Outcomes of primary total hip arthroplasty using 3D image-based custom stems in unselected patients: a systematic review.

To report clinical and radiographic outcomes of primary THA using three-dimensional (3D) image-based custom stems. This systematic review was performed according to PRISMA guidelines and registered with PROSPERO (CRD42020216079). A search was conducted using MEDLINE, Embase and Cochrane. Clinical studies were included if they reported clinical or radiographic outcomes of primary THA using 3D image-based custom stems. Studies were excluded if specific to patients with major hip anatomical deformities, or if not written in English. Fourteen studies were eligible for inclusion (n = 1936 hips). There was considerable heterogeneity in terms of manufacturer, proximal geometry, coating and length of custom stems. Revision rates ranged from 0% to 1% in the short-term, 0% to 20% in the mid-term, and 4% to 10% in the long-term, while complication rates ranged from 3% in the short-term, 0% to 11% in the mid-term and 0% to 4% in the long-term. Post-operative Harris hip scores ranged from 95 to 96 in the short-term, 80 to 99 in the mid-term, and 87 to 94 in the long-term. Radiographic outcomes were reported in eleven studies, although none reported 3D implant sizing or positioning, nor compared planned and postoperative hip architecture. Primary THA using 3D image-based custom stems in unselected patients provides limited but promising clinical and radiographic outcomes. Despite excellent survival, the evidence available in the literature remains insufficient to recommend their routine use. Future studies should specify proximal geometry, length, fixation, material and coating, as well as management of femoral offset and anteversion. The authors propose a classification system to help distinguish between custom stem designs based primarily on their proximal geometry and length.

Coherent Backscattering of Light Off One-Dimensional Atomic Strings.

We present the first experimental realization of coherent Bragg scattering off a one-dimensional system-two strings of atoms strongly coupled to a single photonic mode-realized by trapping atoms in the evanescent field of a tapered optical fiber, which also guides the probe light. We report nearly 12% power reflection from strings containing only about 1000 cesium atoms, an enhancement of 2 orders of magnitude compared to reflection from randomly positioned atoms. This result paves the road towards collective strong coupling in 1D atom-photon systems. Our approach also allows for a straightforward fiber connection between several distant 1D atomic crystals.

The effect of axial rotation of the anterior resection plane in patellofemoral arthroplasty.

BACKGROUND: Patellofemoral arthroplasty (PFA) has a small but definite place in replacement surgery of the knee, especially in young patients. The main surgical considerations in PFA are the patient's anatomy, the type of prosthesis and the surgical technique. The surgical technique and PFA success rely heavily on the anterior resection. In this study we investigate the effect of axial rotation of the anterior resection plane. METHODS: We tested the outcome of PFA fit based on resection footprint measurements, axial and coronal groove angles, and lateral trochlear inclination (LTI) angle in a virtual PFA model. The range of anterior resection plane axial rotations was from five degree internal to five degree external with an increment of one degree. RESULTS: Axial rotation of anterior resection plane changes the resection footprint dimension, which leads to coronal rotation of the femoral component. External rotation of the resection plane results in valgus rotation of the trochlear groove and decreased LTI after PFA and the opposite was observed for internal rotation. CONCLUSION: Our study showed that by changing the axial rotation of the anterior cut, the coronal groove of the prosthesis can be altered to lie more closely with the native groove line without compromising the prosthesis-cartilage transition.

Computational modelling of mobile bearing TKA anterior-posterior dislocation.

Anterior-posterior stability in an unconstrained mobile-bearing total knee arthroplasty (TKA) and one with rotational constraints is compared in a computational model based on an ASTM test. Both TKA designs dislocate at loads greater than reported maximum in vivo forces. The posterior drawer forces (mean: 3027 N vs. 1817 N) needed to induce subluxation increase with a greater anterior jump distance (12 mm vs. 7 mm; refers to the vertical height of the anterior or posterior border of the tibial insert's articulating surface). The posterior jump distance for both tested TKA differed by 1.5 mm and had minimal effect on the magnitude of the anterior drawer forces at dislocation in mid-flexion (unconstrained vs. constrained: 445 N vs. 412 N). The unconstrained insert dislocated by means of spin-out whereas in the constrained TKA the femur dislocated from the bearing during posterior drawer and the bearing from the baseplate during anterior drawer. MCL function is an important consideration during ligament balancing since a ± 10% variation in MCL tension affects dislocation forces by ± 20%. The simulation platform provided the means to investigate TKA designs in terms of anterior-posterior stability as a function of knee flexion, collateral ligament function and mechanical morphology.

Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice.

We demonstrate preparation and detection of an atom number distribution in a one-dimensional atomic lattice with the variance -14 dB below the Poissonian noise level. A mesoscopic ensemble containing a few thousand atoms is trapped in the evanescent field of a nanofiber. The atom number is measured through dual-color homodyne interferometry with a pW-power shot noise limited probe. Strong coupling of the evanescent probe guided by the nanofiber allows for a real-time measurement with a precision of ±8 atoms on an ensemble of some 10(3) atoms in a one-dimensional trap. The method is very well suited for generating collective atomic entangled or spin-squeezed states via a quantum nondemolition measurement as well as for tomography of exotic atomic states in a one-dimensional lattice.

Effect of light assisted collisions on matter wave coherence in superradiant Bose-Einstein condensates.

We investigate experimentally the effects of light assisted collisions on the coherence between momentum states in Bose-Einstein condensates. The onset of superradiant Rayleigh scattering serves as a sensitive monitor for matter-wave coherence. A subtle interplay of binary and collective effects leads to a profound asymmetry between the two sides of the atomic resonance and provides far bigger coherence loss rates for a condensate bathed in blue detuned light than previously estimated. We present a simplified quantitative model containing the essential physics to explain our experimental data and point at a new experimental route to study strongly coupled light matter systems.

High quality anti-relaxation coating material for alkali atom vapor cells.

We present an experimental investigation of alkali atom vapor cells coated with a high quality anti-relaxation coating material based on alkenes. The prepared cells with single compound alkene based coating showed the longest spin relaxation times which have been measured up to now with room temperature vapor cells. Suggestions are made that chemical binding of a cesium atom and an alkene molecule by attack to the C = C bond plays a crucial role in such improvement of anti-relaxation coating quality.

Nondestructive probing of Rabi oscillations on the cesium clock transition near the standard quantum limit.

We report on the nondestructive observation of Rabi oscillations on the Cs clock transition. The internal atomic state evolution of a dipole-trapped ensemble of cold atoms is inferred from the phase shift of a probe laser beam as measured using a Mach-Zehnder interferometer. We describe a single color as well as a two-color probing scheme. Using the latter, measurements of the collective pseudospin projection of atoms in a superposition of the clock states are performed and the observed spin fluctuations are shown to be close to the standard quantum limit.

[Telematics in the health system and data protection]. / Gesundheitstelematik und Datenschutz.

In the health system, telematics are to be used for the benefit of patients and to make it possible for them to receive better medical care. Telematics must be employed in accordance with the guidelines of data protection and this means in particular that the patient must remain the master of his data. Therefore, he must be able to decide in which situation and to whom he wants to reveal his medical data. For this reason, the exact implementation of the introduction of the electronic medical smart card envisaged by the law requires detailed access authorisations and limitations, which must be reinforced by ample technical security measures. These measures must be transmitted to the patients through co-operation of doctors and health insurance companies in such a transparent way that they recognise the advantages of the new technology. The higher the acceptance is on the patients' side, the more they will be willing to participate voluntarily in telematic projects.

Asymmetric Landau-Zener tunneling in a periodic potential.

Using a simple model for nonlinear Landau-Zener tunneling between two energy bands of a Bose-Einstein condensate in a periodic potential, we find that the tunneling rates for the two directions of tunneling are not the same. Tunneling from the ground state to the excited state is enhanced by the nonlinearity, whereas in the opposite direction it is suppressed. These findings are confirmed by numerical simulations of the condensate dynamics. Measuring the tunneling rates for a condensate of rubidium atoms in an optical lattice, we have found experimental evidence for this asymmetry.

Bloch oscillations and mean-field effects of Bose-Einstein condensates in 1D optical lattices.

We have loaded Bose-Einstein condensates into one-dimensional, off-resonant optical lattices and accelerated them by chirping the frequency difference between the two lattice beams. For small values of the lattice well depth, Bloch oscillations were observed. Reducing the potential depth further, Landau-Zener tunneling out of the lowest lattice band, leading to a breakdown of the oscillations, was also studied and used as a probe for the effective potential resulting from mean-field interactions as predicted by Choi and Niu [Phys. Rev. Lett. 82, 2022 (1999)]. The effective potential was measured for various condensate densities and trap geometries, yielding good qualitative agreement with theoretical calculations.

Bridging-to-recovery.

BACKGROUND: Patients with end-stage heart failure placed on a cardiac assist device show at least some degree of improvement of cardiac function. In a subgroup of selected patients, some hearts recovered considerable function. In these patients the device was removed and cardiac transplantation was no longer necessary. We report our long-term experience with these weaned patients. METHODS: As of today, 512 cardiac assist devices of various types (Berlin Heart, Berlin, Germany; Novacor, World Heart, Ottawa, Ontario, Canada; TCI, ThermoCardio Systems, Inc, Woburn, MA; DeBakey, Micromed Technology Inc, Houston, TX) were implanted in patients with end-stage heart failure in our institution. Of these, 95 patients belonged to a subgroup of patients with nonischemic, idiopathic, dilated cardiomyopathy who were implanted with a left ventricular support system (Novacor 84, TCI 10, Berlin Heart 1) between 1994 and 2000. All were routinely examined by echocardiography for improvement of cardiac function. The left ventricular diameter in diastole (LVIDd) and left ventricular ejection fraction (LVEF) served as the main parameters to assess changes in cardiac performance. Under the conditions of a running device, an LVIDd below 60 mm and an LVEF above 40% were the criteria to do further echocardiographic studies when the pump was turned off for up to 20 minutes. RESULTS: Twenty-eight patients (26 men, 2 women; ages 18 to 64 yrs; history of heart failure, 1 to 17 yrs) fulfilled the criteria of improved cardiac performance and were weaned from the device. Since then, 16 patients have continued "normal" heart function with follow-up times ranging from 1 month to 5.5 years (group B). Three patients died of noncardiac causes (group C). Eight patients were transplanted from 1 to 17 months later and one died on the waiting list (group A). Statistically significant differences between groups A and B were calculated for the duration of heart failure (9 versus 2 years, p = 0.0002). Differences in LVIDd before removal of the device (57 versus 51 mm, p = 0.0420), LVEF after 2 months of unloading (30 versus 49%, p = 0.0300), and LVEF preexplantation (43 versus 52%, p = 0.0001) were significant. Overall, 17% of the cohort of 95 patients were weaned successfully. CONCLUSIONS: Weaning from cardiac assist devices is feasible for selected patients; it saves donor hearts and is preferred to cardiac transplantation. However, as of today no reliable parameter predicts outcome after weaning and none determines the possibility of device removal before implantation in advance.

Midterm follow-up of patients who underwent removal of a left ventricular assist device after cardiac recovery from end-stage dilated cardiomyopathy.

OBJECTIVE: Cardiac recovery in end-stage idiopathic dilated cardiomyopathy recently occurred after temporary support with a left ventricular assist device. We report the case histories of patients who underwent removal of the device more than 4 years ago. METHODS: Since June 1994, 23 patients with end-stage idiopathic dilated cardiomyopathy who were supported by a left ventricular assist device or biventricular assist device for 1 to 26 months (mean, 6 months) underwent removal of the device after complete or extensive cardiac recovery, as revealed by echocardiography. RESULTS: Seven patients (group A) had recurrent cardiac failure after 4 to 24 months. Transplantation was performed in 6 patients, and one died while on the waiting list. Three patients died of noncardiac causes within a period of 4 months and 3 days after removal of the assist device. Stable cardiac recovery occurred in 13 patients (group B) for 3 to 49 months (mean, 23 months). At the time of implantation, there were no significant differences between the groups with regard to age, hemodynamics, left ventricular ejection fraction, left ventricular internal diameter in diastole, and autoantibody levels. The increase of ejection fraction and the decrease of left ventricular internal diameter in diastole after 2 months were highly significant. The patients in group A had longer histories of heart failure and first cardiac symptoms and duration of assist when compared with group B. Group B demonstrated a quicker cardiac recovery on the assist device, and thus support was shorter. Also, the degree of recovery at assist device explantation was more complete in group B. The age at the time of device placement was the only influencing factor for duration on the assist device. The probability of recurrence of heart failure was influenced by the duration of heart failure. CONCLUSIONS: In selected patients with idiopathic dilated cardiomyopathy, lasting recovery can be achieved after unloading with a left ventricular assist device. Lasting cardiac recovery seems to be related to functional normalization and a more rapid recovery during the unloading period.

Integrating qualified nurses and non-nurses in midwifery education: the two-year experience of an ACNM DOA Accredited Program.

In 1996, the Division of Accreditation (DOA) of the American College of Nurse-Midwives (ACNM) preaccredited the first direct entry program of midwifery education for candidates who already possess undergraduate degrees in non-nursing disciplines. Inaugurated through the partnership of the State University of New York Health Science Center at Brooklyn and the North Central Bronx Hospital, this 1-year, postbaccalaureate, certificate program of studies graduated two integrated classes of 22 registered nurse (RN) and nine direct entry (DE) students between 1997 and 1998. This article presents the experience of the first 2 years of this innovative program, focusing on the profiles of the DE students, their achievements, and their experiences entering the workforce. All of the data comparing nurse and non-nurse student progress through the program of studies strongly support the conclusion that, within an ACNM DOA preaccredited/accredited midwifery education program, DE students can achieve standards of academic excellence and clinical competency that are at least equivalent to those demonstrated by their RN peers.

Writing for publication: a workshop to prepare faculty as medical writers.

BACKGROUND AND OBJECTIVES: A 2 1/2-day Writing for Publication Workshop was presented to faculty and fellows for 5 successive years, 1991-1995. This paper describes the workshop curriculum and reports evaluation results. METHODS: A three-part evaluation plan incorporated both quantitative and qualitative methods. First, a nine-item questionnaire was administered to the 1992-1995 participants immediately prior to and after the workshop to identify perceived change in knowledge and skills. Second, a follow-up qualitative interview was administered to the 1991 and 1992 participants to identify their perceptions of the workshop's usefulness. Third, pre- and postworkshop publications of the 1991 and 1992 participants were analyzed to identify types of publications and significant differences in rates of publication. RESULTS: Eighty individuals participated in the five workshops given during the 1991-1995 period. Pre/post self-assessment data indicated significant increases in perceived knowledge and skill in all nine areas of assessment. The follow-up interview data showed that participants felt that the workshop motivated them to begin and sustain writing projects, gave them skills that made their writing more effective, and demystified the submission and publication processes. Analysis of the difference between pre- and postworkshop rates of publication showed a significant increase in the rate of publication. CONCLUSIONS: The evaluation findings indicate that the Writing for Publication Workshop met its educational objectives. Future curricula to prepare faculty as medical writers need to be tested using quasi-experimental designs to determine their impact on publication productivity and quality.

Quantitative determination of F:O ratios in rare earth oxide fluorides by energy dispersive X-ray analysis.

The F:O ratio in homogeneous and inhomogeneous rare earth oxide fluoride systems of compositions RO(1+x)F(1-2x) with -0.1