No difference in anterior tibial translation with and without posterior cruciate ligament in less invasive total knee replacement

The relative advantages of cruciate retaining or cruciate resecting total knee replacement are still controversial. If the posterior cruciate ligament (PCL) is preserved, it should be properly balanced. In a previous study, it was demonstrated that increasing the flexion gap leads to an anterior translation of the tibia relative to the femur. Based on these results, we hypothesized that cutting the PCL increases the flexion gap and lessens anterior tibial translation

Image-Less THA Cup Navigation in Clinical Routine Setup: Individual Adjustments, Accuracy, Precision, and Robustness.

Background and Objectives: Even after the 'death' of Lewinnek's safe zone, the orientation of the prosthetic cup in total hip arthroplasty is crucial for success. Accurate cup placement can be achieved with surgical navigation systems. The literature lacks study cohorts with large numbers of hips because postoperative computer tomography is required for the reproducible evaluation of the acetabular component position. To overcome this limitation, we used a validated software program, HipMatch, to accurately assess the cup orientation based on an anterior-posterior pelvic X-ray. The aim of this study were to (1) determine the intraoperative 'individual adjustment' of the cup positioning compared to the widely suggested target values of 40° of inclination and 15° of anteversion, and evaluate the (2) 'accuracy', (3) 'precision', and (4) robustness, regarding systematic errors, of an image-free navigation system in routine clinical use. Material and Methods: We performed a retrospective, accuracy study in a single surgeon case series of 367 navigated primary total hip arthroplasties (PiGalileoTM, Smith+Nephew) through an anterolateral approach performed between January 2011 and August 2018. The individual adjustments were defined as the differences between the target cup orientation (40° of inclination, 15° of anteversion) and the intraoperative registration with the navigation software. The accuracy was the difference between the intraoperative captured cup orientation and the actual postoperative cup orientation determined by HipMatch. The precision was analyzed by the standard deviation of the difference between the intraoperative registered and the actual cup orientation. The outliers were detected using the Tukey method. Results: Compared to the target value (40° inclination, 15° anteversion), the individual adjustments showed that the cups are impacted in higher inclination (mean 3.2° ± 1.6°, range, (-2)-18°) and higher anteversion (mean 5.0° ± 7.0°, range, (-15)-23°) (p < 0.001). The accuracy of the navigated cup placement was -1.7° ± 3.0°, ((-15)-11°) for inclination, and -4.9° ± 6.2° ((-28)-18°) for anteversion (p < 0.001). Precision of the system was higher for inclination (standard deviation SD 3.0°) compared to anteversion (SD 6.2°) (p < 0.001). We found no difference in the prevalence of outliers for inclination (1.9% (7 out of 367)) compared to anteversion (1.63% (6 out of 367), p = 0.78). The Bland-Altman analysis showed that the differences between the intraoperatively captured final position and the postoperatively determined actual position were spread evenly and randomly for inclination and anteversion. Conclusion: The evaluation of an image-less navigation system in this large study cohort provides accurate and reliable intraoperative feedback. The accuracy and the precision were inferior compared to CT-based navigation systems particularly regarding the anteversion. However the assessed values are certainly within a clinically acceptable range. This use of image-less navigation offers an additional tool to address challenging hip prothesis in the context of the hip-spine relationship to achieve adequate placement of the acetabular components with a minimum of outliers

Investigations of the energy efficiency of integrated and organic farming in a long-term field trial on a loamy sand soil

Im Mittel des betrachteten Zeitraums war der Verbrauch fossiler Energie im Ökologischen Landbau (ÖL) um mehr als ein Drittel niedriger als im Integrierten Landbau (IL). Dies ist vorrangig mit dem Verzicht auf den Einsatz von Mineraldüngern im „ÖL“ zu erklären. Der Pflanzenschutzmitteleinsatz übte einen geringen Einfluss auf den Energieinput des „IL“ aus. Infolge der Ausschaltung schaderregerbedingter Ertragsverluste wurde die Energieeffizienz hierdurch jedoch deutlich verbessert. Der Energiegewinn war in der Variante mit situationsbezogener Pflanzenschutzmittelanwendung (100% HF) signifikant höher als im „ÖL“, wobei im Winterweizen größere Unterschiede als im Winterroggen auftraten. Demzufolge kann der Winterroggen unter den gegebenen Standort- und Klimabedingungen als gut geeignet für den Anbau in ökologisch bewirtschafteten Anbausystemen angesehen werden. Für die Energieintensität und das Output/Input-Verhältnis wurden im Gegensatz zum Energiegewinn häufig günstigere Werte im „ÖL“ im Vergleich zum „IL“ ermittelt. Hierbei waren die Unterschiede vor allem im Roggenanbau signifikant. Um eine aussagekräftige Beurteilung komplexer Anbausysteme im Hinblick auf deren Energieeffizienz vornehmen zu können, sind daher möglichst alle der drei genannten Energiebilanzindikatoren zu berücksichtigen. Die Ergebnisse der Untersuchungen zeigen zudem, dass Untersuchungen zur Energieeffizienz unterschiedlicher Anbausysteme möglichst auf Frucht­folge­ebene und unter Berücksichtigung der Langzeit­effekte von Bewirtschaftungsmaßnahmen erfolgen sollten. Ferner zeigte sich, dass eine ausgewogene Frucht­folgegestaltung sowie die Auswahl von gut an die Standortbedingungen und das Anbausystem angepassten Fruchtarten und Sorten von höchster Bedeutung für die Ertragsleistungen und die Energiebilanz des jeweiligen landwirtschaftlichen Systems sind.On average of the period investigated, fossil energy use was lower by more than one third in organic farming (OF) compared with integrated farming (IF). This is predominantly due to not applying mineral fertilisers in OF while using in IF. The fossil energy consumption by using pesticides in IF was comparatively low. Moreover, due to smaller yield losses caused by weeds, diseases or pest infestation, energy efficiency was higher owing to pesticide use. Energy gain was significantly higher in the treatment with situation-related pesticide use (100% HF) compared with OF, whilst differences were greater in winter wheat cropping compared to winter rye cropping. Accordingly, winter rye is regarded to be an appropriate crop for organic farming systems under comparable climatic and site conditions. Energy intensity as well as output/input ratio were predominantly better in OF compared with IF, while significant differences were particularly found in winter rye cropping. In order to meaningfully assess complex cropping systems with respect to their energy efficiency, hence, all three energy balance indicators mentioned should be regarded. Furthermore, the results presented in this paper indicate that investigations on the energy efficiency of different cropping systems should only be proceeded on the level of the crop rotation by taking into account long-term effects of different husbandry. The given results show, moreover, that a balanced crop rotation and crops or varieties being well-adapted to the given site-conditions, are of utmost importance in regard to the yield potential or the energy balance of the respective cropping system

Environmental effects and long-term productivity of arable farming affected by crop rotation and strategy of pesticide use

Auf Grundlage eines 12-jährigen Dauerfeldversuches wurden unterschiedliche Fruchtfolgen und Pflanzenschutzstrategien im Hinblick ihres Einflusses auf Erträge, Humusreproduktion, N-Salden, Energieeffizienz sowie auf das akute und chronische Risikopotenzial für aquatische und terrestrische Organismen infolge der Pflanzenschutzmittelanwendung untersucht. Der Versuch beinhaltete eine Marktfruchtfruchtfolge (Winterraps – Winterweizen – Winterroggen – Erbsen – Winterweizen – Wintergerste; ‚FF 1’) und eine Futterbaufruchtfolge (Winterraps – Wintergerste – Luzerne/Klee/Gras – Winterroggen – Silomais – Winterweizen; ‚FF 2’), wobei in beiden Fruchtfolgen jeweils die situationsbezogene Pflanzenschutzmittelanwendung (100 % HF) im Vergleich zur dazu halbierten Pflanzenschutzintensität (50 % HF) geprüft wurde. Fruchtfolge- und Pflanzenschutzvarianten befanden sich in jedem Jahr auf derselben Stelle. In die Untersuchungen flossen die Ergebnisse der Erntejahre 2003 bis 2006 ein. Eine ausreichende Humusreproduktion konnte in beiden Fruchtfolgen gewährleistet werden. Das Gesamt­ertragspotential der Fruchtfolge wurde in Getreideeinheiten (GE) und durch den Energieoutput ausgedrückt. Hierbei war ein deutlich stärkerer Einfluss der Frucht­folge auf die Ertragsleistungen nachweisbar als durch die unterschiedliche Pflanzenschutzintensität. Im Hinblick auf den GE-Ertrag und Energieoutput war ‚FF 1’ (72,9 GE ha–1; 192,3 GJ ha–1) ‚FF 2’ (70,0 GE ha–1; 100,3 GJ ha–1) leicht überlegen. Die N-Salden von ‚FF 1’ und ‚FF 2’ betrugen 32,0 und 38,2 kg N ha–1. Ähnlich wie die Erträge wurde die Energieeffizienz nennenswert durch die Fruchtfolge, aber deutlich weniger durch die Pflanzenschutzintensität beeinflusst. Das berechnete Risikopotential infolge der Pflanzenschutzmittelanwendung war in allen Varianten gering.On the basis of one 12-year lasting experiment, different crop rotations and strategies of pesticide use were investigated with regard to yield, humus replacement, nitrogen (N) balance, energy use efficiency as well as acute and chronic risk potentials for aquatic and terrestrial organisms due to pesticide application. The experiment comprised one arable crop rotation (winter oilseed rape – winter wheat – winter rye – peas – winter wheat – winter barley, ‘CR 1’) and one fodder crop rotation (winter oilseed rape – winter barley – alfalfa/clover/grass-mixture – winter rye – silage maize – winter wheat, ‘CR 2’) each crop with situation-related pesticide use (100 % HF) or application rates reduced by 50 per cent (50 % HF). Rotations and treatments were located on the same plots in each year. The study comprises the harvest years 2003 to 2006. Humus requirement could be covered in all crop rotations. Total yield potential of the crop rotations was expressed by grain equivalent (GE) yields and energy output. The different crop rotations influenced yield potential to a larger extent than pesticide use intensity. ‘CR 2’ (72.9 GE ha–1; 192.3 GJ ha–1) slightly exceeded ‘CR 1’ (70.0 GE ha–1; 100.3 GJ ha–1) with respect to GE yields and energy outputs. Averaged across all treatments, N surplus for ‘CR 1’ and ‘CR 2’ were 32.0 and 38.2 kg N ha–1, respectively. Similar to yield, energy efficiency was noteworthy affected by crop rotation and minor by pesticide use intensity. The risk potential due to pesticide application was low in all treatments

Periprosthetic Joint Infection After Total Knee Arthroplasty With or Without Antibiotic Bone Cement.

IMPORTANCE Despite increased use of antibiotic-loaded bone cement (ALBC) in joint arthroplasty over recent decades, current evidence for prophylactic use of ALBC to reduce risk of periprosthetic joint infection (PJI) is insufficient. OBJECTIVE To compare the rate of revision attributed to PJI following primary total knee arthroplasty (TKA) using ALBC vs plain bone cement. DESIGN, SETTING, AND PARTICIPANTS This international cohort study used data from 14 national or regional joint arthroplasty registries in Australia, Denmark, Finland, Germany, Italy, New Zealand, Norway, Romania, Sweden, Switzerland, the Netherlands, the UK, and the US. The study included primary TKAs for osteoarthritis registered from January 1, 2010, to December 31, 2020, and followed-up until December 31, 2021. Data analysis was performed from April to September 2023. EXPOSURE Primary TKA with ALBC vs plain bone cement. MAIN OUTCOMES AND MEASURES The primary outcome was risk of 1-year revision for PJI. Using a distributed data network analysis method, data were harmonized, and a cumulative revision rate was calculated (1 - Kaplan-Meier), and Cox regression analyses were performed within the 10 registries using both cement types. A meta-analysis was then performed to combine all aggregated data and evaluate the risk of 1-year revision for PJI and all causes. RESULTS Among 2 168 924 TKAs included, 93% were performed with ALBC. Most TKAs were performed in female patients (59.5%) and patients aged 65 to 74 years (39.9%), fully cemented (92.2%), and in the 2015 to 2020 period (62.5%). All participating registries reported a cumulative 1-year revision rate for PJI of less than 1% following primary TKA with ALBC (range, 0.21%-0.80%) and with plain bone cement (range, 0.23%-0.70%). The meta-analyses based on adjusted Cox regression for 1 917 190 TKAs showed no statistically significant difference at 1 year in risk of revision for PJI (hazard rate ratio, 1.16; 95% CI, 0.89-1.52) or for all causes (hazard rate ratio, 1.12; 95% CI, 0.89-1.40) among TKAs performed with ALBC vs plain bone cement. CONCLUSIONS AND RELEVANCE In this study, the risk of revision for PJI was similar between ALBC and plain bone cement following primary TKA. Any additional costs of ALBC and its relative value in reducing revision risk should be considered in the context of the overall health care delivery system

The use of antibiotic-loaded bone cement and systemic antibiotic prophylactic use in 2,971,357 primary total knee arthroplasties from 2010 to 2020: an international register-based observational study among countries in Africa, Europe, North America, and Oceania.

BACKGROUND AND PURPOSE Antibiotic-loaded bone cement (ALBC) and systemic antibiotic prophylaxis (SAP) have been used to reduce periprosthetic joint infection (PJI) rates. We investigated the use of ALBC and SAP in primary total knee arthroplasty (TKA). PATIENTS AND METHODS This observational study is based on 2,971,357 primary TKAs reported in 2010-2020 to national/regional joint arthroplasty registries in Australia, Denmark, Finland, Germany, Italy, the Netherlands, New Zealand, Norway, Romania, South Africa, Sweden, Switzerland, the UK, and the USA. Aggregate-level data on trends and types of bone cement, antibiotic agents, and doses and duration of SAP used was extracted from participating registries. RESULTS ALBC was used in 77% of the TKAs with variation ranging from 100% in Norway to 31% in the USA. Palacos R+G was the most common (62%) ALBC type used. The primary antibiotic used in ALBC was gentamicin (94%). Use of ALBC in combination with SAP was common practice (77%). Cefazolin was the most common (32%) SAP agent. The doses and duration of SAP used varied from one single preoperative dosage as standard practice in Bolzano, Italy (98%) to 1-day 4 doses in Norway (83% of the 40,709 TKAs reported to the Norwegian arthroplasty register). CONCLUSION The proportion of ALBC usage in primary TKA varies internationally, with gentamicin being the most common antibiotic. ALBC in combination with SAP was common practice, with cefazolin the most common SAP agent. The type of ALBC and type, dose, and duration of SAP varied among participating countries

Short-term functional versus patient-reported outcome of the bicruciate stabilized total knee arthroplasty: prospective consecutive case series

BACKGROUND The main goals of the standard treatment for advanced symptomatic knee osteoarthritis, total knee arthroplasty (TKA), are pain reduction and restoration of knee motion.The aim of this study was to analyse the outcome of the patient-based Knee Injury and Osteoarthritis Outcome Score (KOOS), and the surgeon-based Knee Society Score (KSS) and its Knee Score (KS) and Knee Functional Score (KFS) components after (TKA) using the Journey knee prosthesis, and to assess the correlation of these scores with range of motion (ROM). METHODS In a prospective case series study between August 1st 2008 and May 31st 2011, 99 patients, all operated by a single surgeon, received Journey bicruciate stabilized total knee prostheses. The female/male ratio was 53/34, the mean patient age at surgery was 68 years (range 41-83 years), and the left/right knee ratio was 55/44. The KOOS, range of motion, and KS and KFS were obtained preoperatively and at 1-year follow-up. The pre- and postoperative levels of the outcome measures were compared using the Wilcoxon signed-rank test. Correlation between ROM and patient outcomes was analysed with the Spearman coefficient. RESULTS All KOOS subscores improved significantly. Ninety percent of patients improved by at least the minimum clinically relevant difference of 10 points in stiffness and other symptoms, 94.5% in pain, 94.5% in activities of daily living, 84.9% in sports and recreation, and 90% in knee-related quality of life. The mean passive and active ROM improved from 122.4° (range 90-145°) and 120.4° (range 80-145°) preoperatively to 129.4° (range 90-145°) and 127.1° (range 100-145°) postoperatively. The highest correlation coefficients for ROM and KOOS were observed for the activity and pain subscores. Very low or no correlation was seen for the sport subscore.There was a significant and clinically relevant improvement of KSS (preop/postop 112.2/174.5 points), and its KS (preop/postop 45.6/86.8 points) and KFS (preop/postop 66.6/87.8 points) components. CONCLUSIONS The Journey bicruciate stabilized knee prosthesis showed good 1-year postoperative results in terms of both functional and patient-based outcome. However, higher knee ROM correlates only moderately with patient-based outcome, implying that functionality afforded by the Journey bicruciate TKA is not equivalent to patient satisfaction

Equilibrium Asset Pricing under Incomplete Information on Regimes

Die moderne Finanzierungstheorie akzeptiert weitgehend, dass Entscheider nicht vollkommen über den stochastischen Prozess finanzieller Größen -insbesondere Zahlungen - Bescheid wissen, d. h. es herrscht unvollkommene Information im Sinne unvollständiger Information. Unvollständige Information wird in dieser Dissertation mit Hilfe eines nicht beobachtbaren Regime-Modells eingefangen: Zahlungen können verschiedene Regimes annehmen. Offensichtlich sollte sich unvollständige Information als Risikoquelle in Aktienkursen niederschlagen. Es bleibt hingegen unklar, wie diese zweite Risikoquelle sich genau in Risikoprämien übersetzt: (i) Lässt sie automatisch Risikoprämien ansteigen, weil eine neben das „normale“ Schwankungsrisiko tretende weitere Risikoquelle das Gesamtrisiko erhöht und deshalb kompensiert werden muss? (ii) Oder können unvollständige Information und „normales“ Schwankungsrisiko in einer Weise zusammenspielen, die das Gesamtrisiko und damit auch Risikoprämien senkt? Veronesi (2000) zeigt nun, dass unvollständige Information Risikoprämien im Vergleich zum Fall vollständiger Information reduziert (für realistische Werte des Risikoaversionsparameters) und deswegen Erklärung (ii) zu gelten scheint. Da Veronesi (2000) dieses Ergebnis in einem engen Modellrahmen herleitet, wurde die Wirkungsweise unvollständiger Information in dieser Dissertation in einem erweiterten Rahmen untersucht (verschiedene Nutzenfunktionen, verschiedene Varianten von Regime- und Zahlungsmodellen, sowie mehr als ein riskantes Wertpapier). Die Ergebnisse der Dissertation lassen sich wie folgt zusammenfassen: 1. Der theoretische Teil der Arbeit arbeitet heraus, dass unvollständige Information generell einen starken Einfluss auf Risikoprämien in allen betrachteten Modellerweiterungen hat. Jeder Bewertung von Risiken liegt die Kovarianz zwischen stochastischen Diskontierungsfaktor und Renditen bzw. Zahlungen zugrunde; unvollständige Information beeinflusst diese Kovarianz substanziell. 2. Die numerische Analyse verdeutlicht, dass die theoretischen Ergebnisse auch ökonomisch relevant sind: Risikoprämien unterscheiden sich quantitativ deutlich bei vollständiger und unvollständiger Information; dabei haben die verschiedenen Modellvarianten mitunter einen bedeutenden Einfluss auf die Größe der Risikoprämien. Die Ergebnisse aus Veronesi (2000) bleiben auch in dem weiteren Modellrahmen, der in dieser Arbeit betrachtet wird, weitgehend erhalten

Consecutive series of 226 journey bicruciate substituting total knee replacements: early complication and revision rates

BACKGROUND The Journey bicruciate substituting (BCS) total knee replacement (TKR) is intended to improve knee kinematics by more closely approximating the surfaces of a normal knee. The purpose of this analysis was to address the safety of Journey BCS knees by studying early complication and revision rates in a consecutive case series. METHODS Between December 2006 and May 2011, a single surgeon implanted 226 Journey BCS total knee prostheses in 191 patients (124 women, 67 men) who were eligible for study. Mean age at surgery was 68 years (41-85 years).Outcome measures were early complications and minor and major revision rates. All complications were considered, irrespective of whether conservative treatment or revision was required. RESULTS The average implantation time was 3.5 years (range 1.3-5.8 years). Thirty-three complications (14.6% of 226 knees) required minor or major revision surgery in 25 patients. The remaining eight patients were treated conservatively. Sixteen minor revisions were performed in 12 patients. Thirteen major revisions were required in 13 patients, which results in a rate of 1.65 major revisions per 100 component years. The linear trend of the early complication rate by treatment year was not significant (p = .22).Multivariate logistic regression showed no significant predictors for the occurrence of a complication or for revision surgery. A tendency towards higher complication rates was observed in female patients, although it was not significant (p = .066). CONCLUSIONS The complication and revision rates of the Journey BCS knee implant are high in comparison with those reported for other established total knee systems. Caution is advised when using this implant, particularly for less experienced knee surgeons