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Background: Preliminary results of metal-on-metal (MoM) hip arthroplasty were satisfactory, but since 2004 data showed high failure rates. National joint replacement registries are multi-centre databases comprised of thousands of subjects and implants which allow for identifying variables predictive of implant failure. The aim of the current study was to estimate re-revision rates after revision of a primary MoM hip arthroplasty in the Dutch Arthroplasty Register (LROI) and to assess potential predictor variables of re-revision of these MoM hip arthroplasties. Methods: Eligible procedures were those with a revision for any reason except infection, after an initial primary surgery with a hip resurfacing (HRA) or large-head MoM (LH-MoM) total hip arthroplasty (THA). The probability of re-revision for both types of MoM hip arthroplasty over time was estimated using the cumulative incidence function taking mortality as a competing risk into account. A proportional sub-distribution hazards regression model was used to assess potential predictor variables of re-revision of these MoM hip arthroplasties. Results: A total of 3476 records of revised implants were included, of which 873 (25.2%) were MoM implants. Over the course of follow-up, 101 (11.5%) MoM implants were re-revised. During follow-up 36 (4.3%) patients who received a MoM-implant at primary arthroplasty and a revision afterwards had died. The regression model showed that for primary MoM implants a MoM articulation after revision (HR 2.48; 95% CI 1.53–4.03, p < 0.001), femoral-only revisions (HR 3.20; 95% CI 2.06–4.99, p < 0.001) and periprosthetic fractures (HR 1.98; 95% CI 1.03–3.82, p = 0.042) as reason for the first revision were statistically significant risk factors for re-revision. Conclusion: Both types of large-head MoM hip arthroplasties have shown high revision and re-revision rates; risk factors were identified. The outcome of this study can be helpful in managing expectations of patients and orthopaedic surgeons. [ABSTRACT FROM AUTHOR]

Purpose: Patients with an upper brachial plexus lesion can suffer from dysfunction, joint deformities and instability of the shoulder. The goal of this study was to determine pain, shoulder function, patient satisfaction and muscle strength in shoulder arthrodesis in patients with an upper brachial plexus lesion more than 15 years after surgery. Methods: We retrospectively studied 12 patients with a brachial plexus lesion of mean age 46 years (27-61). At a mean of 19.8 years (15.4-30.3) after shoulder arthrodesis, patient-reported outcome measures (PROMs), range of motion (e.g., active and passive), patient satisfaction, strength of the affected and non-affected side (e.g., maximum isometric strength in Newton in forward and retroflexion, ab- and adduction, internal and external rotation) and position of fusion were obtained. PROMS consisted of the Visual Analogue Scale (VAS; 0-100, 0 being painless) for pain and the Disabilities of the Arm, Shoulder and Hand Score (DASH; 0-100, 0 being the best score) for function. Results: At latest follow-up, the median VAS pain score was 49 (0-96) and 0 for, respectively, the affected and unaffected side. The DASH was 15 (8-46), meaning a reasonable to good function of the upper extremity. Active and passive retroflexion was significantly different (p = 0.028). All subjects stated that in the same situation they would undergo a shoulder arthrodesis again. The unaffected side was significantly stronger in every direction. Arthrodesis showed position of fusion of 31° (12-70) abduction, 20° (10-50) forward flexion and 22° (− 14 to 58) internal rotation. The unaffected side was significantly (p ≤ 0.05) stronger in every movement direction.Conclusion: At a mean of 20 years after shoulder arthrodesis, patients with an upper brachial plexus lesion are still satisfied with a good to moderate functional improvement.Level of evidence III: A retrospective cohort study. [ABSTRACT FROM AUTHOR]

Purpose and Hypothesis: The purpose of this study was to 'objectively' measure improvement of physical activity with the use of an activity monitor between patients who followed an enhanced recovery- or outpatient surgery pathway after total knee arthroplasty (TKA). It was hypothesized that both pathways will have comparable physical activity after TKA at 6-week follow-up.Methods: This prospective observational comparative case study was designed to investigate activity parameters (e.g. physical activity, number of steps, sit-stand transfers) of two different pathways after 6 weeks with the use of a non-invasive triaxial accelerometer activity monitor. This study included 20 patients with a mean age of 65.5 years (SD 6.1) undergoing TKA who were allocated to follow one of the two pathways: enhanced recovery (n = 10) or outpatient surgery (n = 10). Patients were monitored for 4 days pre-, 4 days during and 4 days after 5 weeks postoperatively. Patient-reported outcome measures (PROMs) and range of knee motion were obtained pre- and 6 weeks postoperatively.Results: The activity parameters recovered steeply during the first 4 postoperative days and continued to improve within both pathways (n.s.). Preoperative and during the first 4 days and 5 weeks postoperative, activity parameters were comparable (n.s.) between both pathways but did not reach preoperative levels of physical activity and range of motion (n.s.). PROMs improved within each pathway, and no difference between both pathways was observed (n.s.).Conclusions: This study demonstrates that the early physical activity parameters of patients after TKA, following the outpatient surgery pathway, were similar to patients who followed the standard enhanced recovery pathway. The activity monitor is an added value for a more detailed and objective analysis of the physical performance in patients after TKA.Level Of Evidence: III. [ABSTRACT FROM AUTHOR]

In a consecutive series of 64 patients with an ABG-II stem, we analyzed whether the tightness of the fit of the prosthesis affected bone remodeling and if there was a relation between clinical and radiological results. Radiographic analysis of bone remodeling in different Gruen zones was done. Bone density changes were graded as present or absent in the AP and lateral radiographs as compared with the previous sets of radiographs. Bone remodeling was compared to literature values of the ABG-I stem. Three stem levels were defined. The proximal level was set at the upper border of the lesser trochanter, the mid-stem level at halfway the stem and the distal level 1 cm above the tip of the prosthesis. Femoral fit was defined as tight when the ratio of the fit was ≥0.8 and as non-tight if the fit was <0.8. The incidence of thigh pain was scored using the Merle d’Aubigne (MdA) hip score. Proximal bone resorption in Gruen zone 1 was 26.6% and in zone 7, 34.4% compared to 48 and 45% for the ABG-I stem after 5 years. No correlation was found between femoral fit and radiological changes. Proximal and distal fit was significantly lower for patients with thigh pain than without thigh pain. Patients with a non-tight proximal fit produced significantly more varus (17/30 = 56.7%) than patients with a tight proximal fit (2/34 = 5.9%; P < 0.01). Femoral fit in ABG-II does not predict certain radiological changes, but less proximal bone resorption confirms the design changes from ABG-I to ABG-II. A non-tight proximal fit is correlated with varus position of the stem. Thigh pain is correlated with a poor fit and fill of the femoral stem. [ABSTRACT FROM AUTHOR]

The wave-guided travelling-wave laser action (amplified spontaneous emission) of a neat film of poly(p-phenylenevinylene) (PPV) on a quartz glass substrate prepared by a sulfinyl precursor technique is studied. The samples are transversally pumped with picosecond excitation pulses (wavelength 347.15 nm, duration 35 ps). Lasing occurs at 550 nm. The optical constants of the neat films are determined by transmittance measurements exploiting the multiple beam interference in the transparency region. A fluorescence spectroscopic characterisation is carried out determining the fluorescence quantum distribution, fluorescence quantum yield, degree of fluorescence polarisation, and fluorescence lifetime. The emitting chromophore size (emitting singlet exciton extension) is determined by the ratio of exciton radiative lifetime to repeat-unit based radiative lifetime. The obtained size of about two repeat units is discussed in a disordered solid-state polymer model. [ABSTRACT FROM AUTHOR]

The mechanical properties of morsellized bone allografts and synthetic hydroxapatite/tricalcium-phosphate (HA/TCP) ceramic extender materials for the use in impaction grafting revision hip surgery were investigated using two test methods: a basic compression test and an endurance test in an in-vitro model of an impaction grafted femur. Formalin fixed ovine bone graft was identified as mechanically similar to fresh human bone and thus suitable as an experimental material for in-vitro testing. For 1 : 1 volumetric mixes of bone allograft and synthetic extender, the granular ceramic's properties were varied in porosity, chemical composition, sintering temperature and particle size. Initial mechanical stability, a crucial prerequisite for clinical success in impaction grafting, was increased for all bone/extender mixes. A high porosity, tricalcium-phosphate rich ceramic of medium particle size and sintered at high temperatures was recognized as an optimized extender material for impaction grafting balancing the mechanical and biological demands. Using the extender without bone graft as a pure replacement is not recommended. © 2001 Kluwer Academic Publishers [ABSTRACT FROM AUTHOR]

Selective systems for screening Arabidopsis thaliana(L.) Heynh. mutants with altered sensitivity to the oxidative stress (OS) inductors norflurazon (NF), acifluorfen (AF), and plumbagin (PB) were developed and a collection of 28 mutants was obtained. Dwarf and necrotic forms predominated among the NF-tolerant mutants, while pigment mutants and those with changed root morphology prevailed among the AF-tolerant and PB-sensitive mutants, respectively. Genetic and biochemical analysis of certain mutants was performed; quantitative and qualitative changes in the content of superoxide dismutase and peroxidase isoforms have been revealed. These data, complemented by the data on the cross-tolerance (sensitivity) of the mutants to paraquat, indicate a correlation between tolerance to the OS inductors and the functions of antioxidant systems. [ABSTRACT FROM AUTHOR]

We studied the electronic structure of quasi size-selected silver clusters grown in nanopits of a graphite surface using ultraviolet photoelectron spectroscopy at T=40 K. For clusters with more than 9×102 atoms the initial state of the d-electrons has already reached the bulk limit, but there is a dynamic final-state effect which we can explain with a simple model taking into account the finite lifetime of the photohole (corresponding to a charged cluster) and the cluster-substrate interaction on a femtosecond timescale. Below a critical cluster size of about 5×102 atoms we have observed additional initial-state effects. [ABSTRACT FROM AUTHOR]

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Left ventricular dimensions were measured in Cd arrested (presumably diastolic), openchest rats. Aortic pressure was maintained at 137 cm HO (100 mm Hg) and left-ventricular (luminal) pressures were established and maintained at their chosen values, each by means of reservoir systems. The selected left-ventricular pressures were chosen to be within or to even broaden the range of conceivable diastolic pressures (−3 to 48 cm HO). After in situ fixation with 4 % formaldehyde and gelatin embedding, the hearts were serially sectioned in the apex base direction to obtain information at 11 levels (10, 20, ... 90, 100%). Tracings of selected sections were made along the edge of the left ventricular lumen and the pericardial surface. Volumes, surface areas, and mean external and internal radii of the left ventricle were derived. To quantify the circularity of sections a form factor (FF) was introduced (FF = 1 for a circular cross-section and less than one for other shapes). Ventricular lengths, radial dimensions, endocardial and epicardial surface areas, and total and luminal volumes increased with the increasing intraventricular pressures; as expected, the wall simultaneously thinned. Though its appearance was altered by the wall thinning, the curving muscle fascicular pattern was present over the entire pressure range examined. Endocardial surface areas increased more than did the epicardial surface areas. The endocardial FF value increased (more circular) at each section level as the pressure increased. The epicardial FF relationship was apparently constant (0.798 ± 0.014) for all section levels from 10 % through 90 %, regardless of luminal pressure. These results, when taken in conjunction with the results of our previous published studies, prompted the following speculation. The wall of the diastolic ventricle is a fluid-filled chamber with intramyocardial pressures that may be higher than ventricular pressures. [ABSTRACT FROM AUTHOR]

Sarcomere lengths were measured with an optical microscope at five sites through the free wall of the open-chest rat left ventricle. After pentobarbital anesthesia the hearts were arrested with 5 mM cadmium chloride and 0.9% saline and fixed with formaldehyde solution. Serial sections (250 μm thick) were cut from endocardium to epicardium with a freezing microtome. Selected sections were sonified, mixed with a gelatin-water solution, and placed on a glass slide. There was a progressive increase in mean sarcomere lengths with increasing intraventricular pressures though the sarcomeres did not significantly exceed their optimum length. There was a distinct and statistically significant difference in the pattern of sarcomere lengths through the ventricular wall between our previous closed-chest study and the present open-chest study. In these open-chest animals, there was an almost linear pattern of increasing sarcomere lengths from endocardium to epicardium over the range of semiphysiologic diastolic intraventricular pressures (6, 12, and 24 cm HO − 0.59, 1.18, 2.35 kPa). These results appear to caution against extrapolations on ventricular function derived from open-chest studies to the normal physiologic conditions. [ABSTRACT FROM AUTHOR]

Sea otter, Enhydra lutris, predation had no detectable effect on abundance and size distribution of deep-burrowing bivalve prey in the Elkhorn Slough, California, USA. Up to 23 otters were present for 6 mo of the study period (March 1984 through April 1985). This is in contrast to previous studies of sea otter predation, especially on the shallow-burrowing Pismo clam Tivela stultorum, which can be found along the wave-exposed coast near the slough. The deep-burrowing clams Tresus nuttallii and Saxidomus nuttalli made up 61% of the prey taken in the slough, and are more difficult for otters to excavate than Pismo clams. The occurrence of foraging otters was highest in an area where the two bivalve prey were extremely abundant (∼18 individuals m). However, the otters did not selectively prey on the largest clams available within the study sight, but foraged preferentially in a patch of smaller individuals where bivalve burrow depth was restricted by the presence of a dense clay layer. This foraging strategy maximized the amount of prey biomass obtained per unit volume of sediment excavated. Our findings suggest that in soft-sediment habitats deep-burrowing bivalves may be more resistant to otter predation than shallower burrowers. [ABSTRACT FROM AUTHOR]

Background: Patient-Reported Outcome Measures (PROMs) are widely used for measurement of functional outcomes after orthopaedic trauma. However, PROMs rely on patient collaboration and suffer from various types of bias. Wearable Activity Monitors (WAMs) are increasingly used to objectify functional assessment. The objectives of this systematic review were to identify and characterise the WAMs technology and metrics currently used for orthopaedic trauma research., Methods: PubMed and Embase biomedical literature search engines were queried. Eligibility criteria included: Human clinical studies published in the English language between 2010 and 2019 involving fracture management and WAMs. Variables collected from each article included: Technology used, vendor/product, WAM body location, metrics measured, measurement time period, year of publication, study geographic location, phase of treatment studied, fractures studied, number of patients studied, sex and age of the study subjects, and study level of evidence. Six investigators reviewed the resulting papers. Descriptive statistics of variables of interest were used to analyse the data., Results: One hundred and thirty-six papers were available for analysis, showing an increasing trend of publications per year. Accelerometry followed by plantar pressure insoles were the most commonly employed technologies. The most common location for WAM placement was insoles, followed by the waist. The most commonly studied fracture type was hip fractures followed by fragility fractures in general, ankle, "lower extremity", and tibial fractures. The rehabilitation phase following surgery was the most commonly studied period. Sleep duration, activity time or step counts were the most commonly reported WAM metrics. A preferred, clinically validated WAM metric was not identified., Conclusions: WAMs have an increasing presence in the orthopaedic trauma literature. The optimal implementation of this technology and its use to understand patients' pre-injury and post-injury functions is currently insufficiently explored and represents an area that will benefit from future study., Systematic Review Registration Number: PROSPERO ID:210344., Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-022-00629-0., Competing Interests: Conflict of interestThe authors have no competing interests to declare that are relevant to the content of this article., (© Indian Orthopaedics Association 2022.)