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Human exploratory missions to Moon or Mars are considered the next steps in human space exploration. Such activities result in the exposure of humans to the space environment for long time, especially under the constraints of orbital dynamics as with increasing distances from earth quick return possibilities are ruled out. Crews on these kinds of missions must be self-sustaining in medical treatments, as environmental conditions in space, such as the influence of altered gravity, radiation or isolation, raise health issues. Therefore, astronauts may use the here presented Handheld Bioprinter as part of the first-aid strategy for in situ wound treatment. The device consists of a handle capable of holding an exchangeable "Ink Printing Unit" containing two separate gel-like components (Bioink and Crosslinker), which are extruded during a printing process through a nozzle and form a skin-cell containing bioink band-aid. For ISS experiments cell simulants were used, as in-space experiments first demonstrated the general feasibility of handheld bioprinting under space conditions. On-ground human skin cells were mixed with the biogel, printed via the handheld bioprinter and cultivated, to demonstrate the overall feasibility of the "Bioprint FirstAid" technology. Concluding results were that a mobile, handheld tool like the bioprinter shows good applicability and offers a possibility of in situ wound treatment for in-space applications. The "Bioprint FirstAid" project was coordinated by the German Space Agency at the German Aerospace Center (DLR) in Bonn and funded by the Federal Ministry for Economic Affairs and Climate Action (BMWK). • Handheld Bioprinter offers possibility for in-situ wound treatment in future in-space applications • Human skin cells proliferate in biogels after printing with handheld bioprinter • The customizable Ink-printing unit and nozzle can be tailored to specific printing demands • Bioprinter device has low susceptibility to failure, has a robust design, no electronics, and maintenance-free mechanics • German Astronaut Matthias Maurer conducted the Bioprinting experiment successfully on board the ISS [ABSTRACT FROM AUTHOR]

The accurate and high-throughput generation of kinetic data for combustion detailed chemical kinetic models remains a challenge given the large size of these models. For large organic molecules, the majority of kinetic data of the kinetic models are estimated using quantitative structure activity relationships within reaction classes and reaction rate rules approaches. In this work, we question the limits of the rate rule approach for the isomerization reaction classes, using electronic structure calculations and reaction rate theories. Systematic calculations were performed to investigate the effect of the size and the degree of branching of alkyl radicals on the rate coefficients and their consequences on the rate rule approach. Our computed kinetic data show that when the size of alkyl group is increased, the rate coefficients remains close to each other. This allows the use of methyl as representative models of larger alkyl groups to investigate the influence of increasing the degree of branching. The computed rate coefficients for 1,3- and 1,4-H-atom shifts show that the increase of the branching level, with spectator methyl groups in the transition state cyclic structure can strongly increase the rate coefficients, up to several orders of magnitude. Consequently, a single rate rule is not feasible for any degree of branching of a reaction belonging to the same isomerization reaction class. As variation in rate coefficients are important, this would lead to an explosion of the number rate rules as a function of branching in 5-, 6-, and 7-membered cyclic transition states. A new approach is demonstrated and proposed where model transition states are tabulated, and methyl groups are assumed as alkyl groups and all combinations of substitutions in the model TSs, for a given reaction class, are included in a table with associated ab initio rate coefficients. The automation of the construction of such tables is possible and could be an interesting high-throughput / high-accuracy alternative to on-the-fly ab initio calculations of kinetic parameters. [ABSTRACT FROM AUTHOR]

Telemedicine has become a critical component in the evaluation and management of patients with shoulder pathology. However, the interobserver reliability of findings on virtual physical examination relative to in-person evaluation is unclear. The purpose of this study was to determine the reliability of prerecorded video telemedicine for the evaluation of shoulder pathology compared with traditional in-person physical examination. New patients with unilateral shoulder pain presenting to a single-surgeon shoulder clinic were recruited between July and November 2020. In 1 visit, patients were evaluated with standardized in-person and video-guided telemedicine physical examinations in randomized order. Patients were evaluated for range of motion (ROM) and symptoms including pain, weakness, and apprehension. The telemedicine examination was recorded and consisted of a video guide displaying self-directed shoulder examination maneuvers that patients performed during remote coaching by an independent non-physician observer. The in-person physical examination was performed by the treating physician. The telemedicine videos were evaluated by two independent observers for interobserver reliability. The treating physician subsequently evaluated the telemedicine videos after a minimum two-month washout period for intraobserver reliability and intra-platform reliability. Interobserver and intraobserver reliability analyses were conducted using Kuder-Richardson formula 20 (KR-20). Specificity and likelihood ratios were calculated with P <.05 representing statistical significance. A total of 32 patients (17 male and 15 female patients; average age, 50.2 ± 16.2 years) were included in the analysis. Overall Kuder-Richardson formula 20 (KR-20) reliability across 40 physical examination maneuvers was 0.391 ± 0.332 (76.4% ± 15.4% agreement) between the in-person and telemedicine examinations. Telemedicine maneuvers examining ROM limitations had the highest degree of reliability, sensitivity, specificity, and likelihood of also producing a positive finding on the in-person examination (0.700 ± 0.114, 66.5%, 81.0%, and 6.06, respectively). Telemedicine maneuvers identifying apprehension associated with glenohumeral instability were found to have the lowest reliability, sensitivity, and likelihood of producing a positive finding on the in-person examination (0.170 ± 0.440, 23.5%, and 0.518, respectively). All patients were satisfied with their telemedicine experience. The overall reliability of a non-physician–directed video-guided telemedicine examination ranged from unacceptable to good. Shoulder ROM limitations identified during the telemedicine examinations were found to be the most reliable, whereas evaluations of instability were found to be the least reliable. Although initial telemedicine evaluation by a non-physician may be appropriate for ROM evaluation, in-person physician evaluation is recommended to confirm suspected diagnoses, especially if clinical concern for shoulder instability exists. Alternative methods of telemedicine delivery should be explored to improve the reliability of self-directed physical examination maneuvers. [ABSTRACT FROM AUTHOR]

Recent studies indicate that outpatient total shoulder arthroplasty (TSA) is cost-effective and may have a low complication rate similar to inpatient TSA. However, existing studies have included younger patient cohorts who typically possess fewer medical comorbidities. Patients aged ≥65 years are commonly enrolled in Medicare, which has traditionally designated TSA as an inpatient-only procedure. The purpose of this study was to compare surgical complication rates and 90-day readmission rates between inpatient and outpatient TSA performed in adults aged ≥65 years. Medical records for all patients aged ≥65 years who underwent primary anatomic or reverse TSA by a single surgeon from July 2015 to May 2020 were reviewed. Patients were preselected for outpatient or inpatient surgery based on lack of significant cardiopulmonary comorbidities and patient preference. Demographics, body mass index (BMI), and American Society of Anesthesiologists (ASA) scores were collected in addition to emergency department (ED) visits and readmissions within 90 days of the index surgery. Relationships among frequency and types of complications and surgical setting (inpatients vs. outpatient) were assessed. Complication rates and demographic variables between inpatient and outpatient procedures were compared. Logistic regressions were performed to account for interacting predictor variables on the odds of having complications. A total of 145 shoulders (138 patients; 95 male, 43 female) were included in the analysis, of which 98 received inpatient TSA and 47 received outpatient TSA. Average age was 75.5 ± 7.2 for inpatient TSA and 70.5 ± 4.5 for outpatient TSA (P <.001). Patient age (P <.001), ASA score ≥3 (P <.001), and reverse TSA (P =.002) were significantly positively correlated with receiving inpatient surgery. There were 16 complications (16.3%) in the inpatient group and 9 complications (19.1%) in the outpatient group (P =.648). There were no significant differences in the frequency of postoperative complications, return to the ED, or reoperations between inpatient and outpatient procedures (P >.05). Each 1-year increase in age increased the predicted odds of having a surgical complication by 14% (odds ratio = 1.14; P =.021), irrespective of surgical setting. Those who underwent inpatient TSA had a significantly higher frequency of 90-day readmission (inpatient=16, outpatient=1; P =.034). Postoperative complications and ED returns were not significantly different between inpatient and outpatient TSA. Each 1-year increase in age increased the odds of postoperative surgical complications by 14%, regardless of surgical setting. Outpatient TSA was found to be safe for appropriately selected patients aged ≥65 years, and re-evaluation of TSA as an inpatient-only procedure should be considered. [ABSTRACT FROM AUTHOR]

Introduction: It is accepted dogma in total knee arthroplasty (TKA) that resecting the posterior cruciate ligament (PCL) increases the flexion-space by approximately 4mm. Unfortunately, this doctrine is based on historical studies of limited size with variable technique. The aim of this study was to determine the effect of PCL-resection on in vivo tibiofemoral joint space dimensions in a cohort of modern TKAs.Methods: Tibiofemoral joint space measurements were made during 129 standardized TKAs by two arthroplasty surgeons. A medial parapatellar approach, computer navigation and provisional bone cuts were performed in all cases with particular attention to preserving PCL integrity. The tibiofemoral gap was measured with a calibrated tension device at extension, 45-degrees, and 90-degrees before and after complete PCL-resection.Results: 51% of patients were female (66/129) with mean age and BMI of 69.5 years and 34.2 kg/m2, respectively. After PCL-resection, mean change in center joint space dimension increased 0.33mm at extension, 0.95mm at 45-degrees, and 1.71mm at 90-degrees (P < .001). The 90-degree flexion-space opened ≥4mm in only 10% of patients. Dividing the flexion-space change by femoral implant dimension to account for patient size, the flexion-space at 90-degrees significantly increased more in females compared to males (P = .020).Conclusion: The tibiofemoral joint space increased progressively from extension to mid-flexion through deep-flexion after PCL-resection, yet was substantially less than reported in historical studies. However, large variation in flexion-space opening was observed with some patients failing to increase the flexion-space whatsoever with PCL-resection. This runs counter to conventional TKA understanding and should be considered in modern surgical education.Level Of Evidence: Therapeutic Level III. [ABSTRACT FROM AUTHOR]

Background: Clinicians commonly utilize intra-articular injections to treat symptomatic primary arthritis. Steroid injections are common yet have immune-modulating effects and can alter gene expression which may delay definitive arthroplasty and further damage cartilage. Nonsteroidal anti-inflammatory injections may offer a safer profile due to their differing mechanism of action; however, there is a relative dearth of information regarding their efficacy. This noninferiority study compares the effectiveness of triamcinolone vs ketorolac in treating symptoms of moderate to advanced primary osteoarthritis of the hip and knee.Methods: In total, 110 patients (52 hips and 58 knees) with moderate to severe radiographic primary osteoarthritis of the hip or knee were randomized in a double-blinded study to receive an ultrasound-guided intra-articular injection of ketorolac or triamcinolone. Patient-reported outcome measures were collected pre-injection and at 1 week, 1 month, and 3 months.Results: For hips and knees, intra-articular injections with either ketorolac or triamcinolone led to statistically significant improvements in patient-reported outcome measures. The treatment effect size was largest at 1 week and decreased over time. Primary analysis of variance comparisons revealed no significant differences between ketorolac and triamcinolone. For knee injections, post hoc secondary analysis suggests slight added durability in the triamcinolone group. Adverse effects were minimal with both interventions.Conclusion: Intra-articular ketorolac injections provide comparable improvement to triamcinolone for primary hip and knee osteoarthritis. Ketorolac is an additional low-cost option for conservative management of primary osteoarthritis, and due to its differing mechanism of action, it may not propagate additional cartilage damage or preclude from early surgical intervention if unsuccessful.Trial Registration Number: NCT04441112. [ABSTRACT FROM AUTHOR]

Background: Extensor mechanism (EM) disruption after total knee arthroplasty is a catastrophic complication. Reconstruction using monofilament polypropylene mesh (Marlex Mesh; CR Bard, Franklin Lakes, NJ) has emerged as the preferred treatment, but reports are limited to the designing institution. This study describes a nondesigner experience and compares 2 postoperative immobilization strategies: long leg cast vs knee immobilizer.Methods: A retrospective review of consecutive EM reconstructions between 2012 and 2019 was performed. Primary repairs and allograft reconstructions were excluded, leaving 33 knees (30 patients) who underwent Marlex reconstruction. Mean time from disruption to reconstruction was 14 months, and 14 of 33 (42%) had previous repair or reconstruction attempts. The mean age was 69 years, and mean body mass index was 35 kg/m2. Postoperatively, extension was maintained using a knee immobilizer in 19 of 33 (58%) patients, whereas 14 of 33 (42%) patients were long leg casted. Kaplan-Meier analysis determined all-cause survivorship free of mesh failure.Results: At mean 25-month follow-up, 19 of 33 (58%) EM reconstructions were functioning. Excluding explanted infections (5 recurrent and 2 new), 19 of 26 (73%) EM reconstructions were in situ. Six-year survivorship was 69% and not influenced by immobilization type (cast: 67%, immobilizer: 71%; P = .74). Extensor lag was not associated with immobilization type, improving from a mean preoperative lag of 43° to a mean postoperative lag of 9°. Among successes, University of California at Los Angeles activity and Knee Injury and Osteoarthritis Outcome Score - Joint Replacement score improvements exceeded minimal clinically important difference (2.2-3.3 and 52.5-64.0, respectively).Conclusion: Marlex mesh EM reconstruction is a durable and reliable treatment with acceptable clinical results achievable outside the designer institution. Provided sufficient duration and compliance with postoperative immobilization, similar outcomes can be obtained with either a cast immobilizer or a knee immobilizer. [ABSTRACT FROM AUTHOR]

Background: Adequate interference fit and mechanical stability through optimal surgical technique are essential to prevent subsidence and loosening in cementless total hip arthroplasty. The purpose of this study is to determine the effect of surgical technique on radiographic subsidence and subsequent stability of a modern taper-wedge cementless stem.Methods: A retrospective review of 250 consecutive cementless primary total hip arthroplasties performed by 2 surgeons was completed. Surgeon A vigorously broached, maximizing the mediolateral stem dimension and confirmed final broach stability with a torsional test, whereas Surgeon B did not. All patients received identical taper-wedge stems. Preoperative bone morphology (canal flare index), postoperative subsidence, and canal fill were radiographically assessed.Results: Canal flare index was not different between groups (P = .747). There was significantly less subsidence at 1 month for Surgeon A (0.3 vs 1.3 mm, P < .001). Additional subsidence at 1 year occurred in only 0.8% of Surgeon A (1/119) compared to 51.6% of Surgeon B stems (33/64, P < .001). Surgeon technique and canal fill measured at 60 mm below the lesser trochanter were the only variables predictive for subsidence, where Surgeon A and B had a mean canal fill of 95% and 86%, respectively. Surgeon B had 2 cases of aseptic loosening (2%) at 2 and 3 years postoperatively.Conclusion: These observations support that maximizing mediolateral canal fill and avoiding under-sizing the femoral implant with meticulous broaching technique minimizes subsidence and optimizes stability of modern cementless taper-wedge stems. Failure to optimize canal fill with appropriate broaching and surgical technique may predispose femoral components to failure from aseptic loosening. [ABSTRACT FROM AUTHOR]

Periprosthetic joint infection represents a serious complication following total knee arthroplasty. In the setting of chronic or age-indeterminate total knee arthroplasty infection, a 2-staged approach has been traditionally the preferred method of treatment over single-stage debridement and reimplantation debridement or debridement, antibiotics and implant retention. Two-stage is the preferred treatment method in North America and has demonstrated better overall success than the single stage techniques. Additionally, the 2-stage method is the preferred treatment for difficult to treat pathogens as well as in patients who have already undergone a previous revision procedure. An articulating prefabricated antibiotic spacer has entered the armamentarium of 2-stage revision knee surgery, and has demonstrated comparable results to custom and static spacers in terms of the primary goal of infection control. Importantly, the potential for enhanced mobility and function hold promise by safely providing a more "livable" knee during the convalescent period prior to definitive reimplantation. [ABSTRACT FROM AUTHOR]

Surgical exposure of the glenoid after previous coracoid process transfer is technically challenging as a result of distorted anatomy, obliterated soft-tissue planes, and adhesive scar tissue, which poses additional risk to adjacent neurovascular structures. The purpose of this article is to present a technique for glenoid exposure following coracoid transfer that involves tenotomy of the conjoint tendon to minimize the risk for neurovascular injury while leaving the well-healed coracoid bone graft in place. [ABSTRACT FROM AUTHOR]

Background: Evidence suggests approximately 40% of intramedullary (IM) canals are culture positive at resection for infected knee arthroplasty. While commonly utilized, no clinical data on the efficacy of antibiotic-eluding IM dowels exist. We quantified treatment success with and without the use of antibiotic-eluding IM dowels in two-stage treatment of periprosthetic knee infection using static and articulating antibiotic cement spacers.Methods: 109 consecutive patients who underwent two-stage treatment for periprosthetic knee infection were reviewed. Treatment failure, defined as repeat resection before reimplantation or recurrent infection within 6 months of reimplantation, was evaluated based on spacer type and use of IM dowels, accounting for infection type and systemic host and local extremity grade.Results: After exclusions for confounds, articulating spacers without IM dowels were used in 49 (57.7%) cases, articulating spacers with IM dowels in 14 cases (16.5%), and static spacers with IM dowels in 22 (25.9%) cases. Treatment success regardless of infection classification was 85.7% for articulating spacers with IM dowels, 89.8% for articulating spacers without IM dowels, and 68.2% for static spacers with IM dowels (P = .074). In chronically infected poor hosts with compromised extremities, treatment success remained highest in patients with articulating spacers with (90.9%) or without (92.9%) IM dowels compared with static spacers with IM dowels (68.4%) (P = .061).Conclusion: Findings suggest that the use of IM dowels did not enhance infection eradication above and beyond that observed for articulating spacers alone, including in the worst cases involving chronically infected poor hosts with compromised extremities. [ABSTRACT FROM AUTHOR]