Time-Integrated Neutrino Source Searches with 10 Years of IceCube Data

This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1  TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.

Constraints on Minute-Scale Transient Astrophysical Neutrino Sources

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5}  erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52}  erg. A hypothetical population of transient sources has to be more common than 10^{-5}  Mpc^{-3}  yr^{-1} (5×10^{-8}  Mpc^{-3}  yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.

Search for neutrinos from decaying dark matter with IceCube: IceCube Collaboration

With the observation of high-energy astrophysical neutrinos by the IceCube Neutrino Observatory, interest has risen in models of PeV-mass decaying dark matter particles to explain the observed flux. We present two dedicated experimental analyses to test this hypothesis. One analysis uses 6 years of IceCube data focusing on muon neutrino 'track' events from the Northern Hemisphere, while the second analysis uses 2 years of 'cascade' events from the full sky. Known background components and the hypothetical flux from unstable dark matter are fitted to the experimental data. Since no significant excess is observed in either analysis, lower limits on the lifetime of dark matter particles are derived: we obtain the strongest constraint to date, excluding lifetimes shorter than10 28 s at 90% CL for dark matter masses above 10 TeV .

Measurement of the ν μ energy spectrum with IceCube-79: IceCube Collaboration

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The ν μ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an E ν -range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9 σ in four adjacent bins for neutrino energies E ν ≥ 177.8 TeV . The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos.

[Barriers to treatment-seeking among German veterans: expert interviews]

BACKGROUND

The number of service members of the German armed forces suffering from deployment-related mental health problems is increasing. However, less than 50 % seek professional help, and there is little knowledge about the barriers to treatment-seeking.

METHODS

The article presents data gathered by the Delphi technique combined with focus groups from 55 health service experts regarding the evaluated barriers to treatment-seeking among German veterans.

FINDINGS

According to the interviewed experts, major contextual barriers to treatment-seeking include: 1) intimidating processes and structures, 2) actual stigmatization and discrimination, and 3) health service deficits. Major individual barriers to treatment were: 4) health beliefs, self-perception and fear of stigmatization, and 5) avoidance behavior related to psychopathology. In addition, there is another both contextual and individual barrier, i.e., 6) information deficits.

INTERPRETATION

Individual internal factors like the soldiers' self-perception and their fear of being stigmatized were considered important barriers to treatment-seeking. The experts' opinion about avoidance behavior related to psychopathology and deficits in health services and information coincides with international findings. Compared to research in other countries, actual stigmatization and discrimination were regarded to be an important barrier in itself. According to our findings daunting/intimidating processes and structures like time-consuming and complex expert medical reports rather seem to be a German phenomenon.

Constraints on Ultrahigh-Energy Cosmic-Ray Sources from a Search for Neutrinos above 10 PeV with IceCube

We report constraints on the sources of ultrahigh-energy cosmic rays (UHECRs) above 10^{9}  GeV, based on an analysis of seven years of IceCube data. This analysis efficiently selects very high- energy neutrino-induced events which have deposited energies from 5×10^{5}  GeV to above 10^{11}  GeV. Two neutrino-induced events with an estimated deposited energy of (2.6±0.3)×10^{6}  GeV, the highest neutrino energy observed so far, and (7.7±2.0)×10^{5}  GeV were detected. The atmospheric background-only hypothesis of detecting these events is rejected at 3.6σ. The hypothesis that the observed events are of cosmogenic origin is also rejected at >99% CL because of the limited deposited energy and the nonobservation of events at higher energy, while their observation is consistent with an astrophysical origin. Our limits on cosmogenic neutrino fluxes disfavor the UHECR sources having a cosmological evolution stronger than the star formation rate, e.g., active galactic nuclei and γ-ray bursts, assuming proton-dominated UHECRs. Constraints on UHECR sources including mixed and heavy UHECR compositions are obtained for models of neutrino production within UHECR sources. Our limit disfavors a significant part of parameter space for active galactic nuclei and new-born pulsar models. These limits on the ultrahigh-energy neutrino flux models are the most stringent to date.

Searches for Sterile Neutrinos with the IceCube Detector

The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy in the approximate 320 GeV to 20 TeV range, to search for the oscillation signatures of light sterile neutrinos. No evidence for anomalous ν_{μ} or ν[over ¯]_{μ} disappearance is observed in either of two independently developed analyses, each using one year of atmospheric neutrino data. New exclusion limits are placed on the parameter space of the 3+1 model, in which muon antineutrinos experience a strong Mikheyev-Smirnov-Wolfenstein-resonant oscillation. The exclusion limits extend to sin^{2}2θ_{24}≤0.02 at Δm^{2}∼0.3  eV^{2} at the 90% confidence level. The allowed region from global analysis of appearance experiments, including LSND and MiniBooNE, is excluded at approximately the 99% confidence level for the global best-fit value of |U_{e4}|^{2}.

Evidence for Astrophysical Muon Neutrinos from the Northern Sky with IceCube

Results from the IceCube Neutrino Observatory have recently provided compelling evidence for the existence of a high energy astrophysical neutrino flux utilizing a dominantly Southern Hemisphere data set consisting primarily of ν(e) and ν(τ) charged-current and neutral-current (cascade) neutrino interactions. In the analysis presented here, a data sample of approximately 35,000 muon neutrinos from the Northern sky is extracted from data taken during 659.5 days of live time recorded between May 2010 and May 2012. While this sample is composed primarily of neutrinos produced by cosmic ray interactions in Earth's atmosphere, the highest energy events are inconsistent with a hypothesis of solely terrestrial origin at 3.7σ significance. These neutrinos can, however, be explained by an astrophysical flux per neutrino flavor at a level of Φ(E(ν))=9.9(-3.4)(+3.9)×10(-19)  GeV(-1) cm(-2) sr(-1) s(-1)(E(ν)/100  TeV(-2), consistent with IceCube's Southern-Hemisphere-dominated result. Additionally, a fit for an astrophysical flux with an arbitrary spectral index is performed. We find a spectral index of 2.2(-0.2)(+0.2), which is also in good agreement with the Southern Hemisphere result.

Energy loss and charge transfer of argon in a laser-generated carbon plasma

This Letter reports on the measurement of the energy loss and the projectile charge states of argon ions at an energy of 4  MeV/u penetrating a fully ionized carbon plasma. The plasma of n(e)≈10(20)  cm(-3) and T(e)≈180  eV is created by two laser beams at λ(Las)=532  nm incident from opposite sides on a thin carbon foil. The resulting plasma is spatially homogenous and allows us to record precise experimental data. The data show an increase of a factor of 2 in the stopping power which is in very good agreement with a specifically developed Monte Carlo code, that allows the calculation of the heavy ion beam's charge state distribution and its energy loss in the plasma.

Development of a Nomarski-type multi-frame interferometer as a time and space resolving diagnostics for the free electron density of laser-generated plasma

This article reports on the development and set-up of a Nomarski-type multi-frame interferometer as a time and space resolving diagnostics of the free electron density in laser-generated plasma. The interferometer allows the recording of a series of 4 images within 6 ns of a single laser-plasma interaction. For the setup presented here, the minimal accessible free electron density is 5 × 10(18) cm(-3), the maximal one is 2 × 10(20) cm(-3). Furthermore, it provides a resolution of the electron density in space of 50 μm and in time of 0.5 ns for one image with a customizable magnification in space for each of the 4 images. The electron density was evaluated from the interferograms using an Abel inversion algorithm. The functionality of the system was proven during first experiments and the experimental results are presented and discussed. A ray tracing procedure was realized to verify the interferometry pictures taken. In particular, the experimental results are compared to simulations and show excellent agreement, providing a conclusive picture of the evolution of the electron density distribution.

[A 56-year-old patient with Gaucher's disease sustaining a pathologic subcapital fracture of the humerus]

We present a case of a pathologic humerus fracture in a patient with the initial diagnosis of Gaucher's disease, which is the most frequent form of lipidosis transmitted as an autosomal recessive trait. It often results in orthopaedic complications with pain, osteonecrosis, fractures and joint infractions. If there is cause for suspicion, beta-glucocerebrosidase in white blood cells should be measured because of the important consequences for treatment. Therapy with a modified enzyme is effective in managing the disease.

Planning system for computer assisted total knee replacement

Total knee replacement (TKR) is a common orthopaedic surgical intervention and includes the removal of bone sections from the end of the femur and the top of the tibia for replacement by prosthetic components. Pain relief and functional improvement are predictable clinical results. But the accuracy of the alignment affects the surgical outcome and the longevity of the prosthesis. Hence, current total knee implantation systems attempt to align the knee joint in the mechanical axis for placement of the total knee components. These approaches use templates and plain radiographs for preoperative planning and alignment devices for bone cuts. To overcome the inherent inaccuracy of the presently used systems a computer-assisted planning system has been developed delivering the necessary control data for the intraoperative surgical robot system.

[VRATS--Virtual Reality Arthroscopy Training Simulator]

The subject of this paper is a highly interactive medical training system for arthroscopic surgery; this is based on computer graphics and virtual reality (VR) techniques and offers an alternative to conventional training methods. To provide the virtual environment, a realistic 3D representation of the knee joint is derived from 2D medical image data. The use of tracking techniques guarantees an intuitive handling of the surgical instruments. The system allows navigation via a virtual camera and interaction with the virtual anatomical structures. First approaches for the simulation of tissue deformation caused by collisions with the instruments are implemented. One important advantage over conventional training systems is the possibility of verifying the training progress. Work is in progress on the realization of tactile feedback with the aim of providing a higher degree of interactive realism.

Computer-integrated revision total hip replacement surgery: concept and preliminary results

This paper describes an ongoing project to develop a computer-integrated system to assist surgeons in revision total hip replacement (RTHR) surgery. In RTHR surgery, a failing orthopedic hip implant, typically cemented, is replaced with a new one by removing the old implant, removing the cement and fitting a new implant into an enlarged canal broached in the femur. RTHR surgery is a difficult procedure fraught with technical challenges and a high incidence of complications. The goals of the computer-based system are the significant reduction of cement removal labor and time, the elimination of cortical wall penetration and femur fracture, the improved positioning and fit of the new implant resulting from precise, high-quality canal milling and the reduction of bone sacrificed to fit the new implant. Our starting points are the ROBODOC system for primary hip replacement surgery and the manual RTHR surgical protocol. We first discuss the main difficulties of computer-integrated RTHR surgery and identify key issues and possible solutions. We then describe possible system architectures and protocols for preoperative planning and intraoperative execution. We present a summary of methods and preliminary results in CT image metal artifact removal, interactive cement cut-volume definition and cement machining, anatomy-based registration using fluoroscopic X-ray images and clinical trials using an extended RTHR version of ROBODOC. We conclude with a summary of lessons learned and a discussion of current and future work.

[Computer-assisted surgery for hip endoprosthesis]

The use of computer-controlled robots for implanting cement-free prostheses requires exact preoperative planning on a three-dimensional graphics computer (ORTHODOC). For the first time ever, it has been possible to implement the three-dimensional plan using a computer-controlled robot working on patients. We assume that the considerably improved bone contact provided by the high-precision reaming process--an thus high primary stability--will lead to better incorporation in the bone. In experiments on dogs, in which cement-free hips had been implanted using computer-assisted robots, the animals showed much earlier and more uniform weight-bearing on the affected extremity than animals in a control group that had received conventional implants. In histological therms, the precise fit obtained by the ROBOCOC was accompanied by primary angiogenic healing patterns that all demonstrated labels during the first four weeks. The manually reamed comparators showed more pronounced fissure and defect healing, the healing patterns was irregular, and turnover activity was demonstrate.

Primary and revision total hip replacement using the Robodoc system

The ROBODOC system was designed to address potential human errors in performing cementless total hip replacement. The system consists of a preoperative planning computer workstation (called ORTHODOC) and a five-axis robotic arm with a high speed milling device as an end effector. The combined experience of the United States Food and Drug Administration multicenter trial and the German postmarket use of the system are reported. The United States study is controlled and randomized with 136 hip replacements performed at three centers (65 ROBODOC and 62 control). Followup was 1 year on 127 hip replacements and 2 years on 93 hip replacements. No differences were found in the Harris hip scores or the Short Form Health Survey outcomes questionnaire. Length of stay also was not different, but the surgical time and blood loss were greater in the ROBODOC group. This was attributed to a learning curve at each center. Radiographs were evaluated by an independent bone radiologist and showed statistically better fit and positioning of the femoral component in the ROBODOC group. Complications were not different, except for three cases of intraoperative femoral fracture in the control group and none in the ROBODOC group. The German study reports on 858 patients, 42 with bilateral hip replacements and this includes 30 revision cases for a total of 900 hip replacements. The Harris hip score rose from 43.7 to 91.5. In these cases the surgical time declined quickly from 240 minutes for the first case to 90 minutes. No intraoperative femoral fractures occurred in 900 cases. Other complications were comparable with total hip replacements performed using conventional techniques. The ROBODOC system is thought to be safe and effective in producing radiographically superior implant fit and positioning while eliminating femoral fractures.

[Mobilization of the tibial insertion of the anterior cruciate ligament: new therapeutic possibilities in surgery of the cruciate ligament]

In patients with a significant elongation of the ACL we propose a new therapeutic regimen. After mobilisation of the tibial insertion of the ACL we pull the bone block with the attached ACL distally. Thus the ACL is easily tightened. In accordance with this method, we describe the treatment of a case of a strictly proximal rupture of the ACL: the tibial insertion is mobilised, the bone block with the attached ACL removed from the joint. Ex vivo sutures are placed into the ACL, the ligament is pulled back into the joint, and the shortening of the ligament caused by the sutures is compensated by slight proximal dislocation of the bone block.

[Computer-assisted robotics in hip endoprosthesis implantation]

The most important prerequisite for permanent fixation of an implant is primary stability. Osteointegration of the implant is a major goal in cementless total hip replacement (THR). This means direct contact between bone and implant leading to fixation of the implant in the bone without the interference of fibrous tissue. In addition to the design of the implant, the structure of the implant surface and the material of the implant, the specific operational technique plays a major role in permanent fixation. Only the conical fixation of femoral implants guarantees high primary stability in cementless THR. The type of fixation of the implant in the femoral cavity and the resulting load transfer from implant to bone has a decisive effect on the durability of the prostheses. In order to achieve optimal primary fixation of the implant, robot-assisted implantation of the cementless implant has been performed at the Berufsgenossenschaftliche Unfallklinik Frankfurt am Main since the summer of 1994. After preoperative planning at a three-dimensional graphic work station these data are transferred to the robot, which transforms the preoperative planning by milling the femoral cavity with the highest precision. So far this type of surgery has been performed on 300 patients. The encouraging postoperative results prompted us to install the second system of Robodoc at the Berufsgenossenschaftliche Unfallklinik Frankfurt.

[Computer-guided robot-assisted hip endoprosthesis]

Computer-guided robot-assisted surgery in cementless total hip replacement requires exact preoperative planning at the 3D workstation Orthodoc. Only the Robodoc procedure allows the precise execution of the preoperative plan in surgery. Robot-assisted surgery has been undergoing clinical evaluation at the Berufsgenossenschaftliche Unfallklinik, Frankfurt, since November 1994. In all 465 patients, the preoperative plan was successfully carried out intraoperatively. The high precision in reaming, leading to a superb bone implant contact, guarantees absolute initial stability and is likely to promote primary healing between implant and bone. The common and often published incidence of varus or valgus malpositioning and any fractures or fissures could be avoided through the use of Robodoc. Although immediate full-weight bearing was strongly recommended to the patients, no implant subsidence was seen in the treatment follow-up X ray studies.

[American football in Germany--aspects of trauma surgery]

While football injuries in the USA are well documented and thoroughly studied, informations on injuries caused by this spreading sport in Germany are not available. For this reason the Berufsgenossenschaftliche Unfallklinik in Frankfurt conducted a prospective study to register all injuries in major league football in southern Germany in 1991. In 49 games that were evaluated we found 281 minor injuries, mainly skin lesions and concussions of extremities. In addition 33 significant injuries were registered, amongst them 30% injuries of knee ligaments. The only severe injury was an abdominal hit causing a intrahepatic hematoma. The results of our study are comparable to the injury risks found in US college football as well as to those found in German statistics on soccer and hockey. Although no fatal injuries in our study were registered, this should not lead to neglecting the potential risks in football.

[Arthrodesis of the upper ankle joint. Indications, technique, results]

From 1984 to 1990 a total of 119 arthrodesis of the upper ankle joint were performed at the Hospital of Accident Surgery of the Trade Association in Frankfurt am Main. The results of 98 patients after an arthrodesis of the upper ankle joint are documented by an x-ray control series and patient files, including the expertise on the medical status of pensioners plus a follow-up examination of 34 patients. The indications and the results are discussed on the basis of the various procedures. The results confirm the method of a compressions arthrodesis with an extension screw in case of a posttraumatic arthrosis of the upper ankle joint, while a fixateur externe should be used in case of chronical osteomyelitis, osteoporotic bones, extensive tissue swellings and after a pilon or talus fragment fracture.

[Monteggia injuries in athletes. Causes, classification, results]

Monteggia-fractures are serious combination injuries to the forearm. Sport injuries are being increasingly observed; the reason for this, besides the general expansion of mass sports, is the increasing burden of high-performance sports. Monteggia fractures can occur during a fall on an outstretched arm, for example in motor or bicycle sport injuries, but also when falling from gymnastic equipment. Generally, it is easy to diagnose the monteggia injury. Considerable secondary damage could occur from the frequent failure to notice the involved radiohumeral joint. It should be demanded that in case of an uluar fracture the adjoining joints should be x-rayed on two planes in order not to overlook the possibility of a chisel fracture. The different forms of this combination injury, its classification and the results of our own medical bulletins are presented.

[A new guide and 2 new cruciate ligament anchors for securing prosthetic cruciate ligaments to the femur]

A new drilling device for the correct localization of drilling holes has been developed for the fixation of cruciate ligament prostheses. We describe how the device is employed under surgical operating conditions. Its accuracy in application is demonstrated in a cadaver knee. The device has also been used clinically with success. Two new anchors for the fixation of the ligaments are proposed.

[The treatment of proximal femoral fractures using the interlocking nail]

The good result hoped for with interlocking nailing of the proximal part of the femoral shaft is only possible when precise diagnosis is of the fracture form is made with reference to informative X-rays and a meticulous operative technique is observed. Therefore, positioning of the patient on an extension table, the repositioning of the bone, the choice of the insertion point for the nail, and careful drilling are of the utmost important. All follow-up examinations conducted in 42 patients, we found good or very good results in 32 cases, satisfactory results in 7, and poor results in 3.

[Results of interlocking nailing of distal tibial fractures]

Between 1982 and 1989, 117 fractures of the distal part of the lower leg were surgically treated in the Trauma Clinic belonging to the employers' liability insurance company in Frankfurt/Main. A follow-up examination of 85 of these patients, based on X-ray series, clinical reports, and insurance files, shows the functional results. Because of the high proportion of good to excellent results (95.4%), we consider fracture of the distal tibia a good indication for interlocking nailing, even from the aspect of the borderline indication of fracture in the fifth sixth. In open fractures of the distal part of the lower leg we consider the change of method from primary stabilization with external fixation to secondary interlocking nailing an appropriate procedure. The methods presented for internal fixation of fractures of the distal tibia by interlocking nailing allow early partial and full weight-bearing with the stability needed for exercising.

[The cruciate ligaments as the major mechanism of control of the movement of the knee joint]

The kinematics of the knee joint is considered with the special regard to the cruciate ligaments. An optimum place for the fixation of ligament substitute is calculated. Anatomic preparations of cadaver knee joints proved this predictions to be correct. Placing the ligament substitute at this place the ligaments behave isometrically.

[Fracture of the scaphoid bone--surgical treatment, indications, method and results]

In fractures of the scaphoid bone, conservative treatment leads to an osseous consolidation in 95% of all cases. A primary surgical treatment seems justified in case of instability by torsion, tilting, or shifting of the fragments, associated fractures of the same arm, as well as de Quervain dislocation fracture. The different surgical possibilities are described and the complications are compiled in a special study. The question if a recent fracture of the scaphoid bone should be managed by conservative or surgical treatment ist not justified considering the rate of 14.5% of complications, i.e. formation of pseudarthroses, observed after surgery of recent fractures of the scaphoid bone.

Interlocking nailing of complex fractures of the femur and tibia

The interlocking nail widens the range of indications for medullary osteosynthesis of femoral and tibial shaft fractures. Stability is achieved by transverse threaded bolts in prefabricated holes in the nail, which anchor the implant directly to cortical bone, thereby controlling length, alignment, and rotation of the limb. Two hundred eighty-three femoral and 401 tibial fractures were treated with an interlocking nail and followed for an average of 20 months. Overall, 97% of the femurs and 94.3% of the tibias were judged to have an excellent or good result, based on both clinical and radiographic parameters. Delayed union or nonunion requiring bone grafts occurred in 2% of the femurs and 0.7% of the tibias following interlocking nailing. Deep infection developed in 2.4% of the femurs and 2.2% of the tibias. All of these patients eventually healed their fractures without evidence of chronic osteomyelitis. The main advantage of interlocking nails is that surgery can be performed using closed nailing techniques, allowing early protected weight-bearing and joint motion. The rates of nonunion and infection are very low, and there is little risk of refracture after implant removal.

[Treatment of chronic osteomyelitis with gentamicin PMMA chains]

In the treatment of chronic osteomyelitis radical removal of sequestrated bone fragments is of essential importance. Any antibiotic therapy - whether systemically or locally applied - can only be a supplementary measure. By implantation of gentamicin-PMMA-chains into infected cavities high local concentrations of the antibiotic can be achieved which are far above the minimal bactericidal concentrations of most common pathogens. As result of the very low concentrations of gentamicin in the serum and urine there is no hazard of nephrotoxicity and ototoxicity. Chronic sequestrating osteosyntheses and infected non-unions are the most important indications for the application of gentamicin-PMMA-chains.

[Experimental principles and clinical experiences in the use of allogeneic spongiosa]

Although the biological activity of autologous spongiosa is undisputed, considerable treatment problems can arise when filling up major bone defects, in aseptic pseudarthroses or in pathological fractures. Remaining defects or instabilities which do not allow us to expect osseous bridging-over prompted us to use deep-frozen allogenic spongiosa because of the restricted availability (if at all) of autologous spongiosa. Experimental studies employing Alsatian mongrels using the tracer microsphere method resulted in good blood supply and hence bone healing with good positioning of the graft and compresses spongiosa. The experimental results confirm the clinical experiences with simultaneous stable osteosynthesis.

[Indications for the surgical and conservative treatment of juvenile supracondylar humeral fractures and their results]

In the period from 1977 to 1982 78 children were treated for supracondylar fractures of the humerus at the Berufsgenossenschaftliche Unfallklinik Frankfurt/Main. Indications and methods for operative and conservative treatment are described. The results of therapy were reviewed by means of a questionnaire or reexamination in 68 patients with regard to function, elbow deformity and nerve lesions. Fractures of a grade I severity are to be treated conservatively by immobilisation in a POP-cast. Only in exceptional cases of grade II severity can a closed reduction be recommended. All remaining types of fractures of grade II and III severity should primarily be treated by open operations within 8 hours of the accident. Under these conditions the risk of infection is no higher than with percutaneous Kirschner-wire-osteosynthesis. Complications such as appreciable varus deformity, poor function and nerve lesions can largely be avoided in this way. The so-called extension-treatment offers no advantages in comparison with operative treatment.

[Operative reduction of comminuted fractures of the heel-bone and its results]

Severe comminuted fractures of the heel-bone involving the joint, which have to be classified according to Böhler into group V-VIII, are treated by a modified form of the so-called raising operation of Palmer. 27 patients (= 14,3%) had bilateral heel-bone fractures. The posterior subtalar supporting plate is raised under image-amplifier control, the defect cavity is filled with spongiosa, and the result of reposition is fixed with Kirschner wires laid under the skin. Functional treatment may begin a few days later; loading is generally possible after ten to twelve weeks, when the metal parts have been removed and the fracture has consolidated. Sixteen patients (= 8,5%) do not need orthopedic instruments, 132 patients (= 69,9%) are provided with arch-supports, and 41 (= 69,9%) with orthopedic footwear.

[Classification, treatment and results of fractures of the tibial pilon]

Considering the rate of complications and the remaining disability occurring after compression fractures of the distal end of the tibia - the so-called pilon fracture -, this type of fracture is one of the most serious injuries of the lower extremity. Such fractures of the distal end of the tibia can be caused by compressions as well as by direct of indirect traumatic violence, e.g. shearing, bending, or torsion effects. Of 102 patients with pilon fractures, 63 (= 61.8%) suffered this fracture by falling from a great height. When classifying our cases with fracture of the distal end of the tibia, and the diagnosed accompanying injuries, we found a dependence between expected consequences of the lesion and the seriousness of the accident before surgery already. During the treatment of patients suffering from pilon fractures, complications arose in 0% of group I, in 16.1% of group II, and in 27.6% of group III. With respect to the existing possibilities of surgical treatment of fractures, one should always - if possible - reconstruct the joint surfaces in an anatomically correct manner and apply an early functional treatment with late exertion of stress on the injured part.

[Technic and diagnostic value of so-called stress x-rays in injuries of the fibular ligaments (author's transl)]

To allow a definite diagnosis in cases of rupture of the fibular ligaments of the ankle-joint, stress-x-rays of the upper ankle joint were taken in ap. and lateral view. The intraoperative findings in 150 patients with rupture of the fibular capsule/ligament were compared with the preoperative x-rays. The results justify the conclusion that stress-x-rays in ap.-view are sufficient. Additional information can be obtained about the different components of the capsule and the ligament.

[The fall of Icarus or the seriously injured young motorcyclist (author's transl)]

During 1979 70 motorcyclists were treated in the Department of Traumatology of the "Berufsgenossenschaftliche Unfallklinik" Frankfurt/Main. The psychological reasons of the motorcycle-boom and the consequences are compared. The psychic status of these young motorcyclists was different from that of other patients. An analysis of the data showed that in 24.3% the accident occurred on the way to work or to school; 75.7% of the accidents happened during a pleasure-trip. 58.6% of the motorcyclists suffered injuries with permanent sequels. The different types of permanent damage are described. Based on two case reports the arising costs are analysed.