[Osteoarthritis of the shoulder: pathogenesis, diagnostics and conservative treatment options]

PATHOGENESIS

Osteoarthritis of the shoulder is characterized by a progressive degenerative process, which is based on chronic inflammation with intra-articular release of different cytokines and proteolytic enzymes. The main predisposing factors are a history of trauma or surgery, as well as chronic overuse or instability of the glenohumeral joint. Affected patients especially suffer from impaired joint function and pain, which are often associated with cognitive and psychosocial restrictions.

DIAGNOSTICS

Possible co-pathologies have to be evaluated carefully both clinically and radiologically as they must be taken into account in the therapeutic procedure. If arthroplasty of the shoulder is planned, a pre-operative CT scan is mandatory in order to evaluate the bone stock of the glenoid, which has a decisive influence on the choice of implant.

TREATMENT

Conservative treatment options are oral pain medication, physical therapy, and intra-articular injections, whereby, in comparison to corticosteroids, hyaluronic acid seems to be advantageous especially with respect to the duration of a positive clinical effect.

Retrograde fixation of the lesser trochanter in the adolescent: new surgical technique and clinical results of two cases

INTRODUCTION

Avulsions of the lesser femoral trochanter are rare injuries in the adolescent population. An acute avulsion causes severe functional impairment with compromised hip flexion. Recent literature reports the superiority of surgical treatment for apophyseal avulsion fractures of the pelvis in adolescents. Unfortunately, there are no guidelines for an evidence-based treatment of lesser trochanter avulsions established. We present the cases of two adolescent athletes treated operatively.

MATERIALS AND METHODS

Two adolescent males, 12 and 16 years old, suffered an avulsion of the lesser trochanter during soccer. They reported immobilizing groin pain with subjective impairment in daily activities and inability to perform sports. Surgical treatment with a new retrograde technique by applying an adapted mini-open anterior approach was performed. Intraoperatively, both cases showed an intact musculo-tendinous unit attached to the avulsed fragment.

RESULTS

Both patients showed excellent postoperative results and were satisfied with the clinical outcome. In the postoperative follow-up an adequate consolidation of the lesser trochanter was visible. No complications were postoperatively reported at final follow-up.

CONCLUSIONS

The retrograde fixation technique has led to an excellent outcome without complications in two adolescents with acute lesser trochanter apophyseal avulsions. Further clinical use may support the value of this new surgical technique.

[Distal femoral osteotomy using a lateral opening wedge technique]

OBJECTIVE

To shift the weight-bearing axis of the lower limb medially by opening a lateral-based metaphyseal osteotomy at the distal femur.

INDICATIONS

Femoral-based valgus malalignment and symptomatic lateral unicompartimental osteoarthritis, lateral hyperpression syndrome, cartilage therapy of the lateral compartment, lateral meniscal replacement/transplantation, medial instability with valgus thrust, reconstruction of the medial collateral ligament, patellar instability and/or maltracking.

CONTRAINDICATIONS

Advanced cartilage damage (>grade 2) or subtotal meniscal loss of the medial compartment, age >65 years (relative), nicotine abuse, body mass index >30, flexion contracture >25°, corrections with a wedge base >10 mm in case of congenital deformities, inflammatory or septic arthritis, severe osteoporosis.

SURGICAL TECHNIQUE

Lateral approach to the distal femur; biplanar osteotomy (frontal + axial osteotomy), gradual opening of the osteotomy, osteotomy fixation with a locking plate.

POSTOPERATIVE MANAGEMENT

Free range of motion. Partial weight bearing with 20 kg for 2 weeks, followed by progressive weight bearing thereafter.

RESULTS

Mean improvement of knee scores from 20-30 points and mean 10-year survival rate of 80% in patients with lateral unicompartimental osteoarthritis. Mean complication rate of 9%.

Electrical detection of liquid lithium leaks from pipe joints

A test stand for flowing liquid lithium is under construction at Princeton Plasma Physics Laboratory. As liquid lithium reacts with atmospheric gases and water, an electrical interlock system for detecting leaks and safely shutting down the apparatus has been constructed. A defense in depth strategy is taken to minimize the risk and impact of potential leaks. Each demountable joint is diagnosed with a cylindrical copper shell electrically isolated from the loop. By monitoring the electrical resistance between the pipe and the copper shell, a leak of (conductive) liquid lithium can be detected. Any resistance of less than 2 kΩ trips a relay, shutting off power to the heaters and pump. The system has been successfully tested with liquid gallium as a surrogate liquid metal. The circuit features an extensible number of channels to allow for future expansion of the loop. To ease diagnosis of faults, the status of each channel is shown with an analog front panel LED, and monitored and logged digitally by LabVIEW.

Detection of B-mode polarization in the cosmic microwave background with data from the South Pole Telescope

Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "B-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity-wave signals. In this Letter we present the first detection of gravitational lensing B modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing B-mode signal by combining E-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the B modes measured directly by SPTpol, finding a nonzero correlation at 7.7σ significance. The correlation has an amplitude and scale dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmological observable.

Noninvasive measurement of dissipation in colloidal systems

According to Harada and Sasa [Phys. Rev. Lett. 95, 130602 (2005)], heat production generated in a nonequilibrium steady state can be inferred from measuring response and correlation functions. In many colloidal systems, however, it is a nontrivial task to determine response functions, whereas details about spatial steady state trajectories are easily accessible. Using a simple conditional averaging procedure, we show how this fact can be exploited to reliably evaluate average heat production. We test this method using Brownian dynamics simulations, and apply it to experimental data of an interacting driven colloidal system.

Frequency multiplexed superconducting quantum interference device readout of large bolometer arrays for cosmic microwave background measurements

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ∼MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.

Role of hidden slow degrees of freedom in the fluctuation theorem

The validity of the fluctuation theorem for entropy production as deduced from the observation of trajectories implicitly requires that all slow degrees of freedom are accessible. We experimentally investigate the role of hidden slow degrees of freedom in a system of two magnetically coupled driven colloidal particles. The apparent entropy production based on the observation of just one particle obeys a fluctuation theorem-like symmetry with a slope of 1 in the short time limit. For longer times, we find a constant slope, but different from 1. We present theoretical arguments for a generic linear behavior both for small and large apparent entropy production but not necessarily throughout. By fine-tuning experimental parameters, such an intermediate nonlinear behavior can indeed be recovered in our system as well.

Invited article: millimeter-wave bolometer array receiver for the Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument

The Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument is a millimeter-wave cryogenic receiver designed to observe galaxy clusters via the Sunyaev-Zel'dovich effect from the 12 m APEX telescope on the Atacama plateau in Chile. The receiver contains a focal plane of 280 superconducting transition-edge sensor (TES) bolometers instrumented with a frequency-domain multiplexed readout system. The bolometers are cooled to 280 mK via a three-stage helium sorption refrigerator and a mechanical pulse-tube cooler. Three warm mirrors, two 4 K lenses, and a horn array couple the TES bolometers to the telescope. APEX-SZ observes in a single frequency band at 150 GHz with 1' angular resolution and a 22' field-of-view, all well suited for cluster mapping. The APEX-SZ receiver has played a key role in the introduction of several new technologies including TES bolometers, the frequency-domain multiplexed readout, and the use of a pulse-tube cooler with bolometers. As a result of these new technologies, the instrument has a higher instantaneous sensitivity and covers a larger field-of-view than earlier generations of Sunyaev-Zel'dovich instruments. The TES bolometers have a median sensitivity of 890 μK(CMB)√s (NEy of 3.5 × 10(-4) √s). We have also demonstrated upgraded detectors with improved sensitivity of 530 μK(CMB)√s (NEy of 2.2 × 10(-4) √s). Since its commissioning in April 2007, APEX-SZ has been used to map 48 clusters. We describe the design of the receiver and its performance when installed on the APEX telescope.

[New problems and results in behavior therapy]

What is presently observed is not only a rapid increase in the number of publications, but also a major change in the theoretical principles of behavior therapy. The former onesidedness of a form of behavior therapy theoretically substantiated by classical conditioning only may be regarded as having been completely overcome. For example, this is evident from new approaches to behavior diagnosis as an essential prerequisite of differentiated therapy planning. Recent concepts of the theoretical substantiation of the effectiveness of behavior therapy lead to an increasing consideration of both cognitive and motivational aspects and also take into account the complexity of the patient's social relations. This, in turn, results in the availability of a wide range of indication-specific methods of behavior therapy.

[Theory and method of self-assertion training]

Lack of assertiveness is considered, in the sense of the theoretical concept of Ullrich de Muynck and Ullrich, to be due to such components as 1. abnormal attitude toward oneself, 2. fear of criticism and failure, and 3. inadequately developed social skills; after this, the term 'assertiveness' is defined. Previous therapeutical approaches to the remedying of unassertiveness and the underlying theoretical assumptions are critically examined and discussed with particular reference to their effectiveness. These include the training programs developed by Salter and Wolpe which are characterized by certain onesidedness as well as the concept of Ullrich de Muynck and Ullrich, which has a sound theoretical basis and a rather differentiated or specialized structure. Reference is also made to the author's own research projects.

Roentgen-tele-data: a radiodiagnostic recording system

A radiodiagnostic data-handling system with telephones connected to the hospital exchange is described. Time, date, and location of examination are automatically recorded. The system can deliver spoken instructions from the computer and warns if data are not valid. Diagnosis, their degree of verification, and cases of special interest are added at display terminals. Codes, equipment, and output are described. Costs represent 1% of the department's expenditures. Future plans include a booking sytem, rapid access, and on-line connection to the main data system.

[Aseptic bone infarcts in occupational divers]

A report is given on dispensary investigations of professional divers. In 32 of a control group consisting of altogether 41 scaphander divers radiologically were found changes in the sense of aseptic bone necroses. 18 of the examined persons showed polyostotic affection and 14 had a monostotic localisation of the foci. Divers with no extensive findings could further work in their profession with a limitation of depth up to 13 depth of water. On the other hand examined persons with severe changes had temporarily to leave their profession. Relevant problems of the clinical symptomatology and the radiological differential diagnostics of aseptic bone necroses are discussed.