Der HEPFIEx-Simulator, eine Apparatur zur Bestimmung der Reibzahlen zwischen Hüftkopf-Prothesen und Knorpel / The HEPFlEx Simulator, a Device for Measuring the Friction between Femoral Head Prostheses and Cartilage

We describe a device designed to investigate friction between various femoral head prostheses and human acetabula. It enables not only the determination of friction and the relevance of the play between the femoral head and acetabulum, but also the evaluation of the kinematic behaviour of bipolar prostheses. In the simulator, the various femoral head prostheses are placed on a special cone and tested against a human cadaveric acetabulum. The swiveling range of the device is uniaxial, and the swiveling angle is +/- 35 degrees. The maximum force produced pneumatically is 5kN. Testing of the simulator with a TEP was successful and friction-coefficients of < 0.1 were measured, as are reported i…

Carbonate-coordinated metal complexes precede the formation of liquid amorphous mineral emulsions of divalent metal carbonates†

During the mineralisation of metal carbonates MCO3 (M = Ca, Sr, Ba, Mn, Cd, Pb) liquid-like amorphous intermediates emerge. These intermediates that form via a liquid/liquid phase separation behave like a classical emulsion and are stabilized electrostatically. The occurrence of these intermediates is attributed to the formation of highly hydrated networks whose stability is mainly based on weak interactions and the variability of the metal-containing pre-critical clusters. Their existence and compositional freedom are evidenced by electrospray ionization mass spectrometry (ESI-MS). Liquid intermediates in non-classical crystallisation pathways seem to be more common than assumed.

Characterization of oligomeric compounds in secondary organic aerosol using liquid chromatography coupled to electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

The components of secondary organic aerosols (SOAs) generated from the gas-phase ozonolysis of two C(10)H(16)-terpenes (alpha-pinene; sabinene) and a cyclic C(6)H(10) alkene (cyclohexene) were characterized by the use of a Fourier transform ion cyclotron mass spectrometer equipped with an electrospray ionization source operated in the negative ion mode. Reversed-phase high-performance liquid chromatography was used to achieve chromatographic separation of highly oxidized organic compounds. In addition to the well-known group of low molecular weight oxidation products (monomers; e.g. dicarboxylic acids), higher molecular weight compounds (dimers) were also detected and their exact elemental …

Mid- to long-term results after bipolar radial head arthroplasty.

Background Radial head arthroplasty is considered the treatment of choice for unreconstructable radial head fractures in the acute fracture situation. Although short-term results in the current literature are promising, replacement of the radial head remains controversial as long-term results are still missing. We report our 8.8-year results after treatment with a bipolar radial head prosthesis by Judet. Materials and methods In our department, 19 patients were treated with bipolar radial head arthroplasty between 1997 and 2001. Seventeen of these patients—14 men and 3 women—were examined retrospectively after 106 months (range, 78-139). Of these, 9 patients were treated primarily, 7 patien…

Frozen shoulder: a sympathetic dystrophy?

Diagnostic and clinical features of the frozen shoulder syndrome and the Sudeck syndrome are similar in many aspects. Radioisotope bone scan shows an increased uptake in affected areas in both diseases, while native radiographs show a progressive demineralisation. Measurement of bone mineral density (BMD) by quantitative digital radiography objectified these local decalcification processes in an early stage of the frozen shoulder syndrome; 10 of 12 patients with primary frozen shoulder had BMD decreases greater 21% in the humeral head of the affected shoulder compared to the non-affected side. In the immobilised control group with degenerative changes of the rotator cuff, calcifying tendini…

Radial Head Fractures

Radial head fractures are the most common elbow fractures, accounting for 20–30 %. Typically, the fractures evolve from a fall on the outstretched hand with the elbow extended and the forearm in pronation. The role of the radial head as an important stabilizer of the elbow joint has been recognized in the last decade. Sixty percent of the axial load transmitted through the elbow is conducted through the radial head. Furthermore, the radial head is an important stabilizer against valgus stresses. While the medial collateral ligament (MCL) is the primary stabilizer against valgus stress, the role of the radial head emerges when the MCL is torn. These findings have led to a change in treatment…

Rapid Musculoskeletal Magnetic Resonance Imaging Using Integrated Parallel Acquisition Techniques (IPAT) - Initial Experiences

Purpose To investigate the feasibility of using multiple receiver coil elements for time saving integrated parallel imaging techniques (iPAT) in traumatic musculoskeletal disorders. Material and methods 6 patients with traumatic derangements of the knee, ankle and hip underwent MR imaging at 1.5 T. For signal detection of the knee and ankle, we used a 6-channel body array coil that was placed around the joints, for hip imaging two 4-channel body array coils and two elements of the spine array coil were combined for signal detection. All patients were investigated with a standard imaging protocol that mainly consisted of different turbo spin-echo sequences (PD-, T (2)-weighted TSE with and w…

Hypothenar hammer syndrome in sports

Repetitive blunt trauma or single severe trauma to the hypothenar region may lead to traumatic thrombosis of the distal ulnar artery (hypothenar hammer syndrome, HHS). In the sports-related literature we found and analysed isolated cases attributed to injuries sustained during sporting activities such as baseball, badminton, handball, football, frisbee, softball, karate, weight-lifting and hockey. Further, we report the case of an amateur golf player with ischaemic symptoms of his left hand, where angiography revealed filling defects in the digital arteries associated with a corkscrew-like configuration of the distal ulnar artery. Magnetic resonance imaging (MRI) scan demonstrated, at the l…

Isolated fractures of the greater tuberosity of the proximal humerus

Background and purpose The diagnosis and treatment of isolated greater tuberosity fractures of the proximal humerus is not clear-cut. We retrospectively assessed the clinical and radiographic outcome of isolated greater tuberosity fractures. Patients and methods 30 patients (mean age 58 (26–85) years, 19 women) with 30 closed isolated greater tuberosity fractures were reassessed after an average follow-up time of 3 years with DASH score and Constant score. Radiographic outcome was assessed on standard plain radiographs. Results 14 of 17 patients with undisplaced or slightly displaced fractures (≤ 5 mm) were treated nonoperatively and had good clinical outcome (mean DASH score of 13, mean Co…

The Surgery of Neglected Distal Humerus Fractures in Children and Adults

The restoration of function after a neglected distal humerus fracture presents a formidable challenge to the surgeon because of both the complexity of the regional anatomy and the proximity of numerous neurovascular structures. Inadequate or unstable fixation, a failure to reposition the articular fragments anatomically, prolonged post-operative immobilization, or the development of soft-tissue complications will result in substantial disability for the patient. Complications after injuries affecting a child’s elbow are common due to understimating the severity of the injury on the native X-rays where the growth plates and cartilage structures can not be seen.

Radiation exposure to the hands and the thyroid of the surgeon during intramedullary nailing.

Abstract During 41 procedures of intramedullary nailing of femoral and tibial fractures, the primary surgeon and the first assistant wore ring dosimeters on their dominant index fingers. While the average fluoroscopy time per procedure was 4.6 min, the average dose of radiation to the dominant hand of the primary surgeon was 1.27 mSv and 1.19 mSv to the first assistant. The dose limit for the extremities is 500 mSv per year, as recommended by the International Commission on Radiological Protection. Extrapolation of the mean dose of the primary surgeon and first assistent per procedure of 1.23 mSv leads to the result that the recommended dose limit of 500 mSv would only be exceeded if more t…

Distal Humerus Fractures

Distal humerus fractures display seldom but severe injuries because of the complex distal humerus anatomy and often comminuted fracture types. They account for approximately 2–3 % of all fractures and for 17–30 % of fractures around the elbow. In younger patients, there is a predominance among males. The mechanism of accident is mostly a high-energy trauma in this population. In contrast, among elderly patients, distal humerus fractures concern mostly women with osteoporotic bone. Fractures are caused by a low-energy trauma such as a fall from standing height onto the outstretched or slightly flexed arm. These fractures are often severely comminuted. Because of the thin soft tissue envelope…

Fraktur des Os capitatum bei einem 11-jährigen Jungen

We report the case of an isolated non-displaced fracture of the capitate in an 11-year-old boy. On the basis of the relevant literature we present a survey of the diagnostic and treatment options. To the best of our knowledge this is the first description of a paediatric capitate fracture in the German-speaking area.

Thermolumineszenzdosimetrie zur Ermittlung der Teilkörperdosen der Hände bei unfallchirurgischen Operationen

Zusammenfassung In der Rontgenverordnung 1987 werden vom Gesetzgeber Grenzwerte fur die Teilkorperdosen der Hande beruflich strahlenexponierter Personen genannt. Um zu uberprufen, ob diese bei speziellen Operationsarten erreicht werden konnen, wurde mittels Fingerringdosimeter die Strahlenbelastung der Hande des Operateurs und des 1. Assistenten bei 34 Marknagelungen ermittelt. Die Erfassung der Strahlenbelastung erfolgte mittels Thermolumineszenzdosimetrie. Die ermittelten Werte zeigen, daβ es theoretisch nur dann zu einer Uberschreitung der vom Gesetzgeber vorgeschriebenen Grenzwerte (von 500 mSv fur die Hande bei beruflich strahlenexponierten Personen der Gruppe A) kommen konnte, wenn me…

Primäre Ellenbogenprothese bei distalen Humerustrümmerfrakturen

The use of hip- and shoulder arthroplasty in elderly patients for grossly displaced intraarticular fractures is being more and more accepted. Total elbow replacement (TER) has not been considered as an option for the treatment of extensively comminuted fractures of the distal humerus because surgeons feel the outcome is not predictable after TER generally. On the basis of a Medline literature research of this issue and the documented results based on the improvement of the designs of the implants, operative technique and the selection of patients, TER has a definite role in the treatment of some fractures of the distal humerus. We retrospectively reviewed forty-nine acute distal humeral fra…

Number and Locations of Screw Fixation for Volar Fixed-Angle Plating of Distal Radius Fractures: Biomechanical Study

Purpose To compare the biomechanical properties of different numbers and locations of screws in a multidirectional volar fixed-angle plate in a distal radius osteotomy cadaver model. Methods We created an extra-articular fracture in 16 pairs of fresh-frozen human cadaver radiuses. The 32 specimens were randomized into 4 groups. All fractures were fixated with a multidirectional volar fixed-angle plate. We tested 4 different screw-placement options in the distal fragment. The distal fragment was fixed with 4 locking screws in the distal row of the plate in group a, and with 4 locking screws alternately in the distal and proximal rows in group b. In group c, 3 locking screws were used in the …

Intraoperative C-arm CT imaging in angular stable plate osteosynthesis of distal radius fractures

The purpose of this study was to analyze the practicability and benefit of intraoperative C-arm computed tomography (CT) imaging in volar plate osteosynthesis of unstable distal radius fractures. During a 1 year period, intraoperative three dimensional (3D) imaging with the ARCADIS Orbic 3D was performed in addition to standard fluoroscopy in 51 cases. The volar angular stable plate oesteosyntheses were analyzed intraoperatively and, if necessary, improved immediately. The duration of the scan and radiation exposure dose were measured. On average, performance of the scan and analysis of the CT dataset took 6.7 minutes. In 31.3% of the surgeries a misplacement of screws was detected and cor…

Locking plates for corrective osteotomy of malunited dorsally tilted distal radial fractures: a biomechanical study.

The purpose of the study was to compare the biomechanical properties of five different palmar fixation plate designs in a distal radius osteotomy cadaver model. A 1 cm metaphyseal osteotomy gap was made to simulate a corrective osteotomy and the osteotomy plated. Axial load was applied to the distal end of each construct by a material testing machine under control of a motion analysis video system. The specimens were arranged into five implant groups of eight specimens each. No test group developed deformity and movement of the fracture gap greater than 2 mm with a load of 100 N. Increasing the load to 250 N revealed statistically significant differences in stiffness and failure load betwe…

Total Elbow Replacement as Primary Treatment for Complex Fractures of the Distal Osteopenic Humerus

Background: The use of hip and shoulder arthroplasty in elderly patients for grossly displaced intraarticular fractures is becoming more and more accepted. Total elbow replacement (TER) has not been considered an option for the treatment of extensively comminuted fractures of the distal humerus because surgeons feel the outcome is generally not predictable after TER. Evaluation of TER: On the basis of a MEDLINE literature search of this issue and the documented results based on the improvement of implant designs, operative technique and patient selection, TER has a definite role in the treatment of some fractures of the distal humerus.

Die Röntgenstrahlenbelastung der Hände der Operateur bei Marknagelosteosynthesen

Bei 41 Marknagelungen (21 unaufgebohrte und neun aufgebohrte Tibiamarknagelungen sowie vier unaufgebohrte und sieben aufgebohrte Femurmarknagelungen) trugen Operateur und 1. Assistent Ringdosimeter am dominanten Zeigefinger unter dem sterilen Handschuh. Bei Durchleuchtungszeiten von durchschnittlich 4.6 min pro Eingriff lag die mittlere Strahlenbelastung der Finger der Operateur bei 1.27 mSv und die der 1. Assistenten bei 1,19 mSv. Extrapoliert man den Gesamtmittelwert der ermittelten Strahlenbelastung der Hand der Operateure und 1. Assistenten von 1,23 mSv, wurde der gesetzlich zugelassene Grenzwert fur beruflich strahlenexponierte Personen der Gruppe A von 500 mSv erst bei 407 Marknagelos…

The efficiency of lead thyroid shield in trauma surgery

Die Strahlenbelastung der Operateure bei unfallchirurgischen Eingriffen hat in den letzten Jahren durch den Trend zu biologischen Osteosyntheseverfahren, insbesondere der Marknagelung, zugenommen, da geschlossene Reposition und distale Verriegelung radiologisch kontrolliert werden. Wir wollten jetzt uberprufen, welchen Einflus der Schilddrusenbleischutz auf die Strahlenbelastung der Operateure bei operativen Eingriffen an den unteren Extremitaten hat. Mit Hilfe eines Unterschenkelphantoms wurden unterschiedliche intraoperative Durchleuchtungssituationen simuliert und die Strahlenbelastung der Schilddruse mit und ohne Bleischutz des Operateurs uber ein Dosismesgerat (Szintomat) festgestellt.…

Aging of biogenic secondary organic aerosol via gas-phase OH radical reactions

The Multiple Chamber Aerosol Chemical Aging Study (MUCHACHAS) tested the hypothesis that hydroxyl radical (OH) aging significantly increases the concentration of first-generation biogenic secondary organic aerosol (SOA). OH is the dominant atmospheric oxidant, and MUCHACHAS employed environmental chambers of very different designs, using multiple OH sources to explore a range of chemical conditions and potential sources of systematic error. We isolated the effect of OH aging, confirming our hypothesis while observing corresponding changes in SOA properties. The mass increases are consistent with an existing gap between global SOA sources and those predicted in models, and can be described b…

Is there still an indication for operative treatment of femoral neck fractures with a ceramic hemiprosthesis?

From 1985 to 1995, 417 patients with dislocated medial femoral neck fractures (Garden III–IV) were treated with hemiarthroplasty using a Biolox ceramic head. The average patient age at the time of operation was 81.5 years. A total of 140 survivors was available for follow-up examination with a mean prosthesis longevity of 55.8 months. The Harris hip score recorded a mean of 70.6 points. At the time of follow up, 5 patients had severe hip pain, and in 8 the roentgenographic examination revealed protrusio acetabuli. Five of these 8 patients underwent revision surgery for replacement of the cup, leaving the stem in situ.

The effect of the pro-inflammatory cytokine tumor necrosis factor-alpha on human joint capsule myofibroblasts.

Introduction Previous studies have shown that the number of myoblastically differentiated fibroblasts known as myofibroblasts (MFs) is significantly increased in stiff joint capsules, indicating their crucial role in the pathogenesis of post-traumatic joint stiffness. Although the mode of MFs' function has been well defined for different diseases associated with tissue fibrosis, the underlying mechanisms of their regulation in the pathogenesis of post-traumatic joint capsule contracture are largely unknown. Methods In this study, we examined the impact of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) on cellular functions of human joint capsule MFs. MFs were challenged w…

Pigmented villonodular synovitis of the shoulder: review and case report

Pigmented villonodular synovitis (PVNS) as reviewed in detail elsewhere most frequently involves the knee and finger synovial structures; shoulder involvement is rare: A search through the English literature yielded 18 publications describing 25 cases of PVNS affecting the shoulder joint. Analyzing these reports we found the clinical and radiological findings generally to be nonspecific, often mimicking a malignancy, as in the case presented here of a 16-year-old boy with painful swelling in the area of the left proximal humerus. Magnetic resonance imaging showed a suspected malignant soft tissue mass involving the shoulder capsule and measuring 7.5 x 6 x 4 cm. Preoperatively the patient co…

Locking Reconstruction Double Plating of Distal Humeral Fractures: How Many Screws in the Distal Ulnar Column Segment in A3 Fracture Provide Superior Stability? A Comparative Biomechanical In Vitro Study

Objectives: Two 90-degree configurations of locking reconstruction plates with different numbers of screws in the distal ulnar column segment of distal extra-articular humeral fractures with metaphyseal comminution (A3) were biomechanically investigated. Methods: Eight pairs of fresh-frozen human humeri were used. For paired comparison, the humeri were divided into 2 randomized groups. In both groups, double-plate osteosyntheses with locking reconstruction plates were performed in 90-degree configurations. In group 1, the posteriorly placed radial column plate exceeded the capitellum and the ulnar column plate extended into the ulnar sulcus. The ulnar plate was molded around the medial epic…

Endoscopic carpal tunnel release: results with special consideration to possible complications.

Single-portal endoscopic carpal tunnel release (Agee technique) was carried out in 148 patients. Of these, 100 were examined clinically and electrophysiologically 1 day before surgery and 1 and 3 months thereafter. Ten patients experienced transient ulnar neuropraxia and two patients complained postoperatively of intense pain in the middle and ring fingers. Three patients suffered residual symptoms. In one of these an incomplete release of the distal portion of the retinaculum flexorum was suspected and later confirmed by magnetic resonance imaging. Another patient had applied for pension due to problems associated with a vertebral fracture in addition to his carpal tunnel symptoms. A third…

Reply to “Mirror Symmetry Breaking” of the Centrosymmetric CaCO3 Crystals with Amino Acids

Paradoxical embolism after a femoral fracture

The foramen ovale is anatomically open in 25 % of individuals, but functionally closed by the higher pressure in the left antrum. Right-to-left shunt and subsequent paradoxical embolism may occur when pressure in the left antrum rises, for example, as a result of pulmonary embolism. In the present case we demonstrate a patient who presented 20 days after osteosynthetic treatment of a femoral fracture with word-finding deficits. Cerebral MRT revealed a fresh ischemic insult. Duplex ultrasound of the legs showed a fresh thrombosis of the superficial femoral vein and scintigraphy of the lungs detected pulmonary embolism. Transesophageal contrast echocardiography trapped a hemodynamically spont…

TNF-α in CRPS and 'normal' trauma--significant differences between tissue and serum.

Posttraumatic TNF-alpha signaling may be one of the factors responsible for pain and hyperalgesia in complex regional pain syndromes (CRPS). In order to further specify the role of TNF-alpha we investigated tissue (skin) and serum concentrations in three different patient groups: patients with osteoarthritis and planned surgery, with acute traumatic upper limb bone fracture waiting for surgery, and with CRPS I. Thirty patients (10 in each group) were recruited. Mean CRPS duration was 36.1 ± 8.1 weeks (range 8- 90 weeks). Skin punch biopsies were taken at the beginning of the surgery in osteoarthritis and fracture patients and from the affected side in CRPS patients. Blood samples were taken…

Volar Fixed-Angle Plating of Distal Radius Fractures

The purpose of this biomechanical study was to determine whether a multidirectional fixed-angle plate with locking screws or with locking pegs in the distal fragment would optimize fixation of Orthopaedic Trauma Association (OTA) type A3 distal radius fractures.Eight pairs of fresh-frozen human distal radii were used. Extra-articular distal radius fractures were created and stabilized with a multidirectional volar fixed-angle plate. The radii were randomized into 2 matched-paired groups. The distal fragment in Group I was stabilized with 7 locking screws. The distal fragment in Group II was fixed with 7 locking pegs. The proximal fragment in both groups was fixed with 3 screws. The specimen…