Characterization of Regolith And Trace Economic Resources (CRATER): An Orbitrap-based laser desorption mass spectrometry instrument for in situ exploration of the Moon.

RATIONALE: Characterization of Regolith And Trace Economic Resources (CRATER), an Orbitrap™-based laser desorption mass spectrometry instrument designed to conduct high-precision, spatially resolved analyses of planetary materials, is capable of answering outstanding science questions about the Moon's formation and the subsequent processes that have modified its (sub)surface. METHODS: Here, we describe the baseline design of the CRATER flight model, which requires <20 000 cm3  volume, <10 kg mass, and <60 W peak power. The analytical capabilities and performance metrics of a prototype that meets the full functionality of the flight model are demonstrated. RESULTS: The instrument comprises a high-power, solid-state, pulsed ultraviolet (213 nm) laser source to ablate the surface of the lunar sample, a custom ion optical interface to accelerate and collimate the ions produced at the ablation site, and an Orbitrap mass analyzer capable of discriminating competing isobars via ultrahigh mass resolution and high mass accuracy. The CRATER instrument can measure elemental and isotopic abundances and characterize the organic content of lunar surface samples, as well as identify economically valuable resources for future exploration. CONCLUSION: An engineering test unit of the flight model is currently in development to serve as a pathfinder for near-term mission opportunities.

Five-year clinical follow-up of arthroscopically treated chronic ankle instability.

INTRODUCTION: Arthroscopic treatment of lateral ankle instability is a recent innovation. In 2014, a prospective study was initiated by the French Society of Arthroscopy demonstrating the feasibility, morbidity and short-term results of arthroscopic treatment of ankle instability. HYPOTHESIS: The functional results of arthroscopic treatment of chronic ankle instability found after one year were maintained in the medium term. MATERIAL AND METHODS: The prospective follow-up of the patients included in the initial cohort was continued. The Karlsson and AOFAS scores, as well as patient satisfaction, were assessed. The causes of failure underwent univariate and multivariate analyzes. The results of 172 patients were included (40.2% ligament repairs; 59.7% ligament reconstructions). The average follow-up was 5years. The average satisfaction was 8.6/10, the average Karlsson score was 85 points and the average AOFAS score was 87.5 points. The reoperation rate was 6.4% of patients. The failures were related to an absence of sports practice, a high BMI and female gender. A high BMI and the intense sports practice were associated to ligament repair failure. The absence of sports practice and the intraoperative presence of the anterior talofibular ligament were associated to ligament reconstruction failure. DISCUSSION: Arthroscopic treatment of ankle instability confers high satisfaction in the medium term, as well as long-lasting results with a low reoperation rate. A more detailed evaluation of the failure criteria could help guide the choice of treatment between ligament reconstruction or repair. LEVEL OF EVIDENCE: II.

PT4: New arthroscopic technique for isolated reconstruction of the anterior talofibular ligament using a quadrupled plantaris tendon.

The strategy for surgical treatment of chronic ankle instability is becoming increasingly refined. In instances of isolated symptomatic non-repairable anterior talofibular ligament (ATFL) injury, there is a surgical indication for isolated ATFL reconstruction. However, we feel that the typical gracilis tendon graft is not always appropriate. Interest in using the plantaris tendon as a graft has picked up since a biomechanics study found the tensile strength of a quadrupled plantaris tendon is comparable to that of the ATFL. Here, we describe an original arthroscopic technique for isolated ATFL reconstruction using a quadrupled plantaris tendon (PT4) graft.

Screening of Native Plants Growing on a Pb/Zn Mining Area in Eastern Morocco: Perspectives for Phytoremediation.

Screening of native plant species from mining sites can lead to identify suitable plants for phytoremediation approaches. In this study, we assayed heavy metals tolerance and accumulation in native and dominant plants growing on abandoned Pb/Zn mining site in eastern Morocco. Soil samples and native plants were collected and analyzed for As, Cd, Cu, Ni, Sb, Pb, and Zn concentrations. Bioconcentration factor (BCF), translocation factor (TF), and biological accumulation coefficient (BAC) were determined for each element. Our results showed that soils present low organic matter content combined with high levels of heavy metals especially Pb and Zn due to past extraction activities. Native and dominant plants sampled in these areas were classified into 14 species and eight families. Principal components analysis separated Artemisia herba-alba with high concentrations of As, Cd, Cu, Ni, and Pb in shoots from other species. Four plant species, namely, Reseda alba, Cistus libanotis, Stipa tenacissima, and Artemisia herba-alba showed strong capacity to tolerate and hyperaccumulate heavy metals, especially Pb, in their tissues. According to BCF, TF, and BAC, these plant species could be used as effective plants for Pb phytoextraction. Stipa tenacissima and Artemisia herba-alba are better suited for phytostabilization of Cd/Cu and Cu/Zn, respectively. Our study shows that several spontaneous and native plants growing on Pb/Zn contaminated sites have a good potential for developing heavy metals phytoremediation strategies.

Role of surgery in the management of lesions of the medial collateral ligament of the ankle.

Medial ankle instability is likely underestimated. Three types of medial collateral ligament (MCL) lesion exist: isolated lesions, in case of valgus sprain in external rotation; lesions associated with chronic lateral instability, in case of rotational instability; and lesions associated with medial insufficiency and valgus flat-foot. Diagnostic confirmation and treatment of MCL lesions, isolated or associated with chronic lateral instability, by ligament suture is at present largely arthroscopic. Chronic MCL lesions with valgus flat-foot are probably irreversible: ligament reconstruction is unreliable, and bone surgery (osteotomy, fusion) is required.

Agreement between arthroscopic and imaging study findings in chronic anterior talo-fibular ligament injuries.

BACKGROUND: Imaging studies done to evaluate chronic ankle instability (CAI) often fail to accurately detail injuries to the anterior talo-fibular ligament (ATFL) and may, therefore, also fail to provide guidance for selecting the most appropriate surgical procedure. Arthroscopy is now an indispensable tool for accurately diagnosing ATFL injuries. This study looked at agreement between arthroscopy and imaging study assessments of ATFL injuries. The primary objective was to adapt an arthroscopic classification of chronic ATFL lesions to the pre-operative imaging study findings in order to estimate the performance of computed tomography (CT)-arthrography, ultrasonography, and magnetic resonance imaging (MRI) in diagnosing ATFL lesions, using arthroscopy as the reference standard. HYPOTHESIS: Agreement between arthroscopic and imaging findings of chronic ATFL injuries can be assessed by using a shared classification developed from the arthroscopic evaluation, used as the reference standard. MATERIAL AND METHODS: A prospective multicentre study was conducted in 286 patients with arthroscopically-treated CAI. In each patient, the arthroscopic assessment of the ATFL was compared to the pre-operative findings by CT-arthrography, ultrasonography, and MRI. A classification of ATFL lesions based on the arthroscopic assessment was used to analyse the imaging studies. Using this classification, two independent observers compared the findings and evaluated the agreement between arthroscopy and imaging studies. RESULTS: Of the 286 patients, 157 had complete information on the arthroscopic assessment and on pre-operative imaging studies and were included in the analysis. Imaging studies were CT-arthrography in 49 patients, ultrasonography in 63 patients, and MRI in 45 patients; both ultrasonography and MRI were performed in 3 patients. Agreement with arthroscopy was 82% and 88.5% for CT-arthrography, 66.7% and 76.2% for ultrasonography, 70.5% and 79.5% for MRI, and 73.4% and 81.2% for all imaging studies pooled. DISCUSSION: Arthroscopy plays a crucial role in the definitive assessment of ligament lesions in patients with CAI, as it supplies far more accurate information than any of the current imaging studies and, in addition, provides a dynamic evaluation of the ligaments and assesses mechanical strength. In the study population, a simple arthroscopic evaluation consistently visualised ATFL lesions, thereby either correcting or confirming the pre-operative imaging study findings. Importantly, the arthroscopic assessment provided more accurate information on the lesions and quality of the ATFL compared to the imaging studies. Arthroscopy has improved our knowledge of chronic ATFL lesions and allowed the development of a simple but accurate four-grade classification of direct relevance to choosing the optimal therapeutic procedure. This classification must be disseminated among radiologists to improve the diagnostic performance of pre-operative imaging studies, assist surgeons in selecting the most appropriate ankle-stabilising procedure, and improve patient information. Further studies are needed to confirm the promising results reported here and the usefulness of this common arthroscopy and imaging-study classification for chronic ATFL lesions. LEVEL OF EVIDENCE: II.

Arthroscopic treatment of chronic ankle instability: Prospective study of outcomes in 286 patients.

BACKGROUND: Chronic ankle instability (CAI) is the main complication of ankle sprains and requires surgery if non-operative treatment fails. Surgical ankle stabilisation techniques can be roughly classified into two groups, namely, repair involving retensioning and suturing of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) and reconstruction using a tendon graft. Arthroscopic repair and reconstruction techniques for CAI have been introduced recently. The objective of this prospective multicentre study was to assess the feasibility, morbidity, and short-term outcomes of these arthroscopic ankle-stabilisation techniques. MATERIAL AND METHODS: Consecutive patients scheduled for arthroscopic treatment of CAI were included prospectively. Of the 286 included patients, 115 underwent ligament repair and 171 ligament reconstruction. Mean follow-up was 9.6 months (range, 6-43 months). We recorded the AOFAS and Karlsson scores, patient satisfaction, complications, and time to return to sports. RESULTS: The overall patient satisfaction score was 8.5/10. The AOFAS and Karlsson scores improved significantly between the pre- and postoperative assessments, from 62.1 to 89.2 and from 55 to 87.1, respectively. These scores were not significantly different between the groups treated by repair and by reconstruction. Neurological complications occurred in 10% of patients and consisted chiefly in transient dysesthesia (with neuroma in 3.5% of patients). Cutaneous or infectious complications requiring surgical revision developed in 4.2% of patients. DISCUSSION: Arthroscopic treatment is becoming a method of choice for patients with CAI, as it allows a comprehensive assessment of the ligament lesions, the detection and treatment of associated lesions, and repair or reconstruction of the damaged ligaments. These simple, reliable, and reproducible arthroscopic techniques seem as effective as conventional surgical techniques. The rate of cutaneous complications is at least halved compared to open surgery. CONCLUSION: Arthroscopic ankle stabilisation repair and reconstruction techniques hold considerable promise but require further evaluation to better determine the indications of repair versus reconstruction and to obtain information on long-term outcomes.

Arthroscopic classification of chronic anterior talo-fibular ligament lesions in chronic ankle instability.

BACKGROUND: The surgical treatment of chronic ankle instability (CAI) relies chiefly on anterior talo-fibular ligament (ATFL) repair (with or without augmentation) or anatomical reconstruction with a tendon graft. Arthroscopy enables not only a complete assessment and the same-stage treatment of concomitant articular lesions, but also an accurate assessment of ligament lesions. Pre-operative imaging studies (MRI, CT, US) may fail to provide sufficient detail about chronic ATFL lesions to guide the decision between repair and reconstruction. The aim of this study was to develop an arthroscopic classification of chronic ATFL lesions designed to assist in selecting the optimal surgical technique. MATERIAL AND METHODS: Sixty-nine anterior ankle arthroscopy videos recorded before surgery for CAI were studied retrospectively. ATFL dissection was performed in all patients. Based on the video analysis, five ATFL grades were identified: 0, normal ATFL thickness and tension; 1, ATFL distension with normal thickness; 2, ATFL avulsion with normal thickness; 3, thin ATFL with no resistance during the hook test; and 4, no ATFL, with a bald malleolus. Intra- and interobserver reproducibility of the arthroscopic classification of chronic ATFL lesions was evaluated by computing the kappa coefficients (κ) after assessment by two independent observers. RESULTS: All 69 ATFLs were classified as abnormal (none was grade 0). Each ATFL could be matched to a grade. Intra-observer agreement was good for both observers: κ was 0.67 with 75% of agreement for one observer and 0.68 with 76% of agreement for the other observer. Inter-observer agreement was fair to good, with κ values ranging from 0.59 to 0.88 and agreement from 70% to 91%. DISCUSSION: Arthroscopic ATFL dissection is a simple procedure that provides a highly accurate assessment of ATFL lesions and mechanical resistance, focussing chiefly on the superior ATFL. Grade 1 and 2 lesions can be repaired using the Broström-Gould procedure, whereas grade 3 and 4 lesions require anatomic reconstruction with grafting. CONCLUSION: This arthroscopic classification of chronic ATFL lesions confirms the diagnostic role for arthroscopy in assessing the ligaments in patients with CAI. It is helpful for determining the best surgical technique for stabilising the ankle. These results must be confirmed in a larger study.

An Orbitrap-based laser desorption/ablation mass spectrometer designed for spaceflight.

RATIONALE: The investigation of cryogenic planetary environments as potential harbors for extant life and/or contemporary sites of organic synthesis represents an emerging focal point in planetary exploration. Next generation instruments need to be capable of unambiguously determining elemental and/or molecular stoichiometry via highly accurate mass measurements and the separation of isobaric interferences. METHODS: An Orbitrap™ analyzer adapted for spaceflight (referred to as the CosmOrbitrap), coupled with a commercial pulsed UV laser source (266 nm), was used to successfully characterize a variety of planetary analog samples via ultrahigh resolution laser desorption/ablation mass spectrometry. The materials analyzed in this study include: jarosite (a hydrous sulfate detected on Mars); magnesium sulfate (a potential component of the subsurface ocean on Europa); uracil (a nucleobase of RNA); and a variety of amino acids. RESULTS: The instrument configuration tested here enables: measurement of major elements and organic molecules with ultrahigh mass resolution (m/Δm ≥ 120,000, FWHM); quantification of isotopic abundances with <1.0% (2σ) precision; and identification of highly accurate masses within 3.2 ppm of absolute values. The analysis of a residue of a dilute solution of amino acids demonstrates the capacity to detect twelve amino acids in positive ion mode at concentrations as low as ≤1 pmol/mm2 while maintaining mass resolution and accuracy requirements. CONCLUSIONS: The CosmOrbitrap mass analyzer is highly sensitive and delivers mass resolution/accuracy unmatched by any instrument sent into orbit or launched into deep space. This prototype instrument, which maps to a spaceflight implementation, represents a mission-enabling technology capable of advancing planetary exploration for decades to come.

Subtalar joint configuration on weightbearing CT scan.

BACKGROUND: Standard values that describe the morphology of the subtalar (ST) joint have previously been obtained from cadaveric studies or by using conventional unloaded radiographs. It is known that these parameters differ significantly from those measured in vivo and in loaded images, limiting the diagnostic value of the previously published morphological parameters in the literature. However, the morphology of the ST joint clearly affects its function. The objective of this study was to determine the morphology of the posterior facet of the ST joint using loaded computed tomography (CT) images and to describe the different configurations found in asymptomatic patients. METHODS: A weightbearing CT scan was performed on 59 patients without any history of hindfoot and ankle pathology. The shape of the posterior facet and the subtalar vertical angle (SVA) were measured in 3 different coronal planes of the ST joint. RESULTS: The posterior facet was concave in 88% and flat in 12%. The posterior facet was oriented in valgus in 90% and varus in 10% when measured in the middle coronal plane. However, the SVA changed depending on which coronal plane it was measured in. CONCLUSION: We believe it is important to get a better insight into the morphological parameters of the ST joint. CLINICAL RELEVANCE: Knowledge of subtalar joint morphology could help clarify why certain failures have occurred in reconstructive hindfoot surgery and thus might help plan the surgical procedure to reduce these failures in the future.

Effect of supramalleolar osteotomy and total ankle replacement on talar position in the varus osteoarthritic ankle: a comparative study.

BACKGROUND: In varus osteoarthritic ankles, joint congruency is usually lost leading to progressive wear of the medial tibiotalar joint. Recent studies have shown that balancing the hindfoot with the aid of supramalleolar osteotomy (SMOT) is an effective method to decrease symptoms and to delay progression of osteoarthritis of the ankle joint. Resurfacing the articular surfaces with total ankle replacement (TAR), in contrast, may compensate for the lost joint congruency and lost stability of the talus at the peritalar joint. However, no literature exists with regard to the overall correction of talar position in all 3 planes when using these 2 treatment modalities. The purpose of this study was to determine the effect of SMOT and TAR on talar position in all 3 planes, and to compare the efficiency of both procedures in restoring overall hindfoot geometry. METHODS: Out of 104 ankles with a varus-tilted ankle, 52 patients were treated with SMOT and 52 with TAR. Weight-bearing radiographs were analyzed to measure the talar position in all 3 planes, including the talar tilt angle (TT), the sagittal talocalcaneal inclination angle (TCI), and the talometatarsal 1 angle (TMT1) pre- and postoperatively. RESULTS: Although after TAR the talar position was corrected in all the 3 planes, SMOT on the other hand did not fully correct the TT, and furthermore TMT1 remained unchanged. CONCLUSIONS: Resurfacing of the worn-out articular surface and tensioning of ligaments, as is the case in TAR, radiographically restores the hindfoot geometry in the neutral position better than SMOT does. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Peritalar instability after tibiotalar fusion for valgus unstable ankle in stage IV adult acquired flatfoot deformity: case series.

BACKGROUND: An unstable valgus ankle with an incompetent medial ligament complex is still treated by many surgeons with isolated tibiotalar (TT) arthrodesis. To date, it is unknown whether rigid fixation of the talus within the ankle mortise sufficiently corrects and stabilizes the hindfoot complex. The purpose of this study was to critically analyze patients with this problem and to assess the underlying causes for their acquired peritalar instability. METHODS: This series included 4 male patients (ages 55, 70, 72, and 79 years). Preoperatively, all patients presented with an unstable valgus ankle associated with stage IV adult acquired flatfoot deformity (AAFD), with a valgus talar tilt averaging 12 degrees (ranging from 9 to 14 degrees). All patients had a successful TT fusion, with screws and plates used for fixation. The position of the TT fusion was estimated at the intersection of a line drawn defining the talar shoulders and the longitudinal tibial axis on the anteroposterior weight-bearing radiograph. The hindfoot deformity was measured via the calcaneal offset on the Saltzman view. RESULTS: All patients had a healed TT fusion with the talus remaining in valgus averaging 4.8 degrees (ranging from 4 to 6 degrees). At the latest follow-up (1.2-18 years), all patients showed a progressive destabilization of the hindfoot complex that resulted in a valgus pronation deformity with flattening of the arch and a highly unstable foot that was not manageable with corrective shoes and braces. Key findings were a floppy hindfoot that turned into extreme valgus misalignment while loading. Radiographically, the calcaneal offset was in valgus misalignment of 16 to 54 mm related to the tibial axis on the Saltzman alignment view. In 2 cases, there was a complete medial dislocation of the talus. CONCLUSIONS: Even with rigid stabilization of the talus in the ankle mortise, peritalar instability may persist and allow calcaneus and navicular subluxation around the talus, which can result in progressive destabilization of the hindfoot complex. In stage IV AAFD, incompetent peritalar ligaments may not be able to withstand the increased mechanical load after TT fusion. Persistent valgus talar tilt after fusion may promote this unfavorable process. Therefore, isolated TT fusion should be performed with caution for treatment of valgus tilted ankles in stage IV AAFD. If this is considered, we recommend that fusion in neutral or even slightly varus talar positions be attempted. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Safety and efficiency of a 2-portal lateral approach to arthroscopic subtalar arthrodesis: a cadaveric study.

PURPOSE: To investigate the safety and efficiency of a 2-portal lateral (anterior and middle) approach to arthroscopic subtalar arthrodesis. METHODS: A cadaveric study was performed on 30 feet of 15 fresh cadaveric bodies (15 right and 15 left; 21 female specimens and 9 male specimens). The mean age at death was 78 ± 6.7 years. The procedure was performed with the specimen in the supine position through 2 lateral (anterior and middle) sinus tarsi portals by use of a 4.0-mm arthroscope. A 3.5-mm synovial shaver was used for debridement, and a 4.5-mm shielded bur was used to resect posterior subtalar facets. The feet were then dissected. The primary outcomes were the percentage of resected joint surface and the distances between portals and both sural and superficial peroneal nerves. The secondary outcomes were injury of sinus tarsi ligaments and lateral arterial network, calcaneofibular ligament, peroneal tendons, flexor hallucis longus tendon, and posterior tibial neurovascular bundle. RESULTS: The mean percentages of resected talar and calcaneal posterior subtalar facets were 94% ± 7.2% and 91% ± 6.8%, respectively. The minimum distance of either subtalar portal to the nerves was 4 mm. No nerve injury was observed. In 28 of 30 cases, the lateral sinus tarsi arterial network was found intact. In all cases the inferior retinaculum extensor was transfixed by the portals. In all cases both cervical and interosseous talocalcaneal ligaments were found intact. In 3 cases a shaving lesion was observed on the peroneus brevis tendon. CONCLUSIONS: According to this cadaveric study, more than 90% freshening of the posterior subtalar articular facets can be achieved through a 2-portal lateral (anterior and middle) approach. This technique is reproducible and safe with regard to the surrounding nerves. CLINICAL RELEVANCE: The 2 lateral portals may offer a safe and effective alternative approach for arthroscopic arthrodesis of the posterior subtalar joint.

Effects of graft pretensioning in anterior cruciate ligament reconstruction.

PURPOSE: Graft pretensioning is used in anterior cruciate ligament (ACL) reconstruction to prevent secondary slackening. Its effects on collagen fibrillar ultrastructure are not known. In this study, we hypothesized that graft pretensioning in ACL reconstruction creates ultrastructural changes detectable in scanning electron microscopy (SEM). METHODS: A prospective comparative study was carried out on 38 ACL reconstructions using a 4-strand semitendinosus graft. Samples were harvested intra-operatively before and after pretensioning for 30 s, 2 or 5 min. The images produced in SEM were analyzed using an original semi-quantitative «CIP¼ score taking into account collagen cohesion, integrity, and parallelism. Intra- and inter-tester reliability for the CIP score were tested. RESULTS: The CIP scores decreased by 3.5 (1.6) points after pretensioning (P < 0.05). Significant differences were found in the 5, 2 min and 30 s subgroups for the global CIP score. Relative decrease (Delta CIP) was significantly higher in the 2 and 5 min subgroups after pretensioning in comparison with the 30 s subgroups. Intra- and inter-tester reliability for the CIP score were 0.85 and 0.92 (P < 0.05). CONCLUSION: Pretensioning ACL grafts resulted in alteration of the collagen fibrillar ultrastructure, detectable using SEM. These results confirm the existence of collagen ultrastructural changes after pretensioning that may be related to its duration. LEVEL OF EVIDENCE: Prospective comparative study, Level II.

Occurrence of mycorrhizal symbioses in the metal-rich lateritic soils of the Koniambo Massif, New Caledonia.

The occurrence of arbuscular mycorrhiza (AM) was surveyed in ten endemic plant species of the Koniambo Massif (New Caledonia) and associated metal-enriched ultramafic soils along a topographic sequence ranging from a plateau at 900 m altitude to a valley at 700 m. In the four different plant formations (Araucaria group on the plateau, ligno-herbaceous maquis, Tristaniopsis maquis and Nothofagus forest in the valley), all plants were consistently colonised by AM fungi, even the sedges Costularia arundinacea, C. nervosa and Lepidosperma perteres and the nickel-hyperaccumulating plant Phyllanthus favieri. Dual (AM and ectomycorrhiza EM) colonisation was observed in the two plant formations dominated by the ectomycorrhizal plants Nothofagus balansae for the forest (site 4) and Tristaniopsis guillainii and T. calobuxus for the Tristaniopsis maquis (site 3). In the soils, there are strong positive correlations between microbial activity, black AM spore abundance and concentrations of available metals indicating the role of the biotic component in the release of metals. These results suggest that these symbioses are important in the adaptation of the endemic plants to these soils, and may be relevant to ecological restoration of the ancient nickel mines.