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To determine if a reduced secondary operation rate offsets higher implant charges when utilizing suture button fixation for syndesmotic injuries.Retrospective cohort study.Single, urban, Level 1 trauma center.Three-hundred twenty-seven (N=327) skeletally mature patients with rotational ankle fractures (OTA/AO type 44) necessitating concurrent syndesmotic fixation.Suture button or solid 3.5mm screw syndesmotic fixation.To compare implant charges with secondary operation charges based on differential implant removal rates between screws and suture buttons.Patients undergoing screw fixation were older (48.8 vs 39.6 years, p0.01), had more ground level fall mechanisms (59.3% vs 51.1%, p =0.026), and sustained fewer 44C type injuries (34.7% vs 56.8%, p=0.01). Implant removal occurred at a higher rate in the screw fixation group (17.6% vs 5.7%, p=0.005). Binomial logistic regression identified non-smoker status (B=1.03, p=0.04) and implant type (B=1.41, p=0.008) as factors associated with implant removal. Adjusting for age, the NNT with a suture button construct to prevent one implant removal operation was 9, with mean resulting additional implant charges of $9747 ($1083/case). Backwards calculations using data from previous large studies estimated secondary operation charges at approximately $14220, suggesting a potential 31.5% cost savings for suture buttons when considering reduced secondary operation rates.A reduced secondary operation rate may offset increased implant charges for suture button syndesmotic fixation when considering institutional implant removal rates for operations occurring in tertiary care settings. Given these offsetting charges, surgeons should utilize the syndesmotic fixation strategy they deem most appropriate in their practice setting.Economic Level III. See Instructions for Authors for a complete description of levels of evidence.

To perform a systematic review of return to play (RTP) and return to previous level of performance (RPP) in competitive overhead athletes after SLAP repair to identify factors associated with failure to RTP.Systematic review was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Review was registered with PROSPERO International prospective register of systematic reviews (CRD42020215488). Inclusion criteria were literature reporting RTP or RPP following SLAP repair in overhead athletes were run in the following databases: PubMed/MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Google Scholar. Categories for data collection for each full article included (1) article information; (2) patient demographics; (3) surgical techniques; (4) level of competition; (5) rotator cuff treatment; (6) player position; (7) patient-reported outcome measures; and (8) RTP and RPP rates. The Methodological Index for Non-randomized Studies checklist was used to evaluate quality of all included studies.Eight studies with 333 subjects were identified. Overall RTP and RPP rates were 50% to 83.6% and 35.3% to 64%, respectively. Patients with surgically treated rotator cuff pathology had lower RTP (12.5%-64.7%) rates compared with those without (80.0%-83.6%). Professional athletes had similar RTP rates (62.5%-81.5%) compared with high-school (75.0%-90.0%) and college athletes (12.5%-83.3%). However, professional athletes demonstrated the lowest relative range of reported RPP rates (27.7%-55.6%). Pitchers had lower RTP (62.5%-80.0%) and RPP (52.0%-58.9%) compared with position players (91.3% RTP, 76.3%-78.2% RPP).Studies reviewed reported moderate RTP and RPP rates following SLAP repairs in competitive overhead athletes. Those with associated rotator cuff tear requiring treatment, and baseball pitchers were less likely to RTP and RPP. Professional athletes had similar RTP to an amateur; however, they were less likely to RPP.Level IV, systematic review of Level III-IV studies.

Chemical weathering is an important indicator of past climate and redox state [1-3]. On Mars, weathering profiles may have formed in basaltic sediments or volcanic ash that were altered by surface water and were subsequently buried and persevered in the geological record. Orbital remote sensing of the global Martian surface has detected dioctahedral clay minerals within Noachian layered sedimentary rocks, which are consistent with the precipitation-driven pedogenic weathering of mafic sediments [1]. Noachian sedimentary rocks with spectral signatures of subaerial weathering have been detected in thousands of locations across the surface of Mars [1,4].In this study, orbital imagery, spectroscopy, topographic data and crater chronology are investigated to explore the geologic context, stratigraphy, and relative age of >200 weathering profiles across the Martian southern highlands [4]. The youngest might be Early Hesperian, although virtually all are older than 3.7 Ga. Weathering profiles exist across a wide range of elevations (>11 km), from −5 to 6 km, indicating they developed as a result of top-down, precipitation-driven chemical weathering and this was a global phenomenon. We discovered that almost all exposures show a similar, single stratigraphic relationship of Al/Si material overlying Fe/Mg clays, rather than several, interbedded mineralogy transitions. This points to either a single warming event or, more likely, a chemical resetting scenario in which the most recent event overprints the prior weathering pattern. The time necessary to develop a typical profile is estimated to be several million years, which corresponds to only a portion of the Noachian period. As a result, the broad estimated age span ~700–800 My appears incompatible with a single climate excursion. We consider that the presence of weathering profiles in many geologic units at a wide range of ages over a long period of geologic time and at a wide range of elevations, suggests a top-down, precipitation-driven chemical weathering was global in scope. Fe-mobility was a crucial component of chemically weathering, which happened geologically rapidly under anoxic conditions that might potentially warm the martian surface via reduced greenhouse gas. Collectively, these results indicate that multiple weathering episodes are driven by multiple reduced greenhouse conditions on ancient Mars.[1] Carter et al. 2015, Icarus, 248, 373-382. [2] Bishop et al., 2018, Nature Astronomy, 2(3), 206-213. [3] Liu et al., 2021, Nature Astronomy,5(5), 503-509.[4] Ye & Michalski, Communication Earth & Environments, 3(1), 1-14.

This study provides a comprehensive Raman spectral characterization of nontronite and glauconitenontronite mixed-layer phases from seafloor hydrothermal fields. These 2:1 phyllosilicates, which show isomorphous cation exchange between Mg2++Fe2+ and Fe3++Al3+ in the dioctahedral sheets, exhibit three diagnostic Raman peaks in the low wavenumber region (v1 ~241–257 cm−1; v2 ~600–606 cm−1; v3 ~690 cm−1), and one peak at ~3548–3570 cm−1 (v4). With increasing (Mg2++Fe2+)oct, the presumed stretching band of octahedral OH-O bonds (v1) is displaced to a higher wavenumber, whereas the stretching band of tetrahedral Si-O-Si bonds (v2) is shifted to a lower wavenumber. Peak v4, which relates to O-H bonds of hydroxyls linked to octahedral cations, shows a downshift with increasing (Mg2++Fe2+)oct. The band v4 can be mathematically fitted by three bands, two of which strongly correlate with the cation occupancy in the octahedral sheets; i.e., vibrations of hydroxyls linked to triva-lent cations (Fe3+ and Al3+) are mainly represented by a band at ~3560–3573 cm−1, whereas divalent cations (Mg2+ and Fe2+) mainly contribute to a band at ~3538–3540 cm−1. This result is consistent with theoretical considerations for dioctahedral phyllosilicates, which predict for the incorporation of Mg2+ and Fe2+ a weakening/lengthening of O-H bonds in the OH groups, accounting for a downshift of the O-H vibrations. Hence, this is one of the first studies that trace how even subtle chemical modifications in phyllosilicates influence Raman spectral features. The reported findings have implications for mineral identification and provenance analysis, such as during surface exploration on Mars, where compositionally diverse phyllosilicates occur.

Despite a consensus view that Mars has been cold and icy throughout the Amazonian (3 billion years ago until present), the Zhurong rover has provided striking evidence for aqueous resurfacing processes in and around the landing site during this time period. Here, we report a close association of magmatism (i.e. dikes) and several distinctive landforms (e.g. mud volcanoes and troughs) indicating that ground ice in the Vastitas Borealis Formation (VBF) was thawed by the magma heating causing the collapse of VBF to form distinct landforms and alteration mineralogy. This collapse released pressurized meltwater and mud, producing mud volcanoes and muddy water. Upon freezing, the slurry materials were further buried by younger porous sediments. Freezing of the upwelled chemical-rich groundwater potentially circulated by cryosuction produced large crystals of sulphate (probably selentite) unlike sulphates previously identified on Mars, evidencing relatively young aqueous alteration on Mars driven by magma-ice interactions.

The relatively well-preserved ancient crust of Mars provides a natural window into early planetary evolution not available on Earth due to sustained tectonic recycling and erosion on this planet. Mars has generally been considered a one-plate, basaltic planet though recent evidence suggests magmatic evolution resulting in felsic crust might have occurred sporadically1–6 and some structural data potentially support early forms of regional subduction7. Here we show multiple lines of evidence for diverse volcanism and complex volcanotectonics in the southern highlands of Mars within and around the Eridania basin. Infrared remote sensing reveals bimodal volcanism consisting of olivine-bearing basalts and voluminous, widespread dacitic (64-69% SiO2) volcanic deposits. The diverse igneous compositions are associated with an extraordinary number and morphological range of volcanic structures including domes, stratovolcanoes, calderas and pyroclastic shields. Tectonic escarpments of comparable morphology, length (100s-1000s of km) and height (1-3 km) to convergent tectonic boundaries on Earth are observed to overthrust hydrated crust in the Eridania region, including weathered ash8 and seafloor hydrothermal deposits9. Multiple lines of evidence point to a substantial, vigorous episode of volcanotectonics in the Eridania region (Terras Cimmeria and Sirenum) 3-4 billion years ago that could shed light on processes which operated on the early Earth, before a recognizable form of plate tectonics took hold on this planet c.a. 3 billion years ago10. The various environments associated with emergent volcanoes within and around the large (~2 x 105 km3) Eridania sea are analogous to all widely discussed scenarios for the origin of life for Earth11,12.

To determine the effect of travel distance on achieving the minimal clinically important difference (MCID) on patient-reported outcome measures (PROMs) at least 1 year after arthroscopic rotator cuff repair (RCR).Patients undergoing primary arthroscopic RCR with a minimum 1-year follow-up at a high-volume tertiary referral center between May 2017 and June 2019 were retrospectively reviewed. Patients were divided into two groups: driving distance of50 miles from the institution (referral group) and50 miles (local group). American Shoulder and Elbow Score (ASES), Single Assessment Numeric Evaluation (SANE) score and Constant score at minimum 1-year follow-up were assessed. Chi-square analysis was used to analyze achievement of MCID on any PROM. Subgroup analysis by tear complexity (1 tendon vs.2 tendons torn) was conducted. Logistic regression was performed to determine whether travel distance and other variables of interest had an effect on achieving MCID.Of 996 patients reviewed, 385 patients (38.7%) had minimum 1-year follow-up. Of these, 62 (16%) traveled50 miles to their orthopedic provider, and 212 (55%) had a complex tear. MCID for at least one PROM was reached by 305 (94%) patients in the local group and 56 (90%) patients in the referral group. There was no significant difference between groups in reaching MCID for any PROM. Subgroup analysis by tear complexity revealed no significant difference in preoperative PROMs or achieving MCID postoperatively between referral groups. There was no significant difference between groups when controlling for age, sex, adjusted gross income (AGI), primary health insurance, tear chronicity, and tear complexity.When controlling for age, sex, AGI, primary health insurance, tear chronicity, and tear complexity, distance to a high-volume shoulder arthroscopy surgery center did not have an effect on achieving the MCID for any PROM at least 1 year after arthroscopic RCR.Level III, retrospective cohort study.

A 57-year-old man with diabetes mellitus presented with a 4-day history of left palm pain out of proportion, with swelling, erythema, and dense median and ulnar nerve distribution sensory changes. Magnetic resonance imaging with and without contrast revealed diffuse hand edema and myonecrosis. The patient was treated surgically because the examination was concerning for acute carpal tunnel syndrome and ulnar nerve compression. Spontaneous diabetic myonecrosis is a complication of diabetes mellitus that can be confused with several other conditions. It presents as acute-onset painful swelling in any muscle, and in the hand, may cause compressive neuropathies that necessitate surgical intervention.

Disturbances such as tropical cyclones and insect pests in mangroves can cause defoliation, tree mortality, and other changes in ecosystem processes. Understanding the resistance and resilience of mangroves to disturbance is critical to developing strategies for conservation. However, most studies apply multi-temporal optical data which have limited power to detect structural changes, especially for forests with complex architectures. We combined multispectral Sentinel-2 (S2) images and airborne LiDAR datasets to assemble a comprehensive view of the effects of two disturbance events (a moth pest and a super-typhoon) on mangroves in Mai Po, Hong Kong. A series of normalized difference vegetation index (NDVI) estimates derived from S2 data indicated changes of greenness before and after the moth pest and typhoon events. An object-based stratification method was applied with LiDAR data to separate the overstory and understory to distinguish stratum changes. The results showed that moth larvae were more likely to encroach leafy mangroves of Avicennia marina. Double-layered and single-layered short mangroves have better resistance to typhoons than younger tall mangroves without understory beneath. NDVI recovered rapidly after three to six months post-disturbance but significant changes in canopy structures were found from the LiDAR data. Canopy gaps increased both in size and quantity in mature overstory areas, likely benefitting the growth of the understories beneath. Finally, the understory area grew resulting in a transition from single-layered to double-layered structures. The combination of multi-temporal LiDAR and multispectral data used here highlights the power of complementary remote sensing products in documenting mangrove ecosystem processes.

Context. Olivine responds to space weathering in the fastest and most profound way, which results in significant space weathering spectral alteration effects (SWSAEs) on airless silicate bodies. Although Mg-rich olivine (Fa10) has been subjected to extensive studies, SWSAEs of Fe-rich (Fa# > 20) or Fa-dominant (Fa# ⩾ 50) olivine are still poorly understood. Aims. We aim to systematically characterize the space weathering effects and the associated spectral alterations of Fe-rich olivine on the surface of Phobos and the Moon. Methods. We conducted nanosecond pulsed laser irradiation experiments on a set of synthetic Fe-rich olivine (Fa29, Fa50, Fa71, and Fa100) with energy levels simulated for Phobos and the Moon and analyzed the irradiated olivine for microscopic characteristics and near-infrared (NIR) and Raman spectroscopy. Results. Micron-level thick alteration layers are found in Fa100 compared to those hundreds of nanometers thick in Fa29, Fa50, and Fa71. With increasing irradiation energy levels and Fa# values, nanophase iron (np-Fe0) particles increase in size but decrease in quantity. The np-Fe0 formed via in situ decomposition are ubiquitously present, while those formed via vapor deposition are primarily found in Fa29 but rarely in Fa# ⩾ 50. The size fraction of intermediate (10–40 nm) and large (40–60 nm) np-Fe0 proportionally increases with Fa# values. The NIR spectra of weathered olivine show darkening over reddening in most cases, but Fa100 under the most irradiated condition shows brightening-reddening spectral effects. The Raman spectra of weathered olivine show a reduction in intensity without peak shifts. Conclusions. The Fa# values of olivine are a more critical factor in controlling the SWSAEs on Phobos than those on the Moon. If Phobos and Deimos contain substantial Fe-rich or Fa-dominant olivine, similar to Mars, thick alteration rims and large np-Fe0 formed via space weathering may cause darkening-reddening and potentially brightening-reddening spectral effects on the Martian moons.

Background Proposed benefits of modularity for femoral revisions in total hip arthroplasty (THA) include more precise biomechanical restoration and improved stability, but this has not been proven with use of a splined, tapered design. This study’s purpose is to compare (1) complication rates, (2) functional outcomes, and (3) radiographic measures of subsidence, offset, and leg length discrepancy with the use of modular vs monoblock splined, tapered titanium stems in revision THA. Methods We retrospectively reviewed 145 femoral revisions with minimum 2-year follow-up (mean, 5.12 years; range, 2-17.3 years). Patients receiving a modular (67) or monoblock (78) splined, tapered titanium stem for femoral revision were included. Results There were no statistically significant differences in rates of reoperation (22.3% vs 17.9%; P = .66), intraoperative fracture (9.0% vs 3.8%; P = .30), postoperative fracture (3.0% vs 1.3%; P = .47), dislocation (11.9% vs 5.1%; P = .23), or aseptic loosening (4.5% vs 6.4%; P = .73) between the modular and monoblock cohorts, respectively. There were similar results regarding subsidence >5 mm (10.4% vs 12.8%; P = .22), LLD >1 cm (35.8% vs 38.5%; P = .74), restoration of hip offset (−5.88 ± 10.1 mm vs −5.07 ± 12.1 mm; P = .67), and Harris Hip Score (70.7 ± 17.9 vs 73.9 ± 19.7; P = .36) between groups. Multivariate regression showed no differences in complications (P = .44) or reoperations (P = .20) between groups. Conclusion Modular and monoblock splined, tapered titanium stems demonstrated comparable complication rates, functional outcomes, and radiographic parameters for femoral revisions. However, a limited number of patients with grade IIIB or IV femoral bone loss received a monoblock stem. Future investigations are required to determine whether modularity is beneficial for more complex femoral defects.

Study Design: Retrospective cohort study. Objective: To assess the effect of diabetes mellitus (DM) on clinical and radiographic outcomes in patient with degenerative spondylolisthesis undergoing posterior lumbar spinal fusion. Methods: Analysis of patients who underwent open posterior lumbar spinal fusion from 2011 to 2018. Patients being medically treated for DM were identified and separated from nondiabetic patients. Visual analogue scale Back/Leg pain and Oswestry Disability Index (ODI) were collected, and achievement of minimal clinically important difference was evaluated. Lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and PI-LL difference were measured on radiographs. Rates of postoperative complications were also collected. Results: A total of 850 patients were included; 78 (9.20%) diabetic patients and 772 (90.80%) nondiabetic patients. Final PI-LL difference was significantly larger ( P = .032) for patients with diabetes compared to no diabetes, but there were no other significant differences between radiographic measurements, operative time, or postoperative length of stay. There were no differences in clinical outcomes between the 2 groups. Diabetic patients were found to have a higher rate of discharge to a facility following surgery ( P = .018). No differences were observed in reoperation or postoperative complication. Conclusions: While diabetic patients had more associated comorbidities compared with nondiabetic patients, they had similar patient-reported and radiographic outcomes. Similarly, there are no differences in rates of reoperation or postoperative complications. This study indicates that diabetic patients who have undergone thorough preoperative screening of related comorbidities and appropriate selection should be considered for lumbar spinal fusion.

Category: Other Introduction/Purpose: In our city, the COVID-19 pandemic led to a shelter-in-place ordinance, job loss, gym closures, and employees working from home. As a result, individuals adjusted their daily activities and exercise routines, potentially impacting the burden of foot and ankle disease. The purpose of the present study was to compare diagnoses made in an orthopaedic foot and ankle clinic during the months of the COVID-19 pandemic to diagnoses made during the same months of the previous year. Methods: A retrospective review of new patients presenting to our group of four fellowship-trained orthopaedic foot and ankle surgeons was performed. Patients in the COVID-19 group presented between March 22, 2020 (the beginning of our shelter-in- place ordinance) and July 1, 2020. Patients in the control group presented during the same period of the previous year. Final diagnosis was characterized. Chronicity was classified as acute (symptom duration 1 month). Diagnoses were classified as fractures (e.g. ankle fractures, foot fractures) or activity-related (e.g. plantar fasciitis, ankle sprain). Pearson Chi-squared tests were performed to assess for differences in patient presentations between the COVID-19 and control periods. Results: A total of 1,409 new patient visits were reviewed with 449 visits in the COVID-19 group and 960 visits in the control group. The COVID-19 group had a significantly higher proportion of ankle fractures (8.7% versus 5.4%; p=0.020) and stress fractures (4.2% versus 2.2%, p=0.031), but a smaller proportion of Achilles tendon ruptures (0.7% versus 2.5%; p=0.019). Similarly, the COVID-19 group had a higher proportion of acute injuries (35.4% versus 23.5%; pConclusion: The COVID-19 pandemic caused a marked shift in the pathology presenting to the orthopaedic foot and ankle clinic. There was an increase in ankle fractures, stress fractures, and acute injuries when compared to the previous year, and a decrease in Achilles tendon ruptures and chronic injuries. This shift may reflect both the adoption of different activities during the quarantine period and a reluctance to present to a medical environment for evaluation of non-urgent injuries.

With the growth and development of spine surgery over the past few decades, postoperative complications have become increasingly diverse and challenging to manage. At present, postoperative imaging remains the spine surgeon's greatest asset for diagnosis, and the most cost-effective method of evaluating complications such as fracture, infection, and other perioperative fluid collections. In this section, we will present a diagnostic approach to evaluating some of the most common postoperative complications in spine surgery, using available imaging techniques.