Femoral Neck Design Does Not Impact Revision Risk After Primary Total Hip Arthroplasty Using a Dual Mobility Cup

Background

The use of dual mobility (DM) cups has increased quickly. It is hypothesized that femoral neck taper geometry may be involved in the risk of prosthetic impingement and DM cup revision. We aim to (1) explore the reasons for revision of DM cups or head/liners and (2) explore whether certain femoral neck characteristics are associated with a higher risk of revision of DM cups.

Methods

Primary total hip arthroplasties with a DM cup registered in the Dutch Arthroplasty Register between 2007 and 2021 were identified (n = 7603). Competing risk survival analyses were performed, with acetabular component and head/liner revision as the primary endpoint. Reasons for revision were categorized in cup-/liner-related revisions (dislocation, liner wear, acetabular loosening). Femoral neck characteristics were studied to assess whether there is an association between femoral neck design and the risk of DM cup/liner revision. Multivariable Cox proportional hazard analyses were performed.

Results

The 5- and 10-year crude cumulative incidence of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was 0.5% (CI 0.4-0.8) and 1.9% (CI 1.3-2.8), respectively. After adjusting for confounders, we found no association between the examined femoral neck characteristics (alloy used, neck geometry, CCD angle, and surface roughness) and the risk for revision for dislocation, wear, and acetabular loosening.

Conclusions

The risk of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was low. We found no evidence that there is an association between femoral neck design and the risk of cup or head/liner revision.

[A male with black cartilage]

A 52-year-old men suffered from osteoarthritis of the knee. During knee replacement surgery, the remaining cartilage appeared black. This discoloration and early degeneration of the cartilage is characteristic for the metabolic disorder alkaptonuria in which homogentisic acid accumulates in the body.

Tau PET and relative cerebral blood flow in dementia with Lewy bodies: A PET study

PURPOSE

Alpha-synuclein often co-occurs with Alzheimer's disease (AD) pathology in Dementia with Lewy Bodies (DLB). From a dynamic [18F]flortaucipir PET scan we derived measures of both tau binding and relative cerebral blood flow (rCBF). We tested whether regional tau binding or rCBF differed between DLB patients and AD patients and controls and examined their association with clinical characteristics of DLB.

METHODS

Eighteen patients with probable DLB, 65 AD patients and 50 controls underwent a dynamic 130-minute [18F]flortaucipir PET scan. DLB patients with positive biomarkers for AD based on cerebrospinal fluid or amyloid PET were considered as DLB with AD pathology (DLB-AD+). Receptor parametric mapping (cerebellar gray matter reference region) was used to extract regional binding potential (BPND) and R1, reflecting (AD-specific) tau pathology and rCBF, respectively. First, we performed regional comparisons of [18F]flortaucipir BPND and R1 between diagnostic groups. In DLB patients only, we performed regression analyses between regional [18F]flortaucipir BPND, R1 and performance on ten neuropsychological tests.

RESULTS

Regional [18F]flortaucipir BPND in DLB was comparable with tau binding in controls (p > 0.05). Subtle higher tau binding was observed in DLB-AD+ compared to DLB-AD- in the medial temporal and parietal lobe (both p < 0.05). Occipital and lateral parietal R1 was lower in DLB compared to AD and controls (all p < 0.01). Lower frontal R1 was associated with impaired performance on digit span forward (standardized beta, stβ = 0.72) and category fluency (stβ = 0.69) tests. Lower parietal R1 was related to lower delayed (stβ = 0.50) and immediate (stβ = 0.48) recall, VOSP number location (stβ = 0.70) and fragmented letters (stβ = 0.59) scores. Lower occipital R1 was associated to worse performance on VOSP fragmented letters (stβ = 0.61), all p < 0.05.

CONCLUSION

The amount of tau binding in DLB was minimal and did not differ from controls. However, there were DLB-specific occipital and lateral parietal relative cerebral blood flow reductions compared to both controls and AD patients. Regional rCBF, but not tau binding, was related to cognitive impairment. This indicates that assessment of rCBF may give more insight into disease mechanisms in DLB than tau PET.

Long-term follow-up of distal radius fractures, an evaluation of the current guideline: the relation between malunion, osteoarthritis and functional outcome

BACKGROUND

Last decades there is an increased tendency of performing surgery on displaced distal radius fractures. However, it is unclear whether this affects the development of osteoarthritis. This study aims to determine the relation between anatomical position, radiological osteoarthritis and functional outcome of the elderly wrist, 10-15 years after a distal radius fracture.

PATIENTS AND METHODS

173 patients between the age of 50 and 70 at time of trauma were included in this retrospective cohort study with a 10-15-year follow-up. Based on the reassessed initial X-rays, the patients were placed into 4 groups (1: anatomical, 2a: acceptable, 2b: current operative indication but treated conservative, 2c: operative indication and operated). Functional outcome was measured, questionnaires were answered, and new bilateral X-rays of the wrist were obtained. Factors influencing osteoarthritis, the difference in osteoarthritis between the groups and the difference between the fractured and non-fractured wrists were studied.

RESULTS

Group 2b showed a significantly higher degree of osteoarthritis in comparison with the contralateral wrist. In the other groups, this difference was not observed. We found no significant difference in OA and functional outcomes between the groups. The degree of osteoarthritis of the non-fractured wrist appeared to be highly associated with osteoarthritis of the fractured wrist.

CONCLUSION

The results of this study showed that the degree of radiocarpal osteoarthritis is higher in conservatively treated patients that should have been operated on according to current guidelines in comparison with patients without an indication for surgery. This might suggest that our current guidelines can be effective in prevention of posttraumatic osteoarthritis. However, the effect on the functional outcome is very limited. Since the degree of radiocarpal osteoarthritis of the non-fractured wrist appeared to be highly associated with the degree of osteoarthritis of the fractured wrist, future studies should always assess osteoarthritis of both wrists in order to study the real posttraumatic effect of a fracture.

Optical properties and fabrication of dielectric metasurfaces based on amorphous silicon nanodisk arrays

Dielectric metasurfaces based on amorphous silicon (a-Si) nanodisks are interesting for nanophotonic applications due to the high refractive index and mature/low temperature fabrication of a-Si. The investigated metasurfaces consist of a-Si nanodisk arrays embedded in a transparent film. The diameter-dependent optical properties of the nanodisk Mie resonators have been investigated by finite-difference time-domain (FDTD) simulations and spectrally-resolved reflectivity and transmission measurements. Well-ordered substrate-free a-Si nanodisk arrays were fabricated and characterized with regard to their broadband anti-reflection properties when placed on a crystalline silicon (c-Si) surface, and reflectivity/ transmission properties when embedded in a polydimethylsiloxane (PDMS) film. Our results confirm broadband anti-reflection when placed on silicon, while the optical characteristics of the nanodisks embedded in PDMS are shown to be potentially useful for color/NIR filter applications as well as for coloring on the micro/nanoscale.

Refractive index sensing in the visible/NIR spectrum using silicon nanopillar arrays

Si nanopillar (NP) arrays are investigated as refractive index sensors in the visible/NIR wavelength range, suitable for Si photodetector responsivity. The NP arrays are fabricated by nanoimprint lithography and dry etching, and coated with thin dielectric layers. The reflectivity peaks obtained by finite-difference time-domain (FDTD) simulations show a linear shift with coating layer thickness. At 730 nm wavelength, sensitivities of ~0.3 and ~0.9 nm/nm of SiO₂ and Si₃N₄, respectively, are obtained; and the optical thicknesses of the deposited surface coatings are determined by comparing the experimental and simulated data. The results show that NP arrays can be used for sensing surface bio-layers. The proposed method could be useful to determine the optical thickness of surface coatings, conformal and non-conformal, in NP-based optical devices.

High energy excitations measured by neutron spectroscopy in FePS(3)

The quasi-two-dimensional antiferromagnet FePS(3) has been investigated using inelastic neutron spectroscopy with the time-of-flight spectrometer HET at the ISIS spallation neutron source. In the paramagnetic regime, two clearly resolved, high energy excitations were observed in the low scattering angle detector banks at 195(5) meV and 430(10) meV. The absence of these transitions from the high angle detector banks indicates that they are likely to be due to the crystal fields and magnetic in origin. The two transitions most probably represent electronic transitions in the Fe(2+) ion among the low lying crystal field and spin-orbit split levels raised from the ground state. It has not yet been determined why the energies are greater than those observed in a comparable Raman experiment.

Discovery of a novel carboxylesterase through functional screening of a pre-enriched environmental library

AIMS

The aim of this study was to demonstrate the application of environmental sample pre-enrichment to access novel carboxylesterases from environmental genomes, along with subsequent heterologous expression and characterization of the discovered enzyme(s).

METHODS AND RESULTS

A positive recombinant clone (UVCL29), conferring an esterase phenotype was identified from a shotgun gene library. The complete sequence of the 3.0 kb DNA insert from the pUVCL29 recombinant plasmid was obtained using primer-walking strategies. Nucleotide sequence analysis revealed a complete 945 bp open reading frame (ORF1). Translational analysis of the ORF1 showed a protein of 314 amino acids (named EstAM) with a predicted molecular weight of 34 kDa. EstAM's primary structure showed a classical (-G-D-S-A-G-) motif, corresponding with the generally conserved (G-x-S-x-G) esterase signature motif. Identity searches indicated that EstAM has high sequence similarity with esterases from family IV. EstAM was successfully expressed in Escherichia coli in a biologically active form. Partial purification was achieved using a one-step Pro-PurTM IMAC column. Biochemical characterization revealed that EstAM has a temperature optimum of 40 degrees C.

CONCLUSION

Based on its substrate profile, EstAM was classified as a carboxylesterase because of its preference for short p-nitrophenyl ester substrates.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study is a demonstration of the successful application of environmental sample pre-enrichment technology in accessing novel esterases from a mining environment.

Improved rapid sampling for in vivo kinetics of intracellular metabolites in Saccharomyces cerevisiae

An integrated approach is used to develop a rapid sampling strategy for the quantitative analysis of in vivo kinetic behavior based on measured concentrations of intracellular metabolites in Saccharomyces cerevisiae. Emphasis is laid on small sample sizes during sampling and analysis. Subsecond residence times are accomplished by minimizing the dead volume of the sterile sampling system and by maximizing flow rates through application of vacuum to the sampling tubes in addition to the overpressure in the fermenter. A specially designed sample tube adapter facilitates sampling intervals of 4 to 5 s for various test tube types. Statistical analysis of the results obtained from enzymatic and liquid chromatography mass spectrometry (LC-MSMS) analysis of the metabolite concentrations was used to optimize the sampling protocol. The most notable improvement is reached through the introduction of vacuum drying of the cell extract. The presented system is capable of reliably dealing with fermenter samples as small as 1-g with a variation of less than 3%, and is thus ideally suited for intracellular measurements on small, lab-scale fermenters.

Polymerase chain reaction-restriction fragment-length polymorphism method to distinguish Liriomyza huidobrensis from L. Langei (Diptera: Agromyzidae) applied to three recent leafminer invasions

A molecular method is presented for differentiating the morphologically cryptic leafminers Liriomyza langei Frick and L. huidobrensis (Blanchard). This method requires polymerase chain reaction (PCR) amplification of a 1031-bp region of mitochondrial cytochrome oxidase DNA followed by restriction fragment analysis using the restriction enzymes SpeI and EcoRV. Spel cuts the mitochondrial fragment of L. langei into two fragments, but does not cut the L. huidobrensis fragment. EcoRV cuts the L. huidobrensis fragment into two fragments, but does not cut the L. langei fragment. This PCR-restriction fragment-length polymorphism (RFLP) method is faster and less costly than DNA sequencing,which is currently the only other way to differentiate these two species. We apply the method to samples from recently introduced leafminer populations in Sri Lanka, Canada, and South Africa and find that the invasive leafminer in all three locations is L. huidobrensis.

Glucose and the ATP paradox in yeast

A sustained decrease in the intracellular ATP concentration has been observed when extra glucose was added to yeast cells growing aerobically under glucose limitation. Because glucose degradation is the main source of ATP-derived free energy, this is a counter-intuitive phenomenon, which cannot be attributed to transient ATP consumption in the initial steps of glycolysis. We present a core model for aerobic growth in which glucose supplies carbon, as well as free energy, for biosynthesis. With Metabolic Control Analysis and numerical simulations, we demonstrate that the decrease in the ATP concentration can be reproduced if the biosynthetic route is more strongly activated by carbon substrates than is the catabolic (ATP-producing) route.

Chiral critical exponents of the triangular-lattice antiferromagnet CsMnBr3 as determined by polarized neutron scattering

The critical exponents gamma(c) = 0.84(7) of the chiral susceptibility above the Neel temperature, T(N), and beta(c) = 0. 44(2) of the average chirality below T(N) have been determined for the triangular-lattice antiferromagnet CsMnBr3 by means of polarized neutron scattering. These first experimental values of chiral critical exponents are in line with theoretical predictions and fulfill their scaling relation. The temperature at which the average chirality appears coincides with the spin-order transition temperature, T(N).

Tendency modeling: a new approach to obtain simplified kinetic models of metabolism applied to Saccharomyces cerevisiae

A novel approach to construct kinetic models of metabolic pathways, to be used in metabolic engineering, is presented: the tendency modeling approach. This approach greatly facilitates the construction of these models and can easily be applied to complex metabolic networks. The resulting models contain a minimal number of parameters; identification of their values is straightforward. Use of in vitro obtained information in the identification of the kinetic equations is minimized. The tendency modeling approach has been used to derive a dynamic model of primary metabolism for aerobic growth of Saccharomyces cerevisiae on glucose, in which compartmentation is included. Simulation results obtained with the derived model are satisfying for most of the carbon metabolites that have been measured. Compared to a more detailed model, the simulations of our model are less accurate, but taking into account the much smaller number of kinetic parameters (35 instead of 84), the tendency the modeling approach is considered promising.

Validity of the standard shiftwork index for South African shiftworkers in the transport industry

A major problem in shiftwork research has been the lack of uniform measuring procedures across studies. The Standard Shiftwork Index (SSI) contains a battery of self-report questionnaires which was developed to address this need. The objectives of this study included examining the cross- cultural applicability, internal consistency, and construct validity of the SSI scales for a predominantly Afrikaans-speaking sample of 728 train drivers and to provide normative distribution statistics for this sample. Factor analytic results and the correlations between the various scales supported the constnuct validity of the SSI scales. Means obtained on the scales were compared with means obtained for British shiftworkers and non-shiftworkers. The inclusion of job satisfaction and involvement scales, and scales to assess sleep variables appeared to augment an outcome- based theoretical model proposed by the compilers of the SSI. It was concluded that the SSI is a useful research tool for use with shiftworkers, but that further development of some of the scales is advisable. Opsomming 'n Belangrike leemte in navorsing oor skofwerk is die gebrek aan eenvormige metingsprosedures. Die Standard Shiftwork Index (SSI) behels verskeie selfbeoordelingvraelyste wat in Engeland ontwikkel is om hierdie behoefte aan te spreek. Die doelwitte van hierdie studie was om die tussenkulturele toepaslikheid, interne konsekwentheid en konstrukgeldigheid van die SSI-skale vir 'n hoofsaaklik Afrikaanssprekende steekproef van 728 treindrywers te bepaal en om normatiewe statistiek vir hierdie steekproef te verskaf. Faktoranalitiese resultate en die korrelasies tussen die onderskeie skale het hul konstrukgeldigheid ondersteun. Gemiddeldes wat op die onderskeie vraelyste behaal is, is vergelyk met gemiddeldes wat vir Britse skofwerkers en nieskofwerkers verkry is. Die insluiting van werktevredenheid- en werkbetrokkenheidskale, asook skale oor slaap, het die uitkomsgebaseerde teoretiese model van die opstellers van die SSI aangevul. Die SSI kan beskou word as 'n nuttige navorsingshulpmiddel vir gebruik met skofwerkers, maar verdere ontwikkeling van sommige van die skale is gewens.

Differential item functioning in the figure classification test

The elimination of unfair discrimination and cultural bias of any kind, is a contentious workplace issue in contemporary South Africa. To ensure fairness in testing, psychometric instruments are subjected to empirical investigations for the detection of possible bias that could lead to selection decisions constituting unfair discrimination. This study was conducted to explore the possible existence of differential item functioning (DIF), or potential bias, in the Figure Classification Test (A121) by means of the Mantel-Haenszel chi-square technique. The sample consisted of 498 men at a production company in the Western Cape. Although statistical analysis revealed significant differences between the mean test scores of three racial groups on the test, very few items were identified as having statistically significant DIF. The possibility is discussed that, despite the presence of some DIF, the differences between the means may not be due to the measuring instrument itself being biased/ but rather to extraneous sources of variation, such as the unequal education and socio-economic backgrounds of the racial groups. It was concluded that there is very little evidence of item bias in the test. Opsomming Die uitskakeling van onregverdige diskriminasie en kultuursydigheid van enige aard, is tans 'n omstrede kwessie in die werkpiek in Suid-Afrika. Ten einde regverdigheid in toetsing te verseker, word psigomefrriese toetse onderwerp aan empiriese ondersoeke na die moontlikheid van sydigheid wat kan lei tot keuringsbesluite wat onregverdige diskriminasie meebring. Hierdie ondersoek is ondemeem om die moontlikheid van differensiele itemfunksionering (DIF), of potensiële sydigheid, in die Figuurindelingtoets (A121), met behulp van die Mantel-Haenszel chikwadraattegniek, te ondersoek. Die steekproef het bestaan uit 498 mans by 'n produksiemaatskappy in die Wes-Kaap. Alhoewel statistiese ontleding beduidende verskille in gemiddelde toetstellings van drie rassegroepe op die toets aangedui het, is bate min items aangedui wat statistics beduidende DIF bevat. Die moontlikheid word bespreek dat, hoewel sommige DIF in die toets teenwoordig is, die verskille tussen die gemiddeldes nie die gevolg is van 'n sydige meetinstrument per se nie, maar eerder die gevolg van eksteme bronne van variasie, soos byvoorbeeld die ongelyke opvoedkundige- en sosio-ekonomiese agtergronde van die rassegroepe. Die gevolgtrekking was dat daar bate min getuienis van itemsydigheid in die toets is.

Fungal bezoars as a cause of renal insufficiency in neonates and infants--recommended treatment strategy

Fungal bezoars may be a cause of urinary tract obstruction and acute renal failure in neonates and young infants. We describe a female very low birth weight infant (25+3 weeks, 795 gram) who developed renal insufficiency on the basis of systemic fungal infection with fungal bezoars in both kidneys. The girl was treated by local irrigation of the kidneys and bladder with amphotericin B via percutaneously inserted bilateral nephrostomy catheters, in combination with intravenous fluconazol. Renal function subsequently improved and after 11 weeks of treatment the bezoars had disappeared sonographically. Follow-up of this child and the one we similarly treated for fungal bezoars before, however, shows suboptimal renal function as assessed by the clearance of creatinine and the mercapto acetyl triglycine scan (MAG III). Until now, insufficient data are available yet to assess with certainly the long-term effects of fungal bezoars on renal function. Based on our experience and a review of the recent literature (1980-1996) on systemic candidal infections in premature infants, we recommend to perform regular renal ultrasound in any case of systemic candidal infection in a prematurely born infant. If candidal bezoars are found with pelvic obstruction, we suggest to start treatment by the insertion of bilateral nephrostomy catheters and local irrigation with amphotericin B in combination with systemic antifungal agents, aiming at both the restoration of renal function and the eradication of the fungal infection.

[Nutrition pumps in pediatrics: a comparative study]

Home enteral nutrition as the sole or as an additional way of feeding children is becoming increasingly popular. It can be used in the form of bolus-feeding, or as drip-feeding, either continuous (24 hours) or semicontinuous (nightly). For the latter method usually a feeding pump is used. In the Netherlands several feeding pumps are available, which were tested in this report. These feeding pumps (Compat, Enteroport, Flexiflo Companion, Flocare 500, Frenta Mat, Frenta-System II, Kangaroo 324, Nutromat Päd S, Nutromat S) were investigated for accuracy, available rate-settings, adequate alarming at interruption of the drip feeding, weight and ease of operation. All pumps were tested stationary, and suitable pumps weighing less than 1000 grams were subsequently tested ambulatory. The nine tested pumps were all fairly easy to operate. Three pumps were not suitable for pediatric use, either because the infusion rate was more than 30% out of range (Flexiflo Companion) or because of inadequate rate settings (Nutromat S and Frentasystem II; respectively 20 and 25 ml/hour minimally). Accuracy for the other pumps was always within 10% of the set rate. One pump, the Enteroport, has a rate setting which is suboptimal for pediatric use. In addition this pump does not alarm when the drip feeding is interrupted. The other pumps (Compat, Frenta Mat, Kangaroo 324, Flocare 500, and Nutramat Päd S) are all suitable for pediatric use, both with respect to the rate settings as to the adequate alarming when the drip feeding is interrupted. The Flocare 500 and the Nutromat Päd S, in addition to the Enteroport, have a weight below 1000 grams.(ABSTRACT TRUNCATED AT 250 WORDS)

Fertility after surgical insemination with frozen boar semen

Seventy-six sows and gilts exhibiting natural oestrus were surgically inseminated with semen initially diluted with yolk-tris-EDTA-glycerol diluent and frozen by the pellet method. The inseminations covered three experiments in which volume of inseminate, motile spermatozoa per dose and time of insemination in relation either to the onset of oestrus or to ovulation were examined.

Effect of composition of tris-based diluent on survival of boar spermatozoa following deep freezing

Six factorial experiments were conducted to examine the effects of concentrations of 2-amino-2-hydroxymethylpropane-l,3-diol (tris), sugars, erythritol, catalase, ethylenediaminetetra-acetic acid (EDTA), glycerol and egg yolk in the freezing diluent on the survival of boar spermatozoa after freeze-thawing.

Fertility following inseminations with frozen-thawed reconcentrated and unconcentrated ram semen

Fertility results are presented for ram semen that was pellet-frozen in tris-glucose-yolk-g1ycerol diluent. Lambing following insemination with concentrated and unconcentrated inseminates was 35�0% (49/140) and 38�6% (56/145) respectively. Increasing the number of motile spermatozoa and double insemination improved the fertility.

Fertility of ram spermatozoa frozen in a tris-based diluent

Results of two fertility tests are presented. In the first test the mean lambing rates for semen frozen in Tris-glucose-yolk and raffinose-citrate-yolk and for freshdiluted semen were 40'0% (28/70),44'8% (30/67), and 65'7% (46/70) respectively. Double insemination significantly increased the fertility for both frozen and fresh semen.