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.

Addressing the Challenge of Spine Patient Triage: Development of a Simple Algorithm for Identification of Potential Surgical Candidates

INTRODUCTION

Given that most spine conditions do not require surgical intervention, using surgeons to manage the subset of patients potentially requiring surgery is the most efficient resource allocation strategy. The purpose of this study was to develop a simple algorithm for identifying patients most likely to require spine surgery that could be used to appropriately triage this population to surgeons.

METHODS

A retrospective review of 5,886 consecutive new patients presenting to a multidisciplinary spine clinic from March 2021 to September 2022 was conducted. The primary outcome was whether a patient underwent spine surgery during the study period. A total of 64 independent variables were recorded from patient intake and the first visit. A gradient boosted model was generated to identify the independent variables most associated with undergoing surgery. The five most important variables were entered into a multiple logistic regression model, and a simplified decision support tool was generated and assessed.

RESULTS

Overall, 440 of 5886 patients (7.5%) underwent surgery during the study period. The following variables were identified as the top five predictors of spine surgery: patient goal of interest in learning about spine surgery, history of spine injections, difficulty walking a mile, radicular symptoms greater than axial symptoms, and increased age. Each of these variables was confirmed to be independently associated with undergoing surgery (all P < 0.001). The decision support tool yielded a sensitivity of 60.0%, specificity of 76.6%, likelihood ratio of 2.56, positive predictive value of 17.2%, and negative predictive value of 96.0% for predicting surgery. An AUC of 0.683 was achieved.

CONCLUSION

A simple 5-question algorithm incorporating patient demographics, symptoms, treatment history, physical function, and patient goals may improve the ability of practices to identify potential spine surgery candidates before their first visit. Prospective application and evaluation of the algorithm to evaluate whether it improves the triage of appropriate patients to spine surgeons is warranted.

Disparities in Patient Reported Outcome Measure Completion Rates and Baseline Function in Newly Presenting Spine Patients

STUDY DESIGN

Retrospective Review.

OBJECTIVE

The purpose of this study was to evaluate disparities in patient reported outcome measures (PROM) completion rates and baseline function scores among newly presenting spine patients.

SUMMARY OF BACKGROUND DATA

Prior studies have demonstrated that minority patients and those of low socioeconomic status may present with worse physical and mental health on PROMs. As PROMs are increasingly used in clinical care, research, and health policy, accurate assessment of health status among populations relies on the successful completion of PROM instruments.

METHODS

A retrospective review of 10,803 consecutive new patients presenting to a single multidisciplinary spine clinic from June 2020 to September 2022 was performed. Univariate statistics were performed to compare demographics between patients who did and did not complete PROMs. Multivariable analysis was used to compare PROM instrument completion rates by race, ethnicity, and Social Vulnerability Index (SVI) and baseline scores among responders.

RESULTS

68.4% of patients completed PROMs at the first clinic visit. After adjusting for age, sex, body mass index, and diagnosis type, patients of non-white race (OR=0.661, 95%-CI=0.599-0.729, P<0.001), Hispanic ethnicity (OR=0.569, 95%-CI=0.448-0.721, P<0.001), and increased social vulnerability (OR=0.608, 95%-CI=0.511-0.723, P<0.001) were less likely to complete PROMs. In the multivariable models, patients of non-white race reported lower levels of physical function (β=-6.5, 95%-CI=-12.4 to -0.6, P=0.032) and higher levels of pain intensity (β=0.6, 95%-CI=0.2-1.0, P=0.005). Hispanic ethnicity (β=1.5, 95%-CI=0.5-2.5, P=0.004) and increased social vulnerability (β=1.1, 95%-CI=0.4-1.8, P=0.002) were each associated with increased pain intensity.

CONCLUSION

Among newly presenting spine patients, those of non-white race, Hispanic ethnicity, and with increased social vulnerability were less likely to complete PROMs. As these subpopulations also reported worse physical function or pain intensity, additional strategies are needed to better capture patient reported health status in order to avoid bias in clinical care, outcomes research and health policy.

The Relationship Between Preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference and Pain Intensity Scores and Early Postoperative Pain and Opioid Consumption After Lumbar Fusion

Background The Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference and pain intensity measures quantify separate dimensions of pain from the patient's perspective. This study aimed to assess differences in these outcomes and to evaluate whether baseline PROMIS pain scores could be used as a leading indicator of increased pain and opioid consumption during early recovery after lumbar fusion. Methods A retrospective review of 199 consecutive patients undergoing posterolateral fusion (PLF) at a single institution was performed. All patients underwent one to three level lumbar PLF and preoperatively completed the PROMIS pain intensity and PROMIS pain interference measures. Multivariate linear regression was used to assess the relationship between preoperative PROMIS scores and postoperative pain numeric rating scale (NRS) and oral morphine milligram equivalents (OMME) by day after controlling for age, sex, and body mass index (BMI). Results In comparison to patients with the lowest preoperative pain intensity scores, those with the highest scores required significantly more OMME on postoperative day (POD) zero and one (both p<0.05) and had higher pain NRS on POD one (p=0.02). Patients with the highest pain interference scores reported higher pain NRS on POD zero (p=0.02) but required similar OMME at all time points. After controlling for age, sex, and BMI, each one-point increase in preoperative PROMIS pain interference scores was associated with increased OMME on POD zero (β=0.29, p=0.04) and POD one (β=0.64, p=0.03). Conclusions Patients with high pain intensity reported higher levels of pain and required more opioids during the first 24 hours postoperatively, while those with high pain interference reported higher levels of pain on the day of surgery but utilized similar amounts of opioids. After risk adjustment, increased baseline PROMIS pain interference scores - but not pain intensity - were associated with increased opioid use. These results suggest that both measures should be considered when identifying patients at risk for increased pain and opioid consumption after PLF.

Injections prior to hip arthroscopy are associated with increased risk of repeat hip arthroscopy at 1 and 5 years

INTRODUCTION

Previous studies have shown that intra-articular hip injections prior to hip arthroscopy (HA) can be a helpful diagnostic tool. However, local anesthetic and corticosteroid injections can be chondrotoxic and corticosteroid injections have been shown to increase the risk of infection during subsequent surgical intervention. The purpose of this study was to evaluate whether preoperative injections adversely affect outcomes of HA using a national database.

MATERIALS AND METHODS

The TriNetX database was retrospectively queried. Patients undergoing HA for femoroacetabular impingement with at least 1 year of claims runout were included in the analysis. Patients were grouped by whether they had a hip injection within 1 year prior to HA. The rates of repeat HA, total hip arthroplasty (THA), infection, osteonecrosis, and new onset hip OA at 1- and 5-years postoperatively were compared between groups. Statistical significance was assessed at α = 0.05.

RESULTS

6511 HA patients with previous injection and 1178 HA patients without previous injection were included. Patients with a previous injection were overall younger (32.3 vs. 34.7 years, p < 0.001), more likely to be female (69 vs. 48%, p < 0.001) and had a higher BMI (26.3 vs. 25.7 kg/m2, p = 0.043). At 1 and 5-years postoperatively, patients with any injection were 1.43 (p < 0.001) and 1.89 (p < 0.001) times more likely to undergo repeat HA, respectively. At 1 and 5-years postoperatively, patients who underwent a corticosteroid injection were 2.29 (p < 0.001) and 1.89 (p < 0.001) times more likely to undergo repeat HA than patients with local anesthetic injection only and 1.56 (p < 0.001) and 2.08 (p < 0.001) times more likely to undergo repeat HA than patients with no injection.

CONCLUSIONS

Intraarticular hip injections prior to hip arthroscopy, particularly corticosteroid injections, are associated with increased risk of repeat hip arthroscopy at 1 and 5 years. Additional studies are needed to elucidate this risk.

Outcomes in Lumbar Fusion Patients Stratified by the Clinical and Radiographic Degenerative Spondylolisthesis (CARDS) Classification System

Background and objective The Meyerding classification system remains the most common classification system for spondylolisthesis based on the percentages of vertebral translation. However, the majority of patients with degenerative disease fall into Grade 1, limiting its utility in this subset of patients. The Clinical and Radiographic Degenerative Spondylolisthesis (CARDS) classification system provides a simple radiographic framework for classifying degenerative lumbar spondylolisthesis (DLS) patients by incorporating disc height, kyphosis, and anterior translation. The purpose of this study was to evaluate how clinical characteristics, treatments, and outcomes vary across different CARDS groups in patients undergoing one- or two-level lumbar fusion for DLS. Methods The patients were classified into one of the following four CARDS groups - Type A: advanced disc space collapse with no evidence of kyphosis; Type B: partially preserved disc space with less than 5.0 mm of translation; Type C: partially preserved disc space with greater than 5.0 mm of translation; and Type D: kyphotic alignment. Univariate analyses were performed to compare demographics, symptoms, clinical outcomes, and Patient-Reported Outcomes Measurement Information System (PROMIS) physical (PH) and mental health (MH) scores across groups. Results Ninety-one patients were included in the study. Based on the CARDS classification, there were three (3%) Type A patients, 25 (28%) Type B, 58 (64%) Type C, and five (5%) Type D. No significant differences in baseline demographics, symptom duration, or PROMIS scores were observed across groups. Interbody utilization varied, ranging from 19% in CARDS C (n=11) to 60% in CARDS B (n=15) and D (n=3) patients (p=0.005). Thirty-day clinical outcomes were similar across groups. At an average follow-up of 8.9 months, improvements in PROMIS PH and MH scores and rates of clinically significant improvement were similar across groups. Conclusions Based on our findings, patients undergoing lumbar fusion for DLS present with similar demographic and clinical characteristics and experience similar clinical and patient-reported outcomes when stratified using the CARDS classification system. Posterolateral fusion (PLF) can be effective for various radiographic presentations of DLS. Further research is warranted to assess the utility of CARDS in preoperative planning.

Social Determinants of Health in Maryland Hip Arthroscopy Patients

Background Prior studies have demonstrated racial and socioeconomic disparities in patient-reported outcome measure (PROM) completion rates, and improvement exists across multiple orthopedic conditions. The purpose of this study was to assess whether these disparities are present in patients undergoing hip arthroscopy (HA) procedures. Methods A retrospective study of 306 patients undergoing HA from 2021 to 2023 was performed. Social determinants of health (SDOH) were compared between HA patients and the general Maryland population. Patients were then classified by whether they completed baseline and six-month PROMs (Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF) instrument). Patients who completed PROMIS-PF were classified by whether or not they achieved minimal clinically important difference (MCID) at six months. Demographics and SDOH were compared using univariate analyses between patients who did and did not complete PROMs and between those who did and did not achieve MCID. SDOH were evaluated at the zip-code level using regional health information exchange measures. Results Compared to the Maryland population, HA patients resided in areas of lower social vulnerability. Preoperative and six-month PROMs were completed by 102 (33%) patients. No significant differences in demographics or any SDOH were found between patients who did and did not complete PROMs. Six-month MCID was achieved in 75 of 102 (74%) patients with complete PROMs; no significant differences in demographics or SDOH were observed between patients who did and did not achieve MCID. Conclusions For patients undergoing HA, disparities in patient-reported outcome completion rates and postoperative functional improvement do not appear to be present across demographics and SDOH, indicating equitable care is being delivered.

Total Intravenous Anesthesia Compared to Inhalational Anesthesia in Patients Undergoing Arthroscopic Rotator Cuff Repair

Background Inhalation anesthesia (IA) and total intravenous anesthesia (TIVA) are common general anesthesia techniques. During rotator cuff repair (RCR), an interscalene block is beneficial for intraoperative and early postoperative pain control. This study aimed to evaluate postoperative outcomes and opioid usage in patients undergoing arthroscopic RCR with an interscalene block and either IA or TIVA. Methodology A retrospective observational study was performed of 478 patients undergoing RCR at a single institution. Demographics, surgical details, intra and postoperative medications, and 90-day outcomes were collected. Univariate and multivariate analyses were performed to evaluate differences between groups. Results In total, 309 (64.6%) patients received IA and 169 (35.3%) received TIVA. Patients receiving IA were more likely to have comorbidities, such as diabetes (p = 0.002), sleep apnea (p = 0.006), gastroesophageal reflux disease (p < 0.001), and hypertension (p < 0.001). After adjusting for differences between groups in the multivariate analysis, patients who received TIVA had significantly shorter surgical time (β = -14.85, p < 0.001) and perioperative time (β = -21.01, p < 0.001) and significantly lower first post-anesthesia care unit Pasero opioid-induced sedation scores (β = -0.022, p = 0.040). Patients who received TIVA were less likely to receive intraoperative narcotics (odds ratio = 0.38; p = 0.031). Conclusions TIVA appears to be a safe and effective anesthetic for patients undergoing arthroscopic RCR. TIVA is a potentially beneficial alternative to IA for this patient population.

Optimizing Patient Outcomes in Spinal Surgery: An Investigation Into Anesthesiologists' Case Volume

Introduction Nearly one million patients in the United States undergo spine surgical procedures annually to seek relief from chronic back and neck pain. A multidisciplinary approach is key to ensuring the efficiency and safety of the surgical process, with the anesthesia team, nursing, surgeon, and healthcare facilities all playing a role. The purpose of this study is to capture potential associations between the anesthesiologists' case volume and patient postoperative outcomes in the early recovery period. Methods A retrospective review of anterior cervical discectomy and fusion (ACDF), lumbar decompression (LD), and lumbar fusion (LF) patients from July 2019 to June 2023 was performed. Anesthesiologists were categorized into low, medium, and high volumes of spine surgical cases. Univariate analysis was performed on patient demographics, intraoperative measures, post-anesthesia care unit (PACU) measures, and postoperative measures by anesthesiologist volume. Results This study included 545 ACDF, 815 LD, and 1,144 LF patients. There were no differences between groups in ACDF patients by anesthesiologist volume. When examining patients undergoing LD, there was a difference in patients with an American Society of Anesthesiologists (ASA) physical status classification of three or greater (low volume: 41.7% vs. medium volume: 53.7% vs. high volume: 45.0%; p=0.029). When examining patients undergoing LF, there were differences in patients with low temperatures in PACU (low volume: 2.8% vs. medium volume: 7.3% vs. high volume: 4.2%; p=0.044) and the percentage of patients with a 90-day emergency department return (low volume: 7.7% vs. medium volume: 11.9% vs. high volume: 7.0%; p=0.024). Conclusion While this study found a minimal impact of anesthesiologist volume on postoperative outcomes, recent literature has emphasized the critical role of teamwork and specialized surgical teams to enhance efficiency and patient care. Further studies are warranted to identify other variables in anesthesia, nursing, and surgical team workflow that may impact postoperative outcomes in spinal surgeries.

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 Effect of Preoperative, Low-Dose Intrathecal Morphine on Patient Outcomes Following Lumbar Fusion Surgery: Can We Teach an Old Dog New Tricks?

BACKGROUND

Early pain control after lumbar fusion presents a challenge to patients and providers. Intrathecal morphine (ITM) has been used at the end of these procedures with limited benefit, but recent data suggest low-dose ITM at case initiation may be effective. This study aims to evaluate the use of preoperative ITM during lumbar fusion to determine whether there is a benefit for these patients.

METHODS

One hundred and eighty lumbar fusion patients between 1 January 2018 and 31 May 2022 were evaluated. Patients were grouped by whether they received preoperative, low-dose ITM or not. Outcomes of interest included hospital narcotic consumption, pain scores, opioid-related complications, and complications within the first 90 days.

RESULTS

Sixty-five study patients received 200 µg ITM at case initiation and 115 did not. No differences in length of stay, discharge disposition, or complications in the first 90 days were noted. ITM patients received fewer milligram morphine equivalents in the postanesthesia care unit (9.7 ± 31.23 vs 21.83 ± 21.07; P = 0.006) and on postoperative day 0 (18.60 ± 35.47 vs 35.47 ± 28.51; P = 0.001). Pain scores were lower in the ITM group both in the postanesthesia care unit and on postoperative day 0, with a decrease in extreme pain scores (>7; 35.4% vs 53.0%; P = 0.034).

CONCLUSIONS

ITM appears to be safe and effective for reducing early pain and narcotic consumption on the day of surgery for lumbar fusion patients and may hold value for incorporation into rapid recovery protocols and for improving pain-related patient satisfaction.

CLINICAL RELEVANCE

ITM appears to be safe and effective for reducing early pain and narcotic consumption on the day of surgery for lumbar fusion patients and may hold value for incorporation into rapid recovery protocols and for improving pain-related patient satisfaction.

LEVEL OF EVIDENCE: 3

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.

Predictors of same day cancellation of elective surgery

Same day cancellations of surgery have adverse effects on both patients and health care systems. To date, the majority of research has evaluated reasons for same day cancellation, and relatively little is known about risk factors for cancellation. The aim of this study is to develop and evaluate the accuracy of a model for preoperatively predicting which patients are at risk for experiencing same day cancellation. While accurately predicting which patients are likely to experience same day cancellation remains challenging, predictive models may aid in the early identification of patients at risk for cancellation. Future studies are required to assess whether the use of predictive analytics leads to reduced cancellation rates in practice.

Transosseous Fixation of the Distal Tibiofibular Syndesmosis: Comparison of Interosseous Suture and Endobutton Across Age Groups

Background In the ankle, suture bridge fixation for syndesmotic injuries is commonly employed. Initial recommendations for suture bridge constructs advised against using the device in patients with insufficient quantity or quality of bone. Therefore, many surgeons limit its use to younger, more athletic patients and use traditional screw fixation in older, less active patients. The purpose of this study is to compare the outcomes of suture bridge fixation for syndesmotic repair in patients ≥ 60 years old vs patients < 60 years old. Methods A retrospective review of 140 ankle fracture patients from a single institution who received suture bridge fixation between July 13, 2010, and February 2, 2022, was performed. Patient data was obtained from patient records in the electronic health record. Univariate analysis, including chi-square and independent t-tests, was used. Complications included delayed wound healing, infection, hardware loosening, and non-union. Results There were no significant differences in demographics, comorbidities, primary or other procedures, loss of fixation, and neuropathy between groups. There was also no difference within the distribution of the mechanism of injury, affected side, or Weber classification. Finally, the rate of complication and complication type showed no significant differences between patients 60 years and older versus 60 years and younger. Complication rates and types in patients > 60 years versus < 60 years were not significantly different. Conclusion The use of the suture bridge fixation in patients > 60 years may not lead to an increased risk of complications and appears to be safe for use.

Clinical Results of Knot-tying Versus Knotless Suture Anchors in Arthroscopic Anteroinferior Labral Repair

Background Arthroscopic repair of glenohumeral instability is becoming an increasingly common procedure. These repairs can be undertaken using knot-tying and knotless suture anchors; there is currently no clear consensus in the literature about what type of repair is most cost-effective and provides superior outcomes. The purpose of this study is to examine postoperative outcomes of patients undergoing arthroscopic anteroinferior labral repair (AALR) with either knot-tying or knotless anchors. Methods A single institution retrospective observational cohort study of 122 patients undergoing AALR from January 2014 to June 2021 was conducted. Univariate statistics were used to assess differences in demographics, operative characteristics, and postoperative outcomes between repair types; multivariate analysis was used to evaluate risk factors for recurrent instability and reoperation. Results Patients undergoing AALR with knotless anchors had a shorter case duration than those with knot-tying anchors (112.64 vs. 89.86 minutes, p<0.001). There were no significant differences between groups in the size of labral tear, presence of a glenoid bone defect, or Hill-Sachs lesion. After controlling for age, BMI, sex, glenoid bone defect, number of preoperative dislocations, and fixation type, only age (OR=0.896, p=0.010) and female sex (OR=5.341, p=0.008) were independent risk factors for recurrent instability and no factors were independent predictors of reoperation. Conclusion Patients undergoing AALR experienced similar rates of reoperation and recurrent instability regardless of whether a knot-tying or knotless repair was performed. The use of knotless suture anchors may improve cost-effectiveness due to decreased surgical time without diminishing postoperative outcomes.

Change in Postoperative Weightbearing Protocol Does Not Increase Postoperative Complications Following Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Background Postoperative rehabilitation protocols, including weightbearing restrictions following hip arthroscopy (HA) for femoracetabular impingement syndrome (FAIS), vary widely among surgeons, from complete non-weightbearing to immediate weightbearing as tolerated; it is unclear if weightbearing restrictions affect short-term outcomes in patients undergoing HA. The purpose of this study is to evaluate patients undergoing hip arthroscopy for FAIS before and after a change in weightbearing protocol, from partial weightbearing with crutches for three weeks to weightbearing and weaning from crutches as tolerated, by examining postoperative outcomes. We hypothesize that the change in weightbearing protocol will have no significant effect on patient outcomes. Methods A retrospective review was conducted of 211 patients undergoing hip arthroscopy by a single high-volume surgeon. The change in weightbearing was implemented in February 2022; previously, all patients were toe-touch weightbearing with crutches for the first three weeks postoperatively. Following this change, patients were allowed to weightbear as tolerated with crutches immediately and wean from crutches as tolerated. The patients were divided into two groups: 119 patients pre-implementation (January 2021 to January 2022) and 92 patients post-implementation (February 2022 to December 2022). The primary endpoint was any complication in the first six weeks postoperatively, divided into complications at two and six weeks, emergency department returns in the first 90 days, reoperations in the first 30 days, and pain at six weeks. We also compared patient-reported outcomes at six weeks. Results There were no significant differences in demographics between groups. There were no significant differences in postoperative outcomes between patients that had weightbearing restrictions and those that did not when looking at 30 day return to operating room (0 vs 0%, p=1.000), 90-day return to emergency department (8.4 vs. 13.0%, p=0.386), two-week complications (2.5 vs. 6.5%, p=0.279), six-week complications (1.7 vs. 1.1%, p=1.000), pain score at six weeks postoperatively (0.34 vs. 0.33, p=0.971), any pain at six weeks postoperatively 37.8 vs. 32.6%, p=0.523), and six-week Patient-Reported Outcomes Measurement Information System (PROMIS) physical function (PF) score (36.0 vs. 34.5, p=0.330). Conclusion Patients undergoing HA after the discontinuation of a mandatory period of protected weightbearing did not experience any significant increase in complications or continued pain, and patient-reported outcomes were similar. Routine postoperative weightbearing restrictions may not be necessary for patients undergoing hip arthroscopy for femoroacetabular impingement syndrome. Further study is required to validate these findings and determine the optimal postoperative protocol for this patient population.

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.

Disparities in Hand Surgery Exist in Unexpected Populations

Background The purpose of our study is to investigate disparities in the patient populations and outcomes of carpal tunnel release (CTR) and trigger finger release (TFR).  Methods A retrospective review of 777 CTR and 395 TFR patients from May 2021 to August 2022 was completed. The shortened form of the Disabilities of the Arm, Shoulder, and Hand (DASH) scores (QuickDASH) was recorded to evaluate physical function preoperatively and at one and three months postoperatively. This study was deemed institutional review board-exempt by the institutional clinical research committee. Results Compared to CTR, TFR patients resided in zip codes with higher levels of social vulnerability across dimensions of 'household composition and disability' (p=0.018) and 'minority status and language' (p=0.043). When analyzing QuickDASH scores by demographics and procedure, preoperative scores were statistically significantly higher for non-married (p=0.002), White (p=0.003), and female sex (p=0.001) CTR patients. Further, one-month postoperative scores were statistically higher for White and non-married CTR patients (0.016 and 0.015, respectively). At three months postoperatively, female and non-married patients had statistically significant higher scores (0.010 and 0.037, respectively). In TFR patients, one-month postoperative QuickDASH scores for White and female patients were statistically significantly higher (0.018 and 0.007, respectively). There were no significant differences in QuickDASH scores between rural and non-rural patients, household income (HHI) above or below the median, or the Social Vulnerability Index (SVI) dimensions.  Conclusion Our study found marital status, sex, and race were associated with disparities in pre-and postoperative physical function in patients undergoing carpal tunnel or trigger finger release. However, future studies are warranted to confirm and develop solutions to disparities within this population.

Risk of Lower Extremity Ligamentous Injury Following Concussion Diagnosis: A TriNetX Database Study

Background Concussion is one of the most frequently reported sports-related injuries in the United States; there is evidence that residual deficits in neurocognition may increase the risk of lower extremity musculoskeletal injury after concussion in high school, college, and professional athletes. The purpose of this study is to identify whether similar trends are identified in community-based populations.  Methods The TriNetX Research Network database was queried for patients 10-60 years old who experienced an ambulatory or emergency visit from 2018-2020. Cohorts were defined by patients seen for concussion and patients seen for other reasons. These cohorts were then propensity score matched based on significant differences in demographics; after matching, each cohort included 97,708 patients. The propensity score-matched cohorts were then evaluated to identify patients who experienced subsequent lower extremity ligamentous injury within 12 months. Results Patients with a history of concussion were more likely to experience posterior cruciate ligament (PCL) sprain (0.04% vs. 0.02%, risk ratio (RR)=1.79, p=.039), medial collateral ligament (MCL) sprain (0.18% vs. 0.08%, RR=2.355, p<.001), lateral collateral ligament (LCL) sprain (0.05% vs. 0.02%, RR=2.202, p=.003) and ankle sprain (1.05% vs. 0.47%, RR=2.265, p<.001). Conclusion Patients diagnosed with concussion were more likely to experience a lower extremity ligamentous injury when compared with patients who did not have concussion. Patients should be counseled regarding this increased risk and additional neuromuscular evaluation and injury prevention education may be indicated following concussion diagnosis.

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.

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.

Streptococcus milleri pyomyoma simulating infective endocarditis

A 37-year-old woman with clinically occult, abscessed uterine myomas presented with fever, anemia, splenomegaly, and viridans streptococcal bacteremia. An initial diagnosis of endocarditis was made, but fever persisted despite appropriate antibiotics. Pelvic pain evolved and laparotomy revealed an infected myoma. Streptococcus milleri was isolated from both the blood and the uterine abscess. Infected uterine myomata may be clinically silent despite producing sustained bacteremia. The occurrence of suppurating myomas and the significance of S milleri isolates are briefly reviewed.

The value of preplacement medical examinations for nonhazardous light duty work

A prospective study on 6,125 job applicants for light duty telephone company work is presented, which indicates that a preplacement medical evaluation is not predictive of risks relating to work attendance or job performance in nonhazardous assignments. Results show that between groups of employees, who were medically classified at the time of hire into categories with or without employment risk factors, there was no significant difference relative to sickness, accident or other absence, or to work performance during the first twelve months after hire. A work force loss of 25% is seen during the first year after hire without significant difference between groups for either numbers of employees lost or reason for loss. A cost-benefit analysis based on this study is presented, which demonstrates that the preplacement medical evaluation for light duty assignments is not cost effective. In addition, further unnecessary costs are incurred when job applicants are medically evaluated but not hired, which is shown to occur here for 27.5% of healthy applicants.

Isolation and characterization of viruses from the kidneys of Rana pipiens with renal adenocarcinoma before and after passage in the red eft (Triturus viridescens)

Viruses were isolated from kidneys of normal and renal tumor-bearing Vermont Rana pipiens after subinoculation into red eft newts (Triturus viridescens). Organs of efts inoculated with viable cell suspensions from four of seven tumor-bearing kidneys yielded virus (LT-1, -2, -3, -4) when inoculated into TH-1 (Terrapene heart) cell culture. One tumor-bearing kidney also yielded virus (L-4) by direct inoculation into TH-1 cells. An additional isolate (L-5) was obtained from 1 of 52 normal Vermont frog kidneys inoculated directly into TH-1 cells. LT-1 was propagated with cytopathic effect (CPE) in each of 38 cell types tested, of fish, amphibian, reptilian, avian, and mammalian origin, at 23 or 30 C. LT-1 through LT-4, L-4 and L-5, and FV-1 through FV-3 each induced similar CPE in all cells tested. LT-2, however, induced CPE that progressed at a slower rate than that caused by the other isolates and produced smaller plaques (<0.8 mm) under starch gel overlay. Each of the viruses replicated to high titer in embryonated eggs incubated at 30 C. The viruses also grew in efts and adult newts, but not in bullfrog (Rana catesbeiana) tadpoles or adult leopard frogs. Tumor induction in adult leopard frogs inoculated with LT-1 was not demonstrated. Electron microscopic observations of LT-1 and LT-2 viruses revealed cytoplasmic particles, hexagonal in cross section, approximately 120 to 140 mmu in diameter, containing a dense nucleoid. LT-1 and LT-2 viruses were indistinguishable from FV-1 and Tipula iridescent virus. LT-1 was presumed to be a deoxyribonucleic acid virus on the basis of 5-bromodeoxyuridine inhibition. The isolates were ether-sensitive. On the basis of biological, physicochemical, and antigenic similarities, LT-1 through LT-4, L-4, L-5, FV-1 through FV-3, and isolates recently recovered from the bullfrog and the newt may represent strains of the same amphibian cytoplasmic virus.

The cardiac pathology of chronic exogenous obesity

Appraisal of the gross and microscopic anatomy of the heart was carried out at necropsy in 12 subjects (six men, six women) with marked chronic obesity. In each case the observed heart weight was considerably greater than that predicted at ideal body weight. Nine of the 12 subjects were found to have increase in left ventricular wall thickness, and two increase in right. The increases in heart weight and ventricular wall thickness were due to muscle hypertrophy involving the left ventricle or both left and right ventricles. Neither isolated nor predominant right ventricular hypertrophy was observed.

It has been concluded that myocardial hypertrophy is a more specific and significant anatomic alteration in the hearts of very obese subjects than are the previously reported findings of excess epicardial fat and fatty infiltration of the myocardium. The relationship between chronic augmentation of the work of the heart in these subjects and the development of cardiac hypertrophy has been discussed. The findings in this study have been interpreted as providing further support for the propositions that manifestations of myocardial insufficiency do occur in very obese subjects without evidences of other heart disease, that these manifestations are those of predominant left ventricular or biventricular failure, and that isolated cor pulmonale does not develop in the absence of pulmonary embolization.