Electron emission from condensed phase material induced by fast protons†

Monte Carlo track simulation has become an important tool in radiobiology. Monte Carlo transport codes commonly rely on elastic and inelastic electron scattering cross sections determined using theoretical methods supplemented with gas-phase data; experimental condensed phase data are often unavailable or infeasible. The largest uncertainties in the theoretical methods exist for low-energy electrons, which are important for simulating electron track ends. To test the reliability of these codes to deal with low-energy electron transport, yields of low-energy secondary electrons ejected from thin foils have been measured following passage of fast protons. Fast ions, where interaction cross sections are well known, provide the initial spectrum of low-energy electrons that subsequently undergo elastic and inelastic scattering in the material before exiting the foil surface and being detected. These data, measured as a function of the energy and angle of the emerging electrons, can provide tests of the physics of electron transport. Initial measurements from amorphous solid water frozen to a copper substrate indicated substantial disagreement with MC simulation, although questions remained because of target charging. More recent studies, using different freezing techniques, do not exhibit charging, but confirm the disagreement seen earlier between theory and experiment. One now has additional data on the absolute differential electron yields from copper, aluminum and gold, as well as for thin films of frozen hydrocarbons. Representative data are presented

Defining a successful total knee arthroplasty: a systematic review of metrics of clinically important changes

Abstract Background Despite the increasing use of patient-reported outcome measures (PROMs), the methodology used to evaluate clinically significant postoperative outcomes after total knee arthroplasty (TKA) is variable. The review aimed to survey studies with identified PROM-based metrics of clinical efficacy and the assessment procedures after TKA. Methods The MEDLINE database was queried from 2008–2020. Inclusion criteria were: full texts, English language, primary TKA with minimum one-year follow-up, use of metrics for assessing clinical outcomes with PROMs, and primary derivations of metrics. The following PROM-based metrics were identified: minimal clinically important difference (MCID), minimum detectable change (MDC), patient acceptable symptom state (PASS), and substantial clinical benefit (SCB). Study design, PROM value data, and methods of derivation for metrics were recorded. Results We identified 18 studies (including 46,173 patients) that met the inclusion criteria. Across these studies, 10 different PROMs were employed, and MCID was derived in 15 studies (83%). The MCID was calculated using anchor-based techniques in nine studies (50%) and distribution techniques in eight studies (44%). PASS values were presented in two studies (11%) and SCB in one study (6%) using an anchor-based method; MDC was derived in four studies (22%) using the distribution method. Conclusion There is variability in the TKA literature with respect to the definition and derivation of measurements of clinically significant outcomes. Standardization of these values may have implications for optimal case selection and PROM-based quality measurement, ultimately improving patient satisfaction and outcomes

Patients and surgeons provide endorsement of core domains for total joint replacement clinical trials

Abstract Background Our objective in this study was to examine whether stakeholders further endorse the core domain set proposed by the Outcome Measures in Rheumatology Trials (OMERACT) total joint replacement (TJR) working group. Methods We emailed a survey to 3810 hip/knee arthroplasty patients and 49 arthroplasty surgeons at a high-volume arthroplasty center to rate the importance of each core domain (i.e., pain, function, patient satisfaction, revision surgery, adverse events, and death) and two additional domains (i.e., cost and participation). Ratings were on a 1–9 scale, with 1–3 indicating limited or no importance for patients, 4–6 being important but not critical, and 7–9 being critical. We calculated median (IQR) values and compared ratings by sex, age, and participant type using the Wilcoxon rank-sum test. Results The questionnaire was completed by 1295 patients (34%) and 21 surgeons (43%). Patient nonresponders were similar to responders in age (≥55 years, 85.7% vs. 88.6%), sex (female, 57.5% vs. 57.3%), and joint procedure (total hip replacement, 56.9% vs. 63.2%). Overall, all core domains and one noncore domain (i.e., participation) were confirmed as “critical” by both stakeholder groups. Cost was rated as only “important” but not “critical” by surgeons. A completed consensus for all the core domains persisted even when we stratified by sex, age, arthritis type, and the affected joint (knee vs. hip). We received suggestions for additional critical domains from 217 patients and 5 surgeons, prompting the inclusion of 2 research agenda items. Conclusions Our study confirmed a consensus rating of the OMERACT TJR core domain set as critical for patients. This broad endorsement should encourage the identification of candidate outcome instruments to further develop a TJR core measurement set that can harmonize reporting in TJR clinical trials

Effect of anterior approach compared to posterolateral approach on readiness for discharge and thrombogenic markers in patients undergoing unilateral total hip arthroplasty: a prospective cohort study

INTRODUCTION: The direct anterior approach (DAA) for total hip arthroplasty (THA) is considered less invasive than the posterolateral approach (PLA), possibly leading to earlier mobilization, faster recovery, and lower levels of thrombogenic markers. The purpose of the current study was to prospectively compare readiness for discharge, rehabilitation milestones, markers of thrombosis and inflammation at 6 weeks postoperatively between DAA and PLA. METHODS: A total of 40 patients (20 anterior and 20 posterolateral) were prospectively enrolled. Readiness for discharge, length of stay (LOS), and related outcomes were additionally documented. Blood was drawn at baseline, wound closure, 5-h post-closure, and 24-h post-closure for assays of interleukin-6 (IL-6), PAP (plasmin anti-plasmin), a marker of fibrinolysis, and PF1.2 (Prothrombin fragment 1.2), a marker of thrombin generation. RESULTS: Compared to the PLA group, the DAA group was ready for discharge a mean 13 h earlier (p = 0.03), while rehabilitation milestones were met a mean 10 h earlier (p = 0.04), and LOS was 13 h shorter (p = 0.02) on average. Pain scores at all study timepoints and patient satisfaction at 6 weeks were similar (p \u3e 0.05). At 24 h postoperatively, PAP levels were 537.53 ± 94.1 µg/L vs. 464.39 ± 114.6 µg/L (p = 0.05), and Il-6 levels were 40.94 ± 26.1 pg/mL vs. 60.51 ± 33.0 pg/mL (p = 0.03), in DAA vs. PLA, respectively. CONCLUSIONS: In the immediate postoperative period, DAA patients were ready for discharge before PLA patients. DAA patients had shorter LOS, a lower inflammatory response, and higher systemic markers of fibrinolysis. However, these differences may not be clinically significant. Future studies with larger study populations are warranted to confirm the validity and significance of these findings. LEVEL OF EVIDENCE: Level II, Therapeutic Study