An advanced knee simulator model can reproducibly be used for ligament balancing training during Total Knee Arthroplasty.

Introduction A critical and difficult aspect of total knee arthroplasty (TKA) is ligamentous balancing for which cadavers and models have played a large role in the education and training of new arthroplasty surgeons, though they both have several shortcomings including cost, scarcity, and dissimilarity to in vivo ligament properties. An advanced knee simulator (AKS) model based on computed tomography (CT) scans was developed in the setting of these challenges with cadavers and previous models. In this study, we compared the ligament balancing between AKS and human cadaveric knees to assess the validity of using the AKS for ligament balancing training during TKA. Methods A CT scan of a TKA patient with varus deformity was used to design the AKS model with modular components, using three-dimensional (3D) printing. Three fellowship-trained arthroplasty surgeons used technology-assisted TKA procedure to plan and balance three cadaver knees and the AKS model. Medial and lateral laxity data were captured using manual varus and valgus stress assessments for cadavers and the model in an extension pose (10 ̊ of flexion from terminal extension) and between 90 and 95 degrees for flexion. After pre-resection assessments, surgeons planned a balanced cruciate-retaining TKA. Following bony cuts and trialing, extension and flexion ligament laxity values were recorded in a similar manner. Descriptive statistics and student t-tests were performed to compare the cadavers and model with a p-value set at 0.05. Results Pre-resection medial/lateral laxity data for both extension and flexion were plotted and showed that the highest standard deviation (SD) for the cadavers was 0.67 millimeters, while the highest SD for the AKS was 1.25 millimeters. A similar plot for trialing demonstrated that the highest SD for the cadavers was 0.6 millimeters, while the highest SD for the AKS was 0.61 millimeters Discussion The AKS trialing data was highly reproducible when compared to cadaveric data, demonstrating the value of the AKS model as a tool to teach ligament balancing for TKA and for future research endeavors.

Robotic-assisted Total Knee Arthroplasty Technology Provides a Repeatable and Reproducible Method of Assessing Soft Tissue Balance.

Soft-tissue balancing is an important factor in primary total knee arthroplasty (TKA), with 30 to 50% of TKA revisions attributed to technical operative factors including soft-tissue balancing. Robotic-assisted TKA (RATKA) offers opportunities for improved soft-tissue balancing methods. This study aimed to evaluate the repeatability and reproducibility of ligamentous laxity assessments during RATKA using a digital tensioner.Three experienced RATKA surgeons assessed preresection and trialing phases of 12 human cadaveric knees with varying degrees of arthritis. Ligamentous laxity was assessed with manual varus and valgus stresses in extension and flexion, with a digital tensioner providing feedback on the change of laxity displacement. Intraclass correlation coefficient (ICC) analyses were used to determine the repeatability within a single surgeon and reproducibility between the three surgeons.The results showed excellent repeatability and reproducibility in ligamentous laxity assessment during RATKA. Surgeons had excellent repeatability for preresection and trialing assessments, with median ICC values representing excellent reproducibility between surgeons. Surgeons were repeatable within 1 or 1.5 mm for preresection and trialing assessments. On average, the variation within a surgeon was 0.33 ± 0.26 mm during preresection and 0.29 ± 0.28 mm during trialing. When comparing surgeons to each other, they were reproducible within an average of 0.69 ± 0.33 mm for preresection and 0.65 ± 0.31 mm for trialing.This study demonstrated the reliability of robotic-assisted soft-tissue balancing techniques, providing control over ligamentous laxity assessments, and potentially leading to better patient outcomes. The digital tensioner used in this study provided excellent repeatability and reproducibility in ligamentous laxity assessment during RATKA, highlighting the potential benefits of incorporating robotics in TKA procedures.

Registry Data Show Complication Rates and Cost in Revision Hip Arthroplasty.

BACKGROUND: Revision total hip arthroplaty (rTHA) places a burden on patients, surgeons, and health care systems because outcomes and costs are less predictable than primary THA. The purpose of this study was to define indications and treatments for rTHA, quantify risk for readmissions, and evaluate the economic impacts of rTHA in a hospital system. METHODS: The arthroplasty database of a hospital system was queried to generate a retrospective cohort of 793 rTHA procedures, performed on 518 patients, from 2017 to 2019 at 27 hospitals. Surgeons performed chart reviews to classify indication and revision procedure. Demographics, lengths of stay, discharge dispositions, and readmission data were collected. Analyses of direct costs were performed and categorized by revision type. RESULTS: Totally, 46.3% of patients presented for infection. Patients presenting for infection were 5.6 times more likely to have repeat rTHA than aseptic patients. Septic cases (4.3 days) had longer length of stay than aseptic ones (2.4) (P < .0001). However, 31% of patients discharged to a skilled nursing facility. Direct costs were greatest for a two-stage exchange ($37,642) and lowest for liner revision ($8,979). Septic revisions ($17,696) cost more than aseptic revisions ($11,204) (P < .0001). The 90-day readmission rate was 21.8%. Septic revisions had more readmissions (13.5%) than aseptic revisions (8.3%). CONCLUSIONS: Hip revisions, especially for infection, have an increased risk profile and create a major economic impact on hospital systems. Surgeons may use these data to counsel patients on risks of rTHA and advocate for improved reimbursement for the care of revision patients.

The Economic Impact of Lower Extremity Periprosthetic Fractures in a Large Hospital System.

BACKGROUND: Periprosthetic fractures (PPFs) place a burden on hospital systems. They occur in older patients with medical comorbidities, as unplanned events requiring technically complex surgeries with expensive implants. The purpose of this study was to describe this patient population and evaluate the economic impact of PPFs on a hospital system. METHODS: We conducted a retrospective study of PPFs of the hip and knee between 2018 and 2019. Demographics, length of stay (LOS), and discharge disposition were collected. We performed chart and radiographic reviews to determine the fracture classification and type of treatment performed. An analysis of direct inpatient costs was performed and categorized by a fracture type. RESULTS: We identified 213 periprosthetic hip and 151 periprosthetic knee fractures. The mean age of hip patients was 77 years, and 71% were female. The average surgery time was 194 minutes, LOS was 5.01 days, and 71% were discharged to a skilled nursing facility (SNF). The mean age of knee patients was 76 years, and 79% were female. The average surgery time was 174 minutes, LOS was 5.12 days, and 70% were discharged to a SNF. The median direct cost of hip fractures was $17,108, with Vancouver B2 and B3 costing significantly more at $19,987 and $23,935, respectively (P value <.0001). The median direct cost of knee fractures was $13,713. Type 3 distal femur fractures cost significantly more at $37,445 (P value <.0001). CONCLUSION: PPFs create a significant economic impact on hospital systems. We stratified the costs of treatment based on the fracture type. Significantly higher costs are associated with injuries requiring revision implants.

Aspirin use in the prevention of cardiovascular events.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of death in the United States and Oklahoma, and Oklahoma ranks 50th in CVD deaths. This paper will describe CVD and coronary heart disease (CHD) mortality in Oklahoma and review current recommendations regarding aspirin use for the prevention of CHD events. METHODS: The CDC Compressed Mortality File for 1999-2004 was accessed. Average annual age-adjusted or age-specific death rates per 100,000 population were calculated. A literature review of data and recommendations regarding aspirin use was conducted. RESULTS: From 1999-2004, there were 50,170 CHD deaths in Oklahoma (age-adjusted rate 232.1 per 100,000). Persons 75 years and older, males, and blacks had the highest death rates; the death rates declined for all persons except those aged 35-54 years. Aspirin use has been shown to be effective in reducing the number of nonfatal myocardial infarction (MI) and fatal CHD, though studies of aspirin effects in women have found a significant reduction in ischemic stroke but no significant effect on fatal or nonfatal MI or CVD death. Aspirin use slightly increases rates of gastrointestinal bleeding and hemorrhagic stroke. CONCLUSION: Continued commitment to counseling patients regarding tobacco cessation, nutrition and exercise, and treatment to reduce blood pressure, cholesterol, tobacco use, and blood sugar are essential. The Oklahoma State Medical Association Physicians Campaign for a Healthy Oklahoma has made it a priority to increase awareness of the risk and benefits of aspirin use among high-risk persons. Oklahoma physicians should assess patients at highest risk, such as healthy men older than 40 years, postmenopausal women (especially >or= 65 years), and younger people with risk factors for coronary heart disease (e.g., hypertension, hyperlipidemia, diabetes, or smoking) and discuss the potential benefits and harms of aspirin use.

Fatal necrotizing colitis following a foodborne outbreak of enterotoxigenic Clostridium perfringens type A infection.

BACKGROUND: Enterotoxigenic Clostridium perfringens type A is the third leading cause of foodborne disease in the United States, resulting annually in an estimated 250,000 cases of a typically mild, self-limiting gastrointestinal illness. METHODS: A retrospective cohort study was conducted to determine the cause of a small cluster of cases of gastrointestinal illness, which included cases of severe necrotizing colitis. Participants in the study consisted of residents and staff of a residential care facility for the mentally ill in Oklahoma (n = 20). An inspection of food preparation and food storage areas of the residential care facility was conducted as part of an environmental investigation. The investigation included extensive microbiological and molecular testing of the C. perfringens isolates and tissue specimens collected at autopsy. RESULTS: A total of 7 (3 confirmed and 4 probable) cases of foodborne enterotoxigenic C. perfringens type A were identified (attack rate, 35%) after the consumption of high-risk foods. Three residents developed acute necrotizing colitis; 2 of them died. Each patient with confirmed infection presented with evidence of constipation or fecal impaction. C. perfringens enterotoxin (CPE)-positive C. perfringens type A was cultured on samples from each patient with necrotizing colitis. Although statistical analyses failed to implicate a food source, the isolates carried a chromosomal cpe gene, which supports a foodborne origin. CONCLUSIONS: This study confirms that foodborne CPE-positive C. perfringens type A can affect the colon, resulting in potentially fatal necrotizing colitis. Drug-induced constipation and fecal impaction, resulting in prolonged exposure of the colonic mucosal tissue to C. perfringens type A toxins, contributed to the development of necrotizing colitis.

A large nosocomial outbreak of hepatitis C and hepatitis B among patients receiving pain remediation treatments.

BACKGROUND AND OBJECTIVE: In August 2002, the Oklahoma State Department of Health received a report of six patients with unexplained hepatitis C virus (HCV) infection treated in the same pain remediation clinic. We investigated the outbreak's extent and etiology. DESIGN, SETTING, AND PARTICIPANTS: We conducted a retrospective cohort study of clinic patients, including a serologic survey, interviews of infected patients, and reviews of medical records and staff infection control practices. Patients received outpatient pain remediation treatments one afternoon a week in a clinic within a hospital. Cases were defined as HCV or hepatitis B virus (HBV) infections among patients who reported no prior diagnosis or risk factors for disease or reported previous risk factors but had evidence of acute infection. RESULTS: Of 908 patients, 795 (87.6%) were tested, and 71 HCV-infected patients (8.9%) and 31 HBV-infected patients (3.9%) met the case definition. Multiple HCV genotypes were identified. Significantly higher HCV infection rates were found among individuals treated after an HCV-infected patient during the same visit (adjusted odds ratio [AOR], 6.2; 95% confidence interval [CI95], 2.4-15.8); a similar association was observed for HBV (AOR, 2.9; CI95, 1.3-6.5). Review of staff practices revealed the nurse anesthetist had been using the same syringe-needle to sequentially administer sedation medications to every treated patient each clinic day. CONCLUSIONS: Reuse of needles-syringes was the mechanism for patient-to-patient transmission of HCV and HBV in this large nosocomial outbreak. Further education and stricter oversight of infection control practices may prevent future outbreaks.

Terrorism from a public health perspective.

The use of biological and chemical weapons as agents of warfare and terrorism has occurred sporadically, but recent events demonstrate the increasing risk and possibility that terrorist groups with grievances against the government or groups may employ them. Historically, most evaluations of the potential risk for biological weaponry have focused on the military, but the recent release of anthrax in the United States demonstrates that civilian populations are also at risk. More likely than not, most bioterrorism events will be of a small scale; however, agents such as Bacillus anthracis and Yersinia pestis could leave hundreds of thousands dead or incapacitated. The impact of the attack will depend on a number of variables, including the agent used, method of dispersal, and the responsiveness of the public health system. With any large-scale event, the public health infrastructure will be called upon to deal with mass casualties and the "worried well."

Second-hand tobacco smoke in Oklahoma: a preventable cause of morbidity and mortality and means of reducing exposure.

Evidence has mounted in recent years establishing second-hand tobacco smoke exposure as a cause of morbidity and mortality in nonsmokers. The ratio of deaths is approximately one nonsmoker dying from illness caused by second-hand smoke exposure for every eight smokers who die from diseases caused by tobacco use. This is equivalent to about 750 nonsmoker deaths each year in Oklahoma caused by exposure to second-hand smoke. This article reviews the components of second-hand smoke, its health effects, its prevalence in Oklahoma, and the means of protecting children and nonsmoking adults from exposure. Oklahoma physicians are encouraged to advise their patients about the harmful effects of second-hand smoke and to actively support public policies that decrease exposure to second-hand smoke in public places and workplaces.