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Clinical evaluation of the shoulder range of motion (RoM) may vary significantly depending on the surgeon. We aim to validate an automatic shoulder RoM measurement system associating image acquisition by an RGB-D (red/green/blue-depth) video camera to an artificial intelligence (AI) algorithm.Thirty healthy volunteers were included. A 3D RGB-D sensor that simultaneously generated a colour image and a depth map was used. Then, an open-access convolutional neural network algorithm that was programmed for shoulder recognition provided a 3D motion measure. Each volunteer adopted a randomized position successively. For each position, two observers made a visual (EyeREF) and goniometric measurement (GonioREF), blind to the automated software which was implemented by an orthopaedic surgeon. We evaluated the inter-tester intra-class correlation (ICC) between observers and the concordance correlation coefficient (CCC) between the three methods.For manual evaluations EyeREF and GonioREF, ICC remained constantly excellent for the widest motions in the vertical plane (i.e., abduction and flexion). It was very good for ER1 and IR2 and fairly good for adduction, extension, and ER2. Differences between the measurements' means of EyeREF and shoulder RoM was significant for all motions. Compared to GonioREF, shoulder RoM provided similar results for abduction, adduction, and flexion and EyeREF provided similar results for adduction, ER1, and ER2. The three methods showed an overall good to excellent CCC. The mean bias between the three methods remained under 10° and clinically acceptable.RGB-D/AI combination is reliable in measuring shoulder RoM in consultation, compared to classic goniometry and visual observation.

Resume Introduction Chez un patient au-dela de 50 ans, la litterature est peu fournie, mais les resultats apres chirurgie sont bons, sous reserve que les patients aient ete bien selectionnes. Dans cette tranche d’âge, il est cependant habituel de proposer un traitement non chirurgical, les patients preferant le plus souvent diminuer leurs activites sportives. Les resultats du traitement conservateur restent acceptables mais avec un risque important d’instabilite residuelle, de lesions associees secondaires et d’une modification des activites. L’objectif principal de ce travail etait de comparer les resultats de la prise en charge chirurgicale et non chirurgicale d’une rupture du LCA chez des patients de plus de 50 ans. Les objectifs secondaires etaient : de rechercher l’existence d’eventuels facteurs pronostics de mauvais resultats fonctionnels, et de comparer du point de vue epidemiologique les deux groupes en cherchant les arguments cliniques pouvant aider a la decision therapeutique. L’hypothese etait que les resultats sont comparables entre les 2 groupes. Materiel et methode Le suivi a ete prospectif sur un collectif de 320 patients (92 non operes [GNO], 228 operes [GO]). Les donnees epidemiologiques classiques etaient notees. En pre- et postoperatoire la laxite clinique, la laximetrie differentielle, les scores KOOS, IKDC, Tegner, ACL-RSI et l’evaluation radiologique ont ete realises. Les donnees per-operatoires etaient notees. Les complications precoces et tardives etaient colligees. Resultats Tous les patients etaient revus. Le patient type etait une femme, mais qui etait plus âgee, moins sportive, avec un genou plus stable et une repercussion fonctionnelle moins marquee dans le GNO. Les scores fonctionnels etaient ameliores pour les 2 groupes, mais ils etaient meilleurs pour le GO avec des scores d’activite sportive egalement meilleurs. Pour le GNO la laximetrie au recul etait liee a un Jerk franc preoperatoire (p = 0,024). Le facteur de mauvais pronostic pour le score IKDC etait l’existence d’une laxite differentielle preoperatoire importante (p = 0,06). Concernant le GO l’importance de la laximetrie au recul etait liee a un Jerk explosif preoperatoire (p Discussion/Conclusion Les resultats sont satisfaisants dans les 2 groupes, avec une augmentation significative des scores fonctionnels quelle que soit la prise en charge therapeutique, mais sont meilleurs pour le groupe opere. Pour le GNO les sports pivots sont difficilement praticables, avec une baisse des scores d’activite sportive. En cas de laxite importante au moment du diagnostic un traitement chirurgical doit etre propose. Niveau d’evidence III ; serie prospective comparative non randomisee.

Background Glomus tumors, also known as benign acral tumors are extremely rare. Previous glomus tumors from other regions of the body have been linked to neurological compression symptoms, however axillary compression at the scapular neck has never been described. Case presentation Here, we report a case of axillary nerve compression in a 47-year-old man, secondary to a glomus tumor of the neck of the right scapula, initially misdiagnosed with biceps tenodesis performed and no pain improvement. The magnetic resonance imaging demonstrated a well-contoured, 12 mm tumefaction at the inferior pole of the scapular neck T2-hyperintense and T1-isointense and interpreted as a neuroma. An axillary approach allowed the dissection of the axillary nerve, and the tumor was completely removed. The pathological anatomical analysis resulted in a nodular red lesion measuring 14 × 10 mm, delimited and encapsulated with a definitive diagnostic of glomus tumor. The neurologic symptoms and pain disappeared 3 weeks after surgery and the patient reported satisfaction with the surgical procedure. After 3 months, the results remain stable with a complete resolution of the symptoms. Conclusions In cases of unexplained and atypical pain in the axillary area, and to avoid potential misdiagnoses and inappropriate treatments, an in-depth exploration for a compressive tumor should be performed as a differential diagnosis.

Background The treatment of severe proximal humeral bone loss (PHBL) secondary to tumor resection or failed arthroplasty is challenging. We evaluated the outcomes and complications of reconstruction with reverse shoulder–allograft prosthesis composite (RS-APC), performed with or without tendon transfer. Methods An RS-APC procedure was performed in 25 consecutive patients with severe PHBL (>4 cm): 12 after failed reverse shoulder arthroplasty, 5 after failed hemiarthroplasty for fracture, 6 after failed mega-tumor prosthesis placement, and 2 after tumor resection. The median length of humeral bone loss or resection was 8 cm (range, 5-23 cm). Humeral bone graft fixation was obtained with a long monobloc reverse stem and a “mirror step-cut osteotomy,” without plate fixation. Nine infected shoulders underwent a 2-stage operation with a temporary cement spacer. In addition, 9 patients (36%) underwent an associated L'Episcopo procedure. The median follow-up duration was 4 years (range, 2-11 years). Results Overall, 76% of patients (19 of 25) were satisfied. In 8 patients (32%), a reoperation was needed. At last follow-up, we observed incorporation at the allograft-host junction in 96% of the cases (24/25); partial graft resorption occurred in 3 cases and severe in 1. The median adjusted Constant score was 53% (range 18-105); Subjective Shoulder Value, 50% (range 10%-95%). Additional tendon transfers significantly improved active external rotation (20° vs. 0°, P Conclusions (1) Shoulder reconstruction with RS-APC provides acceptable shoulder function and high rates of graft survival and healing. (2) Additional L'Episcopo tendon transfer (when technically possible) improves active shoulder motion. (3) The use of a long monobloc (cemented or uncemented) humeral reverse stem with mirror step-cut osteotomy provides a high rate of graft-host healing, as well as a limited rate of graft resorption, and precludes the need for additional plate fixation. (4) Although rewarding, this reconstructive surgery is complex with a high risk of complications and reoperations. The main advantages of using an allograft with a reverse shoulder arthroplasty (compared with other reconstruction options) are that this type of reconstruction (1) allows restoration of the bone stock, thus improving prosthesis fixation and stability, and (2) gives the possibility to perform a tendon transfer by fixing the tendons on the bone graft to improve shoulder motion.

How does the cavity size in circumbinary discs depend on disc and binary properties? We investigate by simulating disc cavities carved by binary companions using smoothed particle hydrodynamics (SPH). We find that a cavity is quickly opened on the dynamical time, while the cavity size is set on the viscous time. In agreement with previous findings, we find long term cavity sizes of 2-5 times the binary semi-major axis, increasing with eccentricity and decreasing with disc aspect ratio. When considering binaries inclined with respect to the disc we find three regimes: i) discs that evolve towards a coplanar orbit have a large cavity, slightly smaller than that of an initially coplanar disc; ii) discs that evolve towards a polar orbit by breaking have a small cavity, equal in size to that of an initially polar disc; iii) discs that evolve towards a polar orbit via warping have an intermediate-sized cavity. We find typical gas depletions inside the cavity of $\gtrsim 2$ orders of magnitude in surface density., Comment: 12 pages, 13 figures, accepted to MNRAS

We report a case of a pyrocarbon humeral head resurfacing implant fracture, occurring 6 years after its implantation, without any obvious trauma or dislocation. Initial radiographs showed a proud and oversized pyrocarbon resurfacing implant. On clinical examination, the patient had a painful and pseudoparalyzed shoulder with subscapularis insufficiency. Imaging studies confirmed implant fracture and severe fatty infiltration (Goutallier, grade 4) of the subscapularis muscle. Intraoperatively, the implant was found to be fractured with multiple pyrocarbon debris in the glenohumeral joint. The implant was loose, and gross inspection showed no visible bony adhesion or ongrowth. Histologic analysis showed multiple seats of metallosis in the synovial tissue and cancellous bone of the humeral head. Successful management of this complication was managed with a thorough debridement and irrigation and revision to reverse shoulder arthroplasty. Our observation put into question the use of pyrocarbon as a humeral head resurfacing implant. The material seems to be too fragile to be used as a resurfacing implant and cannot achieve fixation of the implant to bone.

Approximately 20% of patients have persistent unexplained pain after total knee arthroplasty (TKA). Currently available treatments are unsatisfactory. The present report describes four patients in whom transcatheter arterial embolization had a remarkable effect on pain after TKA. Abnormal neovessels were identified in all patients. For 48 h, one patient experienced remarkable postprocedural pain at the inner side of the knee that was subsided by level 1 analgesics and another patient development of a spontaneous skin ulceration resolving within 8 days. The mean Knee injury and Osteoarthritis Outcome Score pain subtotal had increased from 39 to 82 one month after treatment. Endovascular occlusion of neovascularization, decreasing chronic inflammation and the growth of unmyelinated sensory nerves may be treatment options for persistent unexplained pain following TKA. Level of Evidence IV, Case report.

One of the main problems in planet formation, hampering the growth of small dust to planetesimals, is the so-called radial-drift barrier. Pebbles of cm to dm sizes are thought to drift radially across protoplanetary discs faster than they can grow to larger sizes, and thus to be lost to the star. To overcome this barrier, drift has to be slowed down or stopped, or growth needs to be sped up. In this paper, we investigate the role of porosity on both drift and growth. We have developed a model for porosity evolution during grain growth and applied it to numerical simulations of protoplanetary discs. We find that growth is faster for porous grains, enabling them to transition to the Stokes drag regime, decouple from the gas, and survive the radial-drift barrier. Direct formation of small planetesimals from porous dust is possible over large areas of the disc., MNRAS 493, 1788 (2020). 13 pages, 13 figures. Correction of a typo in the algorithm of Appendix A4

In protoplanetary discs, the coagulation of dust grains into large aggregates still remains poorly understood. Grain porosity appears to be a promising solution to allow the grains to survive and form planetesimals. Furthermore, dust shattering has generally been considered to come only from collisional fragmentation; however, a new process was recently introduced, rotational disruption. We wrote a one-dimensional code that models the growth and porosity evolution of grains as they drift to study their final outcome when the two shattering processes are included. When simulating the evolution of grains in a disc model that reproduces observations, we find that rotational disruption is not negligible compared to the fragmentation and radial drift. Disruption becomes dominant when the turbulence parameter $\alpha \lesssim 5\xtenpow{-4}$, if the radial drift is slow enough. We show that the importance of disruption in the growth history of grains strongly depends on their tensile strength., Comment: Published by MNRAS in Dec 2022, 14 pages, 14 figures

Companions at sub-arcsecond separation from young stars are difficult to image. However their presence can be inferred from the perturbations they create in the dust and gas of protoplanetary disks. Here we present a new interpretation of SPHERE polarised observations that reveal the previously detected inner spiral in the disk of HD 100546. The spiral coincides with a newly detected 12CO inner spiral and the previously reported CO emission Doppler-flip, which has been interpreted as the signature of an embedded protoplanet. Comparisons with hydrodynamical models indicate that this Doppler-flip is instead the kinematic counterpart of the spiral, which is likely generated by an inner companion inside the disk cavity., Comment: Accepted to ApJL, 14 pages, 10 figures

On the 16th of March 2020, in the face of a health emergency declared in France, the government imposed containment measures whose impact on orthopaedic and trauma surgery remains to be demonstrated. The hypothesis of this study was that confinement reduced orthopaedic and trauma surgical activity. The main objective was to assess orthopaedic and trauma surgical activity during confinement and to compare it to the activity outside confinement.This was a retrospective, monocentric, observational and comparative study of a continuous cohort of patients included during the confinement period of March 16th to May 11th, 2020. This cohort was retrospectively compared to a group of patients over the same non-confinement period in the previous year, from March 16th to May 11th, 2019. The primary outcome measured was the incidence rate of surgical activity in 2020 versus 2019 over an identical period. The secondary outcome was the analysis of the trauma identified.The number of patients operated on was significantly reduced during confinement: 194 patients were included in 2020, i.e. an incidence of 57 per 100,000 inhabitants against 772 patients included in 2019, i.e. an incidence of 227 per 100,000 inhabitants; p0.001. Planned orthopaedic surgery decreased from an incidence rate of 147 in 2019 to 5 in 2020 per 100,000 inhabitants (p0.001). Trauma surgery decreased from an incidence rate of 80 in 2019 to 50 in 2020 per 100,000 inhabitants (p: NS). We found a significant increase in patients over 65years of age during confinement, 70% compared to 61% in 2019; p=0.04. The rate of femoral neck fractures was significantly increased during confinement, 48.5% compared to 39.3% in 2019; p=0.03. Degenerative surgery was significantly reduced during confinement (p0.001).This study shows that the surgical activity of orthopaedics and trauma was significantly reduced by confinement, with a difference in incidence of 170 per 100,000 inhabitants, thus confirming the hypothesis of the authors. This decrease is due to both the cessation of planned orthopaedics and the 40% decrease in the number of trauma patients. During confinement, the percentage of patients over the age of 65 with a fracture increased significantly.Confinement had a significant impact on orthopaedic and trauma surgical activity.III; comparative and retrospective.

Few studies have investigated postoperative tendon integrity after reoperation for failed rotator cuff repair. The purpose of this study was to evaluate the anatomic and clinical outcomes of arthroscopic revision rotator cuff repair (AR-RCR) and identify the risk factors related to re-retear.Sixty-nine consecutive patients (mean age, 55 years) with primary failed open (38%) or arthroscopic (62%) cuff repairs underwent AR-RCR and were reviewed regarding clinical examination findings and imaging studies. Patients with massive cuff tears and upward humeral migration (acromiohumeral distance6 mm) or glenohumeral osteoarthritis were excluded. Revision repair was performed by a single, experienced shoulder surgeon. Complete footprint coverage was achieved in all cases using a single-row (70%), double-row (19%), or side-to-side (11%) technique. The primary outcome measure was tendon healing assessed with magnetic resonance imaging (57 cases) or computed tomography arthrogram (12 cases) performed at minimum 1-year follow-up. Secondary outcome measures included functional outcome scores, subjective results, and complications. The mean follow-up period was 43 months (range, 12-136 months).The cuff tendons did not heal to the tuberosity in 36% of the shoulders (25 of 69) following revision cuff surgery. Absence of tendon healing was associated with poorer shoulder function (average Constant score, 69 ± 20 vs. 54 ± 18; P = .003) and a decreased Subjective Shoulder Value (72% vs. 54%, P = .002). Factors that were negatively associated with tendon healing were age ≥ 55 years (odds ratio [OR], 4.5 [95% confidence interval, 1.6-12.5]; P = .02), tendon retraction of stage 2 or higher (OR, 4.4 [95% confidence interval, 1.4-14.3]; P = .01), and fatty infiltration index2 (OR, 10.2; P .0001). No differences in retear rates were found between single-row and double-row cases. In 36 shoulders, tissue samples were harvested and submitted for bacteriologic culture analysis; 13 (36%) showed positive findings for infection (Cutibacterium acnes in 12 of 13) and associated antibiotic treatment was given. Overall, 25% of patients had unsatisfactory clinical results and 22% were disappointed or dissatisfied. At last follow-up, 4 patients (5.7%) underwent reoperations, with a second AR-RCR in 1 and conversion to reverse shoulder arthroplasty in 3.Despite careful patient selection and intraoperative complete footprint coverage, in this study the tendons did not heal to bone in 36% of cases after revision cuff surgery. The absence of tendon healing is associated with poorer clinical and subjective results. Patients aged ≥ 55 years and patients with larger tears (stage 2 or higher) and/or muscle fatty infiltration (fatty infiltration index2) have significantly lower rates of healing. Surgeons should be aware that structurally failed cuff repair may also be associated with low-grade infection.

Dust particles need to grow efficiently from micrometre sizes to thousands of kilometres to form planets. With the growth of millimetre to meter sizes being hindered by a number of barriers, the recent discovery that dust evolution is able to create `self-induced' dust traps shows promises. The condensation and sublimation of volatile species at certain locations, called snow lines, is also thought to be an important part of planet formation scenarios. Given that dust sticking properties change across a snow line, this raises the question: how do snow lines affect the self-induced dust trap formation mechanism? The question is particularly relevant with the multiple observations of the carbon monoxide (CO) snow line in protoplanetary discs, since its effect on dust growth and dynamics is yet to be understood. In this paper, we present the effects of snow lines in general on the formation of self-induced dust traps in a parameter study, then focus on the CO snow line. We find that for a range of parameters, a dust trap forms at the snow line where the dust accumulates and slowly grows, as found for the water snow line in previous work. We also find that, depending on the grains sticking properties on either side of the CO snow line, it could either be a starting or braking point for dust growth and drift. This could provide clues to understand the link between dust distributions and snow lines in protoplanetary disc observations., Comment: 14 pages, 14 figures

Resume Introduction La reconstruction du LCA est de plus en plus proposee chez des patients de plus de 50 ans. La chirurgie avait cependant mauvaise reputation dans cette categorie d’âge en raison essentiellement de complications a type de raideur. Une serie prospective de patients de plus de 50 ans operes d’une reconstruction du LCA (groupe 1) a ete comparee dans la meme periode a une population de patients de moins de 40 ans (groupe 2). L’hypothese principale de cette etude etait que la chirurgie du LCA donne les memes resultats fonctionnels apres 50 ans qu’avant 40 ans, sans augmentation du taux de complications. Methodes Il s’agissait d’une etude prospective multicentrique non randomisee de suivi clinique. Le suivi a ete prospectif sur un collectif de 228 patients de plus de 50 ans et 130 patients de moins de 40 ans, au sein de 10 centres prives et public. Les donnees epidemiologiques etaient notees. En pre- et postoperatoire la laxite clinique, la laximetrie differentielle, les scores KOOS, IKDC, Tegner, ACL-RSI et l’evaluation radiologique ont ete realises. Les donnees per-operatoires etaient notees. Les complications precoces (survenant avant 3 mois) et tardives (au-dela de 3 mois) etaient colligees. Les scores fonctionnels au dernier recul (14,2 mois (3,5–30,5) pour le groupe 1 et de 20,5 mois (11,4–29,4) pour le groupe 2) etaient compares entre les 2 groupes. Resultats L’etude epidemiologique a mis en evidence des differences entre les deux groupes : predominance des femmes dans le groupe 1, (59 % versus 35 %), un delai accident-chirurgie plus eleve dans le groupe 2 (23,6 semaines versus 8,7), une predominance des sports pivot-contact (sports d’equipe) dans le groupe 2 (49 % versus 6 %) et une predominance des sports pivot dans le groupe 1 (Ski). De meme, le score de Tegner etait plus faible apres 50 ans (5,2 versus 7,6). Nous avons retrouve plus de lesions meniscales dans le groupe 1 (68 % versus 36 %) et 76 % de lesions chondrales (versus 10 %). La laxite initiale etait identique (6,5 mm dans le groupe 1 et 6,7 mm dans le groupe 2). Le type de chirurgie utilise est similaire avec 86 % de greffe aux ischio-jambiers pour le groupe 1 et 89 % dans le groupe 2. Les complications precoces etaient plus importantes dans le groupe 1 (hematome) et le taux de complications tardives etait similaire. Au dernier recul, la laxite mesuree etait identique dans les deux groupes avec 2,2 mm de laxite residuelle. On retrouvait aussi le meme taux de test de Lachman avec arret dur et d’absence de ressaut rotatoire. Le resultat sur la qualite de vie a montre un score KOOS plus favorable dans le groupe 2 meme si le score ACL-RSI est identique. Le resultat global IKDC etait legerement meilleur dans le groupe 2 bien explique par l’existence des lesions arthrosiques chez les patients plus âges. Conclusion La chirurgie du LCA apres 50 ans donne de bons resultats, elle permet de corriger la laxite de la meme maniere que chez un patient de moins de 40 ans et avec les memes techniques et sans plus de complications. Le retour au sport se fait dans des delais similaires avec un retour au niveau initial. Niveau d’evidence III, etude prospective comparative non-randomisee.

Background Reverse shoulder arthroplasty (RSA) is offered to young patients with a failed previous arthroplasty or a cuff-deficient shoulder, but the overall results are still uncertain. We conducted a systematic review of the literature to report the midterm outcomes and complications of RSA in patients younger than 65 years. Methods A search of the MEDLINE and Cochrane electronic databases identified clinical studies reporting the results, at a minimum 2-year follow-up, of patients younger than 65 years treated with an RSA. The methodologic quality was assessed with the Methodological Index for Non-Randomized Studies score by 2 independent reviewers. Complications, reoperations, range of motion, functional scores, and radiologic outcomes were analyzed. Results Eight articles were included, with a total of 417 patients. The mean age at surgery was 56 years (range, 21-65 years). RSA was used as a primary arthroplasty in 79% of cases and revision of a failed arthroplasty in 21%. In primary cases, the indications were cuff tear arthropathy and/or massive irreparable cuff tear in 72% of cases. The overall complication rate was 17% (range, 7%-38%), with the most common complications being instability (5%) and infection (4%). The reintervention rate was 10% at 4 years, with implant revision in 7% of cases. The mean weighted American Shoulder and Elbow Surgeons score, active forward elevation, and external rotation were 64 points, 121°, and 29°, respectively. Conclusions RSA provides reliable clinical improvements in patients younger than 65 years with a cuff-deficient shoulder or failed arthroplasty. The complication and revision rates are comparable to those in older patients.

Resume Introduction Le 14 juillet 2016 un terroriste utilisant un camion a percute la foule sur la Promenade des Anglais a Nice. Le bilan final sera de 87 morts et de 458 blesses. L’objectif de cette etude etait d’evaluer la strategie de prise en charge des blesses osteo-articulaires lors de cet attentat. L’hypothese etait que cette strategie avait permis de respecter un delai de prise en charge inferieur a 6 heures pour les fractures ouvertes. Materiel et methode Il s’agit d’une etude retrospective monocentrique du 14 au 31 juillet 2016, incluant tous les patients victimes de l’attentat presentant une lesion osteo-articulaire et hospitalises a l’hopital Pasteur 2. Les criteres d’evaluation pour chaque patient etaient : l’âge, le sexe, le type de lesion, l’Injury Severity Score (ISS), le traitement par « Damage Controle Orthopedique » (DCO) ou par « Tout En Un Temps » (TEUT), son delai, la duree operatoire, les reprises. Le critere de jugement principal etait le delai de prise en charge des differentes lesions. Resultats Parmi les 182 patients admis aux urgences, 32 presentant des lesions osteo-articulaires ont necessite une hospitalisation. Dix-huit etaient traumatises severes (ISS > 15) et 11 polyfractures. Ils presentaient des lesions de traumatologie routiere avec 45 % de fractures des membres inferieurs dont 25 % etaient ouvertes. Quatorze patients ont ete operes la premiere nuit et 19 au total. Un DCO a ete utilise 12 fois et une strategie TEUT 7 fois. Tous les patients ont ete pris en charge dans des delais recommandes, en particulier les 21 fractures ouvertes et les 2 fractures fermees de diaphyse femorale. Discussion Tous les patients presentant des lesions osteo-articulaires ont ete pris en charge dans des delais recommandes. Pour 25 % d’entre eux, une chirurgie en un temps aurait ete possible dans ce contexte d’afflux massif non saturant. Type d’etude IV, etude retrospective.

Resume Introduction Le score de Constant permet une evaluation objective et subjective de la fonction de l’epaule. Il a ete montre que sa fiabilite inter-observateur etait mediocre pour certains de ses sous-items et qu’il n’est pas utilisable a distance. Hypothese Le score fonctionnel de Constant-Murley peut etre estime par un auto-questionnaire. Methodes Nous avons realise une etude prospective continue dans un service universitaire specialise en chirurgie de l’epaule. Chaque patient vu en consultation ou hospitalise pour une pathologie de l’epaule a recu un auto-questionnaire et a ete examine par un chirurgien. Le questionnaire en version francaise etait compose seulement de cases a cocher sans texte manuscrit. La correlation avec l’examen du chirurgien etait evaluee a l’aide des coefficients de correlation intra-classe et les ecarts de points a l’aide du test de Student pour echantillons apparies. Resultats Cent patients ont ete examines. La correlation entre les deux scores totaux etait excellente (r = 0,87), de meme que pour les sous-items mobilite (r = 0,85) et douleur (r = 0,78). Elle etait bonne pour le sous-item activite (r = 0,69) et passable pour la force (r = 0,57). Le score total etait en moyenne significativement sous-estime de −3 points par les patients remplissant un auto-questionnaire (CI 95 (−5 ; −1) ; p Conclusion L’auto-Constant en version francaise est un excellent estimateur global du score de Constant-Murley total, et de ses sous-items douleur et mobilite. Il est moins precis pour l’evaluation de la force mais les differences entre les sous-items se compensent et permet son utilisation en pratique courante. Type d’etude Etude prospective continue. Niveau d’etude Niveau II.

To evaluate mid-term clinical outcomes, complications, bone-block healing, and positioning using suture-button fixation for an arthroscopic Latarjet procedure.Patients with traumatic recurrent anterior instability and glenoid bone loss underwent guided arthroscopic Latarjet with suture-button fixation. We included patients with anterior shoulder instability, glenoid bone loss20%, and radiographic and clinical follow-up minimum of 24 months. Patients with glenoid bone loss20% or those that refused computed tomography imaging were excluded. Bone-block fixation was accomplished with 2 cortical buttons connected with a looped suture (4 strands). The looped suture was tied posteriorly with a sliding-locking knot. After transfer of the bone block on the anterior neck of the scapula, compression (100 N) was obtained with the help of a tensioning device. Clinical assessment was performed at 2 weeks, 3 months, 6 months, and then yearly with computed tomography completed at 2 weeks and 6 months to confirm bony union.A consecutive series of 136 patients underwent arthroscopic Latarjet with 121 patients (89%; mean age 27 years) available at final follow-up (mean follow-up, 26 months; range, 24-47 months). No neurologic complications or hardware failures were observed; no patients had secondary surgery for implant removal. The transferred coracoid process healed to the scapular neck in 95% of the cases (115/121). The bone block did not heal in 4 patients; it was fractured in 1 and lysed in another. Smoking was a risk factor associated with nonunion (P.001). The coracoid graft was positioned flush to the glenoid face in 95% (115/121) and below the equator in 92.5% (112/121). At final follow-up, 93% had returned to sports, whereas 4 patients (3%) had a recurrence of shoulder instability. The subjective shoulder value for sports was 94 ± 3.7%. Mean Rowe and Walch-Duplay scores were 90 (range, 40-100) and 91 (range, 55-100), respectively.Suture-button fixation is an alternative to screw fixation for the Latarjet procedure, obtaining predictable healing with excellent graft positioning, and avoiding hardware-related complications. There was no need for hardware removal after suture-button fixation. The systematic identification of the axillary and musculocutaneous nerves reduced risk of neurologic injury. A low instability recurrence rate and excellent return to pre-injury activity level was found. Suture-button fixation is simple, safe, and may be used for both open and arthroscopic Latarjet procedure.Level IV, therapeutic case series.

Background Prosthetic joint infections (PJI) are one of the most serious complication of arthroplasty. The management of PJI needs a multidisciplinary collaboration between orthopaedic surgeon, infectious disease specialist and microbiologist. In France, the management of PJI is organized around reference centres (CRIOACs). Our main objective was to perform an audit through a questionnaire survey based on clinical cases, to evaluate how French physicians manage PJI. Eligible participants were all physicians involved in care of patients presenting a PJI. Physicians could answer individually, or collectively during a multidisciplinary team meeting dedicated to PJI. The survey consisted as three questionnaires organized in a total of six clinical cases. Results Answers from the CRIOACs to the three questionnaires were 92, 77, and 53%. Between 32 and 39% of respondents did not administer antibiotic prophylaxis despite positive S. aureus pre-operative documentation. One-stage exchange strategy was widely preferred in all clinical cases, with no difference between CRIOACs and other centres. Rifampicin was prescribed for S. aureus PJI, in a situation with (90–92%) or without any prosthesis (70%). There was no consensus for the total antibiotic regimen duration, with prescriptions from six to 12 weeks for a majority of respondents. Conclusions Surgical strategy for the management of PJI was homogenous with a preference for a one-stage exchange strategy. Medical management was more heterogenous, which reflects the heterogeneity of those infections and difficulties to perform studies with strong conclusions.

Vortices are one of the most promising mechanisms to locally concentrate millimeter dust grains and allow the formation of planetesimals through gravitational collapse. The outer disk around the binary system HD 142527 is known for its large horseshoe structure with azimuthal contrasts of 3-5 in the gas surface density and of about 50 in the dust. Using 13CO and C18O J = 3-2 transition lines, we detect kinematic deviations to the Keplerian rotation, which are consistent with the presence of a large vortex around the dust crescent, as well as a few spirals in the outer regions of the disk. Comparisons with a vortex model suggest velocity deviations up to 350 m/s after deprojection compared to the background Keplerian rotation, as well as an extension of about 40 au radially on both sides of the vortex and 200 degrees azimuthally, yielding an azimuthal-to-radial aspect ratio of 5. Another alternative for explaining the vortex-like signal implies artificial velocity deviations generated by beam smearing in association with variations of the gas velocity due to gas pressure gradients at the inner and outer edges of the circumbinary disk. The two scenarios are currently difficult to differentiate and, for this purpose, would probably require the use of multiple lines at a higher spatial resolution. The beam smearing effect, due to the finite spatial resolution of the observations and gradients in the line emission, should be common in observations of protoplanetary disks and may lead to misinterpretations of the gas velocity, in particular around ring-like structures., 15 pages, 10 figures

Place: France; International audience; INTRODUCTION: In patients aged over-50 years, although data are sparse, results of anterior cruciate ligament (ACL) surgery are good if selection is correctly performed. However, non-operative treatment is usually proposed for this age group, as patients generally prefer just to scale down their sports activities. Non-operative results are acceptable, but with a high risk of residual instability, secondary lesions and lifestyle alteration. The main aim of the present study was to compare results between surgical versus non-surgical treatment of ACL tear in over-50 year-olds. Secondary objectives comprised assessing prognostic factors for poor functional outcome, and comparing the 2 groups epidemiologically to identify clinical decision-making factors. The study hypothesis was that results are comparable between operative and non-operative treatment of ACL tear.MATERIAL AND METHOD: Three hundred twenty patients were followed up prospectively: 92 non-surgical (NS group) and 288 surgical (S group). Classical epidemiological data were collected. Clinical laxity, differential laximetry, KOOS, IKDC, Tegner and ACL-RSI scores and radiologic assessment were collected pre- and postoperatively, as were intraoperative data. Early and late complications were collected.RESULTS: All patients were followed up. Patients were principally female, and were older, less athletic, with more stable knee and less severe functional impact in the NS group. Functional scores improved in both groups, and especially in group S, where sports scores were also better. In the NS group, laximetry at follow-up correlated with preoperative marked pivot-shift (p=0.024). Severe differential laxity was predictive of poor IKDC score (p=0.06). In the S group, laximetry at follow-up correlated with preoperative explosive pivot-shift (p\textless0.001), lateral meniscal lesion (p=0.007), use of hamstring tendon (p=0.007), and non-operated early complications (p=0.004). Factors for poor global KOOS score in group S comprised female gender (p\textless0.001), high BMI (p\textless0.001) and skiing (p=0.038). Factors for poor Tegner scores comprised skiing or team sport (p\textless0.05), isolated moderate medial osteoarthritis (p=0.01), and non-operated early complications (p=0.022). Factors for poor IKDC score comprised female gender (p=0.064), and non-operated early complications (p=0.019). Complications did not differ between groups. DISCUSSION/CONCLUSION: Results were satisfactory in both groups, with significant improvement in functional scores, but were better in group S. For NS patients, pivot sport was barely feasible and sports activity scores decreased. In case of severe laxity at diagnosis, surgical treatment should be proposed.LEVEL OF EVIDENCE: III; non-randomized prospective comparative series

The origin of the inner dust cavities observed in transition discs remains unknown. The segregation of dust and size of the cavity is expected to vary depending on which clearing mechanism dominates grain evolution. We present the results from the Discs Down Under program, an 8.8 mm continuum Australia Telescope Compact Array (ATCA) survey targeting 15 transition discs with large (> 20 au) cavities, and compare the resulting dust emission to Atacama Large millimetre/sub-millimetre Array (ALMA) observations. Our ATCA observations resolve the inner cavity for 8 of the 14 detected discs. We fit the visibilities and reconstruct 1D radial brightness models for 10 sources with a S/N > 5sigma. We find that, for sources with a resolved cavity in both wavebands, the 8.8 mm and sub-mm brightness distributions peak at the same radius from the star. We suggest that a similar cavity size for 8.8 mm and sub-mm dust grains is due to a dust trap induced by the presence of a companion., 18 pages, 11 figures

We present the implementation of a dust growth and fragmentation module in the public Smoothed Particle Hydrodynamics (SPH) code PHANTOM. This module is made available for public use with this paper. The coagulation model considers locally monodisperse dust size distributions around single values that are carried by the SPH particles. Along with the presentation of the model, implementation and tests, we showcase growth and fragmentation in a few typical circumstellar disc simulations and revisit previous results. The module is also interfaced with the radiative transfer code MCFOST, which facilitates the comparison between simulations and ALMA observations by generating synthetic maps. Circumstellar disc simulations with growth and fragmentation reproduce the `self-induced dust trap' mechanism first proposed by Gonzalez et al., which supports its existence. Synthetic images of discs featuring this mechanism suggest it would be detectable by ALMA as a bright axisymmetric ring at several tens of au from the star. With this paper, our aim is to provide a public tool to be able to study and explore dust growth in a variety of applications related to planet formation., 22 pages, 27 figures, accepted for publication in MNRAS

We present observations of the young multiple system UX Tauri to look for circumstellar disks and for signs of dynamical interactions. We obtained SPHERE/IRDIS deep differential polarization images in the J and H bands. We also used ALMA archival CO data. Large extended spirals are well detected in scattered light coming out of the disk of UX Tau A. The southern spiral forms a bridge between UX Tau A and C. These spirals, including the bridge connecting the two stars, all have a CO (3-2) counterpart seen by ALMA. The disk of UX Tau C is detected in scattered light. It is much smaller than the disk of UX Tau A and has a major axis along a different position angle, suggesting a misalignment. We performed PHANTOM SPH hydrodynamical models to interpret the data. The scattered light spirals, CO emission spirals and velocity patterns of the rotating disks, and the compactness of the disk of UX Tau C all point to a scenario in which UX Tau A has been perturbed very recently (about 1000 years) by the close passage of UX Tau C., Comment: Accepted for publication in Astronomy & Astrophysics Letters. (8pages, 8 figures). 2 movies will be available on-line

PURPOSE: Several studies report satisfactory clinical outcomes following ACLR in older patients, but none evaluated the effects of meniscal and cartilage lesions. The aim was to evaluate the influence of meniscal and cartilage lesions on outcomes of ACLR in patients aged over 50years. METHODS: The authors prospectively collected records of 228 patients that underwent primary ACLR, including demographics, time from injury to surgery, whether injuries were work related, and sports level (competitive, recreational, or none). At a minimum follow-up of 6months, knee injury and osteoarthritis outcome scores (KOOS), International Knee Documentation Committee (IKDC) score and Tegner activity level were recorded, and differential laxity was measured as the side-to-side difference in anterior tibial translation (ATT) using instrumented laximetry devices. Regression analyses were performed to determine associations between outcomes and meniscal and cartilage lesions as well as nine independent variables. RESULTS: A total of 228 patients aged 54.8?±?4.3years at index ACLR were assessed at a follow-up of 14.3?±?3.8months. KOOS subcomponents were 85?±?13 for symptoms, 91?±?10 for pain, 75?±?18 for daily activities, 76?±?18 for sport, and 88?±?12 for quality of life (QoL). The IKDC score was A for 84 (37%) knees, B for 96 (42%) knees, C for 29 (13%) knees, and D for 8 (4%) knees. Tegner scores showed a decrease (median 0, range -4 to 4) and differential laxity also decreased (median - 4, range - 23.5 to 6.0). KOOS symptoms worsened with higher BMI (p?=?0.038), for women (p?=?0.007) and for knees that had medial meniscectomy (p?=?0.029). KOOS pain worsened with higher BMI (p???0.001), for women (p?=?0.002) and for knees with untreated (p?=?0.047) or sutured (p?=?0.041) medial meniscal lesions. Differential laxity increased with follow-up (p?=?0.024) and in knees with lateral cartilage lesions (p?=?0.031). CONCLUSION: In primary ACLR for patients aged over 50years, female gender and medial meniscal lesions significantly compromised KOOS symptoms and pain, while lateral cartilage lesions significantly increased differential laxity. Compared to knees with an intact medial meniscus, those with sutured or untreated medial meniscal lesions had worse pain, while those in which the medial meniscus was resected had worse symptoms. These findings are clinically relevant as they could help surgeons with patient selection and adjusting expectations according to their functional demands. LEVEL OF EVIDENCE: III.

In recent years, several protoplanetary discs have been observed to exhibit spirals, both in scattered light and (sub)millimetre continuum data. The HD 100453 binary star system hosts such a disc around its primary. Previous work has argued that the spirals were caused by the gravitational interaction of the secondary, which was assumed to be on a circular orbit, coplanar with the disc (meaning here the large outer disc, as opposed to the very small inner disc). However, recent observations of the CO gas emission were found incompatible with this assumption. In this paper, we run SPH simulations of the gas and dust disc for seven orbital configurations taken from astrometric fits and compute synthetic observations from their results. Comparing to high-resolution ALMA $^{12}$CO data, we find that the best agreement is obtained for an orbit with eccentricity $e=0.32$ and semi-major axis $a=207$ au, inclined by $61^\circ$ relative to the disc plane. The large misalignment between the disc and orbit planes is compatible with the tidal evolution of a circumprimary disc in an eccentric, unequal-mass binary star., Accepted for publication in MNRAS. 21 pages, 28 figures

International audience; Background: A consequence of the steady growth in the worldwide population of elderly individuals who remain in good health and continue to engage in sports is an increase in the incidence of anterior cruciate ligament (ACL) rupture occurring after 50 years of age. ACL reconstruction was formerly reserved for young athletes but now seems to produce good outcomes in over 50s. The type of graft and graft fixation method were selected empirically until now, given the absence of investigations into potential relationships of these two parameters with the outcomes. The objective of this study was to assess associations linking the type of graft and the method of femoral graft fixation to outcomes in patients older than 50 years at ACL reconstruction. Hypothesis: The operative technique is not associated with the clinical outcomes or differential laxity. Material and methods: A multicentre retrospective cohort of 398 patients operated between 1 January 2011 and 31 December 2015 and a multicentre prospective cohort of 228 patients operated between 1 January 2016 and 30 June 2017 were conducted. Mean follow-up was 42.7 months in the retrospective cohort and 14.2 months in the prospective cohort. The primary evaluation criterion was the clinical outcome as assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Tegner Activity Score (TAS). Differential laxity was the secondary evaluation criterion. The Wilcoxon rank sum test and Kruskal-Wallis test were used to compare groups, and p-values < 0.05 were considered significant. Results: In the retrospective and prospective cohorts, hamstring tendons were used in 269 (67.6%) and 197 (86.4%) patients and extensor apparatus tendons in 124 (31.2%) and 31 (13.6%) patients. Femoral fixation in the retrospective cohort was cortical in 81 (20.4%) cases, by press-fit in 112 (28.1%) cases, and by interference screw in 205 (51.5%) cases; corresponding figures in the prospective cohort were 135 (59.2%), 17 (7.5%), and 76 (33.3%). The multivariate analysis of the retrospective data identified no significant associations of graft type or femoral fixation type with the KOOS, TAS, or differential laxity values. In the prospective cohort, hamstring grafts were associated with 0.6 mm of additional laxity (p = 0.007); compared to cortical fixation, press-fit fixation of patellar tendon grafts was associated with 0.3 mm of additional laxity (p = 0.029) and a 0.5-point lower TAS value (p = 0.033), with no difference in KOOS values. None of these differences were clinically significant. Discussion: The various ACL reconstruction techniques used in patients older than 50 years produce similar outcomes. The technique can be chosen based on surgeon preference without regard for patient age. Level of evidence: IV.

Volar plating is one of the most used surgical treatments for dorsally displaced extra-articular distal radius fractures. However, the reduction of the dorsal tilt can be difficult. It usually requires a flexion maneuver of the wrist while maintaining and screwing the plate, which is cumbersome. Plate positioning also is a crucial step and is sometimes difficult because of the large size of the plate relative to the width of the distal radius. We use an epiphysis-first technique. We place all the epiphyseal screws before reduction, and then we take advantage of the anatomical shape of a locking plate to automatically reduce the dorsal tilt by fixing the proximal radius to the plate with cortical compression screws. To ensure easy and accurate positioning of the plate, we drill a distal medial pilot hole in a free-hand fashion 10 mm proximal to the watershed line and 10 mm lateral to the medial rim of the radius, without positioning the plate. This allows a clear view of the location of this first hole. The locking plate is then applied to the distal radius with help of a monocortical non-locking screw, and it is controlled under fluoroscopy. When this medial pilot hole is properly positioned and the plate correctly tilted on the anteroposterior view, the remaining epiphyseal holes are filled with locking screws. Then the plate is fixed on the proximal radius with bicortical compression screws, allowing an automatic reduction of the epiphyseal dorsal tilt. We believe this technique is a safe and reproducible way to position volar plates and to reduce anatomically the dorsal tilt in extra-articular posteriorly displaced distal radius fractures (AO A2 and A3). Furthermore, the automatic fracture reduction provided by this technique decreases operation time and radiation.

Grain growth and fragmentation are important processes in building up large dust aggregates in protoplanetary discs. Using a 3D two-phase (gas-dust) SPH code, we investigate the combined effects of growth and fragmentation of a multi-phase dust with different fragmentation thresholds in a time-evolving disc. We find that our fiducial disc, initially in a fragmentation regime, moves toward a pure-growth regime in a few thousands years. Timescales change as a function of the disc and dust properties. When fragmentation is efficient, it produces, in different zones of the disc, Fe/Si and rock/ice ratios different from those predicted when only pure growth is considered. Chemical fractionation and the depletion/enrichment in iron observed in some chondrites can be linked to the size-density sorting and fragmentation properties of precursor dusty grains . We suggest that aggregation of chondritic components could have occurred where/when fragmentation was not efficient if their aerodynamical sorting has to be preserved. Chondritic components would allow aerodynamical sorting in a fragmentation regime only if they have similar fragmentation properties. We find that, in the inner disc, and for the same interval of time, fragmenting dust can grow larger when compared to the size of grains predicted by pure growth. This counter-intuitive behaviour is due to the large amount of dust which piles up in a fragmenting zone followed by the rapid growth that occurs when this zone transitions to a pure growth regime. As an important consequence, dust can overcome the radial-drift barrier within a few thousands years., Comment: Accepted, MNRAS. ArXiv version, some figures compressed to fit the max allowed size

Resume Introduction L’objectif de cette etude etait d’evaluer la consolidation osseuse des butees coracoidiennes fixees par suture et boutons corticaux. L’hypothese etait que (1) la fixation des butees coracoidiennes par suture et boutons corticaux pourrait etre une alternative a la fixation par vis, permettant d’obtenir la consolidation osseuse et (2) reduirait le taux de complications traditionnellement rapporte avec les vis. Materiel et methode Etude retrospective de 70 patients (âge moyen 27 ans) presentant une instabilite anterieure recidivante de l’epaule, operes par butee coracoidienne sous arthroscopie. Les patients ont ete inclus dans 2 groupes en fonction du positionnement de la butee sur la face anterieure du col de la glene : groupe A (35 patients) butee en position debout (technique Bristow) et groupe B (35 patients) butee en position couchee (technique Latarjet). La fixation de la butee etait assuree par deux boutons corticaux relies par des fils de suture. Un scanner postoperatoire etait realise a 2 semaines pour controler le positionnement et a 6 mois minimum pour controler la consolidation osseuse de la butee. Resultats La butee etait sous-equatoriale dans 93 % des cas et affleurante au bord anterieur de la glene dans 94 % des cas. La consolidation osseuse globale etait de 83 % (58/70), avec 74 et 91 % respectivement dans les groupes A et B. Il n’a pas ete constate de migration de la butee ni de bris de materiel. Conclusions (1) La fixation de la butee coracoidienne par suture et boutons corticaux est une alternative a la fixation par vis permettant d’obtenir la consolidation osseuse. (2) La consolidation osseuse a ete obtenue de facon plus reproductible en position couchee et (3) les complications signalees classiquement avec les vis n’ont pas ete retrouvees. Niveau de preuve Niveau IV.

Background On 14 July 2016, a terrorist drove a truck through the crowd on the Promenade des Anglais in Nice, France, killing 87 people and injuring 458. The objective of this study was to evaluate the management strategy used to handle the osteo-articular injuries caused by this attack. Hypothesis The management strategy used ensured that open fractures were treated within 6 hours. Material and method This single-centre retrospective study included all victims of the attack admitted to the Pasteur 2 Hospital in Nice, France, for osteo-articular injuries, and treated between 14 and 31 July 2016. The following data were collected for each patient: age, sex, type of injury, Injury Severity Score (ISS), whether the damage control orthopaedics (DCO) or early total care (ETC) approach was followed, time from injurytotreatment, operative time, and surgical revisions. The primary outcome measure was the injury to treatment time for each lesion. Results Of the 182 patients admitted to the emergency department, 32 required admission for osteo-articular injuries, including 18 with severe injuries (ISS > 15) and 11 with multiple fractures. Their injuries were of the type seen in traffic accidents. Of the 87 fractures, 45% involved the lower limbs and 25% were open fractures. Surgery was performed in 14 patients on the first night (14 to 15 July) and in 19 patients overall. The approach was DCO in 12 and ETC in 7 of these 19 patients. All lesions were managed within recommended time intervals, including the 21 open fractures and 2 closed femoral shaft fractures. Discussion Injury-to-surgery time complied with recommendations in all cases. In 25% of cases, ETC would have been feasible during the mass influx of patients without hospital capacity saturation. Level of evidence IV, retrospective observational study.

The Planet Formation Imager (PFI) is a near- and mid-infrared interferometer project with the driving science goal of imaging directly the key stages of planet formation, including the young proto-planets themselves. Here, we will present an update on the work of the Science Working Group (SWG), including new simulations of dust structures during the assembly phase of planet formation and quantitative detection efficiencies for accreting and non-accreting young exoplanets as a function of mass and age. We use these results to motivate two reference PFI designs consisting of a) twelve 3m telescopes with a maximum baseline of 1.2km focused on young exoplanet imaging and b) twelve 8m telescopes optimized for a wider range of young exoplanets and protoplanetary disk imaging out to the 150K H2O ice line. Armed with 4x8m telescopes, the ESO/VLTI can already detect young exoplanets in principle and projects such as MATISSE, Hi-5 and Heimdallr are important PFI pathfinders to make this possible. We also discuss the state of technology development needed to make PFI more affordable, including progress towards new designs for inexpensive, small field-of-view, large aperture telescopes and prospects for Cubesat-based space interferometry., Comment: Presented at 2018 SPIE Astronomical Telescopes + Instrumentation, Austin, Texas, USA. See www.planetformationimager.org for more information

Introduction The Constant score, allows an objective and subjective assessment of the shoulder function. It has been proven to have a poor interobserver reliability for some of its aspects and is not usable as a remote assessment tool. Hypothesis The Constant-Murley functional shoulder score can be assessed with a self-administered questionnaire. Methods We conducted a prospective continuous study in a shoulder-specialized service. For each patient seen in consultation or hospitalized for a shoulder pathology, a self-administered questionnaire was delivered, and a clinical examination was performed by a surgeon. The questionnaire, in French language, was composed of checkboxes only, with pictures preferred over text for most items. Correlations with surgeon examination were assessed with the intraclass correlation coefficients, differences with the paired t-test. Results One hundred consecutive patients were analyzed. Correlation between the two scores was excellent (0.87), as were the range of motion and the pain subscores (0.85 and 0.78), good for the activity (0.69) and fair for the strength (0.57). The mean total score was 3 points lower for the self-administered questionnaire (CI95 [−5; −1]; p 0.05) but pain and force were slightly different (+0.8/15; −3.0/25; p Conclusion The Auto-Constant questionnaire in French is an excellent estimator of the Constant score, and of its pain and mobility sub-scores. It is less accurate for the evaluation of the strength, but differences between sub-scores compensate and allow its use in daily practice. Level of proof II, Prospective continuous clinical series.

Introduction La degenerescence mucoide du ligament croise anterieur (DMLCA) se manifeste par des douleurs posterieures du genou et une limitation de la flexion. Si plusieurs auteurs favorisent les gestes conservateurs (resection partielle du LCA, plastie de l’echancrure), il n’existe pas de consensus concernant le traitement de cette pathologie. L’hypothese de cette etude etait que la resection complete du LCA sans reconstruction permet un traitement efficace de la douleur posterieure et une recuperation de la flexion. Materiel et methodes Vingt-trois patients (24 genoux) âges de 51 ans en moyenne (28 a 74 ; sex ratio 0,4) ont ete operes consecutivement d’une resection complete du LCA pour DMLCA entre 2011 et 2017 ; puis evalues retrospectivement cliniquement, radiologiquement et sur le plan fonctionnel par les scores IKDC subjectif et KOOS, avec un suivi minimum de 12 mois. Les criteres de jugement (CDJ) principaux etaient la diminution de la douleur posterieure a l’echelle numerique simple et le gain de flexion. Les CDJ secondaires etaient la laxite, l’instabilite et l’evolution arthrosique. Resultats La douleur posterieure preoperatoire moyenne etait de 6,5/10 et la flexion pre-operatoire moyenne de 107°. Au recul moyen de 3 ans, la douleur posterieure etait de 1/10 (p = 0,0001) et le gain de flexion de 28 degres (p = 0,0001). L’IKDC subjectif avait progresse de 38,8 a 71,9/100 (p > 0,001). Les items du KOOS Symptomes, Douleur et Vie quotidienne etaient superieurs a 80/100. La laxite differentielle au TELOS ? (n = 18) etait de 4 mm (de 0 a 13 mm). Six patients (25 %) ont developpe une instabilite clinique, dont un seul a necessite une reconstruction secondaire du LCA. Aucun parametre preoperatoire n’etait correle a l’apparition d’instabilite post-operatoire. Pour 7 patients (29 %), l’arthrose radiologique avait progresse d’un grade IKDC. Discussion L’hypothese de cette etude est verifiee : la resection complete du LCA pour DMLCA est efficace sur les douleurs posterieures et sur la flexion du genou. Cependant, elle engendre une laxite anterieure, une instabilite et une evolution arthrosique dont les patients doivent etre prevenus si cette strategie leur est proposee. Conclusion La resection complete du LCA pour Degenerescence Mucoide, si elle engendre des benefices significatifs sur la douleur posterieure et la flexion du genou, expose a des risques de laxite, d’instabilite et d’evolution arthrosique. Elle ne peut etre proposee que dans un cadre precis d’information des benefices et des risques.

Planet formation is thought to occur in discs around young stars by the aggregation of small dust grains into much larger objects. The growth from grains to pebbles and from planetesimals to planets is now fairly well understood. The intermediate stage has however been found to be hindered by the radial-drift and fragmentation barriers. We identify a powerful mechanism in which dust overcomes both barriers. Its key ingredients are i) backreaction from the dust onto the gas, ii) grain growth and fragmentation, and iii) large-scale gradients. The pile-up of growing and fragmenting grains modifies the gas structure on large scales and triggers the formation of pressure maxima, in which particles are trapped. We show that these self-induced dust traps are robust: they develop for a wide range of disc structures, fragmentation thresholds and initial dust-to-gas ratios. They are favored locations for pebbles to grow into planetesimals, thus opening new paths towards the formation of planets., 15 pages, 16 figures. Added a 1-page erratum correcting an inconsequential error in Appendix C. A higher resolution version of the paper, as well as the online videos, are available at https://cral.univ-lyon1.fr/labo/perso/jean-francois.gonzalez/Papers/SIDT/

The size and density of dust grains determine their response to gas drag in protoplanetary discs. Aerodynamical (size x density) sorting is one of the proposed mechanisms to explain the grain properties and chemical fractionation of chondrites. However, the efficiency of aerodynamical sorting and the location in the disc in which it could occur are still unknown. Although the effects of grain sizes and growth in discs have been widely studied, a simultaneous analysis including dust composition is missing. In this work we present the dynamical evolution and growth of multicomponent dust in a protoplanetary disc using a 3D, two-fluid (gas+dust) Smoothed Particle Hydrodynamics (SPH) code. We find that the dust vertical settling is characterised by two phases: a density-driven phase which leads to a vertical chemical sorting of dust and a size-driven phase which enhances the amount of lighter material in the midplane. We also see an efficient radial chemical sorting of the dust at large scales. We find that dust particles are aerodynamically sorted in the inner disc. The disc becomes sub-solar in its Fe/Si ratio on the surface since the early stage of evolution but sub-solar Fe/Si can be also found in the outer disc-midplane at late stages. Aggregates in the disc mimic the physical and chemical properties of chondrites, suggesting that aerodynamical sorting played an important role in determining their final structure., Comment: Astroph version. MNRAS: Accepted 2017 March 30. Received 2017 March 30; in original form 2016 May 10