Is a Rapid Recovery Protocol for THA and TKA Associated With Decreased 90-day Complications, Opioid Use, and Readmissions in a Health Safety-net Hospital?

BACKGROUND: Patients treated at a health safety-net hospital have increased medical complexity and social determinants of health that are associated with an increasing risk of complications after TKA and THA. Fast-track rapid recovery protocols (RRPs) are associated with reduced complications and length of stay in the general population; however, whether that is the case among patients who are socioeconomically disadvantaged in health safety-net hospitals remains poorly defined. QUESTIONS/PURPOSES: When an RRP protocol is implemented in a health safety-net hospital after TKA and THA: (1) Was there an associated change in complications, specifically infection, symptomatic deep venous thromboembolism (DVT), symptomatic pulmonary embolism (PE), myocardial infarction (MI), and mortality? (2) Was there an associated difference in inpatient opioid consumption? (3) Was there an associated difference in length of stay and 90-day readmission rate? (4) Was there an associated difference in discharge disposition? METHODS: An observational study with a historical control group was conducted in an urban, academic, tertiary-care health safety-net hospital. Between May 2022 and April 2023, an RRP consistent with current guidelines was implemented for patients undergoing TKA or THA for arthritis. We considered all patients aged 18 to 90 years presenting for primary TKA and THA as eligible. Based on these criteria, 562 patients with TKAs or THAs were eligible. Of these 33% (183) were excluded because they were lost before 90 days of follow-up and had incomplete datasets, leaving 67% (379) for evaluation. Patients in the historical control group (September 2014 to May 2022) met the same criteria, and 2897 were eligible. Of these, 31% (904) were excluded because they were lost before 90 days of follow-up and had incomplete datasets, leaving 69% (1993) for evaluation. The mean age in the historical control group was 61 ± 10 years and 63 ± 10 years in the RRP group. Both groups were 36% (725 of 1993 and 137 of 379) men. In the historical control group, 39% (770 of 1993) of patients were Black and 33% (658 of 1993) were White, compared with 38% (142 of 379) and 32% (121 of 379) in the RRP group, respectively. English was the most-spoken primary language, by 69% (1370 of 1993) and 68% (256 of 379) of the historical and RRP groups, respectively. A total of 65% (245 of 379) of patients in the RRP group had a peripheral nerve block compared with 54% (1070 of 1993) in the historical control group, and 39% (147 of 379) of them received spinal anesthesia, compared with 31% (615 of 1993) in the historical control group. The main elements of the RRP were standardization of preoperative visits, nutritional management, neuraxial anesthesia, accelerated physical therapy, and pain management. The primary outcomes were the proportions of patients with 90-day complications and opioid consumption. The secondary outcomes were length of stay, 90-day readmission, and discharge disposition. A multivariate analysis adjusting for age, BMI, gender, race, American Society of Anaesthesiologists class, and anesthesia type was performed by a staff biostatistician using R statistical programming. RESULTS: After controlling for the confounding variables as noted, patients in the RRP group had fewer complications after TKA than those in the historical control group (odds ratio 2.0 [95% confidence interval 1.3 to 3.3]; p = 0.005), and there was a trend toward fewer complications in THA (OR 1.8 [95% CI 1.0 to 3.5]; p = 0.06), decreased opioid consumption during admission (517 versus 676 morphine milligram equivalents; p = 0.004), decreased 90-day readmission (TKA: OR 1.9 [95% CI 1.3 to 2.9]; p = 0.002; THA: OR 2.0 [95% CI 1.6 to 3.8]; p = 0.03), and increased proportions of discharge to home (TKA: OR 2.4 [95% CI 1.6 to 3.6]; p = 0.01; THA: OR 2.5 [95% CI 1.5 to 4.6]; p = 0.002). Patients in the RRP group had no difference in the mean length of stay (TKA: 3.2 ± 2.6 days versus 3.1 ± 2.0 days; p = 0.64; THA: 3.2 ± 2.6 days versus 2.8 ± 1.9 days; p = 0.33). CONCLUSION: Surgeons should consider developing an RRP in health safety-net hospitals. Such protocols emphasize preparing patients for surgery and supporting them through the acute recovery phase. There are possible benefits of neuraxial and nonopioid perioperative anesthesia, with emphasis on early mobility, which should be further characterized in comparative studies. Continued analysis of opioid use trends after discharge would be a future area of interest. Analysis of RRPs with expanded inclusion criteria should be undertaken to better understand the role of these protocols in patients who undergo revision TKA and THA. LEVEL OF EVIDENCE: Level III, therapeutic study.

Flow-Optimized Model for Gas Jet Desorption Sampling Mass Spectrometry.

Thermal gas jet probes, including post-plasma desorption/ionization sources, have not been studied using computational fluid dynamics (CFD) models, as have other ambient mass spectrometry sampling techniques. Two systems were constructed: a heated nitrogen jet probe to establish practical bounds for a sampling/transmission experiment and a CFD model to study trajectories of particles desorbed from a surface through optimization of streamlines and temperatures. The physical model configuration as tested using CFD revealed large losses, transmitting less than 10% of desorbed particles. Different distances between the desorption probe and the transport tube and from the sample surface were studied. The transmission improved when the system was very close to the sample, because the gas jet otherwise creates a region of low pressure that guides the streamlines below the inlet. A baffle positioned to increase pressure in the sample region improves collection efficiency. A Lagrangian particle tracking approach confirms the optimal design leading to a transmission of almost 100%.

Measurement and Theory of Gas-Phase Ion Mobility Shifts Resulting from Isotopomer Mass Distribution Changes.

The unanticipated discovery of recent ultra-high-resolution ion mobility spectrometry (IMS) measurements revealing that isotopomers─compounds that differ only in the isotopic substitution sites─can be separated has raised questions as to the physical basis for their separation. A study comparing IMS separations for two isotopomer sets in conjunction with theory and simulations accounting for ion rotational effects provides the first-ever prediction of rotation-mediated shifts. The simulations produce observable mobility shifts due to differences in gas-ion collision frequency and translational-to-rotational energy transfer. These differences can be attributed to distinct changes in the moment of inertia and center of mass between isotopomers. The simulations are in broad agreement with the observed experiments and consistent with relative mobility differences between isotopomers. These results provide a basis for refining IMS theory and a new foundation to obtain additional structural insights through IMS.

1.5-Stage Exchange Arthroplasty for Total Knee Arthroplasty Periprosthetic Joint Infections.

BACKGROUND: Periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) is a challenging problem. The purpose of this study was to outline a novel technique to treat TKA PJI. We define 1.5-stage exchange arthroplasty as placing an articulating spacer with the intent to last for a prolonged time. METHODS: A retrospective review was performed from 2007 to 2019 to evaluate patients treated with 1.5-stage exchange arthroplasty for TKA PJI. Inclusion criteria included: articulating knee spacer(s) remaining in situ for 12 months and the patient deferring a second-stage reimplantation because the patient had acceptable function with the spacer (28 knees) or not being a surgical candidate (three knees). Thirty-one knees were included with a mean age of 63 years, mean BMI 34.4 kg/m2, 12 were female, with a mean clinical follow-up of 2.7 years. Cobalt-chrome femoral and polyethylene tibial components were used. We evaluated progression to second-stage reimplantation, reinfection, and radiographic outcomes. RESULTS: At a mean follow-up of 2.7 years, 25 initial spacers were in situ (81%). Five knees retained their spacer(s) for some time (mean 1.5 years) and then underwent a second-stage reimplantation; one of the five had progressive radiolucent lines but no evidence of component migration. Three knees (10%) had PJI reoccurrence. Four had progressive radiolucent lines, but there was no evidence of component migration in any knees. CONCLUSIONS: 1.5-stage exchange arthroplasty may be a reasonable method to treat TKA PJI. At a mean follow-up of 2.7 years, there was an acceptable rate of infection recurrence and implant durability.

Combination of Lidocaine and IL-1Ra Is Effective at Reducing Degradation of Porcine Cartilage Explants.

BACKGROUND: Posttraumatic inflammation after joint injury, ranging from sprains to articular fracture, contributes to the development of arthritis, and the administration of interleukin 1 (IL-1) receptor antagonist (IL-1Ra) is a potential intervention to mitigate this response. Although IL-1Ra mitigates cartilage degenerative changes induced by IL-1, lidocaine is used for local pain management in acute joint injury. Intra-articular delivery of both drugs in combination would be a novel and possibly disease-modifying treatment. However, it is not known whether the interaction with lidocaine at clinical concentrations (1%) would alter the efficacy of IL-1Ra to protect cartilage from the catabolic effects of IL-1. HYPOTHESIS: Treatment of articular cartilage with IL-1Ra in combination with a clinically relevant concentration of lidocaine (1%) will inhibit the catabolic effects of IL-1α in a manner similar to treatment with IL-1Ra alone. STUDY DESIGN: Controlled laboratory study. METHODS: Fresh porcine cartilage explants were harvested, challenged with IL-1α, and incubated for 72 hours with IL-1Ra or a combination of IL-1Ra and lidocaine. The primary outcome was total sulfated glycosaminoglycan (sGAG) release. Additional experiments assessed the effect of storage temperature and premixing of IL-1Ra and lidocaine on sGAG release. All explants were histologically assessed for cartilage degradation using a modified Mankin grading scale. RESULTS: The combination of IL-1Ra and lidocaine, premixed at various time points and stored at room temperature or 4°C, was as effective as IL-1Ra alone at inhibiting IL-1α-mediated sGAG release. Mankin histopathology scores supported these findings. CONCLUSION: Our hypothesis was supported, and results indicated that the combination of IL-1Ra and lidocaine was as efficacious as IL-1Ra treatment alone in acutely mitigating biological cartilage injury due to IL-1α in an explant model. CLINICAL SIGNIFICANCE: The combination of IL-1Ra and lidocaine is stable when reagents are stored in advance of administration at varying temperatures, providing clinically relevant information about storage of medications. The ability to premix and store this drug combination for intra-articular delivery may provide a novel treatment after joint injury to provide pain relief and block inflammation-induced catabolism of joint tissues.

Erratum to 'Corynebacterium Total Hip and Knee Arthroplasy Prosthetic Joint Infections' [Arthroplasty Today 6 (2020) 163-168].

[This corrects the article DOI: 10.1016/j.artd.2020.03.008.].

Degenerative joint changes following intra-articular fracture are more severe in mice with T cell deficiency.

The inflammatory response to joint injury, specifically intra-articular fracture, has been implicated in posttraumatic arthritis development. However, the role of T cells in regulating the development of posttraumatic arthritis is unclear. We hypothesized that the absence of T cells would lead to less severe posttraumatic arthritis following intra-articular fracture. T cell-deficient, athymic nude, and wild-type C57BL/6NJ mice were assessed at 8 weeks following closed articular fracture. Joints were assessed using histologic scores of arthritis, synovitis, and bone morphology via micro computed tomography. Cells were profiled in whole blood via flow cytometry, and plasma and synovial fluid derived cytokines were quantified by multiplex analysis. Compared to C57BL/6NJ mice, nude mice had significantly greater histologic evidence of arthritis and synovitis. Whole blood immune cell profiling revealed a lower percentage of dendritic cells but increased natural killer (NK) cells in nude mice. Concurrently, nude mice had significantly higher levels of NK cells in synovial tissue. Concentrations of plasma interleukin 1ß (IL-1ß) and tumor necrosis factor α, and synovial fluid IL-12, IL-17, and IL-6 in both knees were greater in nude mice. Outcomes of this study suggest that T cells may play a protective regulatory role against the development of posttraumatic arthritis. Clinical significance: Lack of functional T cells exacerbated the development of posttraumatic arthritis following intra-articular fracture suggesting that critical regulators of the immune responses, contained within the T cell population, are required for protection. Future research identifying the specific T cell subsets responsible for modulating disease immunopathogenesis will lead to new therapeutic targets to mitigate posttraumatic arthritis.

Corynebacterium Total Hip and Knee Arthroplasy Prosthetic Joint Infections.

Prosthetic joint infections (PJIs) are typically caused by Staphylococcus aureus and coagulase-negative Staphylococci species. Corynebacterium species are microorganisms of the human skin and mucous membranes that are often considered contaminants when grown in culture. In the past, Corynebacterium species were often classified as diphtheroids based on growing as gram-positive rods in aerobic environments, but with advances in technology, the identification of Corynebacterium species has improved. Corynebacterium can cause infection, but there are few case reports of orthopaedic infection. We present 3 cases of total hip arthroplasty and 3 cases of total knee arthroplasty PJI caused by Corynebacterium species. We found a high failure rate of surgical treatment of Corynebacterium PJI, defined as reoperation for infection. This information adds to the limited literature on these organisms in total joint arthroplasty PJI.

Biological basis and clinical implications of acetylsalicylic acid resistance.

Acetylsalicylic acid (ASA) is effective in preventing strokes, heart attacks and vascular-related events associated with cardiovascular disease (CVD). Notwithstanding, many patients suffer recurrent events while on ASA therapy. During the past decade, a number of investigators have suggested that these patients are unresponsive to ASA or are 'ASA-resistant'. In the past, this view was met with wide skepticism. Although there is mounting evidence that ASA resistance is a real phenomenon, an understanding of its biological basis and how to measure it is still unclear. The complexity of the problem is discussed below in an attempt to stimulate clinicians and CVD researchers to give serious thought to the ASA resistance problem. It is anticipated that a better understanding of ASA resistance will help us to appreciate its relative importance and its implications in the clinical setting.

Accumulation of radiolabelled platelets and fibrin on the carotid artery of rabbits after angioplasty: effects of heparin and dipyridamole.

We investigated the dynamic accumulation of platelets and fibrin after balloon injury of the carotid arteries in rabbits in vivo. In addition, effects of heparin and dipyridamole treatment were also tested. Autologous (99m)Tc-labelled platelet and (123)I-labelled fibrin accumulation was measured at one minute intervals for 4 hours following balloon injury of the carotid artery. Platelet accumulation occurred rapidly, with an approximately 125% increase occurring within 30 min after injury. There was no further activity for up to 4 hours. This accumulation could be inhibited with an intravenous infusion of PGI2 (500 ng/kg/hr). Fibrin accumulation occurred slowly and continuously over the 4 hour measurement period. Injection of an anti-fibrin antibody inhibited fibrin accumulation. Heparin (25 U/kg/hr for 4 hrs) administration resulted in a significant 82 +/- 19% and 68 +/- 13% reduction in platelet and fibrin accumulation, respectively. This dose of heparin was associated with a 2-fold prolongation of the aPTT. Dipyridamole (0.45 mg/kg/hr for 4 hrs) resulted in a 46 +/- 12% and 70 +/- 25% reduction of platelet and fibrin accumulation, respectively. Thus, we demonstrated that the dynamics of platelet and fibrin accumulation following balloon injury in rabbits are very different. The vessel wall continues to be thrombogenic for fibrin up to 4 hours after injury even though platelet accumulation has ceased after one hour. We conclude that the local thrombotic events following balloon injury are complex and that not only platelets but also fibrin is important in regulating responses to injury.

Gender-related differences in morbidity and mortality during combined valve and coronary surgery.

BACKGROUND: Gender-related differences in morbidity and mortality are well described for coronary artery bypass grafting but are not well understood for combined valve and bypass surgery. METHODS: We reviewed retrospectively the morbidity and mortality of 1570 consecutive patients who underwent combined valve and bypass procedures at the Toronto General Hospital between January 1990 and October 2000. RESULTS: There were 1073 men (68%) and 497 women (32%). The mean ages (+/- 1 SD) of women and men were 69 +/- 9 and 68 +/- 9 years, respectively (P =.02). Of the 1570 total patients, 973 patients (62%) underwent aortic valve and coronary bypass surgery, 481 patients (31%) had mitral valve and coronary bypass operations, and 116 (7%) patients had double or triple valve and coronary bypass operations. Preoperative hypertension (P =.002), diabetes (P =.001), and atrial fibrillation (P =.001) were seen more frequently in women. Body surface area was significantly lower in women (P =.0001). At presentation, more women were in congestive heart failure (69% vs 58%, P =.001) and in New York Heart Association functional class III or IV (25% vs 19%, P =.001). Although there was no difference in the number of women with three or more diseased vessels (32% vs 38%), only 35% of women received three or more grafts compared with 44% of men (P =.001). The use of left internal thoracic grafts, although uncommon in the whole study population (36%), was less common in women than in men (26% vs 41%, P =.001). Multivariable logistic analyses for morbidity and mortality showed female gender to be an independent risk factor. Mitral valve replacement, age, left ventricular dysfunction, New York Heart Association classes III and IV, and association of tricuspid valve disease, diabetes, peripheral vascular disease, and preoperative renal failure were found to be independent risk factors for mortality. CONCLUSION: Female gender is an independent risk factor for combined morbidity and mortality during and after combined valve and coronary bypass surgery. As with isolated coronary artery bypass grafting, women undergoing combined procedures have more premorbid conditions, are more often in heart failure, had an equal incidence of triple vessel disease but received fewer grafts than men, and, therefore, were more frequently incompletely revascularized.

Coagulation disorders of cardiopulmonary bypass: a review.

BACKGROUND: Postoperative bleeding is one of the most common complications of cardiac surgery. DISCUSSION: Extensive surgical trauma, prolonged blood contact with the artificial surface of the cardiopulmonary bypass (CPB) circuit, high doses of heparin, and hypothermia are all possible triggers of a coagulopathy leading to excessive bleeding. Platelet activation and dysfunction also occur and are caused mainly by heparin, hypothermia, and inadequate protamine administration. Heparin and protamine administration based on heparin concentrations as opposed to fixed doses may reduce coagulopathy and postoperative blood loss. CONCLUSIONS: A better comprehension of the multifactorial mechanisms of activation of coagulation, inflammation, and fibrinolytic pathways during CPB may enable a more effective use of the technical and pharmaceutical options which are currently available.

Aspirin "resistance" and risk of cardiovascular morbidity: systematic review and meta-analysis.

OBJECTIVE: To determine if there is a relation between aspirin "resistance" and clinical outcomes in patients with cardiovascular disease. DESIGN: Systematic review and meta-analysis. DATA SOURCE: Electronic literature search without language restrictions of four databases and hand search of bibliographies for other relevant articles. REVIEW METHODS: Inclusion criteria included a test for platelet responsiveness and clinical outcomes. Aspirin resistance was assessed, using a variety of platelet function assays. RESULTS: 20 studies totalling 2930 patients with cardiovascular disease were identified. Most studies used aspirin regimens, ranging from 75-325 mg daily, and six studies included adjunct antiplatelet therapy. Compliance was confirmed directly in 14 studies and by telephone or interviews in three. Information was insufficient to assess compliance in three studies. Overall, 810 patients (28%) were classified as aspirin resistant. A cardiovascular related event occurred in 41% of patients (odds ratio 3.85, 95% confidence interval 3.08 to 4.80), death in 5.7% (5.99, 2.28 to 15.72), and an acute coronary syndrome in 39.4% (4.06, 2.96 to 5.56). Aspirin resistant patients did not benefit from other antiplatelet treatment. CONCLUSION: Patients who are resistant to aspirin are at a greater risk of clinically important cardiovascular morbidity long term than patients who are sensitive to aspirin.

Ethnic diversity: South Asian ethnicity is associated with increased coronary artery bypass grafting mortality.

OBJECTIVE: South Asian ethnicity might result in a higher atherosclerotic vascular risk compared with white ethnicity. However, the effect of South Asian ethnicity on clinical outcomes after cardiac surgery is unknown. Thus, we determined whether South Asian ethnicity is a predictor of a poorer outcome after coronary artery bypass grafting. METHODS: We examined data from 6177 South Asian and white patients who underwent coronary artery bypass grafting at the Toronto General Hospital from January 1994 through June 2003 and used propensity score matching techniques to analyze 917 patients from each group in more detail. Patients were matched for age, sex, body surface area, left ventricular ejection fraction, New York Heart Association class, previous cardiac surgery, number of diseased vessels, and other factors. Independent predictors of operative morbidity and mortality were determined by means of multivariate logistic regression. RESULTS: Overall operative mortality was 1.8%. Mortality was higher in South Asian patients than in white patients (2.5% vs 1.1%, P = .02). Postoperative morbidity (eg, myocardial infarction, sepsis, sternal wound infection, postoperative hospital stay, and use of inotropes) also was higher in the South Asian group. In addition to the standard independent predictors of mortality, South Asian ethnicity was an independent predictor of mortality (odds ratio, 3.1; 95% confidence interval, 1.4-6.8). CONCLUSIONS: These data indicate that South Asian ethnicity per se is an independent predictor of a poorer outcome after coronary artery bypass grafting and suggest that ethnicity is a cardiovascular risk factor that should be considered when assessing clinical outcomes preoperatively before coronary artery bypass grafting or other interventional revascularization procedures.