"It's all in my head now" Readiness for return to sport after anterior cruciate ligament reconstruction

Bakgrunn: Det er utfordrende for klinikere å avgjøre om pasienter er klare for å returnere til idrett etter en korsbåndsoperasjon. Grunnen til dette er uklarhet knyttet til hvilke tester og kriterier som bør utgjøre grunnlaget for avgjørelsen. I tillegg til funksjonelle tester, har evaluering av psykologisk beredskap for å returnere til idrett blitt foreslått som en komponent i vurderingen. Videre er det uklart om undersøkelse av knelaksitet bør vektlegges. Få studier har prospektivt undersøkt prediktiv validitet av psykologisk beredskap, funksjonelle tester og knelaksitet etter korsbåndsoperasjon. Formål: Å undersøke prediktiv validitet av et retur-til-idrett testbatteri, som inkluderer psykologisk og fysisk beredskap, for retur til idrett og risiko for nye kneskader etter korsbåndsoperasjon. Et tilleggsmål var å utforske forholdet mellom de fysiske testene og spørreskjemaene, spesielt forholdet mellom knelaksitet og psykologisk beredskap. Metoder: I denne prospektive studien ble ACL–Return to Sport after Injury Scale (ACL-RSI-skala) oversatt fra engelsk til norsk. Deretter ble måleegenskapene til det norske skjemaet undersøkt. Ni til 12 måneder etter korsbåndsrekonstruksjon ble 197 pasienter inkludert. De fylte ut ACL-RSI-skala og spørreskjema som målte relaterte konstrukt. I tillegg gjennomførte 146 pasienter hoppetester og 142 pasienter styrketester av lårmuskulatur. Sekstien pasienter fylte ut ACL-RSI-skala to ganger med èn ukes mellomrom. For å undersøke prediktiv verdi av den kombinerte retur-til-idrett vurderingen (psykologisk og fysisk beredskap), ble 129 pasienter fra samme kohort fulgt opp to år etter operasjon. Retur til samme nivå og type idrett som før operasjonen (ja/nei) og nye kneskader ble registrert. Pasienter som hadde gjennomgått klinisk undersøkelse og som hadde fylt ut ACL-RSI-skala (N=132) ble inkludert i analysene for å undersøke assosiasjon mellom psykologisk beredskap og knelaksitet samt prediktiv verdi av knelaksitet. Klinisk undersøkelse av knelaksitet bestod av Lachman test, instrumentert måling av knelaksitet (KT-1000) og Pivot Shift test. Resultater: Artikkel I: ACL-RSI-skala hadde gode målegenskaper. Faktoranalyse indikerte at èn underliggende dimensjon kunne beskrive svarene. Intern konsistens (α 0.95) og test-retest reliabilitet (ICC 0.94) var god og målefeilen var liten (SEM 5.7). Seks av syv hypoteser, som utgjorde grunnlaget for å bedømme konstruktvaliditet, ble bekreftet. Artikkel II: Førtito prosent av pasientene hadde returnert til idretten sin to år etter operasjon. Høyere ACL-RSI skår (OR=1.03) og høyere alder (OR=1.05) predikerte retur til idrett. En ACL-RSI skår på ˂47 identifiserte pasienter som stod i risiko for å ikke returnere (area under the curve 0.69) med 85% sensitivitet og 45% spesifisitet. De funksjonelle testene predikerte ikke retur til idrett. Ingen av de 29 pasientene som bestod alle kriteriene i testbatteriet fikk en ny kneskade innen to år etter operasjon, sammenlignet med 13 kneskader blant de som ikke bestod kriteriene (P=0.037). Artikkel III: Det var en liten, men statistisk signifikant assosiasjon mellom psykologisk beredskap for retur til idrett og knelaksitet (Lachman test og KT-1000 måling). Høyere ACL-RSI skår (OR=1.04), mindre knelaksitet (KT-1000 måling, OR=0.79) og høyere alder (OR=1.07) predikerte evne til å returnere til idrett med en forklart varians på 33%. Konklusjoner: ACL-RSI-skala har gode måleegenskaper. Høyere alder, psykologisk beredskap og mindre knelaksitet predikerer pasienters evne til å returnere til idrett to år etter en korsbåndsoperasjon. De funksjonelle testene hadde ikke prediktiv verdi for retur, men funnet av at ingen av pasientene som bestod kriteriene i testbatteriet skadet seg på nytt frem til to års kontrollen er interessant. Dette indikerer at funksjonelle tester kan ha prediktiv verdi for risiko for kneskade. Det var en liten sammenheng mellom mindre knelaksitet og bedre psykologisk beredskap for å returnere til idrett. Implikasjoner: Evaluering av psykologisk beredskap og knelaksitet bør inngå i en retur-til-idrett vurdering fordi disse faktorene er informative om pasienters evne til å returnere til idrett etter en korsbåndsoperasjon. Studiene ga indikasjoner på at de funksjonelle testene kan være informative om pasientenes risiko for å skade kneet sitt på nytt, men videre arbeid trengs for å undersøke dette.Background: Deciding when patients are ready for returning to sport after an ACL injury is challenging because the evidence for which tests and criteria to include in the return-to-sport assessment is unclear. Inclusion of psychological readiness evaluation has been suggested and the role of knee laxity measures in these assessments is unclear. Few studies have prospectively examined the predictive validity of psychological readiness, physical tests and clinical tests for knee laxity for success after ACL reconstruction. Purpose: To examine the predictive validity of return-to-sport assessment for ability to return to pre-injury level of sport and risk of further knee injuries after ACL reconstruction when evaluation of psychological and physical readiness were combined. Further, to explore the relationship between the tests and questionnaires included in the test battery, especially the association between knee laxity and psychological readiness. Methods: In this prospective cohort study, The ACL-Return to Sport after Injury (ACL-RSI) scale was translated into Norwegian (ACL-RSI-No) before the measurement properties were examined. Nine to 12 months after reconstruction, 197 patients completed the ACL-RSI-No and questionnaires hypothesized to measure related constructs. One hundred and forty-six patients completed single-legged hop tests and 142 patients completed knee extension and flexion strength tests. Sixty-one patients completed the ACL-RSI-No twice with a one-week interval. Face and structural validity, internal consistency, test-retest reliability, measurement error and construct validity were examined. To examine predictive validity of the return-to-sport assessment including psychological readiness evaluation, 129 patients from the same cohort were followed-up at two years after surgery. Return to sport (yes/no) and knee injuries were registered. To examine the predictive ability of knee laxity measures and the relationship between knee laxity and psychological readiness, patients from the cohort who had undergone evaluation of psychological readiness and knee laxity nine to twelve months after surgery were included (N=132). The knee laxity measures included The Lachman test, instrumented knee laxity (KT-1000) and the Pivot Shift test. Results: Paper I: The ACL-RSI-No had good measurement properties with factor analyses indicating that one underlying construct determined the responses. Internal consistency (α 0.95) and test-retest reliability (ICC 0.94) were high and measurement error was low (SEM 5.7). Six of seven hypotheses were confirmed when examining construct validity. Paper II: Forty-two percent of the patients returned to pre-injury level of sports two years after surgery. Higher ACL-RSI scores (OR=1.03) and older age (OR=1.05) predicted ability to return. An ACL-RSI score of ˂47 identified patients at risk of not returning to sport (area under the curve 0.69) with 85% sensitivity and 45% specificity. None of the functional tests predicted ability to return. However, none of the 29 patients who passed the return-to-sport criteria sustained a new knee injury during follow-up, compared to the 13 knee injured in the group of non-passers (P=0.037). Paper III: There were small, but statistically significant associations between the Lachman test and the KT-1000 measurements and the ACL-RSI. There was no relationship between the Pivot Shift test and the ACL-RSI. Higher psychological readiness (OR=1.04), less knee laxity measured with the KT-1000 (OR=0.79) and older age (OR=1.07) predicted ability to return to sport with an explained variance of 33%. Conclusions: The ACL-RSI-No had good measurement properties. Older age, higher psychological readiness and less knee laxity predicted ability to return to pre-injury level of sports two years after surgery. None of the patients who passed the return-to-sport criteria sustained a new knee injury during follow-up. There was a statistically significant, but small association between knee laxity and psychological readiness. Implications: Evaluation of psychological readiness and knee laxity should be incorporated into return-to-sport assessments because they provide information about the patient’s ability to return to sport. The functional tests did not predict ability to return to sport, but the finding that none of the patients who passed the return-to-sport criteria suffered a new knee injury indicates that functional tests may be informative about risk of future knee injury. Further studies are needed to determine whether this is the case. Patients who have less knee laxity feel more mentally prepared for sport resumption.Doktorgradsavhandlin

Crustal structure beneath the Trondelag Platform and adjacent areas of the Mid-Norwegian margin, as derived from wide-angle seismic and potential field data

The outer mid-Norwegian margin is characterized by strong breakup magmatism and has been extensively surveyed. The crustal structure of the inner continental shelf, however, is less studied, and its relation to the onshore geology, Caledonian structuring, and breakup magmatism remains unclear. Two Ocean Bottom Seismometer profiles were acquired across the Trøndelag Platform in 2003, as part of the Euromargins program. Additional-land stations recorded the marine shots. The P-wave data were modeled by ray-tracing, supported by gravity modeling. Older multi-channel seismic data allowed for interpretation of stratigraphy down to the top of the Triassic. Crystalline basement velocity is ~6 km s-1 onshore. Top basement is difficult to identify offshore, as velocities (5.3-5.7 km s-1) intermediate between typical crystalline crust and Mesozoic sedimentary strata appear 50-80 km from the coast. This layer thickens towards the Klakk-Ytreholmen Fault Complex and predates Permian and later structur-ing. The velocities indicate sedimentary rocks, most likely Devonian. Onshore late- to post-Caledonian detachments have been proposed to extend offshore, based on the magnetic anomaly pattern. We do not find the expected correlation between upper basement velocity structure and detachments. However, there is a distinct, dome-shaped lower-crustal body with a velocity of 6.6-7.0 km s-1. This is thickest under the Froan Basin, and the broad magnetic anomaly used to delineate the detachments correlates with this. The proposed offshore continuation of the detachments thus appears- unreliable. While we find indications of high density and velocity (~7.2 km s-1) lower crust under the Rås Basin, similar to the proposed igneous underplating of the outer margin, this is poorly constrained near the end of our profiles. The gravity field indicates that this body may be continuous from the pre-breakup basement structures of the Utgard High to the Frøya High, suggesting that it could be an island arc or oceanic terrane-accreted during the Caledonian orogeny. Thus, we find no clear evidence of early Cenozoic igneous underplating of the inner part of the shelf

Bruktkjøp og "som den er"-forbehold. Er reguleringen hensiktsmessig for forbrukere i lys av det grønne skiftet?

En rettsdogmatisk analyse av "som den er"-reglene i kjl. § 19 og fkjl. § 17, med fokus på mangelsvurderingen vedrørende middels dyre forbruksvarer. Videre foretas det en vurderingen av om reglene er hensiktsmessige, eller hvorvidt det vil være en fordel å avskaffe selgers mulighet til å ta alminnelige forbehold i lys av ønske om økt ombruk/ bruktkjøp.MasteroppgaveJUS399MAJURMAJUR-

Late Jurassic to Late Cretaceous canyons on the Måløy Slope: Source to sink fingerprints on the northernmost North Sea rift margin, Norway

The Måløy Slope is a key area for studying the connection between onshore and offshore geology of South Norway. It has functioned as an area of bypass, erosion and deposition between the Norwegian mainland source area and the offshore northern North Sea sink area since the Permian. The slope was faulted into N–S-trending rift fault-blocks through flexural down-bending during the large-scale extension and rapid rift basin subsidence in the Late Jurassic and Early Cretaceous. Mapping of 3D seismic data has revealed a profound network of E–W-oriented erosional submarine canyons. These canyons cut up to 500 m into the crystalline bedrock on the rift-related fault-block crests. We suggest that the canyons were first established prior to the faulting associated with late Jurassic rifting. The canyons may have been important feeders in the Oxfordian, Kimmeridgian and Tithonian like canyons in the Uer Terrace to the south, although we lack direct evidence for this. Further erosion and deepening of the canyons into the basement occurred during Cretaceous in a post-rift setting. The position of the main canyons sustained during recurring periods of erosion from the Late Jurassic until burial within the slope in the Late Cretaceous. By the aid of detailed bathymetric maps, the main canyons can be correlated with onshore faults and drainage systems (fjords and valleys). The evolution of the slope canyon system over time is controlled by both tectonic and isostatic movements and, as discussed in the text, can help understand when and where the pre-fjord drainage was established. Multiple incision events have been detected, and each of these express some correlation to regional tectonic events in (1) Late Jurassic–Earliest Cretaceous, (2) Late Aptian–Albian and (3) Turonian– Coniacian.publishedVersio

Structure and evolution of the Bellsund Graben between Forlandsundet and Bellsund (Spitsbergen) based on marine seismic data

Seismic interpretation of multi-channel seismic data acquired along the western shelf of Spitsbergen allowed identification of the main geological features of the area, including the Hornsund Fault Zone, and the Forlandsundet and Bellsund grabens. The Bellsund Graben is defined as a narrow, N-S trending graben structure which is approximately 20 km wide and 70 km in length. The graben represents a southern continuation of the Forlandsundet Graben in the north and in the south, it is limited by E-W trending dextral transverse faults external to Isfjorden and Van Mijenfjorden. Development of the graben structures was related to the formation of the West Spitsbergen Fold and Thrust Belt and opening of the Norwegian- Greenland Sea. Compressional structures observed within sedimentary strata infilling the graben may support the view that three stages can be discerned with respect to the evolution of these structures: 1) An initial stage of sediment accumulation in basins broader than those at present (probably latest Paleocene – Early Eocene); 2) graben formation, possibly as a pull-apart structures during a dextral strike-slip regime with local compression (latest Eocene); and 3) normal faulting and final graben development since the onset of sea-floor spreading between Svalbard and Greenland in early Oligocene. The lowermost reflector that underlies the Bellsund Graben has been interpreted as a detachment surface formed during the Late Eocene-Oligocene(?) extension as reactivation of a thrust plane developed during formation of the West Spitsbergen Fold and Thrust Belt.publishedVersio

Exploring seismic detection and resolution thresholds of fault zones and gas seeps in the shallow subsurface using seismic modelling

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How post-salt sediment flux and progradation rate influence salt tectonics on rifted margins: Insights from geodynamic modelling

Continental rifted margins can be associated with widespread and thick salt deposits, which are often formed during the final stages of rifting, prior to breakup. These salt-bearing margins are typically characterized by pronounced post-rift salt tectonics with variable and complex structural styles and evolution. We use a lithosphere-scale geodynamic numerical model to investigate the role of varying post-rift sediment fluxes and progradation rates on rifted margin salt tectonics. We focus on a single, intermediate, rifted margin type and salt basin geometry to explore scenarios with different: (i) constant and (ii) time-varying post-salt sediment fluxes. We demonstrate that these promote significant contrasts in the style and magnitude of salt tectonics in the proximal, transitional and distal margin domains. The differences are primarily controlled by the relationship between the rates of sediment progradation (Vprog) and salt flow (Vs). When Vprog > Vs, the salt is rapidly buried and both vertical and lateral salt flow are suppressed across the entire margin. When Vprog < Vs, the salt flows vertically and seaward faster than sediments prograde producing major diapirism in the proximal domain and major distal nappe advance, but only moderate overburden extension and distal diapirism. When Vprog ~ Vs, there is moderate proximal diapirism and distal nappe advance, but major updip extension and downdip shortening, which produces major distal diapirism. Modelling results are comparable to various natural systems and help improve our understanding of the controls and dynamics of salt tectonics along salt-bearing rifted margins.publishedVersio

Basement structure and its influence on the structural configuration of the northern North Sea

The northern North Sea rift basin developed on a heterogeneous crust comprising structures inherited from the Caledonian orogeny and Devonian postorogenic extension. Integrating two-dimensional regional seismic reflection data and information from basement wells, we investigate the prerift structural configuration in the northern North Sea rift. Three seismic facies have been defined below the base rift surface: (1) relatively low-amplitude and low-frequency reflections, interpreted as pre-Caledonian metasediments, Caledonian nappes, and/or Devonian clastic sediments; (2) packages of high-amplitude dipping reflections (>500 ms thick), interpreted as basement shear zones; and (3) medium-amplitude and high-frequency reflections interpreted as less sheared crystalline basement of Proterozoic and Paleozoic (Caledonian) origin. Some zones of Seismic Facies 2 can be linked to onshore Devonian shear zones, whereas others are restricted to the offshore rift area. Interpreted offshore shear zones dip S, ESE, and WNW in contrast to W to NW dipping shear zones onshore West Norway. Our results indicate that Devonian strain and ductile deformation was distributed throughout the Caledonian orogenic belt from central South Norway to the Shetland Platform. Most of the Devonian basins related to this extension are, however, removed by erosion during subsequent exhumation. Basement shear zones reactivated during the rifting and locally control the location and geometry of rift depocenters, e.g., in the Stord and East Shetland basins. Prerift structures with present-day dips >15° were reactivated, although some of the basement shear zones are displaced by rift faults regardless of their orientation relative to rift extension direction

Crustal domains in the Western Barents Sea

The crustal architecture of the Barents Sea is still enigmatic due to complex evolution during the Timanian and Caledonian orogeny events, further complicated by several rifting episodes. In this study we present the new results on the crustal structure of the Caledonian–Timanian transition zone in the western Barents. We extend the work of Aarseth et al. (2017), by utilizing the seismic tomography approach to model Vp, Vs and Vp/Vs ratio, combined with the reprocessed seismic reflection line, and further complemented with gravity modelling. Based on our models we document in 3-D the position of the Caledonian nappes in the western Barents Sea. We find that the Caledonian domain is characterized by high crustal reflectivity, caused by strong deformation and/or emplacement of mafic intrusions within the crystalline crust. The Timanian domain shows semi-transparent crust with little internal reflectivity, suggesting less deformation. We find, that the eastern branch of the earlier proposed Caledonian suture, cannot be associated with the Caledonian event, but can rather be a relict from the Timanian terrane assemblance, marking one of the crustal microblocks. This crustal block may have an E–W striking southern boundary, along which the Caledonian nappes were offset. A high-velocity/density crustal body, adjacent to the Caledonian–Timanian contact zone, is interpreted as a zone of metamorphosed rocks based on the comparison with global compilations. The orientation of this body correlates with regional gravity maxima zone. Two scenarios for the origin of the body are proposed: mafic emplacement during the Timanian assembly, or massive mafic intrusions associated with the Devonian extension.publishedVersio