Prosthesis

The whole body DXA exams in NHANES were acquired according to the procedures recommended by the manufacturer on a QDR 4500A fan beam densitometer (Hologic, Inc., Bedford, MA). All subjects changed into paper gowns and were asked to remove all jewelry and other personal effects that could interfere with the DXA exam. The DXA exams were reviewed and analyzed by the University of California, San Francisco Department of Radiology Bone Density Group using industry standard techniques. Analysis of all exams was performed using Hologic Discovery software version 12.1 in its default configuration. Exams that contained artifacts which could affect the accuracy of the DXA results, such as prosthetic devices, implants or other extraneous objects had the regional and global DXA results for these exams set to missing in the dataset. The precision of the DXA instrument used in the NHANES study has been reported on elsewhere [5] (link), [6] (link), [7] (link).
Body composition measurements are technology and calibration dependent and hence results provided by different instruments vary widely. The DXA instruments used in the NHANES survey employed the calibration proposed by Schoeller et al. [8] (link), whereby DXA lean mass results were calibrated to lean mass measured in 7 independent studies utilizing total body water (4 studies), hydrodensitometry (1 study), and four compartment measures (2 studies). The seven independent studies involved a total of 1195 subjects (602 male, 593 female). The BMD and BMC results were calibrated by the DXA manufacturer and maintained by an internal reference system that periodically measures bone and soft tissue equivalent reference standards during the patient measurement.
The NHANES data sets contained whole body DXA measurements of bone mineral content (BMC, g), areal bone mineral density (BMD, g/cm²), fat mass (g) and lean mass including BMC (g) and percent fat, calculated as (fat mass divided by total mass) ×100 along with demographic information for each subject. The above measurements were also available for a number of pre-defined anatomical regions, including the head, arms, legs, trunk, pelvic regions, sub-total whole body (excluding only the head) and whole body. From these whole body measures the following derivative values were calculated: FMI (fat mass/height²), lean mass/height², appendicular lean mass/height². For adults, only total body reference values and the above derivative reference values were generated. For children, (subjects less than 20 years of age), total body and sub-total body reference values and selected derivative reference values were generated.
There is increasing realization that fat distribution may be as important as total fat mass, so two indices of fat mass distribution, %fat of the trunk divided by %fat of the legs and fat mass of the trunk divided by fat mass of the limbs (fat mass of arms plus legs) were included in this analysis for adults. These indices may have a role in defining metabolic syndrome or lipodystorphy [9] (link), [10] (link).

The implant measured the three contact force components F_x, F_y and F_z in Newton and the three moment components M_x, M_y and M_z in Nm (Fig 1). The moments are caused by friction in the joint and act in addition to the forces. The resultant force F_res and the resultant friction moment M_res were calculated from the vector sums of their components. For the remainder of the study, the term ‘load’ refers to the complete set of all six components and their two resultants, unless otherwise stated. If a force is mentioned without further description, it refers to the peak value during the whole loading cycle.
All loads are reported in the x, y, z coordinate system, which is defined relative to a right-sided femur (Fig 1). This is advantageous because then the loads relative to the implant can be recalculated from that data for any prosthesis which is differently oriented relative to the femur, e.g., has a different anteversion. Data from left-sided implants were mirrored to the right side. The origin of this coordinate system is located at the centre of the femoral head. The +z axis points upward and is defined by the line connecting the two points where the curved femoral mid-line intersected with the neck axis (P1) and where it passes the intercondylar notch (P2). The +x axis points laterally and is oriented parallel to the proximal contour of the condyles. The +y axis points in the anterior direction. This definition is in accordance with the ISB recommendations [23 (link)] but deviates from our earlier definition [24 (link)] for the left hip joint, which defined the +x axis to point medially [4 , 5 (link), 8 (link)].

We assessed the proportion of possible false links by assessing implausible links in a multi-step procedure. First, we checked if a pseudonymized SFK identifier was linked to more than four primary arthroplasties, as one individual can receive four replacements. Secondly, we assessed the prevalence of medication prescribed after death. We also calculated a corrected percentage of prescriptions after death. Some pharmacists work three weeks ahead, hence medication within the first 21 days after death would not necessarily indicate incorrect linkage. If the number of pills from at least one prescription could be divided by 7, and the prescriptions stopped after that specific prescription we assumed a repeat prescription. Third, the prevalence of antibiotic prescriptions dispensed after revision surgery for infection was assessed as this is common practice [17 ]. Lastly, we identified the patients who had multiple prostheses in the LROI and checked if these arthroplasties also belonged to the same records in the SFK. The percentage of persons with multiple arthroplasties matched with the SFK was calculated.
We performed these checks in three subgroups. Group 1: all arthroplasties linked on either patient postcode or hospital postcode with ZIC/AGB-code. Group 2: arthroplasties linked on patient postcode. Groups 1 and 2 were identified irrespective of the thromboprophylaxis they were linked on. Group 3: arthroplasties linked on patient postcode and LWMH as thromboprophylaxis. The latter group was identified since other types of thromboprophylaxis, such as DOACs are also given to a large group of patients for chronic anticoagulation treatment.
To check our linkage we considered the patients solely linked on outpatient pharmacy prescriptions as unlinked. The checks described earlier were performed in the subset that was considered linked on a regular pharmacy prescription, except for the check for prosthesis infection, in which we also used arthroplasties linked on outpatient pharmacies.

The study involved patients aged 50 to 59 years who were made complete removable dentures for the lower jaw for the first time. The distribution of the patients by gender, the degree of atrophy of the alveolar process and the condition of the mucous membrane are presented in Table 1.
Table 1All patients – 23 persons in total were divided into four groups:
- group 1 – persons who used full removable dentures and did not use any fixations and adhered to conventional oral hygiene;
- group 2 – patients with full removable dentures who used the cream “Corega” to strengthen the fixation from the first day of prosthetics and adhered to conventional oral hygiene;
- group 3 – patients with complete removable dentures who used Corega Comfort (GSK – GlaxoSmithKline) to strengthen the fixation from the first day of prosthetics and adhered to conventional oral hygiene;
- group 4 – patients with complete removable dentures who used Corega Comfort (GSK) and performed antibacterial cleaning of dentures with Biotablets “Corega” for cleaning dentures to enhance the fixation from the first day of prosthetics.
The dentures were made of acrylic resin and clinical methods of additional fixation were used if necessary. Mycological examination of the patients included microscopic examination of smears using conventional and luminescent methods of staining smears from the surface of the dentures. Cultural studies with quantitative estimation of the fungi were also conducted. The patients were carried out studies after prosthetics in the terms: 14 days, 1, 2, 6 months after denture fitting. Bacteriological investigations were conducted to study the number and biological properties of microorganisms on the surface of the dentures. A sterile cotton swab soaked in saline was used to take the material from the surface of the dentures for isolation and quantitative estimation of the microorganisms followed by inoculation of the material on yolk-salt agar (YSA). The selection of test colonies on YSA was made after incubation at a temperature of 37°C for 2 days.
The basis for the quantitative estimation of colonies was the severity of the lecithinase reaction (formation of a cloudy zone and a rainbow crown around the colony). Microscopic methods were used to determine the species of selected fungal cultures. To quantify the selected cultures of the fungi, the material was taken from the surface of the denture on an empty stomach. A sterile cotton swab, turning round, carefully wiped the surface of the denture. Then the swab was immersed in a vial of 5 ml of saline and sterile balls. The contents of the vial have been shaken for 5 minutes. Then 0.1 ml of the liquid from the vial was inoculated into a Petri dish with Saburo agar. To suppress other microbial flora and obtain a pure culture of fungi penicillin and streptomycin was added to the culture medium at the rate of 100 IU (international unit) per 1 ml of the medium. The material was evenly distributed on the agar surface with a Drygalsky spatula. The cultures have been incubated at 37°C for 48 hours. To quantify the results, cultures in Petri dishes were divided into a number of sectors, where the number of grown colonies was counted. Then the total number of colonies was determined and multiplied by the degree of dilution of the pathological material in saline.