Surgical Technique: Robotic-Assisted 1.5-Stage Exchange Total Knee Arthroplasty for Periprosthetic Joint Infection.

A 1.5-stage exchange total knee arthroplasty for periprosthetic joint infection has been described; however, achieving a balanced and well-aligned construct can sometimes be difficult given the bony defects often encountered in these cases. The use of robotic navigation technologies allows for accurate and precise implant placement. This technique report details the utilization of robotic navigation in a 1.5-stage exchange total knee arthroplasty for periprosthetic joint infection and describes the outcome of 6 patients. This technique guide highlights how robotic technology can account for many commonly encountered bone voids, joint line identification, and component orientation, while achieving a balanced and well-aligned knee.

Relationship Between Preoperative Nutritional Status and Predicting Short-Term Complications Following Revision Total Hip Arthroplasty.

BACKGROUND: The association between malnutrition and complications following primary total joint arthroplasty is well-delineated; however, nutritional status has yet to be explored specifically in revision total hip arthroplasty (THA). Therefore, our objective was to examine if a patient's nutritional status based on body mass index, diabetic status, and serum albumin predicted complications following a revision THA. METHODS: A retrospective national database review identified 12,249 patients who underwent revision THA from 2006 to 2019. Patients were stratified based on body mass index (<18.5 = underweight, 18.5-29.9 = healthy/overweight, ≥30 = obese), diagnosis of diabetes (no diabetes, insulin-dependent diabetes mellitus (IDDM), non-insulin-dependent diabetes mellitus), and preoperative serum albumin (<3.5 = malnourished, ≥3.5 = non-malnourished). Multivariate analyses were performed using chi-square tests and multiple logistic regressions. RESULTS: In all groups including underweight (1.8%), healthy/overweight (53.7%), and obese (44.5%), those without diabetes were less likely to be malnourished (P < .001), while those with IDDM had a higher rate of malnutrition (P < .001). Underweight patients were significantly more malnourished compared to healthy/overweight or obese patients (P < .05). Malnourished patients had an increased risk of wound dehiscence/surgical site infections (P < .001), urinary tract infection (P < .001), requiring a blood transfusion (P < .001), sepsis (P < .001), and septic shock (P < .001). Malnourished patients also have worse postoperative pulmonary and renal function. CONCLUSION: Patients who are underweight or have IDDM are more likely to be malnourished. The risk of complications within 30 days of surgery following revision THA significantly increases with malnutrition. This study shows the utility of screening underweight and IDDM patients for malnutrition prior to revision THA to minimize complications.

Method for High-Yield Hydrothermal Growth of Silica Shells on Nanoparticles.

Coating processes are commonly used in materials science to protect a core or modify material properties. We describe a hydrothermal coating process using TEOS (tetraethyl orthosilicate), a widely used precursor for silica coatings, on three representative template materials (carbon nanotubes, silica, and polystyrene nanoparticles) with different properties and shapes. We compare the efficiency of previously published protocols for silica coatings at room temperature and atmospheric pressure with the hydrothermal process at 160 °C and 3 bar. The hydrothermal method achieves higher yields and thicker silica coatings with the same amount of precursor when compared to the conventional way, thus offering higher effectiveness. Furthermore, the hydrothermal coating process yields more homogeneous shells with a higher density, making hydrothermal coating the method of choice when mechanical integrity and low permeability of the coating are required.

Thermoresponsive Nanoparticles with Cyclic-Polymer-Grafted Shells Are More Stable than with Linear-Polymer-Grafted Shells: Effect of Polymer Topology, Molecular Weight, and Core Size.

Polymer brush-grafted superparamagnetic iron oxide nanoparticles can change their aggregation state in response to temperature and are potential smart materials for many applications. Recently, the shell morphology imposed by grafting to a nanoparticle core was shown to strongly influence the thermoresponsiveness through a coupling of intrashell solubility transitions and nanoparticle aggregation. We investigate how a change from linear to cyclic polymer topology affects the thermoresponsiveness of poly(2-isopropyl-2-oxazoline) brush-grafted superparamagnetic iron oxide nanoparticles. Linear and cyclic polymers with three different molecular weights (7, 18, and 24.5 kg mol-1) on two different core sizes (3.7 and 9.2 nm) and as free polymer were investigated. We observed the critical flocculation temperature (CFT) during temperature cycling dynamic light scattering experiments, the critical solution temperature (CST), and the transition enthalpy per monomer during differential scanning calorimetry measurements. When all conditions are identical, cyclic polymers increase the colloidal stability and the critical flocculation temperature compared to their linear counterparts. Furthermore, the cyclic polymer shows only one uniform transition, while we observe multiple transitions for the linear polymer shells. We link the single transition and higher colloidal stability to the absence in cyclic PiPrOx shells of a dilute outer part where the particle shells can interdigitate.

Management of Refractory Pain After Total Joint Replacement.

PURPOSE OF REVIEW: Chronic pain after total joint replacement (TJA), specifically total knee replacement (TKA), is becoming more of a burden on patients, physicians, and the healthcare system as the number of joint replacements performed increases year after year. The management of this type of pain is critical, and therefore, understanding the various modalities physicians can use to help patients with refractory pain after TJA is essential. RECENT FINDINGS: The modalities by which chronic pain can be successfully managed include genicular nerve radioablation therapy (GN-RFA), neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), and peripheral subcutaneous field stimulation (PSFS). Meta-analyses and case reports have demonstrated the effectiveness of these treatment options in improving pain and functional outcomes in patients with chronic pain after TKA. The purpose of this paper is to review and synthesize the current literature investigating the different ways that refractory pain is managed after TJA, with the goal being to provide treatment recommendations for providers treating these patients.

Synthesis of short-range ordered aluminosilicates at ambient conditions.

We report here on structure-related aggregation effects of short-range ordered aluminosilicates (SROAS) that have to be considered in the development of synthesis protocols and may be relevant for the properties of SROAS in the environment. We synthesized SROAS of variable composition by neutralizing aqueous aluminium chloride with sodium orthosilicate at ambient temperature and pressure. We determined elemental composition, visualized morphology by microscopic techniques, and resolved mineral structure by solid-state 29Si and 27Al nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Nitrogen sorption revealed substantial surface loss of Al-rich SROAS that resembled proto-imogolite formed in soils and sediments due to aggregation upon freezing. The effect was less pronounced in Si-rich SROAS, indicating a structure-dependent effect on spatial arrangement of mass at the submicron scale. Cryomilling efficiently fractured aggregates but did not change the magnitude of specific surface area. Since accessibility of surface functional groups is a prerequisite for sequestration of substances, elucidating physical and chemical processes of aggregation as a function of composition and crystallinity may improve our understanding of the reactivity of SROAS in the environment.

Theoretical and Experimental Design of Heavy Metal-Mopping Magnetic Nanoparticles.

Herein, we show a comprehensive experimental, theoretical, and computational study aimed at designing macromolecules able to adsorb a cargo at the nanoscale. Specifically, we focus on the adsorption properties of star diblock copolymers, i.e., macromolecules made by a number f of H-T diblock copolymer arms tethered on a central core; the H monomeric heads, which are closer to the tethering point, are attractive toward a specific target, while the T monomeric tails are neutral to the cargo. Experimentally, we exploited the adaptability of poly(2-oxazoline)s (POxs) to realize block copolymer-coated nanoparticles with a proper functionalization able to interact with heavy metals and show or exhibit a thermoresponsive behavior in aqueous solution. We here present the synthesis and analysis of the properties of a high molecular mass block copolymer featured by (i) a polar side chain, capable of exploiting electrostatic and hydrophilic interaction with a predetermined cargo, and (ii) a thermoresponsive scaffold, able to change the interaction with the media by tuning the temperature. Afterward, the obtained polymers were grafted onto iron oxide nanoparticles and the thermoresponsive properties were investigated. Through isothermal titration calorimetry, we then analyzed the adsorption properties of the synthesized superparamagnetic nanoparticles for heavy metal ions in aqueous solution. Additionally, we use a combination of scaling theories and simulations to link equilibrium properties of the system to a prediction of the loading properties as a function of size ratio and effective interactions between the considered species. The comparison between experimental results on adsorption and theoretical prediction validates the whole design process.

Comparative Analysis of 30-Day Readmission, Reoperation, and Morbidity Between Lumbar Disc Arthroplasty Performed in the Inpatient and Outpatient Settings Utilizing the ACS-NSQIP Dataset.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Spine surgery has been increasingly performed in the outpatient setting, providing greater control over cost, efficiency, and resource utilization. However, research evaluating the safety of this trend is limited. The objective of this study is to compare 30-day readmission, reoperation, and morbidity for patients undergoing lumbar disc arthroplasty (LDA) in the inpatient versus outpatient settings. METHODS: Patients who underwent LDA from 2005 to 2018 were identified using the ACS-NSQIP (American College of Surgeons National Surgical Quality Improvement Program) database. Regression was utilized to compare readmission, reoperation, and morbidity between surgical settings, and to evaluate for predictors thereof. RESULTS: We identified 751 patients. There were no significant differences between inpatient and outpatient LDA in rates of readmission, reoperation, or morbidity on univariate or multivariate analyses. There were also no significant differences in rates of specific complications. Inpatient operative time (138 ± 75 minutes) was significantly (P < .001) longer than outpatient operative time (106 ± 43 minutes). In multivariate analysis, diabetes (P < .001, OR = 7.365), baseline dyspnea (P = .039, OR = 6.447), and increased platelet count (P = .048, OR = 1.007) predicted readmission. Diabetes (P = .016, OR = 6.533) and baseline dyspnea (P = .046, OR = 13.814) predicted reoperation. Baseline dyspnea (P = .021, OR = 8.188) and ASA (American Society of Anesthesiologists) class ≥3 (P = .014, OR = 3.515) predicted morbidity. Decreased hematocrit (P = .008) and increased operative time (P = .003) were associated with morbidity in univariate analysis, but not in multivariate analysis. CONCLUSIONS: Readmission, reoperation, and morbidity were statistically similar between surgical setting, indicating that LDA can be safely performed in the outpatient setting. Higher ASA class and specific comorbidities predicted poorer 30-day outcomes. These findings can guide choice of surgical setting given specific patient factors.

Polymer Topology Determines the Formation of Protein Corona on Core-Shell Nanoparticles.

Linear and cyclic poly(2-ethyl-2-oxazoline) (PEOXA) adsorbates provide excellent colloidal stability to superparamagnetic iron oxide nanoparticles (FexOy NPs) within protein-rich media. However, dense shells of linear PEOXA brushes cannot prevent weak but significant attractive interactions with human serum albumin. In contrast, their cyclic PEOXA counterparts quantitatively hinder protein adsorption, as demonstrated by a combination of dynamic light scattering and isothermal titration calorimetry. The cyclic PEOXA brushes generate NP shells that are denser and more compact than their linear counterparts, entirely preventing the formation of a protein corona as well as aggregation, even when the lower critical solution temperature of PEOXA in a physiological buffer is reached.

The etiology, evaluation, and management of plantar fibromatosis.

Plantar fibromatosis (Ledderhose disease) is a rare, benign, hyperproliferative fibrous tissue disorder resulting in the formation of nodules along the plantar fascia. This condition can be locally aggressive, and often results in pain, functional disability, and decreased quality of life. Diagnosis is primarily clinical, but MRI and ultrasound are useful confirmatory adjuncts. Given the benign nature of this condition, treatment has historically involved symptomatic management. A multitude of conservative treatment strategies supported by varying levels of evidence have been described mostly in small-scale trials. These therapies include steroid injections, verapamil, radiation therapy, extracorporeal shock wave therapy, tamoxifen, and collagenase. When conservative measures fail, surgical removal of fibromas and adjacent plantar fascia is often done, although recurrence is common. This review aims to provide a broad overview of the clinical features of this disease as well as the current treatment strategies being employed in the management of this condition.