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- Engler, Ian D, et al.
(author)
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Revision Rates After Primary Allograft ACL Reconstruction by Allograft Tissue Type in Older Patients.
- 2023
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In: Orthopaedic journal of sports medicine. - 2325-9671. ; 11:9
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Journal article (peer-reviewed)abstract
- While there is extensive literature on the use of allograft versus autograft in anterior cruciate ligament (ACL) reconstruction, there is limited clinical evidence to guide the surgeon in choice of allograft tissue type.To assess the revision rate after primary ACL reconstruction with allograft and to compare revision rates based on allograft tissue type and characteristics.Cohort study; Level of evidence, 3.Patients who underwent primary allograft ACL reconstructions at a single academic institution between 2015 and 2019 and who had minimum 2-year follow-up were included. Exclusion criteria were missing surgical or allograft tissue type data. Demographics, operative details, and subsequent surgical procedures were collected. Allograft details included graft tissue type (Achilles, bone-patellar tendon-bone [BTB], tibialis anterior or posterior, semitendinosus, unspecified soft tissue), allograft category (all-soft tissue vs bone block), donor age, irradiation duration and intensity, and chemical cleansing process. Revision rates were calculated and compared by allograft characteristics.Included were 418 patients (age, 39 ± 12 years; body mass index, 30 ± 9 kg/m2). The revision rate was 3% (11/418) at a mean follow-up of 4.9 ± 1.4 years. There were no differences in revision rate according to allograft tissue type across Achilles tendon (3%; 3/95), BTB (5%; 3/58), tibialis anterior or posterior (3%; 5/162), semitendinosus (0%; 0/46), or unspecified soft tissue (0%; 0/57) (P = .35). There was no difference in revision rate between all-soft tissue versus bone block allograft (6/283 [2%] vs 5/135 [4%], respectively; P = .34). Of the 51% of grafts with irradiation data, all grafts were irradiated, with levels varying from 1.5 to 2.7 Mrad and 82% of grafts having levels of <2.0 Mrad. There was no difference in revision rate between the low-dose and medium-to high-dose irradiation cohorts (4% vs 6%, respectively; P = .64).Similarly low (0%-6%) revision rates after primary ACL reconstruction were seen regardless of allograft tissue type, bone block versus all-soft tissue allograft, and sterilization technique in 418 patients with mean age of 39 years. Surgeons may consider appropriately processed allograft tissue with or without bone block when indicating ACL reconstruction in older patients.
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- Herman, Zachary J, et al.
(author)
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Overhead Athletes Have Comparable Intraoperative Injury Patterns and Clinical Outcomes to Nonoverhead Athletes Following Surgical Stabilization for First-Time Anterior Shoulder Instability at Average 6 Year Follow Up
- 2023
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In: Journal of shoulder and elbow surgery. - 1532-6500.
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Journal article (peer-reviewed)abstract
- Anterior shoulder instability is a common problem affecting young, athletic populations that results in potential career-altering functional limitations. However, little is known regarding the differences in clinical outcomes after operative management of overhead versus nonoverhead athletes presenting with first-time anterior shoulder instability. We hypothesized that overhead athletes would have milder clinical presentations, similar surgical characteristics, and diminished postoperative outcomes when compared to nonoverhead athletes after surgical stabilization following first-time anterior shoulder instability episodes.Patients with first-time anterior shoulder instability events (subluxations and dislocations) undergoing operative management between 2013-2020 were included. Exclusion criteria included multiple dislocations and multidirectional shoulder instability. Baseline demographics, imaging, exam, and intraoperative findings were retrospectively collected. Patients were contacted to collect postoperative patient reported outcomes (PROs) including American Shoulder and Elbow Surgeons (ASES) score, Western Ontario Shoulder Instability (WOSI) score, Brophy activity index, Subjective Shoulder Value (SSV), in addition to return to work/sport rates, recurrent dislocation, and revision rates.A total of 256 patients met inclusion criteria, of which 178 (70%) patients were nonoverhead athletes. Mean age of the entire population was 23.1 years. There was no significant difference in concomitant shoulder pathology nor preoperative range of motion or strength between cohorts. A greater proportion of overhead athletes presented with instability events not requiring manual reduction (defined as subluxations; 64.1% vs. 50.6%; p < 0.001) and underwent arthroscopic surgery (97% vs. 76%, p < 0.001) compared to nonoverhead athletes. A smaller proportion of overhead athletes underwent open soft-tissue stabilization compared to nonoverhead athletes (1% vs. 19%, p < 0.001). Outcome data on 60 patients with average follow-up 6.7 years was available. No significant differences were found between groups with respect to recurrent postoperative instability event rate (13.0% overhead vs. 16.8% nonoverhead) or revision (13.0% overhead vs. 11.1% nonoverhead) rates, ASES, WOSI, BROPHY, SSV, or rates return to work/sport.Overhead athletes who underwent surgery after an initial instability event were more likely to present with subluxations compared to nonoverhead athletes. With limited follow-up subject to biases, this study found no differences in recurrence or revision rates, postoperative PROs, or return to work/sport rates between the overhead and nonoverhead athletes undergoing shoulder stabilization surgery following first-time instability events. While larger prospective studies are necessary to draw firmer conclusions, the findings of this study suggest that overhead athletes can be considered in the same treatment pathway for first-time dislocation as nonoverhead athletes.
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- Tinetti, G., et al.
(author)
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A chemical survey of exoplanets with ARIEL
- 2018
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In: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 46:1, s. 135-209
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Journal article (peer-reviewed)abstract
- Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.
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| 5. |
- Tinetti, Giovanna, et al.
(author)
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The EChO science case
- 2015
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In: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 40:2-3, s. 329-391
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Journal article (peer-reviewed)abstract
- The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune-all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10(-4) relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength coverage of at least 0.55 to 11 mu m with a goal of covering from 0.4 to 16 mu m. Only modest spectral resolving power is needed, with R similar to 300 for wavelengths less than 5 mu m and R similar to 30 for wavelengths greater than this. The transit spectroscopy technique means that no spatial resolution is required. A telescope collecting area of about 1 m(2) is sufficiently large to achieve the necessary spectro-photometric precision: for the Phase A study a 1.13 m(2) telescope, diffraction limited at 3 mu m has been adopted. Placing the satellite at L2 provides a cold and stable thermal environment as well as a large field of regard to allow efficient time-critical observation of targets randomly distributed over the sky. EChO has been conceived to achieve a single goal: exoplanet spectroscopy. The spectral coverage and signal-to-noise to be achieved by EChO, thanks to its high stability and dedicated design, would be a game changer by allowing atmospheric composition to be measured with unparalleled exactness: at least a factor 10 more precise and a factor 10 to 1000 more accurate than current observations. This would enable the detection of molecular abundances three orders of magnitude lower than currently possible and a fourfold increase from the handful of molecules detected to date. Combining these data with estimates of planetary bulk compositions from accurate measurements of their radii and masses would allow degeneracies associated with planetary interior modelling to be broken, giving unique insight into the interior structure and elemental abundances of these alien worlds. EChO would allow scientists to study exoplanets both as a population and as individuals. The mission can target super-Earths, Neptune-like, and Jupiter-like planets, in the very hot to temperate zones (planet temperatures of 300-3000 K) of F to M-type host stars. The EChO core science would be delivered by a three-tier survey. The EChO Chemical Census: This is a broad survey of a few-hundred exoplanets, which allows us to explore the spectroscopic and chemical diversity of the exoplanet population as a whole. The EChO Origin: This is a deep survey of a subsample of tens of exoplanets for which significantly higher signal to noise and spectral resolution spectra can be obtained to explain the origin of the exoplanet diversity (such as formation mechanisms, chemical processes, atmospheric escape). The EChO Rosetta Stones: This is an ultra-high accuracy survey targeting a subsample of select exoplanets. These will be the bright "benchmark" cases for which a large number of measurements would be taken to explore temporal variations, and to obtain two and three dimensional spatial information on the atmospheric conditions through eclipse-mapping techniques. If EChO were launched today, the exoplanets currently observed are sufficient to provide a large and diverse sample. The Chemical Census survey would consist of > 160 exoplanets with a range of planetary sizes, temperatures, orbital parameters and stellar host properties. Additionally, over the next 10 years, several new ground- and space-based transit photometric surveys and missions will come on-line (e.g. NGTS, CHEOPS, TESS, PLATO), which will specifically focus on finding bright, nearby systems. The current rapid rate of discovery would allow the target list to be further optimised in the years prior to EChO's launch and enable the atmospheric characterisation of hundreds of planets.
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