Total hip replacement: increasing femoral offset improves functional outcome

INTRODUCTION: The aim of this study was to assess the independent effect of radiographic measures of implant position, relative to pre-operative anatomical assessment, on the functional outcome of total hip arthroplasty according to change in the Oxford hip score (OHS) 1 year post surgery. METHODS: A prospective cohort study was preformed to assess whether improvement in functional outcome (change in OHS at 1 year) and the relationship with femoral offset and length, and acetabular offset and height. After a power calculation 359 patients were recruited to the study and radiographic measures were performed by blinded observers. Regression analysis was used to assess the independent effect of the four radiographic measurements after adjusting for confounding variables. RESULTS: There was a significant (p < 0.001) decrease in acetabular offset [5.3 mm, 95 % confidence interval (CI) 4.4–6.2] and increase in femoral offset (6.1 mm, 95 % CI 5.4–6.8). Hence there was no significant change in overall offset. Femoral offset was the only radiographic measure to be achieved statistical significance (r = 0.198, 95 % CI 0.063–0.333, p = 0.004) in relation to clinical outcome, with increasing offset being associated with a greater improvement in the OHS. On combining femoral and acetabular offset increasing offset was associated with a greater improvement in the OHS (r = 0.10, 95 % CI 0.01–0.19, p = 0.04). CONCLUSION: This study supports the long-held biomechanical theory of medialisation of the acetabular component with compensatory increased femoral offset results in improved functional outcome

The impact of the implementation of physician assistants in inpatient care: A multicenter matched-controlled study

Contains fulltext : 177273.pdf (publisher's version ) (Open Access)BACKGROUND: Medical care for admitted patients in hospitals is increasingly reallocated to physician assistants (PAs). There is limited evidence about the consequences for the quality and safety of care. This study aimed to determine the effects of substitution of inpatient care from medical doctors (MDs) to PAs on patients' length of stay (LOS), quality and safety of care, and patient experiences with the provided care. METHODS: In a multicenter matched-controlled study, the traditional model in which only MDs are employed for inpatient care (MD model) was compared with a mixed model in which besides MDs also PAs are employed (PA/MD model). Thirty-four wards were recruited across the Netherlands. Patients were followed from admission till one month after discharge. Primary outcome measure was patients' LOS. Secondary outcomes concerned eleven indicators for quality and safety of inpatient care and patients' experiences with the provided care. RESULTS: Data on 2,307 patients from 34 hospital wards was available. The involvement of PAs was not significantly associated with LOS (beta 1.20, 95%CI 0.99-1.40, p = .062). None of the indicators for quality and safety of care were different between study arms. However, the involvement of PAs was associated with better experiences of patients (beta 0.49, 95% CI 0.22-0.76, p = .001). CONCLUSIONS: This study did not find differences regarding LOS and quality of care between wards on which PAs, in collaboration with MDs, provided medical care for the admitted patients, and wards on which only MDs provided medical care. Employing PAs seems to be safe and seems to lead to better patient experiences. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01835444

Steenstorten: Voorspelling van het stort als gestort wordt vanuit een vast punt

In the construction of dams and in protection of civil engineering works in water courses often use is made of dumped stones. The dumping process can be divided in two stages. During the first stage the resulting mound of stones on the bottom of the water course is built up vertically. In the second stage the stones are under the angle of repose and increase of height of the mound can only be accomplished together with an increase in width of the basis. In the dumping process four sub-processes can be distinguished, i.e. the positioning of the dumping vessel, the start of the falling process, the falling process itself and jumping and rolling of the stones that hit the bottom. Three different partial processes can take place during the falling process. The first one is a (semi-) diffusion process, which results in a swinging motion of a singular stone. The mathematical description of this process is called the "Single Stone Model". On average the distance of the final position of the stones, measured from the projection on the bottom of the point where the fall is started is zero. The spreading ofthe stones is proportional to the square root ofthe water depth. A second possible partial process is caused by the Magnus effect. A constant horizontal force is executed on the vertically falling body. The third partial process can be caused by asymmetric flow separation. This also causes a horizontal force to act on the body. Drag causes the movement to be uniform. Last two mentioned processes result in a ring- shaped mound. The diameter of the ring is proportional to the water depth. The mathematical model of this process is called the "ring model". In practice all processes will take place. The mathematical descriptions can be combined in a combination model.Hydraulic EngineeringCivil Engineering and Geoscience

Golfbelasting en opwaartse waterdruk op een cilinder met grote diameter t.o.v. de lengte van de invallende golf, gesitueerd op de Bligh bank

Hydraulic EngineeringCivil Engineering and Geoscience

Golfbelasting en opwaartse waterdruk op een cilinder met grote diameter t.o.v. de lengte van de invallende golf, gesitueerd op d Bligh bank

Voorbeeldberekening voor krachten op een monopile (bijv. fundering windgenerator) in offshore conditiesHydraulic EngineeringCivil Engineering and Geoscience

Probabilistische niveau II berekeningen toegelicht aan de hand van voorbeelden met twee stochasten

Hydraulic EngineeringCivil Engineering and Geoscience