[Identification of rheumatological health apps in the Apple app store applying the "semiautomatic retrospective app store analysis" method : A longitudinal observation]. / Identifikation rheumatologischer Gesundheits-Apps im Apple App Store mit der Methode der "semiautomatischen retrospektiven App Store-Analyse" : Eine longitudinale Betrachtung.

BACKGROUND: The Apple and Google app stores offer a wide range of health apps. It is still a challenge to find valuable and qualified apps. OBJECTIVE: Can German language apps be identified using the "semiautomated retrospective app store analysis" (SARASA) method for the field of rheumatology? MATERIAL AND METHOD: The SARASA is a semiautomated method to select and characterize apps listed in the app store. After the first application in February 2018 SARASA was applied again to the Apple app store in February 2020. RESULTS: In February 2018 it was possible to acquire metadata for 103,046 apps and in February 2020 data for 94,735 apps that were listed in the category "health and fitness" or "medicine" in Apple's app store frontend for Germany. After applying the search terms 59 apps with a German language app description were identified for the field of rheumatology in 2018 and 53 apps in 2020. For these, more detailed manual reviews seem worthwhile. In 2018, the apps found were more likely to address patients than physicians and this was more balanced in 2020. In addition, it became apparent that for certain diseases there was no app developer activity. The percentage breakdown of matches by search term revealed substantial fluctuations in the app market when comparing 2018 to 2020. DISCUSSION: The SARASA method provides a useful tool to identify apps from app stores that meet predefined, formal criteria. Subsequent manual checks of the quality of the contents are still necessary. Further development of the SARASA method and consensus and standardization of quality criteria are worthwhile. Quality criteria should be considered for offers of mobile health apps in app stores.

[Future trend medical apps. From the apps store directly into medical practice?]. / Zukunftstrend "Medical Apps". Vom App-Store direkt in die medizinische Anwendung?

In day to day medical care, patients, nursing staff and doctors currently face a bewildering and rapidly growing number of health-related apps running on various "smart" devices and there are also uncountable possibilities for the use of such technology. Concerning regulation, a risk-based approach is applied for development and use (including safety and security considerations) of medical and health-related apps. Considering safety-related issues as well as organizational matters, this is a sensible approach but requires honest self-assessment as well as a high degree of responsibility, networking and good quality management by all those involved. This cannot be taken for granted. Apart from regulatory aspects it is important to not only consider what is reasonable, helpful or profitable. Quality aspects, safety matters, data protection and privacy as well as liability issues must also be considered but are often not adequately respected. If software quality is compromised, this endangers patient safety as well as data protection, privacy and data integrity. This can for example result in unwanted advertising or unauthorized access to the stored data by third parties; therefore, local, regional and international regulatory measures need to be applied in order to ensure safe use of medical apps in all possible areas, including the operating room (OR) with its highly specialized demands. Lawmakers need to include impulses from all stakeholders in their considerations and this should include input from existing private initiatives that already deal with the use and evaluation of apps in a medical context. Of course, this process needs to respect pre-existing national, European as well as international (harmonized) standards.

[Implant-free tibial fixations of the posterior cruciate ligament. Development and biomechanical testing]. / Implantatfreie tibiale Fixierung des hinteren Kreuzbandes. Entwicklung und biomechanische Testung.

BACKGROUND: A secure tibial press fit technique in posterior cruciate ligament reconstructions may be a relevant alternative to common techniques because no hardware is necessary. Up to the present point in time no biomechanical data exist for a tibial press fit posterior cruciate ligament (PCL) reconstruction. This study compares the biomechanical properties of hamstring and quadriceps tendon grafts using a press fit technique with those of an interference screw fixation. METHODS: Quadriceps and hamstring tendons of 20 human cadavers (age 49.2±18.5 years) were used. A press fit fixation with a knot in the semitendinosus tendon (K) and a quadriceps tendon bone block graft (Q) were compared to an interference screw fixation (I) in 27 porcine tibiae. In each group, nine constructs were cyclically stretched and then loaded until failure. Maximum load to failure, stiffness and elongation during failure testing and cyclical loading were investigated. RESULTS: The maximum load to failure was 518±157 N (387-650 N) for the K group, 558±119 N (466-650 N) for the I group and 620±102 N (541-699 N) for the Q group. The stiffness was 55±27 N/mm (18-89 N/mm) for the K group, 117±62 N/mm (69-165 N/mm) for the I group and 65±21 N/mm (49-82 N/mm) for the Q group. The stiffness of the I group was significantly larger (ANOVA on ranks, P=0.01). The elongation during cyclical loading was significantly larger for all groups from the 1st to the 5th cycle compared to the elongation in between the 5th and the 20th cycle (P<0.03). CONCLUSION: All techniques exhibited larger elongation during initial loading. Load to failure and stiffness were significantly different between the fixations. The Q fixation showed equal biomechanical properties compared to a pure tendon fixation (I) with an interference screw. The results of group K were inferior. All three investigated fixation techniques exhibit comparable biomechanical properties. Preconditioning of the constructs is critical. Future randomized, clinical trials have to investigate the biological effectiveness of these fixation techniques.

Anatomic double-bundle ACL reconstruction restricts knee extension in knees with hyperextension.

PURPOSE: Double-bundle ACL reconstruction has been demonstrated to be at least as effective as single-bundle reconstruction in terms of restoring knee rotational and translational stability. Until now, the influence on knees with hyperextension has not been evaluated. It was the purpose of this study to evaluate whether double-bundle ACL reconstruction restricts extension in hyperextendable knees. METHODS: Hamstring tendon reconstructions of 10 human cadaveric knees with the ability of hyperextension (age: 48 ± 14 years) were performed as single bundle (SB) on one side and double bundle (DB) on the other side. A surgical navigation system (BrainLab, Germany) was used to assess the kinematics of each knee at the intact and reconstructed state. A difference with regard to the anterior-to-posterior translation (AP) and rotational stability at 30° of knee flexion, 90° of flexion and the hyperextension capability of each specimen was analysed. RESULTS: The difference in AP translation before and after the reconstruction was not significantly different in 30° and 90° of flexion (n.s). Both single- and double-bundle reconstructions restored the preoperative kinematics at 30° and 90° of knee flexion (n.s). The knee extension was 4° ± 1.8° with the intact ACL and 4° ± 1.7° after reconstruction in the SB group (n.s). The knee extension was 5° of hyperextension ± 1.1° with the intact ACL and 0° ± 0.4° after reconstruction in the DB group; the limitation of the extension was significantly larger in this group (p = 0.013). CONCLUSION: Both single- and double-bundle ACL reconstruction techniques are capable of restoring knee anteroposterior and rotational stability. Double-bundle reconstructions significantly reduce knee extension in knees with hyperextension capability. Care must be taken when using double-bundle techniques in patients with knee hyperextension as this procedure may limit the knee extension after double-bundle ACL reconstruction.

Comparison of three suture techniques and three suture materials on gap formation and failure load in ruptured tendons: a human cadaveric study.

INTRODUCTION: There is a large variety of ruptures of tendons and ligaments in trauma surgery. Reliable data about the most appropriate suture technique and suture material for ruptured tendons are sparse. This human cadaveric study compares the biomechanical properties of three suture materials and three suture techniques for semitendinosus tendon repair. METHOD: Sixty-three human cadaver hamstring tendons underwent tenotomy and repair with either Baseball suture, Kessler suture, or a novel "Hannover" suture, using either PDS 2-0, Ethibond 2-0, or Fiberwire 2-0. Biomechanical analysis included pretensioning the constructs with 2 N for 50 s, then cyclic loading of 500 cycles between 2 and 15 N at 1 Hz in a servohydraulic testing machine with measurement of elongation. After this, ultimate failure load and failure mode analysis was performed. RESULTS: Ruptures repaired by Fiberwire™ as suture material and the Baseball suture technique were able to withstand significantly higher maximum failure loads (72.8 ± 22.0 N, p < 0.001) than the Kessler suture and the Hannover suture, while ruptures repaired by Fiberwire and the Kessler suture technique showed the lowest elongation after cyclic loading (14.6 ± 3.8 mm, p = 0.15). CONCLUSION: These findings may be of relevance for the future clinical treatment of tendon ruptures. Further in vivo clinical application studies are desirable for the future.

The fixation strength of tibial PCL press-fit reconstructions.

PURPOSE: A secure tibial press-fit technique in posterior cruciate ligament reconstructions is an interesting technique because no hardware is necessary. For anterior cruciate ligament (ACL) reconstruction, a few press-fit procedures have been published. Up to the present point, no biomechanical data exist for a tibial press-fit posterior cruciate ligament (PCL) reconstruction. The purpose of this study was to characterize a press-fit procedure for PCL reconstruction that is biomechanically equivalent to an interference screw fixation. METHODS: Quadriceps and hamstring tendons of 20 human cadavers (age: 49.2 ± 18.5 years) were used. A press-fit fixation with a knot in the semitendinosus tendon (K) and a quadriceps tendon bone block graft (Q) were compared to an interference screw fixation (I) in 30 porcine femora. In each group, nine constructs were cyclically stretched and then loaded until failure. Maximum load to failure, stiffness, and elongation during failure testing and cyclical loading were investigated. RESULTS: The maximum load to failure was 518 ± 157 N (387-650 N) for the (K) group, 558 ± 119 N (466-650 N) for the (I) group, and 620 ± 102 N (541-699 N) for the (Q) group. The stiffness was 55 ± 27 N/mm (18-89 N/mm) for the (K) group, 117 ± 62 N/mm (69-165 N/mm) for the (I) group, and 65 ± 21 N/mm (49-82 N/mm) for the (Q) group. The stiffness of the (I) group was significantly larger (P = 0.01). The elongation during cyclical loading was significantly larger for all groups from the 1st to the 5th cycle compared to the elongation in between the 5th to the 20th cycle (P < 0.03). CONCLUSION: All techniques exhibited larger elongation during initial loading. Load to failure and stiffness was significantly different between the fixations. The Q fixation showed equal biomechanical properties compared to a pure tendon fixation (I) with an interference screw. All three fixation techniques that were investigated exhibit comparable biomechanical properties. Preconditioning of the constructs is critical. Clinical trials have to investigate the biological effectiveness of these fixation techniques.

[The unrecognized myocardial infarction]. / Der nicht erkannte Myokardinfarkt.

BACKGROUND AND OBJECTIVES: despite the improved quality of diagnostic technology, myocardial infarction still belongs to the diseases that are most frequently overlooked. Especially asymptomatic patients or patients with atypical symptoms are more common to be misdiagnosed. Failure to correctly diagnose is the leading cause of malpractice claims. It was the aim of this study to evaluate the records of patients who died from myocardial infarction and to analyse whether medical malpractice had occured in those who had undergone a medical examination shortly before their death. METHODS: in the years 2008 and 2009 myocardial infarction had been diagnosed in 109 auotopsies performed at the Institute of Legal Medicine of the Hanover Medical School. The records of these patients who had died from myocardial infarction were retrospectively analysed with particular emphasis on an antemortem medical consultation, reported symptoms and diagnostic measures. RESULTS: in 38 persons (34.9 %) an antemortem medical consultation or hospitalisation has taken place, whereby in five persons the diagnosis of myocardial infarction was suspected. In 33 persons, a myocardial infarction could not be diagnosed antemortem. In two cases an additionally cardiologic assessment was recommended to estimate if medical malpractice was present and in another two cases with insufficient diagnostic measures medical malpractice was reproached from forensic pathologists. CONCLUSION: autopsy give the most accurate diagnostic information. On the other hand, it may provide an effective defence against medical malpractice litigation.

[A rare cause of dysphagia and bolus obstruction in adults]. / Seltene Ursache einer Dysphagie und Bolusobstruktion bei Erwachsenen.

HISTORY: An otherwise healthy 20-year-old man was admitted to our hospital with obstruction of the oesophagus by a bolus after eating a chicken meal. These symptoms continued over the past 12 years and required multiple interventions at different hospitals. There was no history of any other previous illness and both the physical examination and routine laboratory tests were unremarkable. INVESTIGATIONS: Esophagogastroduodenoscopy (EGD) revealed segmental circular trachea-like constrictions of the esophagus and two stenoses at 35 cm and 40 cm. Histopathology of several biopsies favored the diagnosis of eosinophilic esophagitis. TREATMENT AND FURTHER COURSE: After initial balloon dilatation and dilatation with a Savary bougie the patient was put on systemic steroids and montelukast (a leukotriene receptor antagonist). The symptoms subsequently disappeared. CONCLUSION: Eosinophilic esophagitis, a unique form of esophageal inflammatory disease, consists of dense eosinophilic infiltration of the epithelium and is associated with various macroscopic findings, such as the rare but striking circular trachea-like constrictions, nodules, plaques and other forms of constriction of the esophagus. Several lines of evidence favor an allergic cause. The leading symptom is recurrent dysphagia after solid foods, sometimes accompanied by heart-burn. Medical treatment consists of topical or systemic administration of steroids and/or montelukast. A history of chronic dysphagia after eating solid food, combined with endoscopic findings atypical for reflux disease is highly suspicious of eosinophilic esophagitis in the differential diagnosis of gastroesophageal reflux disease in adults.

Intracartilaginous haemorrhagic lesions in strangulation?

This case control study was designed to investigate if laryngeal haemorrhages occur in cases of strangulation and whether these lesions are specific to strangulation. In the study 30 larynges from victims of fatal strangulation were examined (7 cases of manual strangulation, 12 cases of ligature strangulation, 11 cases of combined manual and ligature strangulation). The control group comprised 40 cases of death without any neck injuries and another group consisted of 5 cases of death caused by trauma with findings of non-strangulation neck injuries. In all the groups, only four solitary haemorrhages (two cases, one control, one non-strangulation neck injury) were observed that did not occur in the proximity of areas of blood accumulation. The results of our investigation suggest that histological evidence of blood accumulation or of haemorrhages in thyroid cartilage is not a reliable criterion to distinguish between haemorrhagic lesions due to strangulation and other types of blood accumulation or artefacts.