Human-sized magnetic particle imaging for brain applications.

Determining the brain perfusion is an important task for diagnosis of vascular diseases such as occlusions and intracerebral haemorrhage. Even after successful diagnosis, there is a high risk of restenosis or rebleeding such that patients need intense attention in the days after treatment. Within this work, we present a diagnostic tomographic imager that allows access to brain perfusion quantitatively in short intervals. The device is based on the magnetic particle imaging technology and is designed for human scale. It is highly sensitive and allows the detection of an iron concentration of 263 pmolFe ml-1, which is one of the lowest iron concentrations imaged by MPI so far. The imager is self-shielded and can be used in unshielded environments such as intensive care units. In combination with the low technical requirements this opens up a variety of medical applications and would allow monitoring of stroke on intensive care units.

Geometry planning and image registration in magnetic particle imaging using bimodal fiducial markers.

PURPOSE: Magnetic particle imaging (MPI) is a quantitative imaging modality that allows the distribution of superparamagnetic nanoparticles to be visualized. Compared to other imaging techniques like x-ray radiography, computed tomography (CT), and magnetic resonance imaging (MRI), MPI only provides a signal from the administered tracer, but no additional morphological information, which complicates geometry planning and the interpretation of MP images. The purpose of the authors' study was to develop bimodal fiducial markers that can be visualized by MPI and MRI in order to create MP-MR fusion images. METHODS: A certain arrangement of three bimodal fiducial markers was developed and used in a combined MRI/MPI phantom and also during in vivo experiments in order to investigate its suitability for geometry planning and image fusion. An algorithm for automated marker extraction in both MR and MP images and rigid registration was established. RESULTS: The developed bimodal fiducial markers can be visualized by MRI and MPI and allow for geometry planning as well as automated registration and fusion of MR-MP images. CONCLUSIONS: To date, exact positioning of the object to be imaged within the field of view (FOV) and the assignment of reconstructed MPI signals to corresponding morphological regions has been difficult. The developed bimodal fiducial markers and the automated image registration algorithm help to overcome these difficulties.

[Mondor's disease of penis: A case report]. / La maladie de Mondor pénienne : une observation.

INTRODUCTION: Mondor's disease is a rare superficial thrombophlebitis, historically involving the thoracic venous system of women. However, it can occur in both gender and all over the skin. CASE REPORT: We report a 40-year-old man with type one diabetes who presented with a thrombosis of the superficial dorsal vein of the penis that he treated as a fungal infection. Treatment with non-steroidal anti-inflammatory drugs and low molecular weight heparin contributed to a favorable outcome in 2 weeks. CONCLUSION: Pathogenesis and treatment of Mondor's disease remain incompletely dominated. Some predisposing factors have been highlighted in the literature. It might be interesting to add diabetes, due to its frequent pelvic problems leading to a potential venous inflammatory trigger.

[Elastic Stable Intramedullary Nailing (ESIN) of Metatarsal Fractures]. / Elastisch stabile intramedulläre Nagelung (ESIN) von Mittelfußfrakturen.

AIM: In the treatment of metatarsal fractures, the objective is early restoration of the physiological painless function of the foot. While undisplaced metatarsal fractures can be treated non-surgically, displaced fractures are a valid indication for reduction and internal fixation. Whereas plate fixation may lead to soft tissue irritation involving tendon adhesions and scar formation, retrograde percutaneous pinning may harm the intact metatarsophalangeal joint and lead to joint stiffness. We have therefore used the technique of elastic stable intramedullary nailing (ESIN) with titanium elastic nails (TEN) to achieve minimally invasive, antegrade splinting of short metatarsal shaft and neck fractures. METHOD: Within 7 years, ESIN was performed in 22 patients. The surgical technique is presented and the functional results and complications were retrospectively evaluated using the AOFAS Midfoot Score. RESULTS: Nineteen patients were analysed after an average follow-up of 25.6 ± 21.3 months (range: 3-72 months). The mean AOFAS score was 93.9 ± 10.4 (range 62-100) points. One case of skin irritation required TEN shortening. Pseudarthrosis, secondary fracture dislocation and nail breakage were not observed. After TEN removal 13.4 ± 12.9 (range: 5-52) weeks after implantation, no refracture occurred. CONCLUSION: Antegrade, minimally invasive, elastic stable intramedullary nailing of short metatarsal shaft and neck fractures using titanium nails (TEN) is a safe surgical procedure and achieves primary functional stability. It reliably leads to fracture healing and produces good functional results.

Combined Preclinical Magnetic Particle Imaging and Magnetic Resonance Imaging: Initial Results in Mice.

PURPOSE: Magnetic particle imaging (MPI) is a new radiologic imaging modality. For the first time, a commercial preclinical scanner is installed. The goal of this study was to establish a workflow between MPI and magnetic resonance imaging (MRI) scanners for a complete in vivo examination of a mouse and to generate the first co-registered in vivo MR-MP images. MATERIALS AND METHODS: The in vivo examination of five mice were performed on a preclinical MPI scanner and a 7 Tesla preclinical MRI system. MRI measurements were used for anatomical referencing and validation of the injection of superparamagnetic iron oxide (SPIO) particles during a dynamic MPI scan. We extracted MPI data of the injection phase and co-registered it with MRI data. RESULTS: A workflow process for a combined in vivo MRI and MPI examination was established. A successful injection of ferucarbotran was proven in MPI and MRI. MR-MPI co-registration allocated the SPIOs in the inferior vena cava and the heart during and shortly after the injection. CONCLUSION: The acquisition of preclinical MPI and MRI data is feasible and allows the combined analysis of MR-MPI information.

Real-time dosimetry reduces radiation exposure of orthopaedic surgeons.

BACKGROUND: Cancer prevalence of orthopaedic surgeons is elevated and chronic exposure to occupational ionizing radiation is seen as one reason. HYPOTHESIS: Use of a new dosimeter enabling radiation dose monitoring in real-time may reduce radiation exposure of orthopaedic surgeons. MATERIALS AND METHODS: Over a period of four months, the surgeon and the C-arm operator were equipped with a novel dosimeter called DoseAware(®) (DA) while using the C-arm fluoroscope intraoperatively. Data of 68 patients DA were retrospectively compared using matched-pair analysis with 68 controls without DA. Both groups were assessed regarding fluoroscopic time (FT) and radiation dose (RD). Seven types of operative procedures were performed: internal fixation of subcapital humerus fractures, midshaft clavicular fractures, distal radius fractures, pertrochanteric femoral fractures, ankle fractures, traumatic vertebral fractures and osteoporotic vertebral fractures. RESULTS: Concerning the FT, use of DoseAware(®) led to a significant reduction for all evaluated operation types except for internal fixation of distal radius fractures (P=0.0511). Regarding the RD, use of DoseAware(®) led to a significant reduction for all evaluated operation types except trochanteric femoral fractures with a PFNA(®) (P=0.0841). CONCLUSION: DoseAware(®) allowing real-time radiation dose monitoring reduces radiation exposure of the orthopaedic surgeon and instantly demonstrates the effects of dose-reduction techniques. LEVEL OF EVIDENCE: Level III retrospective case control study.

[Use of gonadorelin[6-D-Phe] at day 0 or 12 after insemination to increase the conception rate in a large dairy herd in Saxony/Germany]. / Einsatz von Gonadorelin[6-D-Phe] am Tag 0 oder 12 post inseminationem zur Steigerung der Konzeptionsrate in einer sächsischen Milchviehgroßanlage.

OBJECTIVE: To increase conception rates in lactating dairy cows by the application of a gonadotropin-releasing-hormone (GnRH)-agonist after insemination. MATERIAL AND METHODS: A total of 3125 inseminations of 1634 cows were included in this study. The animals were randomized into three groups at the time of insemination (day 0) using the final numeral of the ear-tag number: The cows of the GnRH0 group were treated using 100 µg gonadorelin[6-D-Phe] intramuscularly immediately after insemination (day 0), while those of the GnRH12 group were treated similarly at day 12. The cows of the control group received no hormonal treatment after insemination. An examination for pregnancy was performed at day 28 using transrectal ultrasonography. Analysis of the data sets was conducted for the number of inseminations (NI) 1-4 and for the last observed insemination of the respective cow during the experimental period, respectively. In a second step, statistical analysis was performed for the first service of cows with a lactation number of 1 versus > 1, with emphasis on the daily milk yield. In addition, a metritis diagnosed after the previous parturition was investigated as a possible factor influencing NI 1. RESULTS: Pregnancy risk at day 28 was decreased for NI 2 (n = 792) in the GnRH0 group compared to the control group (odds ratio [OR] = 0.69; 95% confidence interval [CI95] = 0.5-1.0; p = 0.04). A similar observation was found for NI 3 (n = 495) for the GnRH12 group (OR = 0.54; CI95 = 0.3-0.9; p = 0.01). In contrast, the pregnancy risk was increased for cows with a lactation number ≥ 2 and with a daily milk yield ≥ 42.5 kg (7-day-mean at day 0) at the first service (n = 364) by treatment with gonadorelin immediately after insemination (OR = 2.0; CI95 = 1.2-3.4; p = 0.01). No significant differences in the pregnancy risk were observed for the remaining analysed classes. CONCLUSION: An increased conception rate was only achieved for the first service of high-yield dairy cows (lactation number ≥ 2) by gonadorelin treatment at day 0. Presumably, the higher incidence of delayed ovulations in this group was treated successfully by gona- dorelin administration.

[Thromboembolic complications 6 months after plate osteosynthesis of a mid-clavicular fracture]. / Thrombembolische Komplikation 6 Monate nach Plattenosteosynthese einer Klavikulaschaftfraktur.

A 32-year-old patient suffered from progredient intermittent claudication of the left arm 6 months after plate fixation of a midshaft clavicular fracture (OTA classification type A). The radiological analysis revealed a subacute stenosis of the left subclavian artery, caused by a granuloma at the tip of a protruding screw, which triggered recurrent emboli and symptoms. Reperfusion was achieved by catheter embolectomy and complete removal of the plate. The case shows that, when performing plate osteosynthesis of clavicular fractures, special consideration has to be given to the length and protrusion of the applied screws. Due to the anatomic proximity not only acute, but also subsequent irritation of the subclavian vessels is possible.

[Treatment of isolated fractures of the olecranon: percutaneous double-screw fixation versus conventional tension band wiring]. / Behandlung von isolierten Olekranonfrakturen: Perkutane Doppelschraubenosteosynthese vs. konventionelle Zuggurtung.

BACKGROUND: Isolated fractures of the olecranon account for 7-10% of all osseous injuries in adults. These fractures are usually treated surgically by conventional tension band wiring. The percutaneous double-screw fixation is an optional treatment in patients with two fragment olecranon fractures with some postoperative advantages. PATIENTS AND METHODS: A total of 13 patients with isolated fractures of the olecranon (Schatzker-Schmelling type A) treated by percutaneous double-screw fixation were included in this prospective study. The mean age of patients was 43.6 ± 11.0 years. Intraoperative and postoperative complications were recorded. Functional results were assessed after a mean follow-up of 38.2 ± 11.5 months using the Quick-DASH score. The results were compared with those obtained in the control group including 26 patients treated by conventional tension band wiring. RESULTS: No intraoperative complications were observed in both groups. In the group with percutaneous double-screw fixation the scar length was significantly shorter (2.4 ± 0.4 cm vs. 11.0 ± 1.8 cm, p < 0.001) and the hardware removal was substantially less frequent that in the group with conventional tension band wiring with 38.5 % and 73.1 %, respectively. At the minimum follow-up of 2 years comparable functional results were obtained in both groups (Quick-DASH score 2.3 vs. 0.0 points, respectively, p = 0.155); however, the range of elbow motion was significantly higher in the group with percutaneous double-screw fixation (extension/flexion 145° vs. 130°, p < 0.001; pronation/supination 165° vs. 155°, p < 0.001). CONCLUSIONS: The percutaneous double-screw fixation is a safe and viable treatment option in patients with isolated fractures of the olecranon (Schatzker-Schmelling type A). The functional results regarding DASH scores obtained using this technique were comparable with those observed in patients with conventional tension band wiring; however, range of elbow motion and cosmetic results were significantly better in the patient group with percutaneous double-screw fixation.

Therapeutic immunomodulation using a virus--the potential of inactivated orf virus.

Viruses can manipulate the immune response against them by various strategies to influence immune cells, i.e. by over-activation leading to functional inactivation, bypassing antigen presentation or even suppression of effector functions. Little is known, however, about how these features of immune regulation and modulation could be used for therapeutic purposes. Reasons for this include the complexity of immune regulatory mechanisms under certain disease conditions and the risks that infections with viruses pose to human beings. The orf virus (ORFV), a member of the Parapoxvirus genus of the poxvirus family, is known as a common pathogen in sheep and goats worldwide. The inactivated ORFV, however, has been used as a preventative as well as therapeutic immunomodulator in veterinary medicine in different species. Here, we review the key results obtained in pre-clinical studies or clinical studies in veterinary medicine to characterise the therapeutic potential of inactivated ORFV. Inactivated ORFV has strong effects on cytokine secretion in mice and human immune cells, leading to an auto-regulated loop of initial up-regulation of inflammatory and Th1-related cytokines, followed by Th2-related cytokines that attenuate immunopathology. The therapeutic potential of inactivated ORFV has been recognised in several difficult-to-treat disease areas, such as chronic viral diseases, liver fibrosis or various forms of cancer. Further research will be required in order to evaluate the full beneficial potential of inactivated ORFV for therapeutic immunomodulation.

[Preparedness of hospital physicians for a mass casualty incident. A German survey amongst 7,700 physicians]. / Wie gut sind Ärzte auf einen Massenanfall von Verletzten vorbereitet?. Ergebnisse einer bundesweiten Umfrage bei 7700 Klinikärzten.

INTRODUCTION: The bomb attacks in Madrid (2004) and London (2005) have increased awareness that terrorist attacks are also a real threat in Germany. Hospitals and health care providers should be prepared. METHODS: We distributed an anonymous online questionnaire to physicians working in trauma centers of different categories. The results were analyzed using descriptive statistical methods. RESULTS: The questionnaire was returned by 1,204 of 7,700 physicians. This reflects a response rate of 15.6%. Of the participants, 53.3% answered that their hospital had a disaster control plan and that they knew the content; 33.9% reported that their hospital had participated in a disaster training scenario. CONCLUSION: As only 53.3% of physicians in hospitals know their disaster control plan and only 33.9% of hospitals have participated in a disaster training scenario we conclude that more action is needed to increase awareness of the problem. Furthermore standardized training programs are needed to disseminate knowledge and skills in order to enable health care providers to face the occurrence of terroristic attacks in Germany.

[The one- and two-stage distally pedicled sural flap : surgical technique and clinical results]. / Der ein- und zweizeitige distal gestielte Suralislappen : Operationstechnik und klinische Ergebnisse.

BACKGROUND: The distally pedicled suralis flap is used to cover local defects of the distal lower leg, ankle and hind foot. It is a local flap with no need for microvascular anastomosis, a constant blood supply and ease of elevation. Disadvantages are lack of sensation, donor site morbidity and venous congestion. METHODS AND MATERIAL: This study includes 25 patients. Apart from the defect extent, cause and location, complications were also determined. RESULTS: The defect site was located in the hind foot in 5 cases and the distal lower leg in 14 cases. In four patients the soft tissue of the lateral calcaneal region and in two cases the sole of the foot were affected. Severe venous congestion, which was only detected in 180° turned flaps, was seen in five cases. In five patients we successfully performed a two-stage flap transposition procedure to avoid venous congestion. CONCLUSION: The sural flap remains a reliable solution for soft tissue defects. Under inappropriate circumstances (small pedicle or severe torque of pedicle) venous congestion or even thrombosis is possible. A two-stage approach with conditioning of venous drainage can have a positive effect on these problems.

[Evaluation of a 2D fluoroscopy-based navigation system for insertion of femoral neck screws. An experimental study]. / Evaluation eines 2-D-fluoroskopiebasierten Navigationssystems zur Implantation von Schenkelhalsschrauben. Eine experimentelle Studie.

INTRODUCTION: The aim of this study was the evaluation of a new computer-assisted planning and navigation system based on 2D-fluoroscopy for guidewire insertion in order to perform cannulated screw placement into the femoral neck. The image acquisition process was supported by a radiation-saving procedure called Zero-dose C-arm navigation. MATERIAL AND METHODS: In the context of a sawbone study, we performed insertion of 3 cannulated screws positioned under navigation control as well as using the conventional technique in 12 sawbones. Both procedures were performed using open and closed techniques. RESULTS: The computer-assisted technique significantly reduced the amount of intraoperative fluoroscopic images (open technique: -14±3 images, closed technique: -29.4±6 images). Drilling attempts were reduced in the computer-assisted groups (open technique: -1.2±1 attempts, closed technique: -1.7±1.5 attempts) and the femoral neck area covered by the screws was greater in the navigation-assisted groups (open technique: +32.1±16.3 mm(2), closed technique: +32.6±14.9 mm(2)), There was no difference concerning parallelism of the screws or perforation of femoral neck or head. The operation time was significantly longer in the navigation-assisted groups (open technique: +24.2±2.1 min, closed technique: +22.8±5.8 min). CONCLUSION: The addition of computer-assisted planning and surgical guidance supported by Zero-dose C-arm navigation can be useful for the fixation of medial femoral neck fractures with cannulated screws. Further studies with the goal of reducing the operation time are indispensable before integrating this navigation system into the clinical workflow.

[Extended lateral gastrocnemius transposition flap for reconstruction of open knee extensor disruption]. / Rekonstruktion eines offenen Quadrizepssehnendefekts mit dem erweiterten lateralen Gastrocnemiussehnenlappen.

We describe a modified technique to reconstruct a damaged knee extensor mechanism after infected patellar fracture. After resection of infected soft tissue and quadriceps tendon a compound suprapatellar defect existed. Due to compromised tissue on the medial aspect of the calf, we used this flap, which consists of the lateral gastrocnemius muscle with parts of the adjacent Achilles tendon. After a follow-up period of several months the range of movement is 0-0-120°.

[Comparison of clinical and radiological data in the treatment of patients with osteoporotic vertebral compression fractures using radiofrequency kyphoplasty or balloon kyphoplasty]. / Vergleich klinischer und radiologischer Daten bei der Behandlung von Patienten mit osteoporotischen Wirbelkörper-Kompressionsfrakturen mit Radiofrequenz-Kyphoplastie oder mit Ballon-Kyphoplastie.

PURPOSE: Since the 1990s, balloon kyphoplasty has been proven as an effective method of treating patients with painful vertebral compression fractures (VCF). The radiofrequency kyphoplasty is an innovative procedure available since 2009, for which an ultra-high viscosity cement is used. For the statistical comparison of the two methods of augmentation, the clinical and radiological data of 2 larger patient groups were evaluated. MATERIALS AND METHODS: As part of the surgical treatment of patients with conservative therapy-resistant osteoporotic vertebral fractures, a prospective study of radiofrequency kyphoplasty (RFK) was performed between 2009 and September 2010. The treatment was minimally invasive using the StabiliT® Vertebral Augmentation System by DFine for which the StabiliT® multiplex controller, the articulating VertecoR® Midline Osteotome, and the radiofrequency-sensitive StabiliT® ER2 bone cement were applied. From the clinical aspect, measurement parameters for efficacy and safety were the course of pain intensity using a visual analogue scale (VAS: 0 to 100 mm) and the Oswestry disability score (0-100%). For the radiological outcome the increase in the middle and anterior parts of the treated vertebra and also the reduction of kyphosis after surgery and after 6 months were evaluated. Furthermore, the extent of cement extrusion and the duration of operation time were compared. There were 2 groups of patients chosen with the same indication, and with the same average VAS prior to treatment. For the balloon kyphoplasty (BKP) the Kyphon® technology was used. For the BKP group the same parameters as in the first group were evaluated (matched pairs). To compare the data statistically, parametric and non-parametric tests were applied. RESULTS: For the radiofrequency kyphoplasty group (RFK) 114 patients were recruited, and for the balloon kyphoplasty group (BKP) 114 appropriate patients were selected. In 48% of the RFK patients and in 44% of the BKP patients more than one vertebral body were treated (thoracic or lumbar). Prior to treatment 84 mm on the VAS were calculated in both groups. The decrease in VAS values (RFK vs. BKP) immediately after surgery was 58.8 vs. 54.7 mm (p = 0.02), and 73.0 vs. 58.9 mm after 6 months (p < 0.001). In both groups improvements in the Oswestry scores were registered after 6 months without a statistically significant difference. In both groups, the middle part of the vertebral bodies was increased by an average of 3.1 mm. RFK yielded a decrease in the average kyphosis angle of 4.4, the BKP resulted in about 3.8 degrees. Concerning cement leakage a key difference in favor of the radio frequency kyphoplasty was detected (6.1 % vs. 27.8%; p < 0.0001). For RFK a significant shorter duration of operation time was calculated (28.2 vs. 49.6 min; p < 0.001). CONCLUSIONS: The RFK has proven to be a clinically very effective procedure that does somewhat better than BKP in long-lasting pain relief. No differences could be detected regarding improvement of functioning and the mean restoration of mid- and anterior vertebral height. As far as the safety aspect is concerned the RFK offers the advantage of a statistically significant lower proportion of cement extrusion.

Evaluation of a new computer-assisted surgical planning and navigation system based on two-dimensional fluoroscopy for insertion of a proximal femoral nail: an experimental study.

Pertrochanteric femoral fractures are common and intramedullary nailing is an accepted method for their surgical treatment. Accurate placement of the implant is essential to ensure fixation. The conventional technique can require multiple guide wire passes, and relies heavily on fluoroscopy. A computer-assisted planning and navigation system based on two-dimensional fluoroscopy for guide wire placement in the femoral neck has been developed, in order to perform intramedullary pertrochanteric fracture fixation using the proximal femoral nail (PFNA). The planning process was supported by a 'zero-dose C-arm navigation' system. The PFNA was inserted into 12, intact, femoral sawbones guided by the computer-based navigation, and into 12, intact, femoral sawbones using a conventional fluoroscopic-assisted technique. Guide wire and subsequent blade placement in the femoral neck was evaluated. The computer-assisted technique achieved a significant decrease in the number of required fluoroscopic images and in the number of guide wire passes. The obtained average blade placement accuracy in the femoral neck was equivalent to the conventional technique. The operation time was significantly longer in the navigation-assisted group. The addition of computer-assisted planning and surgical guidance to the intramedullary nailing of pertrochanteric femoral fractures offers a number of clinical benefits based on the results of this sawbone study. Further studies including fractured sawbones and cadaver models with extension of the navigation process to all steps of PFNA introduction and with the goal of reducing operation time are indispensable before integration of this navigation system into clinical practice.

[Refixation of distal biceps tendon rupture using 2 anchor sutures - sports ability after 1 year follow-up and operative technique]. / Refixation der distalen Bicepssehne mit 2 Fadenankern - Sportfähigkeit im 1-Jahres-Follow-up und operative Technik.

BACKGROUND: Rupture of distal biceps tendon often occurs in physical active male persons between 30 and 50 years. The standard treatment consists of operative refixation of the ruptured tendon stump. In literature there are various methods described. Due to the high expectations of this group of patients, we examined the sports ability after 1 year follow-up and describe our employed operative fixation technique. MATERIAL: Between 2004 and 2008 we treated 20 male persons in a prospective study with distal biceps tendon rupture. Applying the score of Rattanen and Orawa we evaluated the M. biceps force in flexion and supination and changes in the patients' sports activity. Furthermore we documented complications and the anchor localization via x-ray. RESULTS: The score results varied between excellent in 14 patients and good and fair in 3 cases respectively. Using only 1 suture anchor (3 patients), either a knot or a wire failure appeared within 5 days. Anchor malpositions were discovered in 2 patients. The force measurement showed threetimes minor but in 3 patients major force deficits. Lack of extension or supination movement could be stated in 3 cases. Changes in their sports ability reported 8 persons. Of the remaining 12 patients, the original sports level was reached after 9 months. CONCLUSION: Two anchors proved to guarantee a stable fixation of the distal biceps tendon stump. On the contrary we see the danger of fixation failure in using only 1 anchor. The best results achieved patients with a primer stable and correct located anchoring, therefore we recommend two anchors placed under radiological control. Regarding the score results, fixation of the distal biceps tendon is a demanding procedure, that should be performed by experienced surgeon.

[Diagnosis and treatment of radiocarpal fracture dislocations]. / Diagnostik und Therapie von radiokarpalen Luxationsfrakturen.

In contrast to the common intra- or extra-articular fractures of the distal radius, radiocarpal fracture dislocations are rare injuries. Concerning this issue, only a small number of publications can be found. Nevertheless, it is important to be informed about this injury since prompt operative treatment is often required and immobilization alone will not be sufficient. Sometimes, radiocarpal fracture dislocations are combined with carpal injuries. In such cases, both the radiocarpal dislocation and carpal injury have to be treated. Diagnostic difficulties can lead to misinterpretation or underdiagnosis. Insufficient reduction and fixation may result in joint incongruity and subsequent osteoarthritis. Reconstruction of the radiocarpal ligaments is a substantial part of operative treatment.

[Evaluation of a 2D fluoroscopy-based navigation system for insertion of the dynamic hip screw (DHS): an experimental study]. / Evaluation eines 2-D-Fluoroskopie-basierten Navigationssystems zur Implantation der dynamischen Hüftschraube (DHS): eine experimentelle Studie.

PURPOSE: Dynamic hip screw (DHS) insertion for the fixation of lateral femoral neck fractures is an accepted surgical treatment method. A computer-assisted planning and navigation system based on 2D fluoroscopy has been developed for guidewire insertion in order to perform screw placement. The image acquisition process was supported by a radiation-saving procedure called "zero-dose C-arm navigation". The aim of this study was to evaluate this new system. MATERIALS AND METHODS: In the context of a sawbone study, we inserted dynamic hip screws. The procedure was performed under navigation control and in the conventional technique in 12 sawbones. Both procedures were performed in an open and closed technique. RESULTS: The computer-assisted technique significantly reduced the number of intraoperative fluoroscopic images (open technique: -8.1 ± 0.5; p < 0.001 - closed technique: -12.3 ± 3.7; p < 0.001) and the number of guidewire passes (open technique: -1.3 ± 1.2; p < 0.05 - closed technique: -1.5 ± 1.2; p < 0,05). There was no difference with respect to precision in both groups. The operation time was significantly longer in the navigation-assisted groups (open technique: + 14.6 ± 5.4 min; p < 0.001 - closed technique: + 13 ± 3 min; p < 0.001). CONCLUSION: The addition of computer-assisted planning and surgical guidance supported by "zero-dose C-arm navigation" may be useful for the fixation of lateral femoral neck fractures by the DHS as it reduces the amount of fluoroscopic images and requires fewer drill tracks. Further studies with the goal of reducing the operation time are necessary.

[Replacement of the comminuted radial head fracture by a bipolar radial head prosthesis]. / Der endoprothetische Ersatz der nichtrekonstruierbaren Speichenkopffraktur mit einer bipolaren Radiuskopfprothese.

OBJECTIVE: Radial head arthroplasty as a treatment of non-reconstructable, comminuted fractures of the radial head in order to achieve elbow stability and to prevent secondary complications, such as valgus elbow instability and radius proximalization. INDICATIONS: In acute trauma, a radial head fracture not suitable for internal fixation without (Mason grade III) and with (Mason grade IV) concomitant destabilizing injury, Essex-Lopresti injury, sequelae following radial head resection (e.g., elbow instability or wrist pain), failed reconstruction of the radial head, and tumor-associated radial head or neck resection. CONTRAINDICATIONS: General medical contraindications for surgical intervention, cobalt-chromium allergy, and osteoporosis of the proximal radius. SURGICAL TECHNIQUE: In supine position, a lateral or posterolateral approach at the elbow was used. The annular ligament was exposed and the radial neck identified just above the bicipital tuberosity. In pronation of the forearm in order to protect the radial nerve, the medullary canal was prepared using rasps. The size of the implant was determined using trial stems. A distance of 0.5 mm between the head of the prosthesis and the capitulum humeri was recommended. After using a small bone plug, the prosthesis was cemented with respect to the anatomical radial curvature. After reconstruction of the annular ligament, the stability of the elbow was verified. In case of instability, the medial collateral ligament was reconstructed and afterwards the wound closed. POSTOPERATIVE MANAGEMENT: Early mobilization begins the day after surgery. In case of additional injuries, the elbow was supported by an above-elbow cast for 3-4 weeks. To prevent heterotopic ossification, nonsteroidal antiinflammatory drugs were used for up to 4 weeks with gastric protection. RESULTS: A total of 13 patients with 15 radial head prosthesis were analyzed at a mean follow-up of 29.5±20.8 months. In all patients, the elbow was stable. Subjectively, good and excellent results were found with one exception. Compared to the pretrauma status, the subjective rate was 78±12%. Based on the Radin and Riseborough score, 6 of the results were good and 9 were fair. According to the Broberg and Morrey score, 1 result was very good, 8 were good, and 6 were fair. The mean DASH score was 9.9±9.7 points. Two temporary nerve lesions were observed. Five patients were diagnosed with heterotopic ossification stage I, while 2 patients were classified with stage II on the Brooker scale.