+17}  M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28}  M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4}  Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30}  Gpc^{-3} yr^{-1}.

Outpatient, Home-Based Physical Therapy Promotes Decreased Length of Stay and Post-Acute Resource Utilization After Total Joint Arthroplasty

BACKGROUND

Patients and healthcare systems are increasingly focused on evaluating interventions that increase the value of care delivered. Our objective of this study is to evaluate early post-operative outcomes among those patients who underwent total joint arthroplasty with and without the participation in our piloted Outpatient Physical Therapy Home Visits (OPTHV) program.

METHODS

A retrospective analysis of patients undergoing total hip arthroplasty and total knee arthroplasty at a single institution from July 2016 to September 2017 was performed. Matched cohorts were compared according to OPTHV enrollment status.

RESULTS

In total, 1729 patients were included in this study. Two hundred ninety-three patients were enrolled in OPTHV, while 1436 patients received institutional standard care. Patients were matched by gender (56.7% vs 57.7% female, P = .751), age (67.75 vs 66.95 years, P = .167), body mass index (30.18 vs 30.12 kg/m², P = .859), and average American Society of Anesthesiologists score (2.31 vs 2.36, P = .131). OPTHV patients had a shorter length of stay (1.39 vs 1.64 days, P < .001) and were more likely to discharge to home (89.8% vs 74.7%, P < .001). Ninety-day re-admissions (2.7% vs 2.6%, P = .880) and emergency room visits (4.1% vs 4.3%, P = .864) were equivalent.

CONCLUSION

OPTHV is a novel program that facilitates discharge home and decreased length of stay after total joint arthroplasty without increasing re-admissions or emergency room visits. Utilization of OPTHV may contribute toward reducing the episode of care costs by reducing utilization of skilled nursing facility and home health services. Further prospective studies are needed to evaluate the effect of OPTHV on the total cost of care and functional outcomes.

The Effect of Neuraxial Anesthesia on Postoperative Outcomes in Total Joint Arthroplasty With Rapid Recovery Protocols

BACKGROUND

Compared to general anesthesia (GA), neuraxial anesthesia (NA) has been associated with improved outcomes after total joint arthroplasty (TJA). We examined the impact of NA on patient outcomes in an institution with an established rapid recovery protocol.

METHODS

This is a single-institution retrospective analysis of 5914 consecutive primary TJA performed from July 2015 to June 2018. Univariate tests and multivariate regression compared length of stay (LOS), transfusion rates, hematocrit levels, discharge disposition, and emergency room returns between patients receiving GA and NA.

RESULTS

Patients receiving NA had a significantly shorter LOS (total hip arthroplasty [THA]: GA 1.74 vs NA 1.36 days, P < .001; total knee arthroplasty [TKA]: GA 1.77 vs NA 1.64 days, P < .001). Both THA and TKA patients receiving NA were less likely to require transfusion (THA: GA 5.8% vs NA 1.6%, P < .001; TKA: GA 2.5% vs NA 0.5%, P < .001) and had a higher postoperative hematocrit (THA: GA 32.50% vs NA 33.22%, P < .001; TKA GA 33.57 vs NA 34.50%, P < .001). Patients receiving NA were more likely to discharge home (THA: GA 83.4% vs NA 92.3%, P < .001; TKA: GA 83.3% vs NA 86.3%, P = .010) (THA: NA adjusted OR [aOR] 2.04, P < .001; TKA: NA aOR 1.23, P = .048) and had significantly lower rates of 90-day emergency room visits (THA: NA aOR 0.61, P = .005; TKA: NA aOR 0.74, P = .034).

CONCLUSION

NA appears to contribute to decreased LOS, short-term complications, and transfusions while facilitating home discharge following TKA and THA. These trends are consistent when controlling for patient-specific risk factors, suggesting NA may enhance outcomes for patients with increased age, body mass index, and comorbidities.

LEVEL OF EVIDENCE

Level III Retrospective Cohort Study.

Quantum-Enhanced Advanced LIGO Detectors in the Era of Gravitational-Wave Astronomy

The Laser Interferometer Gravitational Wave Observatory (LIGO) has been directly detecting gravitational waves from compact binary mergers since 2015. We report on the first use of squeezed vacuum states in the direct measurement of gravitational waves with the Advanced LIGO H1 and L1 detectors. This achievement is the culmination of decades of research to implement squeezed states in gravitational-wave detectors. During the ongoing O3 observation run, squeezed states are improving the sensitivity of the LIGO interferometers to signals above 50 Hz by up to 3 dB, thereby increasing the expected detection rate by 40% (H1) and 50% (L1).

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2  M_{⊙}-1.0  M_{⊙}. We use the null result to constrain the binary merger rate of (0.2  M_{⊙}, 0.2  M_{⊙}) binaries to be less than 3.7×10^{5}  Gpc^{-3} yr^{-1} and the binary merger rate of (1.0  M_{⊙}, 1.0  M_{⊙}) binaries to be less than 5.2×10^{3}  Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2  M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0  M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

The Effect of Psychiatric Diagnosis and Psychotropic Medication on Outcomes Following Total Hip and Total Knee Arthroplasty

BACKGROUND

Nearly 20% of the US adult population lives with mental illness, and less than 50% of these receive treatment. Preoperative mental health may affect postoperative outcomes in patients undergoing total joint arthroplasty (TJA), yet is rarely addressed; poor outcomes increase the cost of care and burden on the healthcare system. This study examines the influence of patients with psychiatric diagnosis (PD) and taking psychotropic medication (PM) on emergency room visits, readmissions, and discharge disposition following TJA.

METHODS

Single institution retrospective analysis of a consecutive series of 3020 primary TJA performed between January 2017 and June 2018. Chi-squared, t-tests, and analysis of variance were used to quantify differences between groups.

RESULTS

Nine hundred seventy-six (32.3%) patients had a PD, most had depression (10.1%), anxiety (8.6%), or both (8.4%); 808 (26.8%) patients were on PM. Patients with PD were more likely to experience emergency room visits (6.3% vs 10.0%, P = .034) and skilled nursing facility discharge (11.6% vs 17.9%, P = .005). Patients taking PM were more likely to experience skilled nursing facility discharge (12.4 vs 17.1, P = .047); those taking >2 PM had the highest rate (21.6%).

CONCLUSION

Patients with PD on or off PM may experience increased healthcare utilization in the postoperative period. Increased patient education and support may reduce these discrepancies. PD is not a deterrent for TJA, but targeted interventions should be developed to provide additional support where needed and avoid unnecessary utilization of resources.

Simultaneous combined retroperitoneal and posterior hip approach for the treatment of iliopsoas abscess with extension to a metal-on-metal prosthetic hip joint

Iliopsoas abscess is an uncommon entity that has only rarely been associated with periprosthetic hip infection; to our knowledge, these are the first reported cases in patients with metal-on-metal (MoM) hip arthroplasty. We report 2 cases of iliopsoas abscess and concomitant periprosthetic hip infection in patients with a history of MoM hip arthroplasty. Case 1 presented with an acute infection 18 months after revision total hip arthroplasty (THA) for instability and adverse local tissue reaction after MoM THA. Case 2 presented with an acute infection in a previously well-functioning MoM THA. Both cases were treated with combined hip and retroperitoneal approaches and required more aggressive and longer treatment than is typical for periprosthetic infection, but ultimately resulted in successful revision THAs. We outline the treatment of these 2 patients and review the previously reported literature.

Tests of General Relativity with GW170817

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

Differences in Perioperative Outcomes and Complications Between African American and White Patients After Total Joint Arthroplasty

BACKGROUND

Racial disparities in healthcare utilization and outcomes have been reported and have wide-reaching implications for individual patient and healthcare system; as providers we bear an ethical burden to address this disparity and provide culturally competent care. This study will examine the influence of race on length of stay, discharge disposition, and complications requiring reoperation following total joint arthroplasty (TJA).

METHODS

Single institution retrospective analysis of a consecutive series of 7208 primary TJA procedures performed between July 2013 and June 2017 was conducted. Chi-squared and t-tests were used to quantify differences between the groups and multiple logistic regression was used to identify race as an independent risk factor.

RESULTS

In total, 6182 (84.3%) white and 1026 (14.0%) African American (AA) patients were included. AA patients were younger (63.62 vs 66.84 years, P < .001), more likely female (68.8% vs 57.0%, P < .001), had a longer length of stay (2.19 vs 2.00 days, P < .001), more likely to experience septic complications (1.3% vs 0.5%, P = .002) and manipulation under anesthesia (3.9% vs 1.8%, P < .001), and less likely to discharge home (67.1% vs 81.1%, P < .001). Multiple logistic regression showed that AA patients were more likely to discharge to a facility (adjusted odds ratio 2.63, 95% confidence interval 2.19-3.16, P < .001) and experience a manipulation under anesthesia (adjusted odds ratio 1.90, 95% confidence interval 1.26-2.85, P = .002).

CONCLUSION

AA patients undergoing TJA were younger with longer length of stay and a higher rate of nonhome discharge; AA race was identified as an independent risk factor. Further study is required to understand the differences identified in this study. Targeted interventions should be developed to attempt to eliminate the disparity.

Constraining the p-Mode-g-Mode Tidal Instability with GW170817

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4  M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70  Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51}  erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Evaluation of the Learning Curve When Transitioning From Posterolateral to Direct Anterior Hip Arthroplasty: A Consecutive Series of 1000 Cases

BACKGROUND

The direct anterior approach (DAA) for primary hip replacement has been gaining more attention and widespread use in recent years. There are a number of published studies evaluating the learning curve when a surgeon changes technique; these studies typically look at complications during the initial cases. This study examines procedure and total operating room (OR) time along with all complications for a surgeon transitioning from the posterolateral approach (PA) to DAA.

METHODS

A retrospective review of a single surgeon series of 1000 initial DAA procedures. Total OR time, procedure time, and complications were collected and analyzed. One-way analysis of variance and post hoc least significant difference tests were used for statistical analysis.

RESULTS

There was an initial increase in both procedure and OR times compared with the mature PA, by 34% and 30%, respectively. The procedure time became statistically equivalent to the mature PA time after the 400th DAA case, and significantly shorter after the 850th case. The total OR time became statistically equivalent after the 900th DAA case. There were 18 early (<90 days) and 18 late reoperations performed in this series with a nonsignificant trend toward femoral complications occurring early in the series. Minimum follow-up time was 2 years.

CONCLUSION

There was an initial increase in both total OR time and procedure time when an experienced surgeon introduced the DAA. By the end of the series, procedure time was significantly shorter and total OR time was equivalent. Complications overall were low and femoral complications decreased with time.

Minimum 5-Year Follow-up of Articular Surface Replacement Acetabular Components Used in Total Hip Arthroplasty

The articular surface replacement (ASR) monoblock metal-on-metal acetabular component was recalled due to a higher than expected early failure rate. We evaluated the survivorship of the device and variables that may be predictive of failure at a minimum of 5-year follow-up. A single-center, single-surgeon retrospective review was conducted in patients who received the DePuy Synthes ASR™ XL Acetabular hip system from December 2005 to November 2009. Mean values and percentages were calculated and compared using the Fisher's exact test, simple logistic regression, and Student's t-test. The significance level was P ≤ .05. This study included 29 patients (24 males, 5 females) with 32 ASR™ XL acetabular hip systems. Mean age and body mass index (BMI) reached 55.2 years and 28.9 kg/m², respectively. Mean postoperative follow-up was 6.2 years. A total of 2 patients (6.9%) died of an unrelated cause and 1 patient was lost to follow-up (3.4%), leaving 26 patients with 28 hip replacements, all of whom were available for follow-up. The 5-year revision rate was 34.4% (10 patients with 11 hip replacements). Mean time to revision was 3.1 years. Age (P = .76), gender (P = .49), BMI (P = .29), acetabular component abduction angle (P = .12), and acetabulum size (P = .59) were not associated with the increased rate for hip failure. Blood cobalt (7.6 vs 6.8 µg/L, P = .58) and chromium (5.0 vs 2.2 µg/L, P = .31) levels were not significantly higher in the revised group when compared with those of the unrevised group. In the revised group, a 91% decrease in cobalt and 78% decrease in chromium levels were observed at a mean of 6 months following the revision. This study demonstrates a high rate of failure of ASR acetabular components used in total hip arthroplasty at a minimum of 5 years of follow-up. No variable that was predictive of failure could be identified in this series. Close clinical surveillance of these patients is required.

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω_{0}^{T}<5.58×10^{-8}, Ω_{0}^{V}<6.35×10^{-8}, and Ω_{0}^{S}<1.08×10^{-7} at a reference frequency f_{0}=25  Hz.

GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences

The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude Ω_{GW}(f=25  Hz)=1.8_{-1.3}^{+2.7}×10^{-9} with 90% confidence, compared with Ω_{GW}(f=25  Hz)=1.1_{-0.7}^{+1.2}×10^{-9} from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.

First Search for Nontensorial Gravitational Waves from Known Pulsars

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper limits for scalar and vector strains, finding values comparable in magnitude to previously published limits for tensor strain. Our results may be translated into constraints on specific alternative theories of gravity.

Insulin-Dependent Diabetes Is an Independent Risk Factor for Complications and Readmissions After Total Joint Replacements

This study examined the risk for postoperative complications, reoperations, and readmissions for patients with insulin-dependent diabetes mellitus (IDDM), patients with non-insulin-dependent diabetes mellitus (NIDDM), and patients without diabetes undergoing total joint replacements (TJRs). The American College of Surgeons National Surgical Quality Improvement Program database was queried for all primary TJRs in 2015. The study identified 78,744 TJRs (84.1% nondiabetic patients, 12.0% NIDDM, and 3.9% IDDM). Multiple logistic regression models identified IDDM as an independent risk factor for increased blood loss, myocardial infarctions, pneumonia, renal insufficiency, urinary tract infections, and readmissions when compared with both NIDDM and nondiabetics. Risk for wound complications and reoperations were comparable between all three groups. IDDM increases the risk for medical complications and readmissions after TJRs. Physicians must counsel patients on the increased risks associated with IDDM before elective surgery and provide appropriate medical support for these patients. (Journal of Surgical Orthopaedic Advances 27(4):294-298, 2018).

Opioid Prescriptions After Total Joint Arthroplasty

Prescription opioids are commonly prescribed for pain relief after total joint arthroplasty (TJA), yet little is known about the quantity of opioids prescribed after surgery. This study retrospectively reviewed a consecutive series of 1000 TJAs from April 2014 through September 2015. Postoperative opioid prescriptions were quantified using standardized morphine milligram equivalents (MME). Eighty-four percent of total knee arthroplasty (TKA) and 77% of total hip arthroplasty (THA) patients were opioid naïve. The median opioid volume of the first prescription for those undergoing TKA was greater than for those undergoing THA (600 vs. 450 MME), as was the proportion of individuals requiring one or more refills (48% vs. 32%). The total volume of opioids after TKA was also higher than for total hip replacement (870 vs. 525 MME). Patients who were not opioid naïve were prescribed substantially more opioids than their counterparts after TKA (mean 1593 vs. 1064 MME, p < .001) and THA (mean 1031 vs. 663 MME, p < .001). Decreasing opioid use before surgery may decrease total volume of opioid prescriptions after TJA. (Journal of Surgical Orthopaedic Advances 27(3):231-236, 2018).

Effects of transients in LIGO suspensions on searches for gravitational waves

This paper presents an analysis of the transient behavior of the Advanced LIGO (Laser Interferometer Gravitational-wave Observatory) suspensions used to seismically isolate the optics. We have characterized the transients in the longitudinal motion of the quadruple suspensions during Advanced LIGO's first observing run. Propagation of transients between stages is consistent with modeled transfer functions, such that transient motion originating at the top of the suspension chain is significantly reduced in amplitude at the test mass. We find that there are transients seen by the longitudinal motion monitors of quadruple suspensions, but they are not significantly correlated with transient motion above the noise floor in the gravitational wave strain data, and therefore do not present a dominant source of background noise in the searches for transient gravitational wave signals. Using the suspension transfer functions, we compared the transients in a week of gravitational wave strain data with transients from a quadruple suspension. Of the strain transients between 10 and 60 Hz, 84% are loud enough that they would have appeared above the sensor noise in the top stage quadruple suspension monitors if they had originated at that stage at the same frequencies. We find no significant temporal correlation with the suspension transients in that stage, so we can rule out suspension motion originating at the top stage as the cause of those transients. However, only 3.2% of the gravitational wave strain transients are loud enough that they would have been seen by the second stage suspension sensors, and none of them are above the sensor noise levels of the penultimate stage. Therefore, we cannot eliminate the possibility of transient noise in the detectors originating in the intermediate stages of the suspension below the sensing noise.

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^{4}  years. We infer the component masses of the binary to be between 0.86 and 2.26  M_{⊙}, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60  M_{⊙}, with the total mass of the system 2.74_{-0.01}^{+0.04}M_{⊙}. The source was localized within a sky region of 28  deg^{2} (90% probability) and had a luminosity distance of 40_{-14}^{+8}  Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.

GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence

On August 14, 2017 at 10∶30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of ≲1 in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are 30.5_{-3.0}^{+5.7}M_{⊙} and 25.3_{-4.2}^{+2.8}M_{⊙} (at the 90% credible level). The luminosity distance of the source is 540_{-210}^{+130}  Mpc, corresponding to a redshift of z=0.11_{-0.04}^{+0.03}. A network of three detectors improves the sky localization of the source, reducing the area of the 90% credible region from 1160   deg^{2} using only the two LIGO detectors to 60  deg^{2} using all three detectors. For the first time, we can test the nature of gravitational-wave polarizations from the antenna response of the LIGO-Virgo network, thus enabling a new class of phenomenological tests of gravity.

The Cost of Unnecessary Hospital Days for Medicare Joint Arthroplasty Patients Discharging to Skilled Nursing Facilities

BACKGROUND

The 72-hour Medicare mandate (3-night stay rule) requires a 3-day inpatient stay for patients discharging to skilled nursing facilities (SNFs). Studies show that 48%-64% of Medicare total joint arthroplasty (TJA) patients are safe for discharge to SNFs on postoperative day (POD) #2. The purpose of this study was to extrapolate the financial impact of the 3-night stay rule.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried for all primary TJAs performed in 2015. Discharge destination was recorded. Institutional cost accounting examined costs for patients discharging on POD #2 vs POD #3.

RESULTS

A total of 42,423 TJAs (14,395 total hip arthroplasties [THAs] and 28,028 total knee arthroplasties [TKAs]) were performed in patients over the age of 65 years. Of these patients, 5252 THAs (36.5%) and 12,022 TKAs (42.9%) were discharged from the hospital on POD #3, with 2404 THAs (16.7%) and 5083 TKAs (18.1%) being discharged to SNFs. Institutional cost accounting revealed hospital costs for THA were $2014 more, whereas hospital costs for TKA were $1814 more for a 3-day length of stay when compared with a 2-day length of stay (P < .001). The mean charge per day for an SNF was $486.

CONCLUSION

The National Surgical Quality Improvement Program database is a representative sample of all surgeries performed in the United States. Extrapolating our findings to all Medicare TJAs nationally gives an estimated $63 million in annual savings. Medicare mandated, but potentially medically unnecessary inpatient days at a higher level of care increase the total cost for TJAs. Policies regarding minimum stay requirements before discharge should be re-evaluated.